Can someone elaborate on Yield and tensile strength of metals and how
they are measured? For instance, I'm searching McMaster Carr for various
ideas and types of metals and question the strength ratings.

When the stats indicate 35,000 yield strength, is that per inch, per
foot, per yard, etc? What happens when I cut it down? I'm also comparing
a flat stock aluminum at 1/4" thick x 2" wide to a 2" wide(base) x 1"
high(leg) x 1/4" thick and a 1/8" thick aluminum channel. The 1/8" thick
channel has the same yield strength as the flat stock. Is it due to the
1/8" difference in thickness? Would a 1/4" thick channel have a greater
yield? Does that have anything to do with flexibility?

My objective is to weld pieces of aluminum into this shape
........https://www.flickr.com/photos/18223943@N06/14816003838/ which I
already did with the 2" x 1/4" aluminum I mentioned. Through trial and
error, I learned it flexes too much for my need. Therefore, I need
stronger and less flexing(preferably none). I choose aluminum due to
it's lightweight, but if necessary, then I will use steel or something
else anyone may want to suggest. Overall, I assume channel or even
rectangular tube would be more ideal to eliminate flex and provide more
strength but I need to stay at 1/4" thickness and 2" width.

All help appreciated.

Thank you

I wanted to add, as I search the McMaster Carr website for those various
metals, I'm seeing the same yield strength for many different metals
comparing the same type of layout which adds to my confusion.

Thanks again.

On Fri, 22 Aug 2014 17:07:36 -0400, Meanie
wrote:

Can someone elaborate on Yield and tensile strength of metals and how
they are measured? For instance, I'm searching McMaster Carr for various
ideas and types of metals and question the strength ratings.

When the stats indicate 35,000 yield strength, is that per inch, per
foot, per yard, etc?

Per square inch of cross-sectional area.

What happens when I cut it down?

How are you cutting it? Yield strength tells you how much tensile load
you can put on it before it takes a permanent "set." In other words,
it's the elastic limit. At any level of stress below that, the steel
will spring back like a rubber band.

It doesn't matter how long or short the piece is. What matters is its
cross-sectional area perpendicular to the load you're applying to it.

Tensile strength is the value of the load you can apply before the
metal breaks. It's higher than the yield strength, but sometimes it's
very close.

BTW, these values are measured with tensile-testing machines, which
are lab equipment. Instron is the best-known brand. They clamp each
end of a test sample and pull on the ends. 'Sounds simple, but they
cost a bundle.

I'm also comparing
a flat stock aluminum at 1/4" thick x 2" wide to a 2" wide(base) x 1"
high(leg) x 1/4" thick and a 1/8" thick aluminum channel. The 1/8" thick
channel has the same yield strength as the flat stock. Is it due to the
1/8" difference in thickness? Would a 1/4" thick channel have a greater
yield? Does that have anything to do with flexibility?

It has nothing to do with flexibility (stiffness). The yield and
tensile strengths depend only on the material, the temperature, and,
for all practical purposes, the total cross-sectional area of the
material.


My objective is to weld pieces of aluminum into this shape
.......https://www.flickr.com/photos/18223943@N06/14816003838/ which I
already did with the 2" x 1/4" aluminum I mentioned. Through trial and
error, I learned it flexes too much for my need. Therefore, I need
stronger and less flexing(preferably none). I choose aluminum due to
it's lightweight, but if necessary, then I will use steel or something
else anyone may want to suggest. Overall, I assume channel or even
rectangular tube would be more ideal to eliminate flex and provide more
strength but I need to stay at 1/4" thickness and 2" width.

All help appreciated.

Thank you

I'm hoping someone else will answer that last one. I'm pooped for the
day. d8-)

--
Ed Huntress

On Fri, 22 Aug 2014 17:14:06 -0400, Meanie
wrote:

I wanted to add, as I search the McMaster Carr website for those various
metals, I'm seeing the same yield strength for many different metals
comparing the same type of layout which adds to my confusion.

Thanks again.

You're probably looking at the *per square inch* material strength,
which is the same for different sections. What matters is the area of
a cross-section of that material section -- like L-channels, round
rods, etch.

Cut across them and measure the area of the cut.

--
Ed Huntress

BTW, these values are measured with tensile-testing machines, which
are lab equipment. Instron is the best-known brand. They clamp each
end of a test sample and pull on the ends. 'Sounds simple, but they
cost a bundle.

Hmm, I was the startup engineer on Post-IT notepads 30 years ago. We
used and instron to measure the adhesive strength at a target of 80
grams peeling a one inch wide polyester strip off. Instron must have
a WIDE range of load cells.

Karl

On Fri, 22 Aug 2014 16:44:01 -0500, Karl Townsend
wrote:


BTW, these values are measured with tensile-testing machines, which
are lab equipment. Instron is the best-known brand. They clamp each
end of a test sample and pull on the ends. 'Sounds simple, but they
cost a bundle.

Hmm, I was the startup engineer on Post-IT notepads 30 years ago. We
used and instron to measure the adhesive strength at a target of 80
grams peeling a one inch wide polyester strip off. Instron must have
a WIDE range of load cells.

Karl

Oh, yeah. Instron makes a machine to test the strength of just about
anything you can think of.

The ahrd part in many cases is figuring out how to clamp the material.
With wood, for example, it's hard not to wind up testing the
along-the-grain shear strength, or the strength of cross-grain
compression, when you want to test the strength of linear tension.

--
Ed Huntress

On Fri, 22 Aug 2014 17:07:36 -0400, Meanie wrote:

Can someone elaborate on Yield and tensile strength of metals and how
they are measured? For instance, I'm searching McMaster Carr for various
ideas and types of metals and question the strength ratings.

When the stats indicate 35,000 yield strength, is that per inch, per
foot, per yard, etc?

There should be units. The units should be of pressure -- PSI or Pascals.

What happens when I cut it down? I'm also comparing
a flat stock aluminum at 1/4" thick x 2" wide to a 2" wide(base) x 1"
high(leg) x 1/4" thick and a 1/8" thick aluminum channel. The 1/8" thick
channel has the same yield strength as the flat stock. Is it due to the
1/8" difference in thickness? Would a 1/4" thick channel have a greater
yield? Does that have anything to do with flexibility?

You are probably seeing the yield strength of the METAL, not of the PART.
Yield strength (in PSI) is a property of the stuff the part is made out
of. The strength at which the part will deform or break will be in units
of force (pounds or Newtons) and is a function of the material and the
part geometry.

My objective is to weld pieces of aluminum into this shape
.......https://www.flickr.com/photos/18223943@N06/14816003838/ which I
already did with the 2" x 1/4" aluminum I mentioned. Through trial and
error, I learned it flexes too much for my need. Therefore, I need
stronger and less flexing(preferably none). I choose aluminum due to
it's lightweight, but if necessary, then I will use steel or something
else anyone may want to suggest. Overall, I assume channel or even
rectangular tube would be more ideal to eliminate flex and provide more
strength but I need to stay at 1/4" thickness and 2" width.

You're looking for stiffness, not ultimate strength. Stiffness of a
material is called Young's modulus. It's also in PSI, and you'll have to
look up just what it means -- but a higher Young's modulus means a stiffer
part.

If you're pulling on it where you say "Fig 2", and it's pulling on
something where you say "Fig 1", then between the 210 degree bends it's
going to be all floppy, no matter what. You're putting a bending stress
on it that's strongest at your "Fig 2" point, and flat strap just doesn't
resist bending well. If you could substitute bigger material (tubing or
bar) for the cross piece up to the bend, and just use thin strap to the
ends, then you'd be a lot better.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

O

If you're pulling on it where you say "Fig 2", and it's pulling on
something where you say "Fig 1", then between the 210 degree bends it's
going to be all floppy, no matter what. You're putting a bending stress
on it that's strongest at your "Fig 2" point, and flat strap just doesn't
resist bending well. If you could substitute bigger material (tubing or
bar) for the cross piece up to the bend, and just use thin strap to the
ends, then you'd be a lot better.


You're dead on. The "fig 2" is where an adapter/mount is attached for a
very small trailer. The "fig 1" is where the drawbar attaches to an
axle. After my test run, the area in "fig 2" is bending inward, most
likely from inertia when braking, but overall, I realize the stop and go
will apply the most pressure in that area and soon break.

When you say bigger material, are you indicating an aluminum channel or
rectangular tube will work much better? This is my thought due to the
supporting sides/legs which I am hoping will eliminate the flexing and
strengthen that "fig 2" area.

Thank you

On 08/22/2014 5:19 PM, Meanie wrote:
O

If you're pulling on it where you say "Fig 2", and it's pulling on
something where you say "Fig 1", then between the 210 degree bends it's
going to be all floppy, no matter what. You're putting a bending stress
on it that's strongest at your "Fig 2" point, and flat strap just doesn't
resist bending well. If you could substitute bigger material (tubing or
bar) for the cross piece up to the bend, and just use thin strap to the
ends, then you'd be a lot better.


You're dead on. The "fig 2" is where an adapter/mount is attached for a
very small trailer. The "fig 1" is where the drawbar attaches to an
axle. After my test run, the area in "fig 2" is bending inward, most
likely from inertia when braking, but overall, I realize the stop and go
will apply the most pressure in that area and soon break.

When you say bigger material, are you indicating an aluminum channel or
rectangular tube will work much better? This is my thought due to the
supporting sides/legs which I am hoping will eliminate the flexing and
strengthen that "fig 2" area.

I can't really envision exactly what you're trying to show here --
what/how does a "drawbar attach to an axle"??? If the circle/"adapter"
at 2 is intended to be a location for ball hitch and you're pulling at
that point and (whew, lot's of and's) it's a top-view, either weld a
good chunk of angle on the flat or fill in the open area on the behind
side with flat plate (assuming you don't want anything on the top).

What size/material is hard to say w/o any weights at all so I won't even
try to guess on that part...

--

On Fri, 22 Aug 2014 18:19:57 -0400, Meanie
wrote:

O

If you're pulling on it where you say "Fig 2", and it's pulling on
something where you say "Fig 1", then between the 210 degree bends it's
going to be all floppy, no matter what. You're putting a bending stress
on it that's strongest at your "Fig 2" point, and flat strap just doesn't
resist bending well. If you could substitute bigger material (tubing or
bar) for the cross piece up to the bend, and just use thin strap to the
ends, then you'd be a lot better.


You're dead on. The "fig 2" is where an adapter/mount is attached for a
very small trailer. The "fig 1" is where the drawbar attaches to an
axle. After my test run, the area in "fig 2" is bending inward, most
likely from inertia when braking, but overall, I realize the stop and go
will apply the most pressure in that area and soon break.

When you say bigger material, are you indicating an aluminum channel or
rectangular tube will work much better? This is my thought due to the
supporting sides/legs which I am hoping will eliminate the flexing and
strengthen that "fig 2" area.

Thank you

Making the frame as close to a triangle as possible (in other words,
reducing the 5-1/2" & 8" dimensions) will increase the stiffness.
Assuming the loads are all in the plane of the drawing, laying the bar
flat will make the frame *much* stiffer; 64x if I did the mental
arithmetic right. And switching to steel will make it 3x stiffer (and
3x heavier).

--
Ned Simmons

On Fri, 22 Aug 2014 18:19:57 -0400, Meanie
wrote:

O

If you're pulling on it where you say "Fig 2", and it's pulling on
something where you say "Fig 1", then between the 210 degree bends it's
going to be all floppy, no matter what. You're putting a bending stress
on it that's strongest at your "Fig 2" point, and flat strap just doesn't
resist bending well. If you could substitute bigger material (tubing or
bar) for the cross piece up to the bend, and just use thin strap to the
ends, then you'd be a lot better.


You're dead on. The "fig 2" is where an adapter/mount is attached for a
very small trailer. The "fig 1" is where the drawbar attaches to an
axle. After my test run, the area in "fig 2" is bending inward, most
likely from inertia when braking, but overall, I realize the stop and go
will apply the most pressure in that area and soon break.

When you say bigger material, are you indicating an aluminum channel or
rectangular tube will work much better? This is my thought due to the
supporting sides/legs which I am hoping will eliminate the flexing and
strengthen that "fig 2" area.

Thank you
One thing you need to remember when deciding between steel and
aluminum. If steel flexes, but does not bend bast it's elastic limit,
there is little or no "fatigue" introduced, but if aluminum moves AT
ALL it is building up "fatique" damage and will soon break. For a
trailer hitch you do not want ANY flex if it is aluminum, and more
important, you do not want aluminum if there is any possibility of
movement/bending. Also, welding aluminum structures where repetitive
stresses are expected is a job for an EXPERT with engineering knowlege
as well as welding ability. I was not able to access the diagram -
will try later - but from the description so far I'm thinking you
should be using square steel tubing with fish-plates or gussets welded
to the angle joints

On Fri, 22 Aug 2014 18:43:06 -0400, Ned Simmons
wrote:

On Fri, 22 Aug 2014 18:19:57 -0400, Meanie
wrote:

O

If you're pulling on it where you say "Fig 2", and it's pulling on
something where you say "Fig 1", then between the 210 degree bends it's
going to be all floppy, no matter what. You're putting a bending stress
on it that's strongest at your "Fig 2" point, and flat strap just doesn't
resist bending well. If you could substitute bigger material (tubing or
bar) for the cross piece up to the bend, and just use thin strap to the
ends, then you'd be a lot better.


You're dead on. The "fig 2" is where an adapter/mount is attached for a
very small trailer. The "fig 1" is where the drawbar attaches to an
axle. After my test run, the area in "fig 2" is bending inward, most
likely from inertia when braking, but overall, I realize the stop and go
will apply the most pressure in that area and soon break.

When you say bigger material, are you indicating an aluminum channel or
rectangular tube will work much better? This is my thought due to the
supporting sides/legs which I am hoping will eliminate the flexing and
strengthen that "fig 2" area.

Thank you

Making the frame as close to a triangle as possible (in other words,
reducing the 5-1/2" & 8" dimensions) will increase the stiffness.
Assuming the loads are all in the plane of the drawing, laying the bar
flat will make the frame *much* stiffer; 64x if I did the mental
arithmetic right. And switching to steel will make it 3x stiffer (and
3x heavier).
Would be a lot easier if we knew what this contraption is supposed to
do, and what it is supposes to attach to. I finally got the diagram to
open.

I'm assuming the two ends (diagram 1) are drilled and an
axle/pivot/pin runs through it and the framework you are building is
somehow supported at the "rear" (diagram 2) to keep it from dropping,
and there is a pivot(ball or pin) connecting it to the drawbar of
theis "lightweight trailer".

If it doesn't pivot at "diagram 1) and is not supported at "diagram 2"
you have a lot of other problems. What fits inside the frame that
requires it to be that shape??? If anything??.

We REALLY need more information to give you any kind of usefull
input.

Making the frame as close to a triangle as possible (in other words,
reducing the 5-1/2" & 8" dimensions) will increase the stiffness.
Assuming the loads are all in the plane of the drawing, laying the bar
flat will make the frame *much* stiffer; 64x if I did the mental
arithmetic right. And switching to steel will make it 3x stiffer (and
3x heavier).


Can't do that. The "drawbar" encases the rear wheel of a motorcycle.
It's width(two ends of fig 1)is the exact distance of the rear wheel
axle and the depth is about 3" from the back of the tire. Therefore, I
cannot make it smaller without interfering with the movement of the tire.

Obviously, there is another drawing displaying fig 1 and fig 2. Fig 1 is
a hole which fits over the axle and locked in with a bushing and pin
enabling it to pivot on the axle. Fig 2 is a flat plate welded to the
drawbar. The trailer has a two piece coupling and one side is bolted to
the flat plate. The other is obviously on the trailer's tongue. It can
be detached with the removal of a hitch bolt/pin and separated from the
drawbar.

I'm assuming the two ends (diagram 1) are drilled and an
axle/pivot/pin runs through it and the framework you are building is
somehow supported at the "rear" (diagram 2) to keep it from dropping,
and there is a pivot(ball or pin) connecting it to the drawbar of
theis "lightweight trailer".

If it doesn't pivot at "diagram 1) and is not supported at "diagram 2"
you have a lot of other problems. What fits inside the frame that
requires it to be that shape??? If anything??.

We REALLY need more information to give you any kind of usefull
input.

You are correct in your guess. It pivots at the end of fig 1 and
attached at fig 2.

As explained to Ned above......(cut and paste)

The "drawbar" in the drawing, encases the rear wheel of a motorcycle.
It's width(two ends of fig 1)is the exact distance of the rear wheel
axle and the depth is about 3" from the back of the tire. Therefore, I
cannot make it smaller without interfering with the movement of the tire.

Obviously, there is another drawing displaying fig 1 and fig 2. Fig 1 is
a hole which fits over the axle and locked in with a bushing and pin
enabling it to pivot on the axle. Fig 2 is a flat plate welded to the
drawbar. The trailer has a two piece coupling and one side is bolted to
the flat plate. The other is obviously on the trailer's tongue. It can
be detached with the removal of a hitch bolt/pin and separated from the
drawbar.

To help anyone get a clearer picture, here are two photos of the drawbar
hook-up on the bike and trailer.

https://www.flickr.com/photos/18223943@N06/14817388677/

https://www.flickr.com/photos/182239...n/photostream/

On Fri, 22 Aug 2014 20:19:57 -0400, Meanie
wrote:



Making the frame as close to a triangle as possible (in other words,
reducing the 5-1/2" & 8" dimensions) will increase the stiffness.
Assuming the loads are all in the plane of the drawing, laying the bar
flat will make the frame *much* stiffer; 64x if I did the mental
arithmetic right. And switching to steel will make it 3x stiffer (and
3x heavier).


Can't do that. The "drawbar" encases the rear wheel of a motorcycle.
It's width(two ends of fig 1)is the exact distance of the rear wheel
axle and the depth is about 3" from the back of the tire. Therefore, I
cannot make it smaller without interfering with the movement of the tire.

Obviously, there is another drawing displaying fig 1 and fig 2. Fig 1 is
a hole which fits over the axle and locked in with a bushing and pin
enabling it to pivot on the axle. Fig 2 is a flat plate welded to the
drawbar. The trailer has a two piece coupling and one side is bolted to
the flat plate. The other is obviously on the trailer's tongue. It can
be detached with the removal of a hitch bolt/pin and separated from the
drawbar.
I suspected that was what you were working on. The "drawbar" pivots
on the rear axle of the bike, and the trailer pivots on a pin - with
no support at the back of the hitch. NO WAY would I attempt to do it
that way - particularly with aluminum. You WILL lose the trailer, and
you could very likely cause a serious accident when that happens.

There are lots of well engineered bike hitches readily available - and
some for not much more than it would cost you in materials. Look at
the Kuryakyn line - most models are less than $300 and they are a VERY
well designed and built hitch. KhromeWerks, HitchDoc, Bushtec and
custoncruiserchrome all make decent units as well - but I'd be taking
a close look at the Kuryakyn - best value for money.

On Fri, 22 Aug 2014 20:27:05 -0400, Meanie
wrote:

https://www.flickr.com/photos/182239...n/photostream/
5/16X2" 4140 bent, not welded would mabee work - but not be light.
1/4" MIGHT even work, I'd gusset the back angles. What provision are
you making for leaning the bike???.

Another option would be a side pivot hitch, with the hitch of the
trailer attached to one side instead of the center, with a bend in
towards the center to allow you to make right turns. Ball hitch bolted
to the rear bike axle. Like a bicycle trailer.(look at the Burley
Nomad as an example) or the CTS (Thule) system -
https://www.youtube.com/watch?v=KiwTHlz4Gw0 gives you an idea ov what
I'm talking about, but still using a pin. (as does Burley)

The 4140 is going to cost you at least half the price of a Kuryakyn
hitch. Whan make model and year is the bike??

I suspected that was what you were working on. The "drawbar" pivots
on the rear axle of the bike, and the trailer pivots on a pin - with
no support at the back of the hitch. NO WAY would I attempt to do it
that way - particularly with aluminum. You WILL lose the trailer, and
you could very likely cause a serious accident when that happens.


Not sure what you mean "no support at back of the hitch" but it's a
similar design as this https://www.youtube.com/watch?v=XTbbfny0stk

http://www.mono-trail.co.uk/motorcyc...r-fitment.html

and many of these
http://www.mono-trail.co.uk/motorcyc...r-fitment.html


There are lots of well engineered bike hitches readily available - and
some for not much more than it would cost you in materials. Look at
the Kuryakyn line - most models are less than $300 and they are a VERY
well designed and built hitch. KhromeWerks, HitchDoc, Bushtec and
custoncruiserchrome all make decent units as well - but I'd be taking
a close look at the Kuryakyn - best value for money.


I do not want a permanent hitch. I want something removable. I like to
keep the lines of my bike clean and only use the trailer on long trips,
otherwise, I can assure you, I would have had any of those retailers on it.

On 8/22/2014 9:13 PM, wrote:
On Fri, 22 Aug 2014 20:27:05 -0400, Meanie
wrote:

https://www.flickr.com/photos/182239...n/photostream/
5/16X2" 4140 bent, not welded would mabee work - but not be light.
1/4" MIGHT even work, I'd gusset the back angles. What provision are
you making for leaning the bike???.

It's a single wheel trailer. It leans with the bike.
http://www.uni-go.com/videos/WindowsMediaServer.wmv



Another option would be a side pivot hitch, with the hitch of the
trailer attached to one side instead of the center, with a bend in
towards the center to allow you to make right turns. Ball hitch bolted
to the rear bike axle. Like a bicycle trailer.(look at the Burley
Nomad as an example) or the CTS (Thule) system -
https://www.youtube.com/watch?v=KiwTHlz4Gw0 gives you an idea ov what
I'm talking about, but still using a pin. (as does Burley)

The 4140 is going to cost you at least half the price of a Kuryakyn
hitch. Whan make model and year is the bike??


02 Kawasaki Mean Streak

BTW, none of those retailers/manufacturers make a hitch for my bike.
There are a few (less than a handful) who can custom make a permanent
hitch. The single wheel manufacturers also custom make them with two
options of a permanent or the axle hook-up which is where I obtained the
idea.

On Fri, 22 Aug 2014 17:07:36 -0400, Meanie
wrote:

My objective is to weld pieces of aluminum into this shape
.......https://www.flickr.com/photos/18223943@N06/14816003838/ which I
already did with the 2" x 1/4" aluminum I mentioned. Through trial and
error, I learned it flexes too much for my need. Therefore, I need
stronger and less flexing(preferably none). I choose aluminum due to
it's lightweight, but if necessary, then I will use steel or something
else anyone may want to suggest. Overall, I assume channel or even
rectangular tube would be more ideal to eliminate flex and provide more
strength but I need to stay at 1/4" thickness and 2" width.

All help appreciated.

Thank you


Well I can think of one material that would make this easier. It's
lightweight, strong, and you determine the overall rigidity.
Easy to work with and wouldn't require welding.

Carbon fiber.

I tried your photo link, Are you making the hitch for the bike or is
that the wrong thing? If so why is the 1/4 inch a fixed dimension?
The hitch on my bike is 3/4" tubing that is welded like a truss. It
bolts to the frame at the swing arm and the rear pegs. I've also seen
sport bikes with a bent tube hitch that attached to the rear frame under
the seat.

--
Steve W.

On Fri, 22 Aug 2014 22:13:50 -0400, Meanie
wrote:

On 8/22/2014 9:13 PM, wrote:
On Fri, 22 Aug 2014 20:27:05 -0400, Meanie
wrote:

https://www.flickr.com/photos/182239...n/photostream/
5/16X2" 4140 bent, not welded would mabee work - but not be light.
1/4" MIGHT even work, I'd gusset the back angles. What provision are
you making for leaning the bike???.

It's a single wheel trailer. It leans with the bike.
http://www.uni-go.com/videos/WindowsMediaServer.wmv



Another option would be a side pivot hitch, with the hitch of the
trailer attached to one side instead of the center, with a bend in
towards the center to allow you to make right turns. Ball hitch bolted
to the rear bike axle. Like a bicycle trailer.(look at the Burley
Nomad as an example) or the CTS (Thule) system -
https://www.youtube.com/watch?v=KiwTHlz4Gw0 gives you an idea ov what
I'm talking about, but still using a pin. (as does Burley)

The 4140 is going to cost you at least half the price of a Kuryakyn
hitch. Whan make model and year is the bike??


02 Kawasaki Mean Streak
OK so it's like the "bob" bicycle trailer - you should have said so
in the first place!!

On Fri, 22 Aug 2014 22:10:19 -0400, Meanie
wrote:

http://www.mono-trail.co.uk/motorcyc...r-fitment.html
What's wrong with making it of steel tube like the MonoTrail? I'd
use 4140 ChroMo tubing. .040 to .065 wall. (.060 would be my preferred
minimum) Round tubing gives you the best rigidity per lb.

wrote:
On Fri, 22 Aug 2014 22:10:19 -0400, Meanie
wrote:

http://www.mono-trail.co.uk/motorcyc...r-fitment.html
What's wrong with making it of steel tube like the MonoTrail? I'd
use 4140 ChroMo tubing. .040 to .065 wall. (.060 would be my preferred
minimum) Round tubing gives you the best rigidity per lb.

You definitely want it rigid, if it flexes into the wheel/tire....
I also wouldn't want to connect it to the trailing arm. The added weight
while maneuvering could cause some bad things to happen.
Easier to bend two pieces of tubing. Flatten the ends, attach them to 4
solid points on the bike and then weld a reinforcement plate at the rear.

Like this style. Just add an adapter for the other hitch.

http://www.customcruiserchrome.com/f...ed/172-002.jpg

--
Steve W.

On 8/23/2014 12

Well I can think of one material that would make this easier. It's
lightweight, strong, and you determine the overall rigidity.
Easy to work with and wouldn't require welding.

Carbon fiber.

I tried your photo link, Are you making the hitch for the bike or is
that the wrong thing? If so why is the 1/4 inch a fixed dimension?
The hitch on my bike is 3/4" tubing that is welded like a truss. It
bolts to the frame at the swing arm and the rear pegs. I've also seen
sport bikes with a bent tube hitch that attached to the rear frame under
the seat.


I'm making the "drawbar" so to speak, which will pull the trailer.

My axle has 1/2" protruding ends/nipples. A 1/2' bushing with 1/4"
flange and drilled hole for the pin uses the other 1/4" to fit into the
hole of the drawbar. Therefore, it has to be 1/4", at least where it
attaches to the axle.

Never thought of Carbon Fiber. I'll have to investigate that more.

Thanks

On 8/23/2014 1:23 AM, wrote:
On Fri, 22 Aug 2014 22:10:19 -0400, Meanie
wrote:

http://www.mono-trail.co.uk/motorcyc...r-fitment.html
What's wrong with making it of steel tube like the MonoTrail? I'd
use 4140 ChroMo tubing. .040 to .065 wall. (.060 would be my preferred
minimum) Round tubing gives you the best rigidity per lb.


Actually, nothing and I agree. I was looking for something more simpler
to do which I can do with what tools I have. I thought of doing it
exactly like the Mono Trail and even contacted them asking to buy their
fitment kit and attachment bar. My emails are ignored and he's in the
UK. This is something I may now seriously consider again.

wrote in message
...
One thing you need to remember when deciding between steel and
aluminum. If steel flexes, but does not bend bast it's elastic
limit,
there is little or no "fatigue" introduced, but if aluminum moves AT
ALL it is building up "fatique" damage and will soon break. ...

The rule of thumb I learned from Segway's head of mechanical
engineering was to stay below 1/2 of the ultimate tensile strength for
steel. I asked because I was designing the transmission for my
sawmill.

http://en.wikipedia.org/wiki/Fatigue_limit

1 ksi = 1000 pounds per square inch.

-jsw

On Fri, 22 Aug 2014 20:27:05 -0400, Meanie
wrote:

To help anyone get a clearer picture, here are two photos of the drawbar
hook-up on the bike and trailer.

https://www.flickr.com/photos/18223943@N06/14817388677/

https://www.flickr.com/photos/182239...n/photostream/


That one is very easy to make. However..Ill guarantee that it will not
stay horizontal for very long. First time you have to hit the brakes
hard..its GOING to shift upwards or downwards..bending the back flat
section where it attaches to the trailer hitch.

It HAS to be attached somewhere above the aluminum flats..a riser up
under the rear fender all the way to a hard spot on the frame.

Id make a hoop under the rear fender, attached to the same mount the
tops of the rear shocks attach to. Tig welded flat bar down to the top
of your hitch point should do it..same size as the aluminum flat bar
from the axle.

And Id be using nylon filled aircraft self locking nuts on those
bolts..lock washers wont do it in this application. Least..not for
long.

Gunner

--
"Living in the United States now is like being a Tampon.
We're in a great place, just at a bad time."

On Fri, 22 Aug 2014 20:27:05 -0400, Meanie
wrote:

To help anyone get a clearer picture, here are two photos of the drawbar
hook-up on the bike and trailer.

https://www.flickr.com/photos/18223943@N06/14817388677/

https://www.flickr.com/photos/182239...n/photostream/

Excuse me..not the shock bolts..but the farthest rear seat bolts

Gunner

--
"Living in the United States now is like being a Tampon.
We're in a great place, just at a bad time."

On 8/23/2014 4:25 PM, Gunner Asch wrote:
On Fri, 22 Aug 2014 20:27:05 -0400, Meanie
wrote:

To help anyone get a clearer picture, here are two photos of the drawbar
hook-up on the bike and trailer.

https://www.flickr.com/photos/18223943@N06/14817388677/

https://www.flickr.com/photos/182239...n/photostream/

Excuse me..not the shock bolts..but the farthest rear seat bolts

Gunner

--
"Living in the United States now is like being a Tampon.
We're in a great place, just at a bad time."


My intent is to avoid a permanent mount. I want to keep the lines of the
bike clean, thus, a removable drawbar is my objective and preferably,
one that doesn't require a great deal of time to install and remove.

If there is a way to mount something under the fender (hidden) then have
the capability to attach a removable connector to that mount, I would
consider it. The problem is that attachment would be too close to the
tire since it would need to drop behind the plate, which itself is about
2" from the tire.

Meanie wrote:
My intent is to avoid a permanent mount. I want to keep the lines of the
bike clean, thus, a removable drawbar is my objective and preferably,
one that doesn't require a great deal of time to install and remove.

If there is a way to mount something under the fender (hidden) then have
the capability to attach a removable connector to that mount, I would
consider it. The problem is that attachment would be too close to the
tire since it would need to drop behind the plate, which itself is about
2" from the tire.

Shouldn't be hard to make it easily removable. You would only have 4
points of contact to deal with.

--
Steve W.

On Sat, 23 Aug 2014 22:04:30 -0400, Meanie
wrote:

On 8/23/2014 4:25 PM, Gunner Asch wrote:
On Fri, 22 Aug 2014 20:27:05 -0400, Meanie
wrote:

To help anyone get a clearer picture, here are two photos of the drawbar
hook-up on the bike and trailer.

https://www.flickr.com/photos/18223943@N06/14817388677/

https://www.flickr.com/photos/182239...n/photostream/

Excuse me..not the shock bolts..but the farthest rear seat bolts

Gunner

--
"Living in the United States now is like being a Tampon.
We're in a great place, just at a bad time."


My intent is to avoid a permanent mount. I want to keep the lines of the
bike clean, thus, a removable drawbar is my objective and preferably,
one that doesn't require a great deal of time to install and remove.

You can either lift the seat and unbolt it, or have a couple inches
showing at the very bottom of the fender


If there is a way to mount something under the fender (hidden) then have
the capability to attach a removable connector to that mount, I would
consider it. The problem is that attachment would be too close to the
tire since it would need to drop behind the plate, which itself is about
2" from the tire.

If you hug the fender..you arent going to hit it. Else you would be
hitting the fender now.

The engineering is easy..application...shrug


--
"Living in the United States now is like being a Tampon.
We're in a great place, just at a bad time."