I dabble in metalworking for fun. I also run marathons and some triathlons. Been thinking it would be neat to be able to say I built a bike and used it in the triathlon. I have a road bike but not a triathlon bike.

As far as frame, I am limited becasue I dont have a tig welder. I do however have a mig, oxy torch/weld set and arc welder.

I am guessing my choices are aluminum tubing or chrome moly steel.

I can mig weld the tubing with argon and aluminum wire but not sure if this is ideal. I have read you can braze it.

I have read conflicting advice as to whehter it is recommended to mig 4130 or not. (The same for brazing it).

Weight is an issue. I want it to be light but at the same time be strong enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

"stryped" wrote in message
...
I dabble in metalworking for fun. I also run marathons and some triathlons.
Been thinking it would be neat to be able to say I built a bike and used it
in the triathlon. I have a road bike but not a triathlon bike.

As far as frame, I am limited becasue I dont have a tig welder. I do
however have a mig, oxy torch/weld set and arc welder.

I am guessing my choices are aluminum tubing or chrome moly steel.

I can mig weld the tubing with argon and aluminum wire but not sure if
this is ideal. I have read you can braze it.

I have read conflicting advice as to whehter it is recommended to mig 4130
or not. (The same for brazing it).

Weight is an issue. I want it to be light but at the same time be strong
enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

sci.engr.joining.welding would be the better ng for this.

As far as projects go, my understanding is that unless you will be hacking
together black plumbing pipe and couplings, a bicycle frame is probably one
of THE most difficult welding projects to tackle -- a deceptively difficult
project all the way around, incl. fixturing.

The custom shop I visited used very high end dedicated tig, one brand being
Thermal Dynamics, and one other, something-arc (not lincoln or miller).
Fishmouthed thinwall tubing joints are not the easiest welds, a lot of
machine control is required. He showed me an innocuous small bundle of
tubing for his next build, a ridiculous price tag for a few feet of tubing,
iirc on the order of $500. Whatever it was made me gag.

Custom frames (the frame alone) start at $3K, and go up to $10K, mebbe more.
I assume there is good reason for this, but I'll spend only $19.99 on
running shoes, so I'm not exactly on the same wavelength as this crowd.
I know they get the frame custom fitted for their body dimensions, a big
time consuming deal unto itself for pro's. I assume there is a rec.cycling
ng you could post to, to get some idea of their bike requirements.
--
EA

"Existential Angst" wrote in message
...
"stryped" wrote in message
...
I dabble in metalworking for fun. I also run marathons and some
triathlons. Been thinking it would be neat to be able to say I built a
bike and used it in the triathlon. I have a road bike but not a triathlon
bike.

As far as frame, I am limited becasue I dont have a tig welder. I do
however have a mig, oxy torch/weld set and arc welder.

I am guessing my choices are aluminum tubing or chrome moly steel.

I can mig weld the tubing with argon and aluminum wire but not sure if
this is ideal. I have read you can braze it.

I have read conflicting advice as to whehter it is recommended to mig
4130 or not. (The same for brazing it).

Weight is an issue. I want it to be light but at the same time be strong
enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

sci.engr.joining.welding would be the better ng for this.

As far as projects go, my understanding is that unless you will be hacking
together black plumbing pipe and couplings, a bicycle frame is probably
one of THE most difficult welding projects to tackle -- a deceptively
difficult project all the way around, incl. fixturing.

The custom shop I visited used very high end dedicated tig, one brand
being Thermal Dynamics, and one other, something-arc (not lincoln or
miller). Fishmouthed thinwall tubing joints are not the easiest welds, a
lot of machine control is required. He showed me an innocuous small
bundle of tubing for his next build, a ridiculous price tag for a few feet
of tubing, iirc on the order of $500. Whatever it was made me gag.

Custom frames (the frame alone) start at $3K, and go up to $10K, mebbe
more. I assume there is good reason for this, but I'll spend only $19.99
on running shoes, so I'm not exactly on the same wavelength as this crowd.
I know they get the frame custom fitted for their body dimensions, a
big time consuming deal unto itself for pro's. I assume there is a
rec.cycling ng you could post to, to get some idea of their bike
requirements.
--
EA



It think if I were going to build a frame without proper tools and
fixturing, I would look at making a carbon fiber frame. Working with carbon
fiber is a lot like fiber glass. It is a lot of time and tedious
craftsmanship, but it seems very do-able at home. There are several people
on the web describing how they made theirs. Here is one:
http://theprojectjunkie.com/composit...e-project.html

Besides, your first homemade aluminum frame is probably going to look second
rate, but even a ratty-looking carbon fiber frame will be cool.

"anorton" wrote in message
...

"Existential Angst" wrote in message
...
"stryped" wrote in message
...
I dabble in metalworking for fun. I also run marathons and some
triathlons. Been thinking it would be neat to be able to say I built a
bike and used it in the triathlon. I have a road bike but not a triathlon
bike.

As far as frame, I am limited becasue I dont have a tig welder. I do
however have a mig, oxy torch/weld set and arc welder.

I am guessing my choices are aluminum tubing or chrome moly steel.

I can mig weld the tubing with argon and aluminum wire but not sure if
this is ideal. I have read you can braze it.

I have read conflicting advice as to whehter it is recommended to mig
4130 or not. (The same for brazing it).

Weight is an issue. I want it to be light but at the same time be strong
enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

sci.engr.joining.welding would be the better ng for this.

As far as projects go, my understanding is that unless you will be
hacking together black plumbing pipe and couplings, a bicycle frame is
probably one of THE most difficult welding projects to tackle -- a
deceptively difficult project all the way around, incl. fixturing.

The custom shop I visited used very high end dedicated tig, one brand
being Thermal Dynamics, and one other, something-arc (not lincoln or
miller). Fishmouthed thinwall tubing joints are not the easiest welds, a
lot of machine control is required. He showed me an innocuous small
bundle of tubing for his next build, a ridiculous price tag for a few
feet of tubing, iirc on the order of $500. Whatever it was made me gag.

Custom frames (the frame alone) start at $3K, and go up to $10K, mebbe
more. I assume there is good reason for this, but I'll spend only $19.99
on running shoes, so I'm not exactly on the same wavelength as this
crowd. I know they get the frame custom fitted for their body
dimensions, a big time consuming deal unto itself for pro's. I assume
there is a rec.cycling ng you could post to, to get some idea of their
bike requirements.
--
EA



It think if I were going to build a frame without proper tools and
fixturing, I would look at making a carbon fiber frame. Working with
carbon fiber is a lot like fiber glass. It is a lot of time and tedious
craftsmanship, but it seems very do-able at home. There are several people
on the web describing how they made theirs. Here is one:
http://theprojectjunkie.com/composit...e-project.html

Besides, your first homemade aluminum frame is probably going to look
second rate, but even a ratty-looking carbon fiber frame will be cool.

Indeed.
How much do you think carbon fiber tubing would cost for a bike? I imagine
the weight would come in around 5# or under.
--
EA

On Thu, 9 Aug 2012 12:58:59 -0400, "Existential Angst"
wrote:

"anorton" wrote in message
...

"Existential Angst" wrote in message
...
"stryped" wrote in message
...
I dabble in metalworking for fun. I also run marathons and some
triathlons. Been thinking it would be neat to be able to say I built a
bike and used it in the triathlon. I have a road bike but not a triathlon
bike.

As far as frame, I am limited becasue I dont have a tig welder. I do
however have a mig, oxy torch/weld set and arc welder.

I am guessing my choices are aluminum tubing or chrome moly steel.

I can mig weld the tubing with argon and aluminum wire but not sure if
this is ideal. I have read you can braze it.

I have read conflicting advice as to whehter it is recommended to mig
4130 or not. (The same for brazing it).

Weight is an issue. I want it to be light but at the same time be strong
enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

sci.engr.joining.welding would be the better ng for this.

As far as projects go, my understanding is that unless you will be
hacking together black plumbing pipe and couplings, a bicycle frame is
probably one of THE most difficult welding projects to tackle -- a
deceptively difficult project all the way around, incl. fixturing.

The custom shop I visited used very high end dedicated tig, one brand
being Thermal Dynamics, and one other, something-arc (not lincoln or
miller). Fishmouthed thinwall tubing joints are not the easiest welds, a
lot of machine control is required. He showed me an innocuous small
bundle of tubing for his next build, a ridiculous price tag for a few
feet of tubing, iirc on the order of $500. Whatever it was made me gag.

Custom frames (the frame alone) start at $3K, and go up to $10K, mebbe
more. I assume there is good reason for this, but I'll spend only $19.99
on running shoes, so I'm not exactly on the same wavelength as this
crowd. I know they get the frame custom fitted for their body
dimensions, a big time consuming deal unto itself for pro's. I assume
there is a rec.cycling ng you could post to, to get some idea of their
bike requirements.
--
EA



It think if I were going to build a frame without proper tools and
fixturing, I would look at making a carbon fiber frame. Working with
carbon fiber is a lot like fiber glass. It is a lot of time and tedious
craftsmanship, but it seems very do-able at home. There are several people
on the web describing how they made theirs. Here is one:
http://theprojectjunkie.com/composit...e-project.html

Besides, your first homemade aluminum frame is probably going to look
second rate, but even a ratty-looking carbon fiber frame will be cool.

Indeed.
How much do you think carbon fiber tubing would cost for a bike? I imagine
the weight would come in around 5# or under.
Do it the old, well-proven way. Set up your frame in Chro-Mo tubing,
pinned together, then braze with oxy acet torch

On Thursday, August 9, 2012 12:09:46 PM UTC-5, Clare wrote:
On Thu, 9 Aug 2012 12:58:59 -0400, "Existential Angst"

wrote:



"anorton" wrote in message

...



"Existential Angst" wrote in message

...

"stryped" wrote in message

...

I dabble in metalworking for fun. I also run marathons and some

triathlons. Been thinking it would be neat to be able to say I built a

bike and used it in the triathlon. I have a road bike but not a triathlon

bike.



As far as frame, I am limited becasue I dont have a tig welder. I do

however have a mig, oxy torch/weld set and arc welder.



I am guessing my choices are aluminum tubing or chrome moly steel.



I can mig weld the tubing with argon and aluminum wire but not sure if

this is ideal. I have read you can braze it.



I have read conflicting advice as to whehter it is recommended to mig

4130 or not. (The same for brazing it).



Weight is an issue. I want it to be light but at the same time be strong

enough to do a half or full ironman. 56 miles/112 miles.



I appreciate it!



sci.engr.joining.welding would be the better ng for this.



As far as projects go, my understanding is that unless you will be

hacking together black plumbing pipe and couplings, a bicycle frame is

probably one of THE most difficult welding projects to tackle -- a

deceptively difficult project all the way around, incl. fixturing.



The custom shop I visited used very high end dedicated tig, one brand

being Thermal Dynamics, and one other, something-arc (not lincoln or

miller). Fishmouthed thinwall tubing joints are not the easiest welds, a

lot of machine control is required. He showed me an innocuous small

bundle of tubing for his next build, a ridiculous price tag for a few

feet of tubing, iirc on the order of $500. Whatever it was made me gag.



Custom frames (the frame alone) start at $3K, and go up to $10K, mebbe

more. I assume there is good reason for this, but I'll spend only $19..99

on running shoes, so I'm not exactly on the same wavelength as this

crowd. I know they get the frame custom fitted for their body

dimensions, a big time consuming deal unto itself for pro's. I assume

there is a rec.cycling ng you could post to, to get some idea of their

bike requirements.

--

EA







It think if I were going to build a frame without proper tools and

fixturing, I would look at making a carbon fiber frame. Working with

carbon fiber is a lot like fiber glass. It is a lot of time and tedious

craftsmanship, but it seems very do-able at home. There are several people

on the web describing how they made theirs. Here is one:

http://theprojectjunkie.com/composit...e-project.html



Besides, your first homemade aluminum frame is probably going to look

second rate, but even a ratty-looking carbon fiber frame will be cool.



Indeed.

How much do you think carbon fiber tubing would cost for a bike? I imagine

the weight would come in around 5# or under.

Do it the old, well-proven way. Set up your frame in Chro-Mo tubing,

pinned together, then braze with oxy acet torch

Not sure what you mean by "pinned" togther but that is kind of the way I was leaning. (The cro mo).However, I have read you should not braze it. Something about the brass causing the wood like grain in cro mo tubing to crack.

I thought of carbon fiber hoever have no experience in it. I do not know how you would ensure it ould carry the reqhuired static and dynamic loads.

There are certain companies that offer "luggs". Basically you stick the round tubing into these pre made fittings to hold the material. It was the way bikes were made some time ago. Problem is a tri bike has a steeper seat post angle. (almost straight up). I have not seen pre made lugs that would allow you to do this.

"Existential Angst" wrote in message
...
"anorton" wrote in message
...

"Existential Angst" wrote in message
...
"stryped" wrote in message
...
I dabble in metalworking for fun. I also run marathons and some
triathlons. Been thinking it would be neat to be able to say I built a
bike and used it in the triathlon. I have a road bike but not a
triathlon bike.

As far as frame, I am limited becasue I dont have a tig welder. I do
however have a mig, oxy torch/weld set and arc welder.

I am guessing my choices are aluminum tubing or chrome moly steel.

I can mig weld the tubing with argon and aluminum wire but not sure if
this is ideal. I have read you can braze it.

I have read conflicting advice as to whehter it is recommended to mig
4130 or not. (The same for brazing it).

Weight is an issue. I want it to be light but at the same time be
strong enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

sci.engr.joining.welding would be the better ng for this.

As far as projects go, my understanding is that unless you will be
hacking together black plumbing pipe and couplings, a bicycle frame is
probably one of THE most difficult welding projects to tackle -- a
deceptively difficult project all the way around, incl. fixturing.

The custom shop I visited used very high end dedicated tig, one brand
being Thermal Dynamics, and one other, something-arc (not lincoln or
miller). Fishmouthed thinwall tubing joints are not the easiest welds, a
lot of machine control is required. He showed me an innocuous small
bundle of tubing for his next build, a ridiculous price tag for a few
feet of tubing, iirc on the order of $500. Whatever it was made me gag.

Custom frames (the frame alone) start at $3K, and go up to $10K, mebbe
more. I assume there is good reason for this, but I'll spend only $19.99
on running shoes, so I'm not exactly on the same wavelength as this
crowd. I know they get the frame custom fitted for their body
dimensions, a big time consuming deal unto itself for pro's. I assume
there is a rec.cycling ng you could post to, to get some idea of their
bike requirements.
--
EA



It think if I were going to build a frame without proper tools and
fixturing, I would look at making a carbon fiber frame. Working with
carbon fiber is a lot like fiber glass. It is a lot of time and tedious
craftsmanship, but it seems very do-able at home. There are several
people on the web describing how they made theirs. Here is one:
http://theprojectjunkie.com/composit...e-project.html

Besides, your first homemade aluminum frame is probably going to look
second rate, but even a ratty-looking carbon fiber frame will be cool.

Indeed.
How much do you think carbon fiber tubing would cost for a bike? I
imagine the weight would come in around 5# or under.
--
EA


I have never tried making anything myself in carbon fiber. It is used in
some lightweight, airborne assemblies I have designed optics for.
Here are some retail prices of pre-made tubes:
http://www.rockwestcomposites.com/br...n-frame-tubing

And raw cloth:
http://www.tapplastics.com/product/f...cialty_fabrics

It looks like you might spend $200 to $300 on frame materials and epoxy plus
the purchased metal components. Of course the real cost would be time.

On 8/9/2012 11:28 AM, anorton wrote:

"Existential Angst" wrote in message
...
"anorton" wrote in message
...

"Existential Angst" wrote in message
...
"stryped" wrote in message
...
I dabble in metalworking for fun. I also run marathons and some
triathlons. Been thinking it would be neat to be able to say I
built a bike and used it in the triathlon. I have a road bike but
not a triathlon bike.

As far as frame, I am limited becasue I dont have a tig welder. I
do however have a mig, oxy torch/weld set and arc welder.

I am guessing my choices are aluminum tubing or chrome moly steel.

I can mig weld the tubing with argon and aluminum wire but not sure
if this is ideal. I have read you can braze it.

I have read conflicting advice as to whehter it is recommended to
mig 4130 or not. (The same for brazing it).

Weight is an issue. I want it to be light but at the same time be
strong enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

sci.engr.joining.welding would be the better ng for this.

As far as projects go, my understanding is that unless you will be
hacking together black plumbing pipe and couplings, a bicycle frame
is probably one of THE most difficult welding projects to tackle --
a deceptively difficult project all the way around, incl. fixturing.

The custom shop I visited used very high end dedicated tig, one
brand being Thermal Dynamics, and one other, something-arc (not
lincoln or miller). Fishmouthed thinwall tubing joints are not the
easiest welds, a lot of machine control is required. He showed me
an innocuous small bundle of tubing for his next build, a ridiculous
price tag for a few feet of tubing, iirc on the order of $500.
Whatever it was made me gag.

Custom frames (the frame alone) start at $3K, and go up to $10K,
mebbe more. I assume there is good reason for this, but I'll spend
only $19.99 on running shoes, so I'm not exactly on the same
wavelength as this crowd. I know they get the frame custom fitted
for their body dimensions, a big time consuming deal unto itself for
pro's. I assume there is a rec.cycling ng you could post to, to get
some idea of their bike requirements.
--
EA



It think if I were going to build a frame without proper tools and
fixturing, I would look at making a carbon fiber frame. Working with
carbon fiber is a lot like fiber glass. It is a lot of time and
tedious craftsmanship, but it seems very do-able at home. There are
several people on the web describing how they made theirs. Here is one:
http://theprojectjunkie.com/composit...e-project.html


Besides, your first homemade aluminum frame is probably going to look
second rate, but even a ratty-looking carbon fiber frame will be cool.

Indeed.
How much do you think carbon fiber tubing would cost for a bike? I
imagine the weight would come in around 5# or under.
--
EA


I have never tried making anything myself in carbon fiber. It is used in
some lightweight, airborne assemblies I have designed optics for.
Here are some retail prices of pre-made tubes:
http://www.rockwestcomposites.com/br...n-frame-tubing


And raw cloth:
http://www.tapplastics.com/product/f...cialty_fabrics

It looks like you might spend $200 to $300 on frame materials and epoxy
plus the purchased metal components. Of course the real cost would be time.



carbon fiber tubes are commonly made in the sailing community. i have a
tiller that is made out of this, really strong and light.

Weight is an issue. I want it to be light but at the same time be strong
enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

sci.engr.joining.welding would be the better ng for this.

As far as projects go, my understanding is that unless you will be hacking
together black plumbing pipe and couplings, a bicycle frame is probably one
of THE most difficult welding projects to tackle -- a deceptively difficult
project all the way around, incl. fixturing.

The custom shop I visited used very high end dedicated tig, one brand being
Thermal Dynamics, and one other, something-arc (not lincoln or miller).
Fishmouthed thinwall tubing joints are not the easiest welds, a lot of
machine control is required. He showed me an innocuous small bundle of
tubing for his next build, a ridiculous price tag for a few feet of tubing,
iirc on the order of $500. Whatever it was made me gag.

Custom frames (the frame alone) start at $3K, and go up to $10K, mebbe more.
I assume there is good reason for this, but I'll spend only $19.99 on
running shoes, so I'm not exactly on the same wavelength as this crowd.
I know they get the frame custom fitted for their body dimensions, a big
time consuming deal unto itself for pro's. I assume there is a rec.cycling
ng you could post to, to get some idea of their bike requirements.


You forgot to mention the use of stretched tubing to reduce weight.
the ends are still full thickness for braizing(!), but the middle
section can be as much as half the wall thickness.

stryped wrote:
On Thursday, August 9, 2012 12:09:46 PM UTC-5, Clare wrote:

On Thu, 9 Aug 2012 12:58:59 -0400, "Existential Angst"

wrote:




"anorton" wrote in message

...

"Existential Angst" wrote in message

...

"stryped" wrote in message

...

I dabble in metalworking for fun. I also run marathons and some

triathlons. Been thinking it would be neat to be able to say I built a

bike and used it in the triathlon. I have a road bike but not a triathlon

bike.

As far as frame, I am limited becasue I dont have a tig welder. I do

however have a mig, oxy torch/weld set and arc welder.

I am guessing my choices are aluminum tubing or chrome moly steel.

I can mig weld the tubing with argon and aluminum wire but not sure if

this is ideal. I have read you can braze it.

I have read conflicting advice as to whehter it is recommended to mig

4130 or not. (The same for brazing it).

Weight is an issue. I want it to be light but at the same time be strong

enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

sci.engr.joining.welding would be the better ng for this.

As far as projects go, my understanding is that unless you will be

hacking together black plumbing pipe and couplings, a bicycle frame is

probably one of THE most difficult welding projects to tackle -- a

deceptively difficult project all the way around, incl. fixturing.

The custom shop I visited used very high end dedicated tig, one brand

being Thermal Dynamics, and one other, something-arc (not lincoln or

miller). Fishmouthed thinwall tubing joints are not the easiest welds, a

lot of machine control is required. He showed me an innocuous small

bundle of tubing for his next build, a ridiculous price tag for a few

feet of tubing, iirc on the order of $500. Whatever it was made me gag.

Custom frames (the frame alone) start at $3K, and go up to $10K, mebbe

more. I assume there is good reason for this, but I'll spend only $19.99

on running shoes, so I'm not exactly on the same wavelength as this

crowd. I know they get the frame custom fitted for their body

dimensions, a big time consuming deal unto itself for pro's. I assume

there is a rec.cycling ng you could post to, to get some idea of their

bike requirements.

--

EA

It think if I were going to build a frame without proper tools and

fixturing, I would look at making a carbon fiber frame. Working with

carbon fiber is a lot like fiber glass. It is a lot of time and tedious

craftsmanship, but it seems very do-able at home. There are several people

on the web describing how they made theirs. Here is one:

http://theprojectjunkie.com/composit...e-project.html

Besides, your first homemade aluminum frame is probably going to look

second rate, but even a ratty-looking carbon fiber frame will be cool.

Indeed.

How much do you think carbon fiber tubing would cost for a bike? I imagine

the weight would come in around 5# or under.

Do it the old, well-proven way. Set up your frame in Chro-Mo tubing,

pinned together, then braze with oxy acet torch


Not sure what you mean by "pinned" togther but that is kind of the way I was leaning. (The cro mo).However, I have read you should not braze it. Something about the brass causing the wood like grain in cro mo tubing to crack.



Tell that problem with brazing to the big Italian tube maker, Columbus,
that tube is Cr Mo. The classic Reynolds 531, 753 and maybe a few of
their other tube sets were Mn Mo. IIRC the classic Italian bike were
often set-up on a jig and the joints drilled and pinned then removed
from the jig for final brazing. The last stage was then cold setting the
frame to make sure it was straight as intended. A number of other makers
did all the brazing in the jig to help keep the frame straight or
straighter.
I thought of carbon fiber hoever have no experience in it. I do not know how you would ensure it ould carry the reqhuired static and dynamic loads.

There are certain companies that offer "luggs". Basically you stick the round tubing into these pre made fittings to hold the material. It was the way bikes were made some time ago. Problem is a tri bike has a steeper seat post angle. (almost straight up). I have not seen pre made lugs that would allow you to do this.

Make your own lugs. They came as sheet steel formings or investment cast
but I suspect you could fabricate your own. The other option is fillet
brazing.

One of the benefits of buying a standard tube set is that the tubes are
butted so thicker at the ends where required and thinner in the middle,
at least for some tubes, IIRC the seat tube is only thicker at the
bottom end where it fits the bottom bracket shell. The butting will be
one of the reasons a bike tube set is more expensive than just buying
standard Cr Mo tubing.

Richard wrote:

Weight is an issue. I want it to be light but at the same time be
strong
enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

sci.engr.joining.welding would be the better ng for this.

As far as projects go, my understanding is that unless you will be
hacking
together black plumbing pipe and couplings, a bicycle frame is
probably one
of THE most difficult welding projects to tackle -- a deceptively
difficult
project all the way around, incl. fixturing.

The custom shop I visited used very high end dedicated tig, one brand
being
Thermal Dynamics, and one other, something-arc (not lincoln or miller).
Fishmouthed thinwall tubing joints are not the easiest welds, a lot of
machine control is required. He showed me an innocuous small bundle of
tubing for his next build, a ridiculous price tag for a few feet of
tubing,
iirc on the order of $500. Whatever it was made me gag.

Custom frames (the frame alone) start at $3K, and go up to $10K,
mebbe more.
I assume there is good reason for this, but I'll spend only $19.99 on
running shoes, so I'm not exactly on the same wavelength as this
crowd.
I know they get the frame custom fitted for their body dimensions, a big
time consuming deal unto itself for pro's. I assume there is a
rec.cycling
ng you could post to, to get some idea of their bike requirements.


You forgot to mention the use of stretched tubing to reduce weight.
the ends are still full thickness for braizing(!), but the middle
section can be as much as half the wall thickness.


Butted tubing. The tubing has a mandrel inserted and is then drawn
through a die to squeeze the tube onto the mandrel to form the butted
tube, the clever bit is the process to get the mandrel back out.

On Thursday, August 9, 2012 2:34:58 PM UTC-5, David Billington wrote:
stryped wrote:

On Thursday, August 9, 2012 12:09:46 PM UTC-5, Clare wrote:



On Thu, 9 Aug 2012 12:58:59 -0400, "Existential Angst"



wrote:









"anorton" wrote in message



...



"Existential Angst" wrote in message



...



"stryped" wrote in message



...



I dabble in metalworking for fun. I also run marathons and some



triathlons. Been thinking it would be neat to be able to say I built a



bike and used it in the triathlon. I have a road bike but not a triathlon



bike.



As far as frame, I am limited becasue I dont have a tig welder. I do



however have a mig, oxy torch/weld set and arc welder.



I am guessing my choices are aluminum tubing or chrome moly steel.



I can mig weld the tubing with argon and aluminum wire but not sure if



this is ideal. I have read you can braze it.



I have read conflicting advice as to whehter it is recommended to mig



4130 or not. (The same for brazing it).



Weight is an issue. I want it to be light but at the same time be strong



enough to do a half or full ironman. 56 miles/112 miles.



I appreciate it!



sci.engr.joining.welding would be the better ng for this.



As far as projects go, my understanding is that unless you will be



hacking together black plumbing pipe and couplings, a bicycle frame is



probably one of THE most difficult welding projects to tackle -- a



deceptively difficult project all the way around, incl. fixturing.



The custom shop I visited used very high end dedicated tig, one brand



being Thermal Dynamics, and one other, something-arc (not lincoln or



miller). Fishmouthed thinwall tubing joints are not the easiest welds, a



lot of machine control is required. He showed me an innocuous small



bundle of tubing for his next build, a ridiculous price tag for a few



feet of tubing, iirc on the order of $500. Whatever it was made me gag.



Custom frames (the frame alone) start at $3K, and go up to $10K, mebbe



more. I assume there is good reason for this, but I'll spend only $19.99



on running shoes, so I'm not exactly on the same wavelength as this



crowd. I know they get the frame custom fitted for their body



dimensions, a big time consuming deal unto itself for pro's. I assume



there is a rec.cycling ng you could post to, to get some idea of their



bike requirements.



--



EA



It think if I were going to build a frame without proper tools and



fixturing, I would look at making a carbon fiber frame. Working with



carbon fiber is a lot like fiber glass. It is a lot of time and tedious



craftsmanship, but it seems very do-able at home. There are several people



on the web describing how they made theirs. Here is one:



http://theprojectjunkie.com/composit...e-project.html



Besides, your first homemade aluminum frame is probably going to look



second rate, but even a ratty-looking carbon fiber frame will be cool.



Indeed.



How much do you think carbon fiber tubing would cost for a bike? I imagine



the weight would come in around 5# or under.



Do it the old, well-proven way. Set up your frame in Chro-Mo tubing,



pinned together, then braze with oxy acet torch





Not sure what you mean by "pinned" togther but that is kind of the way I was leaning. (The cro mo).However, I have read you should not braze it. Something about the brass causing the wood like grain in cro mo tubing to crack.







Tell that problem with brazing to the big Italian tube maker, Columbus,

that tube is Cr Mo. The classic Reynolds 531, 753 and maybe a few of

their other tube sets were Mn Mo. IIRC the classic Italian bike were

often set-up on a jig and the joints drilled and pinned then removed

from the jig for final brazing. The last stage was then cold setting the

frame to make sure it was straight as intended. A number of other makers

did all the brazing in the jig to help keep the frame straight or

straighter.

I thought of carbon fiber hoever have no experience in it. I do not know how you would ensure it ould carry the reqhuired static and dynamic loads..



There are certain companies that offer "luggs". Basically you stick the round tubing into these pre made fittings to hold the material. It was the way bikes were made some time ago. Problem is a tri bike has a steeper seat post angle. (almost straight up). I have not seen pre made lugs that would allow you to do this.



Make your own lugs. They came as sheet steel formings or investment cast

but I suspect you could fabricate your own. The other option is fillet

brazing.



One of the benefits of buying a standard tube set is that the tubes are

butted so thicker at the ends where required and thinner in the middle,

at least for some tubes, IIRC the seat tube is only thicker at the

bottom end where it fits the bottom bracket shell. The butting will be

one of the reasons a bike tube set is more expensive than just buying

standard Cr Mo tubing.

How would I go about making my own lugs without a mill????

stryped wrote:
On Thursday, August 9, 2012 2:34:58 PM UTC-5, David Billington wrote:

stryped wrote:


On Thursday, August 9, 2012 12:09:46 PM UTC-5, Clare wrote:



On Thu, 9 Aug 2012 12:58:59 -0400, "Existential Angst"

wrote:



"anorton" wrote in message



...



"Existential Angst" wrote in message



...



"stryped" wrote in message



...



I dabble in metalworking for fun. I also run marathons and some



triathlons. Been thinking it would be neat to be able to say I built a



bike and used it in the triathlon. I have a road bike but not a triathlon



bike.



As far as frame, I am limited becasue I dont have a tig welder. I do



however have a mig, oxy torch/weld set and arc welder.



I am guessing my choices are aluminum tubing or chrome moly steel.



I can mig weld the tubing with argon and aluminum wire but not sure if



this is ideal. I have read you can braze it.



I have read conflicting advice as to whehter it is recommended to mig



4130 or not. (The same for brazing it).



Weight is an issue. I want it to be light but at the same time be strong



enough to do a half or full ironman. 56 miles/112 miles.



I appreciate it!



sci.engr.joining.welding would be the better ng for this.



As far as projects go, my understanding is that unless you will be



hacking together black plumbing pipe and couplings, a bicycle frame is



probably one of THE most difficult welding projects to tackle -- a



deceptively difficult project all the way around, incl. fixturing.



The custom shop I visited used very high end dedicated tig, one brand



being Thermal Dynamics, and one other, something-arc (not lincoln or



miller). Fishmouthed thinwall tubing joints are not the easiest welds, a



lot of machine control is required. He showed me an innocuous small



bundle of tubing for his next build, a ridiculous price tag for a few



feet of tubing, iirc on the order of $500. Whatever it was made me gag.



Custom frames (the frame alone) start at $3K, and go up to $10K, mebbe



more. I assume there is good reason for this, but I'll spend only $19.99



on running shoes, so I'm not exactly on the same wavelength as this



crowd. I know they get the frame custom fitted for their body



dimensions, a big time consuming deal unto itself for pro's. I assume



there is a rec.cycling ng you could post to, to get some idea of their



bike requirements.



--



EA



It think if I were going to build a frame without proper tools and



fixturing, I would look at making a carbon fiber frame. Working with



carbon fiber is a lot like fiber glass. It is a lot of time and tedious



craftsmanship, but it seems very do-able at home. There are several people



on the web describing how they made theirs. Here is one:



http://theprojectjunkie.com/composit...e-project.html



Besides, your first homemade aluminum frame is probably going to look



second rate, but even a ratty-looking carbon fiber frame will be cool.



Indeed.



How much do you think carbon fiber tubing would cost for a bike? I imagine



the weight would come in around 5# or under.



Do it the old, well-proven way. Set up your frame in Chro-Mo tubing,

pinned together, then braze with oxy acet torch



Not sure what you mean by "pinned" togther but that is kind of the way I was leaning. (The cro mo).However, I have read you should not braze it. Something about the brass causing the wood like grain in cro mo tubing to crack.




Tell that problem with brazing to the big Italian tube maker, Columbus,

that tube is Cr Mo. The classic Reynolds 531, 753 and maybe a few of

their other tube sets were Mn Mo. IIRC the classic Italian bike were

often set-up on a jig and the joints drilled and pinned then removed

from the jig for final brazing. The last stage was then cold setting the

frame to make sure it was straight as intended. A number of other makers

did all the brazing in the jig to help keep the frame straight or

straighter.


I thought of carbon fiber hoever have no experience in it. I do not know how you would ensure it ould carry the reqhuired static and dynamic loads.

There are certain companies that offer "luggs". Basically you stick the round tubing into these pre made fittings to hold the material. It was the way bikes were made some time ago. Problem is a tri bike has a steeper seat post angle. (almost straight up). I have not seen pre made lugs that would allow you to do this.



Make your own lugs. They came as sheet steel formings or investment cast

but I suspect you could fabricate your own. The other option is fillet

brazing.



One of the benefits of buying a standard tube set is that the tubes are

butted so thicker at the ends where required and thinner in the middle,

at least for some tubes, IIRC the seat tube is only thicker at the

bottom end where it fits the bottom bracket shell. The butting will be

one of the reasons a bike tube set is more expensive than just buying

standard Cr Mo tubing.


How would I go about making my own lugs without a mill????

Possibly with difficulty. The local frame maker near me uses or used to
use a Myford for the mitering of the frame tubes, lugs were bought in.
With the various jigs and other bits you're likely to need I think a
lathe and mill would be a worthwhile additional to the tool set. If you
can fashion wax masters and can get them investment cast in steel then
that would be a tried and tested method if not cheap. Hard silver
soldering requires tight fits, IIRC around 0.002"gap is optimum, brazing
is more tolerant of fit. Whatever you do it would be good to be able to
ream or bore the lugs to get a good fit. Then of course you need to be
able to braze a lug properly, I heard of a few cases in the US in the
early 1980s of frame makers popping up and making frames that fell apart
in use as they couldn't braze a lugged joint and get proper penetration
of the braze filler through the lugged joint.

Regarding lathe and/or mill if you don't want to get them and learn to
use them then I suppose a vice, files, and lots of time would suffice or
have someone else do it.

stryped wrote:
On Thursday, August 9, 2012 12:09:46 PM UTC-5, Clare wrote:
On Thu, 9 Aug 2012 12:58:59 -0400, "Existential Angst"

wrote:



"anorton" wrote in message

...



"Existential Angst" wrote in message

...

"stryped" wrote in message

...

I dabble in metalworking for fun. I also run marathons and some

triathlons. Been thinking it would be neat to be able to say I built a

bike and used it in the triathlon. I have a road bike but not a triathlon

bike.



As far as frame, I am limited becasue I dont have a tig welder. I do

however have a mig, oxy torch/weld set and arc welder.



I am guessing my choices are aluminum tubing or chrome moly steel.



I can mig weld the tubing with argon and aluminum wire but not sure if

this is ideal. I have read you can braze it.



I have read conflicting advice as to whehter it is recommended to mig

4130 or not. (The same for brazing it).



Weight is an issue. I want it to be light but at the same time be strong

enough to do a half or full ironman. 56 miles/112 miles.



I appreciate it!



sci.engr.joining.welding would be the better ng for this.



As far as projects go, my understanding is that unless you will be

hacking together black plumbing pipe and couplings, a bicycle frame is

probably one of THE most difficult welding projects to tackle -- a

deceptively difficult project all the way around, incl. fixturing.



The custom shop I visited used very high end dedicated tig, one brand

being Thermal Dynamics, and one other, something-arc (not lincoln or

miller). Fishmouthed thinwall tubing joints are not the easiest welds, a

lot of machine control is required. He showed me an innocuous small

bundle of tubing for his next build, a ridiculous price tag for a few

feet of tubing, iirc on the order of $500. Whatever it was made me gag.



Custom frames (the frame alone) start at $3K, and go up to $10K, mebbe

more. I assume there is good reason for this, but I'll spend only $19.99

on running shoes, so I'm not exactly on the same wavelength as this

crowd. I know they get the frame custom fitted for their body

dimensions, a big time consuming deal unto itself for pro's. I assume

there is a rec.cycling ng you could post to, to get some idea of their

bike requirements.

--

EA







It think if I were going to build a frame without proper tools and

fixturing, I would look at making a carbon fiber frame. Working with

carbon fiber is a lot like fiber glass. It is a lot of time and tedious

craftsmanship, but it seems very do-able at home. There are several people

on the web describing how they made theirs. Here is one:

http://theprojectjunkie.com/composit...e-project.html



Besides, your first homemade aluminum frame is probably going to look

second rate, but even a ratty-looking carbon fiber frame will be cool.



Indeed.

How much do you think carbon fiber tubing would cost for a bike? I imagine

the weight would come in around 5# or under.

Do it the old, well-proven way. Set up your frame in Chro-Mo tubing,

pinned together, then braze with oxy acet torch

Not sure what you mean by "pinned" togther but that is kind of the way I was leaning. (The cro mo).However, I have read you should not braze it. Something about the brass causing the wood like grain in cro mo tubing to crack.

I thought of carbon fiber hoever have no experience in it. I do not know how you would ensure it ould carry the reqhuired static and dynamic loads.

There are certain companies that offer "luggs". Basically you stick the round tubing into these pre made fittings to hold the material. It was the way bikes were made some time ago. Problem is a tri bike has a steeper seat post angle. (almost straight up). I have not seen pre made lugs that would allow you to do this.



Oxy/acyl will work fine if you have the skill for it. Most of the
older small aircraft was done that way with all tubular construction.

John

On Thu, 9 Aug 2012 05:52:51 -0700 (PDT), stryped
wrote:

I dabble in metalworking for fun. I also run marathons and some triathlons. Been thinking it would be neat to be able to say I built a bike and used it in the triathlon. I have a road bike but not a triathlon bike.

As far as frame, I am limited becasue I dont have a tig welder. I do however have a mig, oxy torch/weld set and arc welder.

I am guessing my choices are aluminum tubing or chrome moly steel.

I can mig weld the tubing with argon and aluminum wire but not sure if this is ideal. I have read you can braze it.

I have read conflicting advice as to whehter it is recommended to mig 4130 or not. (The same for brazing it).

Weight is an issue. I want it to be light but at the same time be strong enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

Having built a few bikes I have a few comments.

All of the top triathlete people are riding carbon fiber bikes which
are notably lighter then metal bikes, which has an effect on climbing.
But that being said,

If you use aluminum you not only need to weld it (TIG or MIG) but you
need to heat treat it after it is welded. Columbus, for example,
states " The heat treatment is strictly recommended, 4/5 days after
welding: artificial ageing 6h at 90°C, then 4h at 150°C."

This presents a problem to most builders as it requires an oven large
enough to hold the entire frame.

Steel frames can be built by using lugs and silver brazing the joints
or by filet bronze brazing the joints or by TIG/MIG welding the
joints. The lugged frame will probably be a few ounces heavier then a
non lugged frame.

The question of 4130 really doesn't enter into the equation as if you
are planning a serious bike you will want to use butted tubes and so
will need to buy the tubes from companies that make special tubes for
bike frames and they will be weldable.

I suggest that you download Columbus' catalog
http://www.columbustubi.com/eng/1.htm
There are recommendations for welding/brazing each type of material.

Columbus also sells carbon fiber tubes and other bits. I'm not really
familiar with building carbon fiber frames but I assume that you cut
and fit the tubes and then wrap the joints with carbon cloth and epoxy
them.

Some added comments. A carbon fiber frame can be as light as 900 gms.
The lightest lugged frame I've built (52 cm top tube) is 1300 gms. for
the bare unpainted frame.

Depending your weight it would be difficult using normal bicycle
tubes to build a frame that would not be strong enough.

Frame alignment will be difficult to control without some form of jig
to hold things. There is some question as to just how accurately the
frame needs to be aligned but certainly there is some point where
misalignment will effect handling.

Tri bikes have different geometry then normal road bikes. Usually a
more upright seat post and shorter top tube as they are usually
designed to be used with aero bars. However, this will also move the
CG forward and I'm not sure how much this effects handling.

Download THE PATEREK MANUAL
(icelord.net/bike/paterek.pdf) and read it. It is the original
edition and there is a later version that Paterek sells but the older
(free) edition contains all the information you need.

That is all I can think of at the moment but if you want more
information just ask.
Cheers,
John B.

On Thursday, August 9, 2012 7:52:51 AM UTC-5, stryped wrote:
I dabble in metalworking for fun. I also run marathons and some triathlons. Been thinking it would be neat to be able to say I built a bike and used it in the triathlon. I have a road bike but not a triathlon bike.



As far as frame, I am limited becasue I dont have a tig welder. I do however have a mig, oxy torch/weld set and arc welder.



I am guessing my choices are aluminum tubing or chrome moly steel.



I can mig weld the tubing with argon and aluminum wire but not sure if this is ideal. I have read you can braze it.



I have read conflicting advice as to whehter it is recommended to mig 4130 or not. (The same for brazing it).



Weight is an issue. I want it to be light but at the same time be strong enough to do a half or full ironman. 56 miles/112 miles.



I appreciate it!

Very interesting. Again, I am not as experienced as you guys as to metalworkig here. I have the equipment but have never brazed. I have miged, however heard mig is not good for 4130. (NHRA does not allow it). I have read on brazing and it sounded simple enough, get the temp to a certain point and melt the brazing material into it. Capilary action would fill the joint.

I have toyed with the idea of buying a cheap harbor freight tig. However, I know some of you would frown on harbor freight stuff.

You are right, the weight concerns me and most of the bikes are carbon fiber. I have toyed with the idea of carbon, but have no experince with it and not sure how to ensure it would be safe enough when complete to average 20-30 mph.

The only advantage to steel, as I have read, is I have heard it is more "comfortable" for lack of a better term longer distances, something about absorbing road bumps. This would be benificial in a long triathlon in terms of saving your legs for the run.

But I agree, lighter is better.

Again, I am new to all this so forgive my ignorance but the lugged frame set up looks like you would just stick the tubes into the lugs, that the tubes would not have to be mitered. Is this true? (Kind of like thise strong tier kits you can buy to build a table ot whatever without having to cut miters).

I have no jig and would have to rely on a table or system of 2x4's. Some kind person on here mentioned somethign that I had read but forgot about, pinning. Seems the old timers if I understand it correctly would drill the lugs and tube and insert "nails" to hold the assemply togther before brazing. WOuld this negate the need for a jig?

I am just mentally trying to grasp all these concepts.

Thanks,

Don.

Bikeforums.net have a framebuilding discussion forum. Don't have to subscribe to read, only to post.A wealth of info there. Pat

On Fri, 10 Aug 2012 05:37:58 -0700 (PDT), stryped
wrote:

On Thursday, August 9, 2012 7:52:51 AM UTC-5, stryped wrote:
I dabble in metalworking for fun. I also run marathons and some triathlons. Been thinking it would be neat to be able to say I built a bike and used it in the triathlon. I have a road bike but not a triathlon bike.



As far as frame, I am limited becasue I dont have a tig welder. I do however have a mig, oxy torch/weld set and arc welder.



I am guessing my choices are aluminum tubing or chrome moly steel.



I can mig weld the tubing with argon and aluminum wire but not sure if this is ideal. I have read you can braze it.



I have read conflicting advice as to whehter it is recommended to mig 4130 or not. (The same for brazing it).



Weight is an issue. I want it to be light but at the same time be strong enough to do a half or full ironman. 56 miles/112 miles.



I appreciate it!

Very interesting. Again, I am not as experienced as you guys as to metalworkig here. I have the equipment but have never brazed. I have miged, however heard mig is not good for 4130. (NHRA does not allow it). I have read on brazing and it sounded simple enough, get the temp to a certain point and melt the brazing material into it. Capilary action would fill the joint.

I have toyed with the idea of buying a cheap harbor freight tig. However, I know some of you would frown on harbor freight stuff.

You are right, the weight concerns me and most of the bikes are carbon fiber. I have toyed with the idea of carbon, but have no experince with it and not sure how to ensure it would be safe enough when complete to average 20-30 mph.

The only advantage to steel, as I have read, is I have heard it is more "comfortable" for lack of a better term longer distances, something about absorbing road bumps. This would be benificial in a long triathlon in terms of saving your legs for the run.

But I agree, lighter is better.

Again, I am new to all this so forgive my ignorance but the lugged frame set up looks like you would just stick the tubes into the lugs, that the tubes would not have to be mitered. Is this true? (Kind of like thise strong tier kits you can buy to build a table ot whatever without having to cut miters).

I have no jig and would have to rely on a table or system of 2x4's. Some kind person on here mentioned somethign that I had read but forgot about, pinning. Seems the old timers if I understand it correctly would drill the lugs and tube and insert "nails" to hold the assemply togther before brazing. WOuld this negate the need for a jig?

I am just mentally trying to grasp all these concepts.

Thanks,

Don.
I'll just answer the last question first - the simplest - YES.

stryped wrote:
On Thursday, August 9, 2012 7:52:51 AM UTC-5, stryped wrote:

I dabble in metalworking for fun. I also run marathons and some triathlons. Been thinking it would be neat to be able to say I built a bike and used it in the triathlon. I have a road bike but not a triathlon bike.



As far as frame, I am limited becasue I dont have a tig welder. I do however have a mig, oxy torch/weld set and arc welder.



I am guessing my choices are aluminum tubing or chrome moly steel.



I can mig weld the tubing with argon and aluminum wire but not sure if this is ideal. I have read you can braze it.



I have read conflicting advice as to whehter it is recommended to mig 4130 or not. (The same for brazing it).



Weight is an issue. I want it to be light but at the same time be strong enough to do a half or full ironman. 56 miles/112 miles.



I appreciate it!


Very interesting. Again, I am not as experienced as you guys as to metalworkig here. I have the equipment but have never brazed. I have miged, however heard mig is not good for 4130. (NHRA does not allow it). I have read on brazing and it sounded simple enough, get the temp to a certain point and melt the brazing material into it. Capilary action would fill the joint.

Simple in theory but you want to try it on test pieces first. It is not
as easy as it sounds to balance the heat and get a large area of the
lugged joint hot enough to braze and get complete penetration of the
filler into the joint. Ideally you want the capillary action to take the
filler through the joint and appear at the other side as a good
indication of a good joint. Over heating the joint is a possibility and
can damage the flux, filler and the tube material. I wouldn't do a frame
before doing many test joints and sectioning them until I was happy I
could braze them properly. I've never made a full frame but have made a
few forks for myself.
I have toyed with the idea of buying a cheap harbor freight tig. However, I know some of you would frown on harbor freight stuff.

You are right, the weight concerns me and most of the bikes are carbon fiber. I have toyed with the idea of carbon, but have no experince with it and not sure how to ensure it would be safe enough when complete to average 20-30 mph.

The only advantage to steel, as I have read, is I have heard it is more "comfortable" for lack of a better term longer distances, something about absorbing road bumps. This would be benificial in a long triathlon in terms of saving your legs for the run.

But I agree, lighter is better.

Again, I am new to all this so forgive my ignorance but the lugged frame set up looks like you would just stick the tubes into the lugs, that the tubes would not have to be mitered. Is this true? (Kind of like thise strong tier kits you can buy to build a table ot whatever without having to cut miters).


Good lugged joints are mitered for maximum strength so plan on mitering
the tubes.
I have no jig and would have to rely on a table or system of 2x4's. Some kind person on here mentioned somethign that I had read but forgot about, pinning. Seems the old timers if I understand it correctly would drill the lugs and tube and insert "nails" to hold the assemply togther before brazing. WOuld this negate the need for a jig?

I expect you can do without a proper jig if you have some sort of flat
surface as a reference and can set-up the frame and pin it before final
brazing. A decent spirit level, angle gauge and packers should get a
level frame set-up whic can be pinned and brazed.

I am just mentally trying to grasp all these concepts.

Thanks,

Don.

On Fri, 10 Aug 2012 05:37:58 -0700 (PDT), stryped
wrote:

On Thursday, August 9, 2012 7:52:51 AM UTC-5, stryped wrote:
I dabble in metalworking for fun. I also run marathons and some triathlons. Been thinking it would be neat to be able to say I built a bike and used it in the triathlon. I have a road bike but not a triathlon bike.



As far as frame, I am limited becasue I dont have a tig welder. I do however have a mig, oxy torch/weld set and arc welder.



I am guessing my choices are aluminum tubing or chrome moly steel.



I can mig weld the tubing with argon and aluminum wire but not sure if this is ideal. I have read you can braze it.



I have read conflicting advice as to whehter it is recommended to mig 4130 or not. (The same for brazing it).



Weight is an issue. I want it to be light but at the same time be strong enough to do a half or full ironman. 56 miles/112 miles.



I appreciate it!

Very interesting. Again, I am not as experienced as you guys as to metalworkig here. I have the equipment but have never brazed. I have miged, however heard mig is not good for 4130. (NHRA does not allow it). I have read on brazing and it sounded simple enough, get the temp to a certain point and melt the brazing material into it. Capilary action would fill the joint.

What you are describing is the technique used to braze lugged frames
usually with silver. There are also frames made by fitting the tubes
and then brazing the bare tubes. To reinforce the joint a fillet of
brazing material is made.


Most bicycle frame tubes are not SAE 4130 but are slightly modified
alloys. for example Columbus says:

NIOBIUM is a special steel with manganese, chrome, nickel, molybdenum
and niobium. Columbus's special chemical composition, the combined
effect of strengthening for precipitation and reducing the alloy
grain size are incredibly enhanced compared to standard steels.
Niobium proves more effective than Vanadium as an alloy-strengthening
agent. After specific processes of progressive drawing and forming,
NIOBIUM undergoes a special heat treatment that gives the steel its
final characteristics. It is a steel designed to provide superior
mechanical characteristics and higher resistance to environmental
effects than conventional carbon steels. The only serious choice
for a competition or top-of-the-line frame, where lightweight and
reliability are essential.
Mechanical characteristics: Rm = 1050÷1250 MPa, Rp0.2 \u2265 750 MPa,
Ap5 14%.
Material suggested for TIG welding: OK TIGROD 13.12 (AWS 5.28 ER
80S-G). MIG: OK AUTROD 13.12 (AWS 5.28 ER 80S-G).

I have toyed with the idea of buying a cheap harbor freight tig. However, I know some of you would frown on harbor freight stuff.

You only need the TIG machine if you are welding the frame. You will
need some practice to make consistently good welds. The top of the
line Columbus tubes are butted 0.5 - 0.38 - 0.5mm wall thickness, or
0.018 - 0.014 - 0.018 inch.

You are right, the weight concerns me and most of the bikes are carbon fiber. I have toyed with the idea of carbon, but have no experince with it and not sure how to ensure it would be safe enough when complete to average 20-30 mph.


It might be that learning to built a carbon frame would be easier then
learning to weld thin steel tubes.

As for 30 MPG crashes :-( If you are building a carbon frame you
usually use a purchased carbon fiber fork rather then trying to build
one. If the fork breaks you are in serious trouble but if, for
example, the rear part of the frame breaks you probably won't get hurt
badly.

The only advantage to steel, as I have read, is I have heard it is more "comfortable" for lack of a better term longer distances, something about absorbing road bumps. This would be benificial in a long triathlon in terms of saving your legs for the run.

This is a highly over rated subject. If you are talking about riding
on extremely rough pavement then yes, steel might be a bit more
comfortable, but how many events are run over cobblestones? I have
ridden steel, aluminum and carbon frames and to my mind the tire size
is a far more important factor then type of material. A 19mm tire
pumped up to 150 psi rides a whole lot harder then a, say 25 mm tire
at 90 psi.

But I agree, lighter is better.

Again, I am new to all this so forgive my ignorance but the lugged frame set up looks like you would just stick the tubes into the lugs, that the tubes would not have to be mitered. Is this true? (Kind of like thise strong tier kits you can buy to build a table ot whatever without having to cut miters).

No the length and thickness of the lugs themselves is insufficient to
make strong joints. Remember that the silver braze is not as strong as
a TIG or bronze welding, so lugged joints are first mitered to fit
then inserted into the lugs and brazed.

You can do this by hand (or actually a combination of grinding and
hand filing) but the alternate is having a milling machine and tooling
to accurately cut the bevels. Doing it by hand takes longer but is as
accurate and notably cheaper :-)

I have no jig and would have to rely on a table or system of 2x4's. Some kind person on here mentioned somethign that I had read but forgot about, pinning. Seems the old timers if I understand it correctly would drill the lugs and tube and insert "nails" to hold the assemply togther before brazing. WOuld this negate the need for a jig?

A couple of points. First, you are talking about some fairly small
variations here. Example, a normal road bike seat tube is at an angle
of about 73 degrees and the head tube is, perhaps 72 degrees. These
angles can vary but if you design for, say a 72 degree head tube and
then you can't hold the tolerance it will change the geometry of the
front end and the bike may not handle as well. Additionally it will
effect the angle of the other tubes that you have so carefully mitered
to fit your original design and they may no longer fit.

As for pinning joints. It isn't fool proof. You usually use two pins
(nails) at 90 degrees to each other but after you nail the joint you
can still flex it so it isn't a bullet proof way of making joints.
Pinning or nailing is done mostly with lugged frames.

Yes, you can build a bicycle frame on a wooden frame but it probably
won't be as accurate as a proper jig - which costs a fortune. On the
other hand there are a number of jigs that people have built from some
sort of pre-fabricated aluminum material - look at
http://www.littlefishbicycles.com/ for additional information but I'd
advise taking most of her comments with a grain of salt as a lot of
what she says is a bit.... well. Her first frame broke at the bottom
bracket. Later she cut the broken joint apart and discovered that it
broke because she hadn't brazed it completely. But she never seems to
have drawn the conclusion that if you've never done it before maybe a
little practice is a good idea :-)

I am just mentally trying to grasp all these concepts.

Really, truly; download a copy of the Paterek manual that I mentioned.
Reading it will answer most of your questions.

Thanks,

Don.

Although you haven't mentioned it you will need access to some
specialized tooling.

You need a tool to recut the threads in the bottom bracket and face
the sides. While most bottom brackets are tapped when you receive them
you usually need to re-tap and face the sides after you weld/braze
them together.

You need to face and ream the head tube to fit the head bearings as
welding/brazing usually distorts the tube.

You need to ream the seat tube to fit the seat post after you
weld/braze it.

There are fairly expensive tools so you don't want to have to purchase
them. You can usually find a bike shop that has a set and pay them to
do the work.

If you use steel fork you probably will want a fork blade bending jig.

Somebody mentioned pressed lugs. don't bother with them as the cast
lugs and bottom bracket are much more accurate. It takes me a good
part of one day to fit the three lugs, the bottom bracket, the fork
crown and the front and rear dropouts. Using pressed lugs and bottom
bracket might double that time.

Cheers,
John B.

On Thu, 9 Aug 2012 05:52:51 -0700 (PDT), stryped
wrote:

I do however have a mig, oxy torch/weld set and arc welder.

Keep your MIG welder as far from your expensive bike tubing as
possible. MIG is not suitable for what you are trying to do.
Dave

On Sat, 11 Aug 2012 03:51:34 -0400, lid wrote:

On Thu, 9 Aug 2012 05:52:51 -0700 (PDT), stryped
wrote:

I do however have a mig, oxy torch/weld set and arc welder.

Keep your MIG welder as far from your expensive bike tubing as
possible. MIG is not suitable for what you are trying to do.
Dave

Why do you say that? TIG welded steel frames are quite common. In fact
the Columbus catalog specifications for TIB welding all of their tube
sets. However, I'm sure that the assumption is that the welder is
competent and qualified :-)


Cheers,
John B.

In rec.crafts.metalworking on Fri, 10 Aug 2012 20:56:08 +0100
David Billington wrote:
stryped wrote:

Again, I am new to all this so forgive my ignorance but the lugged frame set up looks like you would just stick the tubes into the lugs, that the tubes would not have to be mitered. Is this true? (Kind of like thise strong tier kits you can buy to build a table ot whatever without having to cut miters).


Good lugged joints are mitered for maximum strength so plan on mitering
the tubes.
I have no jig and would have to rely on a table or system of 2x4's. Some kind person on here mentioned somethign that I had read but forgot about, pinning. Seems the old timers if I understand it correctly would drill the lugs and tube and insert "nails" to hold the assemply togther before brazing. WOuld this negate the need for a jig?

I expect you can do without a proper jig if you have some sort of flat
surface as a reference and can set-up the frame and pin it before final
brazing. A decent spirit level, angle gauge and packers should get a
level frame set-up whic can be pinned and brazed.

You might find
http://www.littlefishbicycles.com/

useful.

She covers everything from design to brazing to building without a
jig, bidon mounts, the lot.

Zebee

In rec.crafts.metalworking on Sat, 11 Aug 2012 19:50:39 +0000 (UTC)
Zebee Johnstone wrote:

You might find
http://www.littlefishbicycles.com/

useful.

She covers everything from design to brazing to building without a
jig, bidon mounts, the lot.

for the "coming soon" stuff, check her blog, link on the page...

Zebee

"stryped" wrote in message
...

I dabble in metalworking for fun. I also run marathons and some triathlons.
Been thinking it would be neat to be able to say I built a bike and used it
in the triathlon. I have a road bike but not a triathlon bike.

As far as frame, I am limited becasue I dont have a tig welder. I do
however have a mig, oxy torch/weld set and arc welder.

I am guessing my choices are aluminum tubing or chrome moly steel.

I can mig weld the tubing with argon and aluminum wire but not sure if this
is ideal. I have read you can braze it.

I have read conflicting advice as to whehter it is recommended to mig 4130
or not. (The same for brazing it).

Weight is an issue. I want it to be light but at the same time be strong
enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

I looked at info for homebuilt aircraft a few years back, at the time they
used oxy/acetylene torches to weld 4130 chrome moly tube for steel frame
aircraft. They would put linseed oil in the frame to get rid of oxygen and
prevent rust from the inside, some would put air pressure in the frame, if
the frame lost it's pressure then the owner would look for the damage that
caused the leak, perhaps corrosion or a crack.

Anyway it sounds like a good technique to build a steel frame bike since you
already have the torch/weld set.

RogerN

On Sun, 12 Aug 2012 01:42:00 -0500, "RogerN"
wrote:

"stryped" wrote in message
...

I dabble in metalworking for fun. I also run marathons and some triathlons.
Been thinking it would be neat to be able to say I built a bike and used it
in the triathlon. I have a road bike but not a triathlon bike.

As far as frame, I am limited becasue I dont have a tig welder. I do
however have a mig, oxy torch/weld set and arc welder.

I am guessing my choices are aluminum tubing or chrome moly steel.

I can mig weld the tubing with argon and aluminum wire but not sure if this
is ideal. I have read you can braze it.

I have read conflicting advice as to whehter it is recommended to mig 4130
or not. (The same for brazing it).

Weight is an issue. I want it to be light but at the same time be strong
enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

I looked at info for homebuilt aircraft a few years back, at the time they
used oxy/acetylene torches to weld 4130 chrome moly tube for steel frame
aircraft. They would put linseed oil in the frame to get rid of oxygen and
prevent rust from the inside, some would put air pressure in the frame, if
the frame lost it's pressure then the owner would look for the damage that
caused the leak, perhaps corrosion or a crack.

Anyway it sounds like a good technique to build a steel frame bike since you
already have the torch/weld set.

RogerN


I certified on aircraft frames many years ago and my memory of it was
the troubles of fitting the tubes, not the actual welding. Of course,
in those days it was a few pieces of tube, a hacksaw and some files
not a computer controlled tube mitering machine :-)

The linseed oil was mandated by the FAA. by the way.
Cheers,
John B.

On Aug 9, 6:52*am, stryped wrote:
I dabble in metalworking for fun. I also run marathons and some triathlons. Been thinking it would be neat to be able to say I built a bike and used it in the triathlon. I have a road bike but not a triathlon bike.

As far as frame, I am limited becasue I dont have a tig welder. I do however have a mig, oxy torch/weld set and arc welder.

I am guessing my choices are aluminum tubing or chrome moly steel.

I can mig weld the tubing with argon and aluminum wire but not sure if this is ideal. I have read you can braze it.

I have read conflicting advice as to whehter it is recommended to mig 4130 or not. (The same for brazing it).

Weight is an issue. I want it to be light but at the same time be strong enough to do a half or full ironman. 56 miles/112 miles.

I appreciate it!

Any heat at all will change properties on aluminum alloys, post-
welding heat-treat may be necessary to get strength back.

Brazing or welding 4130 shouldn't be a problem, the aircraft frame
guys have been doing it for decades. Oxy-acetylene in the early days,
just needs the right filler rod. Lug fittings were the old-timey
method of making a bike, you can make your own from short lengths of
chrome-moly that will make a slip fit on your frame tubing. Get a
book on home-built aircraft, they'll show you some jigs and such that
should be easy enough to put together from plywood.

How about a bamboo bike? Local outfit makes them, gets big bucks,
too. The secret is in the joints. google it up.

Stan