Â* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .

https://www.youtube.com/results?sear...dsaw+blade s+

Silver soldering works for me. Ive had problems keeping tig welded
blades from breaking again.

__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .

For whatever it is worth, I seem to remember a band saw with an
attached blade welder that clamped the blade in a holder with two
sections, a fixed clamp and a movable clamp. When you hit the switch
the current was applied and the spring loaded clamp moved that end of
the blade toward the fixed end of the blade, sort of like a spot
welder. There was no filler material. When the weld was finished there
was some "bead" on both sides of the blade and the welder had a small
grinding wheel attachment so that the weld "beads" could be ground
smooth. No annealing or filler metal

Earlier on we used to grind each end of the blade to a knife edge, and
then overlap the ends and silver solder them together.

Given that most band saws have large enough wheels that the blade is
not bent sharply I suspect that the joining is not a really critical
thing.

--
Cheers,
John B.

"John B. Slocomb" wrote in message
...
On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

I've read about it somewhere , but don't recall the details ...
Broke
the last (nearly new) band for my horizontal , figured I have
nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh
,
and I'll need to make a clamp block to keep the blade aligned as I
weld
on it . Got a new blade on the way , but just got a bug to try this
. I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) ,
ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin
(IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A
torch
OK for the task if it's needed ? I know I want to minimize the HAZ .

For whatever it is worth, I seem to remember a band saw with an
attached blade welder that clamped the blade in a holder with two
sections, a fixed clamp and a movable clamp. When you hit the switch
the current was applied and the spring loaded clamp moved that end
of
the blade toward the fixed end of the blade, sort of like a spot
welder. There was no filler material. When the weld was finished
there
was some "bead" on both sides of the blade and the welder had a
small
grinding wheel attachment so that the weld "beads" could be ground
smooth. No annealing or filler metal

Earlier on we used to grind each end of the blade to a knife edge,
and
then overlap the ends and silver solder them together.

Given that most band saws have large enough wheels that the blade is
not bent sharply I suspect that the joining is not a really critical
thing.

--
Cheers,
John B.

http://www.neme-s.org/Shaper%20Books...t%20Welder.pdf

On 3/4/2019 4:14 AM, John B. Slocomb wrote:
On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

Â* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .
For whatever it is worth, I seem to remember a band saw with an
attached blade welder that clamped the blade in a holder with two
sections, a fixed clamp and a movable clamp. When you hit the switch
the current was applied and the spring loaded clamp moved that end of
the blade toward the fixed end of the blade, sort of like a spot
welder. There was no filler material. When the weld was finished there
was some "bead" on both sides of the blade and the welder had a small
grinding wheel attachment so that the weld "beads" could be ground
smooth. No annealing or filler metal

Earlier on we used to grind each end of the blade to a knife edge, and
then overlap the ends and silver solder them together.

Given that most band saws have large enough wheels that the blade is
not bent sharply I suspect that the joining is not a really critical
thing.

--
Cheers,
John B.


Â* I used a band welder of that type long ago in a place far from here .
BUT the one that I used did have an anneal function , and it did help
extend blade life . I suppose I could rig up something to do that butt
weld using my TIG welder as a power source ... it has a spot weld
function .

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

On Monday, March 4, 2019 at 7:40:11 AM UTC-5, Terry Coombs wrote:
On 3/4/2019 4:14 AM, John B. Slocomb wrote:
On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

Â* I've read about it somewhere , but don't recall the details .... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .
For whatever it is worth, I seem to remember a band saw with an
attached blade welder that clamped the blade in a holder with two
sections, a fixed clamp and a movable clamp. When you hit the switch
the current was applied and the spring loaded clamp moved that end of
the blade toward the fixed end of the blade, sort of like a spot
welder. There was no filler material. When the weld was finished there
was some "bead" on both sides of the blade and the welder had a small
grinding wheel attachment so that the weld "beads" could be ground
smooth. No annealing or filler metal

Earlier on we used to grind each end of the blade to a knife edge, and
then overlap the ends and silver solder them together.

Given that most band saws have large enough wheels that the blade is
not bent sharply I suspect that the joining is not a really critical
thing.

--
Cheers,
John B.


Â* I used a band welder of that type long ago in a place far from here .
BUT the one that I used did have an anneal function , and it did help
extend blade life . I suppose I could rig up something to do that butt
weld using my TIG welder as a power source ... it has a spot weld
function .


Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

I would suggest ordering some silver solder and flux. Band saw blades can be tig welded, but it is easy to screw it up. Silver solder is easier. Mean while make a jig to hold the blade and try tigging. You can anneal using a hand held propane torch.

Long term make a band saw blade welder. A microwave oven transformer can be rewound to have a low voltage winding.

Dan

On Mon, 4 Mar 2019 08:31:54 -0800 (PST), "
wrote:

On Monday, March 4, 2019 at 7:40:11 AM UTC-5, Terry Coombs wrote:
On 3/4/2019 4:14 AM, John B. Slocomb wrote:
On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .
For whatever it is worth, I seem to remember a band saw with an
attached blade welder that clamped the blade in a holder with two
sections, a fixed clamp and a movable clamp. When you hit the switch
the current was applied and the spring loaded clamp moved that end of
the blade toward the fixed end of the blade, sort of like a spot
welder. There was no filler material. When the weld was finished there
was some "bead" on both sides of the blade and the welder had a small
grinding wheel attachment so that the weld "beads" could be ground
smooth. No annealing or filler metal

Earlier on we used to grind each end of the blade to a knife edge, and
then overlap the ends and silver solder them together.

Given that most band saws have large enough wheels that the blade is
not bent sharply I suspect that the joining is not a really critical
thing.

--
Cheers,
John B.


* I used a band welder of that type long ago in a place far from here .
BUT the one that I used did have an anneal function , and it did help
extend blade life . I suppose I could rig up something to do that butt
weld using my TIG welder as a power source ... it has a spot weld
function .


Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

I would suggest ordering some silver solder and flux. Band saw blades can be tig welded, but it is easy to screw it up. Silver solder is easier. Mean while make a jig to hold the blade and try tigging. You can anneal using a hand held propane torch.

Long term make a band saw blade welder. A microwave oven transformer can be rewound to have a low voltage winding.

Dan

If you want to ake a big project of it, that would be one way to go.
But, as Gunner said, it's hard to beat scarfing the break and
silver-brazing it with O/A. That, too, requires a jig to hold it, but
it's a simple one. It's not used in industry as often as it once was,
because it's not as fast as just placing the ends in a jig and pushing
a button.

It's not widely recognized that a properly-gapped and -heated silver
braze joint can achieve over 100,000 pounds per square inch of shear
strength. You won't quite achieve that with a simple jig (the gap is
catch-as-catch-can; ideally, it's around 0.001 - 0.002 inches), but it
still is stronger than the parent metal, because the scarf multiplies
the joint area by a factor of three or so. Just the bulk strength of
the silver braze metal is on the order of 1/3 the strength of the
blade. And the embrittlement problem that comes from heating and
self-quenching with electric welding methods more or less solves
itself.

I used to do it, but I haven't broken a blade in a long while.

--
Ed Huntress

On 3/4/2019 10:56 AM, Ed Huntress wrote:
On Mon, 4 Mar 2019 08:31:54 -0800 (PST), "
wrote:

On Monday, March 4, 2019 at 7:40:11 AM UTC-5, Terry Coombs wrote:
On 3/4/2019 4:14 AM, John B. Slocomb wrote:
On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

Â* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .
For whatever it is worth, I seem to remember a band saw with an
attached blade welder that clamped the blade in a holder with two
sections, a fixed clamp and a movable clamp. When you hit the switch
the current was applied and the spring loaded clamp moved that end of
the blade toward the fixed end of the blade, sort of like a spot
welder. There was no filler material. When the weld was finished there
was some "bead" on both sides of the blade and the welder had a small
grinding wheel attachment so that the weld "beads" could be ground
smooth. No annealing or filler metal

Earlier on we used to grind each end of the blade to a knife edge, and
then overlap the ends and silver solder them together.

Given that most band saws have large enough wheels that the blade is
not bent sharply I suspect that the joining is not a really critical
thing.

--
Cheers,
John B.


Â* I used a band welder of that type long ago in a place far from here .
BUT the one that I used did have an anneal function , and it did help
extend blade life . I suppose I could rig up something to do that butt
weld using my TIG welder as a power source ... it has a spot weld
function .


Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !
I would suggest ordering some silver solder and flux. Band saw blades can be tig welded, but it is easy to screw it up. Silver solder is easier. Mean while make a jig to hold the blade and try tigging. You can anneal using a hand held propane torch.

Long term make a band saw blade welder. A microwave oven transformer can be rewound to have a low voltage winding.

Dan
If you want to ake a big project of it, that would be one way to go.
But, as Gunner said, it's hard to beat scarfing the break and
silver-brazing it with O/A. That, too, requires a jig to hold it, but
it's a simple one. It's not used in industry as often as it once was,
because it's not as fast as just placing the ends in a jig and pushing
a button.

It's not widely recognized that a properly-gapped and -heated silver
braze joint can achieve over 100,000 pounds per square inch of shear
strength. You won't quite achieve that with a simple jig (the gap is
catch-as-catch-can; ideally, it's around 0.001 - 0.002 inches), but it
still is stronger than the parent metal, because the scarf multiplies
the joint area by a factor of three or so. Just the bulk strength of
the silver braze metal is on the order of 1/3 the strength of the
blade. And the embrittlement problem that comes from heating and
self-quenching with electric welding methods more or less solves
itself.

I used to do it, but I haven't broken a blade in a long while.

Â* If only I could find that silver solder I bought just to repair
bandsaw blades ... got flux and know where it is , but the SS has eluded
me for now . I'll find it a couple of days after I order more .

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .
I use bi-metal blades. They are hard to weld properly with the
resistance weld method. TIG welding with SS works very well though.
Just for kicks I decided, years ago, to see how well TIG welding would
work. See this link:
https://groups.google.com/forum/#!to...ng/uPXdZXEsyGc
Ernie Leimkuhler explains how he does it. I didn't have any of the
filler he was using so I tried ER309 filler. I was sawing 5" diameter
6061 bar. Very aggressively with a coarse variable pitch blade. The
blade was old and broke. I ended up welding the blade in 3 places.
None of my welds failed. After the blade broke in yet another place I
switched blades.
Eric

On 3/4/2019 11:55 AM, wrote:
On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

Â* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .
I use bi-metal blades. They are hard to weld properly with the
resistance weld method. TIG welding with SS works very well though.
Just for kicks I decided, years ago, to see how well TIG welding would
work. See this link:
https://groups.google.com/forum/#!to...ng/uPXdZXEsyGc
Ernie Leimkuhler explains how he does it. I didn't have any of the
filler he was using so I tried ER309 filler. I was sawing 5" diameter
6061 bar. Very aggressively with a coarse variable pitch blade. The
blade was old and broke. I ended up welding the blade in 3 places.
None of my welds failed. After the blade broke in yet another place I
switched blades.
Eric

Â* Thanks for the link Eric , that answered all my questions in one place .

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

On Mon, 4 Mar 2019 11:40:19 -0600, Terry Coombs
wrote:

On 3/4/2019 10:56 AM, Ed Huntress wrote:
On Mon, 4 Mar 2019 08:31:54 -0800 (PST), "
wrote:

On Monday, March 4, 2019 at 7:40:11 AM UTC-5, Terry Coombs wrote:
On 3/4/2019 4:14 AM, John B. Slocomb wrote:
On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .
For whatever it is worth, I seem to remember a band saw with an
attached blade welder that clamped the blade in a holder with two
sections, a fixed clamp and a movable clamp. When you hit the switch
the current was applied and the spring loaded clamp moved that end of
the blade toward the fixed end of the blade, sort of like a spot
welder. There was no filler material. When the weld was finished there
was some "bead" on both sides of the blade and the welder had a small
grinding wheel attachment so that the weld "beads" could be ground
smooth. No annealing or filler metal

Earlier on we used to grind each end of the blade to a knife edge, and
then overlap the ends and silver solder them together.

Given that most band saws have large enough wheels that the blade is
not bent sharply I suspect that the joining is not a really critical
thing.

--
Cheers,
John B.


* I used a band welder of that type long ago in a place far from here .
BUT the one that I used did have an anneal function , and it did help
extend blade life . I suppose I could rig up something to do that butt
weld using my TIG welder as a power source ... it has a spot weld
function .


Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !
I would suggest ordering some silver solder and flux. Band saw blades can be tig welded, but it is easy to screw it up. Silver solder is easier. Mean while make a jig to hold the blade and try tigging. You can anneal using a hand held propane torch.

Long term make a band saw blade welder. A microwave oven transformer can be rewound to have a low voltage winding.

Dan
If you want to ake a big project of it, that would be one way to go.
But, as Gunner said, it's hard to beat scarfing the break and
silver-brazing it with O/A. That, too, requires a jig to hold it, but
it's a simple one. It's not used in industry as often as it once was,
because it's not as fast as just placing the ends in a jig and pushing
a button.

It's not widely recognized that a properly-gapped and -heated silver
braze joint can achieve over 100,000 pounds per square inch of shear
strength. You won't quite achieve that with a simple jig (the gap is
catch-as-catch-can; ideally, it's around 0.001 - 0.002 inches), but it
still is stronger than the parent metal, because the scarf multiplies
the joint area by a factor of three or so. Just the bulk strength of
the silver braze metal is on the order of 1/3 the strength of the
blade. And the embrittlement problem that comes from heating and
self-quenching with electric welding methods more or less solves
itself.

I used to do it, but I haven't broken a blade in a long while.

* If only I could find that silver solder I bought just to repair
bandsaw blades ... got flux and know where it is , but the SS has eluded
me for now . I'll find it a couple of days after I order more .

I have numerous collections of things like that. It becomes worse as I
grow older and buy bulk quantities of things from Costco.

I'll never have to buy a pack of contractor's plastic bags for the
rest of my life. d8-)

--
Ed Huntress

On Mon, 4 Mar 2019 11:40:19 -0600
Terry Coombs wrote:

snip
If only I could find that silver solder I bought just to repair
bandsaw blades ... got flux and know where it is , but the SS has eluded
me for now . I'll find it a couple of days after I order more .

It was the handy little roll of bailing wire you used a while back

Seriously, sometimes I luck out by thinking I have some in my hand and
where would I go stash it right now...

--
Leon Fisk
Grand Rapids MI

On Mon, 04 Mar 2019 17:14:52 +0700, John B. Slocomb wrote:


For whatever it is worth, I seem to remember a band saw with an attached
blade welder that clamped the blade in a holder with two sections, a
fixed clamp and a movable clamp.

Yes, DoAll saws have a built-in shear/welder/grinder. Very simple, does
an AMAZING job. I got an ancient German blade welder on eBay, it works
but not as well as the DoAll. No filler needed, it is resistive welding,
and the jaws move together under light pressure to "upset" the weld area
a little. Then, you grind down the flash at the weld and anneal.

Jon

On 3/4/2019 1:42 PM, Leon Fisk wrote:
On Mon, 4 Mar 2019 11:40:19 -0600
Terry Coombs wrote:

snip
If only I could find that silver solder I bought just to repair
bandsaw blades ... got flux and know where it is , but the SS has eluded
me for now . I'll find it a couple of days after I order more .
It was the handy little roll of bailing wire you used a while back

Seriously, sometimes I luck out by thinking I have some in my hand and
where would I go stash it right now...

Â* But it's not in the bottom of the top right hand drawer of my
computer desk ... and I just looked again to make sure ! I'm pretty sure
it made it out to the shop , but exactly where in the shop is a true
puzzler . It should be in the plastic tub that all the welding/brazing
supplies are in . It ain't .

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

On Mon, 4 Mar 2019 14:43:58 -0600
Terry Coombs wrote:

But it's not in the bottom of the top right hand drawer of my
computer desk ... and I just looked again to make sure ! I'm pretty sure
it made it out to the shop , but exactly where in the shop is a true
puzzler . It should be in the plastic tub that all the welding/brazing
supplies are in . It ain't .

Been there, done that Try not to move stuff around much anymore
because I always go to where it used to be, not where I moved it too...

Mine is suppose to be in the little box/tray on the front of the
Oxy/Acy cart. Bought it years ago for just in case and have never
needed it so far. Knock on wood...

--
Leon Fisk
Grand Rapids MI

On Mon, 4 Mar 2019 11:58:41 -0600, Terry Coombs
wrote:

On 3/4/2019 11:55 AM, wrote:
On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .
I use bi-metal blades. They are hard to weld properly with the
resistance weld method. TIG welding with SS works very well though.
Just for kicks I decided, years ago, to see how well TIG welding would
work. See this link:
https://groups.google.com/forum/#!to...ng/uPXdZXEsyGc
Ernie Leimkuhler explains how he does it. I didn't have any of the
filler he was using so I tried ER309 filler. I was sawing 5" diameter
6061 bar. Very aggressively with a coarse variable pitch blade. The
blade was old and broke. I ended up welding the blade in 3 places.
None of my welds failed. After the blade broke in yet another place I
switched blades.
Eric

* Thanks for the link Eric , that answered all my questions in one place .
You're welcome. Ernie's very good at welding and welding advice.
Somewhere he also explains how to make a fixture to hold the blades
but I couldn't find the link. Doesn't matter though, you'll figure it
out easily enough. When I made my blade welding guide I milled a
little pocket under the weld zone so that the argon would also flow
under the weld and prevent sugaring.
Eric

On Mon, 04 Mar 2019 11:56:46 -0500, Ed Huntress
wrote:

On Mon, 4 Mar 2019 08:31:54 -0800 (PST), "
wrote:

On Monday, March 4, 2019 at 7:40:11 AM UTC-5, Terry Coombs wrote:
On 3/4/2019 4:14 AM, John B. Slocomb wrote:
On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .
For whatever it is worth, I seem to remember a band saw with an
attached blade welder that clamped the blade in a holder with two
sections, a fixed clamp and a movable clamp. When you hit the switch
the current was applied and the spring loaded clamp moved that end of
the blade toward the fixed end of the blade, sort of like a spot
welder. There was no filler material. When the weld was finished there
was some "bead" on both sides of the blade and the welder had a small
grinding wheel attachment so that the weld "beads" could be ground
smooth. No annealing or filler metal

Earlier on we used to grind each end of the blade to a knife edge, and
then overlap the ends and silver solder them together.

Given that most band saws have large enough wheels that the blade is
not bent sharply I suspect that the joining is not a really critical
thing.

--
Cheers,
John B.


* I used a band welder of that type long ago in a place far from here .
BUT the one that I used did have an anneal function , and it did help
extend blade life . I suppose I could rig up something to do that butt
weld using my TIG welder as a power source ... it has a spot weld
function .


Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

I would suggest ordering some silver solder and flux. Band saw blades can be tig welded, but it is easy to screw it up. Silver solder is easier. Mean while make a jig to hold the blade and try tigging. You can anneal using a hand held propane torch.

Long term make a band saw blade welder. A microwave oven transformer can be rewound to have a low voltage winding.

Dan

If you want to ake a big project of it, that would be one way to go.
But, as Gunner said, it's hard to beat scarfing the break and
silver-brazing it with O/A. That, too, requires a jig to hold it, but
it's a simple one. It's not used in industry as often as it once was,
because it's not as fast as just placing the ends in a jig and pushing
a button.

It's not widely recognized that a properly-gapped and -heated silver
braze joint can achieve over 100,000 pounds per square inch of shear
strength. You won't quite achieve that with a simple jig (the gap is
catch-as-catch-can; ideally, it's around 0.001 - 0.002 inches), but it
still is stronger than the parent metal, because the scarf multiplies
the joint area by a factor of three or so. Just the bulk strength of
the silver braze metal is on the order of 1/3 the strength of the
blade. And the embrittlement problem that comes from heating and
self-quenching with electric welding methods more or less solves
itself.

I used to do it, but I haven't broken a blade in a long while.
El-cheapo propane torch works fine for me! My jig is a piece of
channel with angle attached and clamp screws to hold the blade between
the flange of the channel and the inside of the leg of the angle and a
gap cut in the flange of the channel to let the flame come up under
the joint. To scarf the joint, I just clamp two ends together and
touch them on the grinder. After brazing, I do touch up with the
Dremel.

On Mon, 04 Mar 2019 23:21:52 -0500, Gerry
wrote:

On Mon, 04 Mar 2019 11:56:46 -0500, Ed Huntress
wrote:

On Mon, 4 Mar 2019 08:31:54 -0800 (PST), "
wrote:

On Monday, March 4, 2019 at 7:40:11 AM UTC-5, Terry Coombs wrote:
On 3/4/2019 4:14 AM, John B. Slocomb wrote:
On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .
For whatever it is worth, I seem to remember a band saw with an
attached blade welder that clamped the blade in a holder with two
sections, a fixed clamp and a movable clamp. When you hit the switch
the current was applied and the spring loaded clamp moved that end of
the blade toward the fixed end of the blade, sort of like a spot
welder. There was no filler material. When the weld was finished there
was some "bead" on both sides of the blade and the welder had a small
grinding wheel attachment so that the weld "beads" could be ground
smooth. No annealing or filler metal

Earlier on we used to grind each end of the blade to a knife edge, and
then overlap the ends and silver solder them together.

Given that most band saws have large enough wheels that the blade is
not bent sharply I suspect that the joining is not a really critical
thing.

--
Cheers,
John B.


* I used a band welder of that type long ago in a place far from here .
BUT the one that I used did have an anneal function , and it did help
extend blade life . I suppose I could rig up something to do that butt
weld using my TIG welder as a power source ... it has a spot weld
function .


Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

I would suggest ordering some silver solder and flux. Band saw blades can be tig welded, but it is easy to screw it up. Silver solder is easier. Mean while make a jig to hold the blade and try tigging. You can anneal using a hand held propane torch.

Long term make a band saw blade welder. A microwave oven transformer can be rewound to have a low voltage winding.

Dan

If you want to ake a big project of it, that would be one way to go.
But, as Gunner said, it's hard to beat scarfing the break and
silver-brazing it with O/A. That, too, requires a jig to hold it, but
it's a simple one. It's not used in industry as often as it once was,
because it's not as fast as just placing the ends in a jig and pushing
a button.

It's not widely recognized that a properly-gapped and -heated silver
braze joint can achieve over 100,000 pounds per square inch of shear
strength. You won't quite achieve that with a simple jig (the gap is
catch-as-catch-can; ideally, it's around 0.001 - 0.002 inches), but it
still is stronger than the parent metal, because the scarf multiplies
the joint area by a factor of three or so. Just the bulk strength of
the silver braze metal is on the order of 1/3 the strength of the
blade. And the embrittlement problem that comes from heating and
self-quenching with electric welding methods more or less solves
itself.

I used to do it, but I haven't broken a blade in a long while.
El-cheapo propane torch works fine for me! My jig is a piece of
channel with angle attached and clamp screws to hold the blade between
the flange of the channel and the inside of the leg of the angle and a
gap cut in the flange of the channel to let the flame come up under
the joint. To scarf the joint, I just clamp two ends together and
touch them on the grinder. After brazing, I do touch up with the
Dremel.

G That's about the level of sophistication of the rig I used, when I
was bandsawing metal -- right down to the Dremel.

Now I bandsaw wood and composites. No breaks for years.

--
Ed Huntress

On 2019-03-04, John B Slocomb wrote:
On Sun, 3 Mar 2019 21:16:51 -0600, Terry Coombs
wrote:

* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .

For whatever it is worth, I seem to remember a band saw with an
attached blade welder that clamped the blade in a holder with two
sections, a fixed clamp and a movable clamp. When you hit the switch
the current was applied and the spring loaded clamp moved that end of
the blade toward the fixed end of the blade, sort of like a spot
welder. There was no filler material. When the weld was finished there
was some "bead" on both sides of the blade and the welder had a small
grinding wheel attachment so that the weld "beads" could be ground
smooth. No annealing or filler metal

These are made both to build into the bandsaw, and for benchtop
use. They also include a lever-operated shear to cut the blade cleanly.

One reason for them being mounted on the bandsaw is so you can
drill a hole in the workpiece, thread the cut blade through the hole,
weld the blade, and then cut along a line which never intersects the
outside edge of the workpiece, to cut out an inner piece.

An example of the benchtop version (similar to what I have) is
this one on eBay:

Auction # 273699228238

Note the semi-repaired "Anneal" switch. After the welding, you are
supposed to loosen the clamps, slide them back, center the welded spot
between the clamps, and then start out with long pulses of the anneal
switch, moveing slowly to very short ones to let it cool slowly. After
this, you grind off the flash.

The rotary switch sets the current for the width of the blade.
And you need more current for a bi-metal blade than for a carbon-steel
one.


Earlier on we used to grind each end of the blade to a knife edge, and
then overlap the ends and silver solder them together.

Given that most band saws have large enough wheels that the blade is
not bent sharply I suspect that the joining is not a really critical
thing.

You do want to anneal it properly -- especially if you have
something like my 4x6 Horizontal/Vertical bandsaw.

Enjoy,
DoN.

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On 4/03/2019 2:16 pm, Terry Coombs wrote:
Â* I've read about it somewhere , but don't recall the details ... Broke
the last (nearly new) band for my horizontal , figured I have nothing to
lose but a little time , a bit of shield gas and some 'lectrons - oh ,
and I'll need to make a clamp block to keep the blade aligned as I weld
on it . Got a new blade on the way , but just got a bug to try this . I
know low amps DCEN , what filler ? Got ER70S2 ,ER70S6 (MIG wire) , ER
308/309/312 and some Invar 42 nickel/iron . The blade is an Irwin (IIRC)
bimetal 10/14 pitch . Am I going to need to anneal the weld ? O/A torch
OK for the task if it's needed ? I know I want to minimize the HAZ .


I had a Roll-In saw that seemed to be hard on blades, breaking well
before they dulled. Machined up a fixture to hold the blade in
alignment, and tig welded with 308SS rod, no anneal. Never had a blade
break at the weld.
Had one blade with 5 or 6 welds before it dulled enough to discard. Gave
the fixture to my friend whose welder I'd been using.
Took a picture last time I was visiting, if I can dig it up, will email.

Jon

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