Band saw blades, welding vs brazing, and home made resistance welders?

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I've got a Roll-In saw which takes a 9' blade. Not the most common length, I seldom find them on ebay at the right length. Quality blades run $35 each and up.

I discovered that I could TIG weld the bimetal blades using 308SS alloy, and made up a nice fixture to do this after having initial trouble with blades breaking. They usually broke somewhere other than the weld, with cracks starting at the bottom of the gullet. Figured out I was pulling too much tension and have backed off. I get great blade life now, but...

I know many folks silver solder or braze blades, but from my recollection these are folks running regular band saws. Is anyone silver soldering/brazing blades on a cut off type band saw where the blade must endure two 45 degree twists each pass?

With regards to resistance welders, the last time I looked them up there is a big price difference between carbon steel blade welders and bi-metal welders. Anyone know what the difference is? Higher current needed?

Anyone successfully build a resistant butt welder capable of welding 3/4 x .032 bi-metal blades?

Last question, I have a Grainger hand held spot welder. It's rated 5500 amps output at 1.6 volts with 6" long tongs. I'm wondering if I could build the jaws portion of a blade welder and connect up the spot welder with heavy welding cables?

Ok, ONE last question. Anyone know of an outfit in central to southern California or Reno that would weld up blades from my supplied stock?

Thanks,

Jon

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Silver soldering works okay for cut off band saws. The trick is to put the ends so one can grind a scarf on both ends at the same time. And then some sort of jig to hold the blades in alignment while one silver solders.

Dan

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snipped-for-privacy@krl.org wrote:

Ok, think I'll make up a fixture and give it a try.

Thank you,

Jon

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Before I had a blade welder, I took a coil to a local supplier and he welded 20 blades for me for $50.

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Tom Gardner wrote:

I'd happily pay that if I could find someone nearby, I'd still be getting blades for less than half retail. But Sacramento is the nearest region likely to have someone that can do it, and that's a 120 mile round trip... I do get down there though, so combined with other business it's easy to justify. Willing to ship my bulk blade too, if the overall costs still work out.

But I am going to try silver soldering, if it works for me, I'm set!

Jon

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I've silver soldered them, it's a bit tricky but works.

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Hey, that sounds like my saw as well. Is it the 14" throat model? I have to say, it's one of the best things I ever stole, er.. bought for $75. A couple hundred later in rebuild parts, and it works great. Never did set up the hydraulic damping cylinder, probably need a new one. but for my occasional use, I'm really happy with it.

bill

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Bill Martin wrote:

$75???? Yeah, you got yourself a hell of a deal! I paid about 12x that, though I still consider mine a good deal. I've only had to replace the rubber tires on mine. It's a 9" throat. I think it's the best overall compromise for a small shop. I'd love to have a real bandsaw, and a good cutoff saw, and a cold saw, but I'd need another couple hundred square feet of shop.... Bought it from ggmachine on ebay, out of Florida. It was looking to sell for more than one from Reliable, but the Florida seller get some killer rates on shipping. Got it shipped to Northern California for about half what Reliable wanted to ship theirs 600 miles.

One thing I love is the ability to set up and saw most anything. I've made a couple jobs -real- profitable by sawing 90% of the material I used to machine out.

Jon

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Jon Anderson wrote:

I can help you on this one.

I silver solder up my band saw blades. I do this as follows. The 1st thing is tocut to length. the 2nd is to scarf the ends, I use the top wheel of my linisher for this. Scarf about 1/4in. then I made a jig from 2 4in long 1in by 1in angle with a gap in the middle. I clamp the jig in the leg vice and clamp the band saw blade down to the angle to line it up over the gap.. Essential!!! Bend the blade do that they spring toward each other. Put a strip of silver solder foil if you have it or say 1/32nd easy flo wire between the 2 scarfs. flux all over with easyflo stainless steel grade flux. Best there is. then heat till it all flows together . the springy ness of the 2 blade parts will pull them together. Heat a little up to 1/2 in either side of the solder to anneal. dont quench!!

Remove flux and clean up on said linisher or use a hand grinder.

Run a trial in sone scrap ones to start with to perfect your process. My band saw machine doesnt twist the blade.

Keep us informed how you get on. Ted Dorset UK

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Jon Anderson wrote:

Yes, and I had very variable results with brazing. Some blades would last months, others would break at the joing in a couple turns around the wheels.

I started to build one, wound my own transformer, and was getting promising results when I got a real DEAL on a German blade welder on eBay. The problem that held me back was the sliding upset mechanism that brings the ends together DURING the weld. This welder still isn't perfect, but I get usable blades most of the time.

This sounds quite promising. You need the right amount of upset (maybe 1/8" or so), the right pressure, VERY accurate movement to keep the blade ends parallel, and the weld current needs to turn off as soon as the upset completes. I think you need to be able to turn down the current quite a bit, maybe to 1000 - 1500 A or it will just blow the joint to bits. The blade holders on mine were shop-made, I'm guessing in a previous-previous life the welder was adapted for something else, and they are not quite perfect, but workable.

Jon

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Jon Elson wrote:

Well, maybe I will experiment with this then. I have linear slide assembly that's too rough to do much else with, but still as or more precise as anything I could make up. Just need to make SURE one side is insulated from the rest!

There's no way to vary current, except perhaps to use a couple extra feet of welding cable. Ratings drop significantly from 6" tongs out to 18" tongs, resistance losses in the copper tongs I'm guessing?

Timing, I'd just have to wing it I think. I've got good reflexes still, I think I could do it. And, it would be easy to anneal, just as with a purpose made welder, bump the weld button until the blade is the right color.

I think I'll try the silver solder first as it's the easiest, but for sure I'll try using the spot welder too. If that works out, I'll do up plans/notes/photos for the drop box.

Jon

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I built a band saw blade welder in the early '90's... It was briefly described in HSM and Projects in Metal #7 IIRC.

The most important parameters are stick-out of the blade ends from the clamps, upsetting force, shut-off of welding current at the end of the upset stroke, and post-weld annealing.

The actual welding current is not THAT critical it the current is shut off automatically at the end of the welding stroke. If the current is way too high the band saw blade ends will disappear in a shower of sparks; too little current and the weld is incomplete. Between these two limits there is considerable latitude.

There are some very good power control circuits published on the 'net using 40 amp triacs. At 220 VAC that ought to be enough for any band saw.

After successful welding the annealing process makes or breaks the joint. Follow the directions on the blade container TO THE LETTER. I learned this the hard way. For example on my DART blades box it says: "Anneal in subdued light to faint red." Following this rule I found every weld a winner.

Wolfgang

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Hey Kusti,

Two that look good came up on modeleng-list.

<http://wiki.owwm.com /(X(1)S(oqv5z445kadkcmbrhhlmtb45))/Default.aspx?PagendsawBladeSoldering&AspxAutoDetectCookieSupport=1>

and

<http://weldingweb.com/showthread.php?t03

Take care. Make sure you are NOT part of the meat-saw's diet.

Brian Lawson, Bothwell, Ontario.

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On Sun, 21 Sep 2008 09:08:12 -0700 (PDT), snipped-for-privacy@hotmail.com wrote:

Ive got 3 commercial blade welders, and damned if I can get any of them to work properly.

Id be tickled to have someone snag all 3, fix em up and give me back one that works properly and they could keep the rest.

Gunner

"Obama, raises taxes and kills babies. Sarah Palin - raises babies and kills taxes." Pyotr Flipivich

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Gunner Asch wrote:

Too bad youre not closer. I'd love to try that. I have very good luck with the one at school, from 1/4" up to 1" blades. ...lew...

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On Mon, 22 Sep 2008 06:44:46 -0600, Lew Hartswick

Know anyone coming this way?

Gunner

"Obama, raises taxes and kills babies. Sarah Palin - raises babies and kills taxes." Pyotr Flipivich

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On Sun, 21 Sep 2008 20:05:19 -0700, Gunner Asch

Any DoAlls amongst them? If so, look for an adjustment buried in the center of the insulating bushing that goes thru the power contacts. It's a hex socket screw that adjusts when the weld current shuts off as the clamps move together. I don't remember how I found the adjustment on my saw's welder, but until I did it wouldn't weld worth a damn. If it shuts off to early the weld does not upset enough, too late and you get holes blown out of the joint. When it's right the rest of the adjustments seem to be minor tweaks and not very fussy.

--
Ned Simmons

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Jon Anderson wrote:

The welders I've used have a kind of "latch" mechanism that applies upset pressure and turns on the weld current, and when the clamps move together a certain amount a catch trips and the current is shut off.

Jon

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Jon Elson wrote:

Well, maybe I could put a contactor between the spot welder and the outlet, and switch it off there for the welding cycle. I don't want to hack the spot welder to the point I can't use it for that purpose. I'm sure I can wing it enough to see if it's even going to work, and if it looks promising I'll add the contactor and a switch to cut it out.

Or, drive down to Gunners and see if I think I can get two working welders out of three... <G>

Jon

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On Fri, 19 Sep 2008 17:05:31 -0800, Jon Anderson

I tig weld mine, have very good results, except for Hertel brand blades, they break repeatedly when welded. Lenox Diemaster 2 works great, I have a little clamp fixture, weld, and grind flush. Sometimes I will anneal on the blade welder on my vertical saw. I never could get a good weld on that welder, most likey 1950's vintage saw.

www.enter.net/~rbraun/fixture1.jpg

never tried brazing.

picture soon, batteries charging.....

Thank You, Randy

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