View Full Version : Bandsaw blade brazing jig
01-15-2004, 09:51 AM
I broke a few teeth of of my lennox blade on my HF bandsaw. My fault, but it was getting dull anyway.
So after reading a couple of articles, I thought I would go with bulk blade stock. I made a copy of a jig I saw on the metalworking webb site.
I just ordered a 100' roll of Starrett blade stock. when it gets in I'll post about brazing the blades.
Here's a picture of the jig in the mill
01-15-2004, 09:52 AM
Here's the finished jig
01-15-2004, 10:28 AM
Say Jim what did that run you to build, I'd gladly pay you to build me one. Hmmm a mill....geez all those toys and so little money. I'm thinking the millermatic 210 or 251 better come first.
01-15-2004, 11:53 AM
I know I posted this someplace, but evidently, it wasn't here.
I have the vise built, and have set the project on the back burner for want of more information.
2 things come into play when brazing band saw blades, the first being full support of the blade itself to prevent the saw from warping during the process. Believe me, they will and do warp when heated.
The second is how the blade material is heated, and cooled. Using aluminum for the vise, while it is easy to machine, could become a problem due to the aluminum's ability to drink the heat away from the brazing area.
I stold the idea from www.beaumontmetalworks.com/index.html
When I started the project, I was thinking he is using an air/maap torch, but since I wasn't sure, I contacted beaumont.
His response was that he doesn't remember what kind of torch he used.
Air/Maap will produce enough heat to melt brass, and is a less concentrated heat than an O/A torch will be.
Jim, I think you may want to cut the vise back to have about 1/2" of shelf for the blade to sit on. If you get ahead of me on this project, keep me updated. I'm particularly interested in learning what torch works best.
Welding or brazing band blades together isn't the hard part, keeping the weld together on the saw is.
01-15-2004, 04:18 PM
I've done a lot of bandsaw blades with heliarc...I wouldn't dare try brazing it, and I'm certified. What type of brazing rod are you using?
01-15-2004, 05:30 PM
I got the idea from a post over on the "Dark Side":realmad:
This is the sight
I had a chunk of aluminum left over from a barscreen job
(don't worry Franz, that was barscreen:blush: )
I thought aluminum would be good to sink heat away from the blade.
I've silver soldered blades before with mixed results. Some times evan the welder on a duall will pooch one once in a while.
When my blades come, in I'll keep everybody posted of my success (hopefully:laugh: )
01-15-2004, 09:12 PM
Jim, you and I are workin from the same basic stolen design, and the only advantage I have is having silver soldered bread slicing blades MANY years ago.
Rocky, I thought you been out long enough you got paroled from the certification thing, or didn't Arnold come thru.
The concept Jim and I are working from is a lap joynt that is at least 2x the blade thickness across the braze joynt. The pics are better at the site Jim mentioned.
I haven't yet brazed one, and I'm thinking about taking a worn out blade and experimenting with both brass and German Silver, and seeing how they survive a bend test.
The bread saws I did years back were butt joynts, done with german silver, and they would run about 15 hours before leting go.
I've never tried a balde with TIG, and the guys I've talked to say TIG doesn't last unless it's running over a HUGE wheel.
Did you just TIG up a butt joynt, or TIG and then anneal yours?
01-17-2004, 07:58 PM
I'm attempting to attach a photo of the fixtures etc, that I use for silver soldering blades from .062 to .500. It's very reliable if done right. One comment about the fixtures I see in this thread is that the "shelf" for the blade should only be as wide as the body of the blade. Let the teeth and the set hang over or the joint won't close correctly!
01-17-2004, 08:10 PM
Your correct on the shelf size on the jig.
I made mine so the teeth will hang over the edge. with a 1/2" x 10 TPI blade. I made the shelf depth and the clamp so that a .025" thick blade will clamp flat
01-17-2004, 08:48 PM
Bob, what are you using for a torch?
01-18-2004, 08:53 AM
I've used a common propane torch in the past, for blades of .025 thickness, but I now use MAPP, as it is capable of doing the .032-.035 thickness blades. I beat the silver solder wire into a foil thickness on a clean anvil, clip off a piece with the dikes, and put it along with the flux, between the halves of the joint. You want a good fitup on the scarf joint (I grind mine at 5 deg. in a jig on the beltsander), and make the joint as thin as possible. I tension my silver soldered blades to the same 25,000 psi as my welded blades. Only ones I've ever had break, were the .062-14, which are a b**ch to do!
01-18-2004, 08:58 AM
what is wrong with using a #2 tip on a A/O torch?
01-18-2004, 10:16 AM
Nothing wrong with o/a, I've used it for silver soldering blades. I just find it easier not to mess with dragging hoses across the shop cuz I'm a little crowded here! Whatever gets the job done!
01-18-2004, 10:42 AM
Your crowdwd. Look at the pictures I posted of the Magic Garage:laugh:
01-18-2004, 01:01 PM
Jim, the main reason I've wanted to stay away from O/A on this job is that it's almost too hot for silver, and a more concentrated flame than Turbotorch running MAAP.
My thinking is the TurboTorch will generalize the heat on the blade, and yield a better joynt than concentrating the heat directly on the skived joynt. OK, there's also the 1# tank size convenience factor too, since I'm playin with this in the heated basement shop. Since you're in hanging chad land, I probably oughta splain what a basement is, that's a hole under the house, same size as the house, with concrete block walls, that contains a lot of toy er I mean tools. We even have pumps down there that keep the hole dewatered, and one of us uses that water in a tank called a cistern, to flush the GumpMatic electrified toilet. That saves considerable draw on the well.
Basements are also crouded chambers, similar to magic garages.
01-18-2004, 01:51 PM
My Youngest son lives in the country. He has something similiar, but no tools and stuff. I believe he calls it a septic tank:confused:
01-18-2004, 02:10 PM
Jim, I think we are havin one of them failures to communicate.
Basements, a/k/a cellars ain't septic tanks. Actually, that comment sorta worries me comin from a man who knows his s#!t as well as you. I've always looked up to you when it came to S#!t, and now I'm wonderin if your knowledge is just limited to book learnin and no actual experience.
I'm gonna think on this for a while.
01-18-2004, 04:31 PM
OK Bob, I went and looked at mine, and since I didn't really like the clamping action, took some cuts with the mill and put some tooth releif on the block & jaws. Now I have virtually paralell clamping on the blade stock
Thanks for the heads up.
01-18-2004, 08:39 PM
I hope things work out and the jigs work for brazing, soldering, or tig welding the blades together. If not this is an alternative.
Badger Blade welder
01-18-2004, 08:49 PM
Try this link instead
01-18-2004, 08:51 PM
I give up!:mad:
01-18-2004, 09:52 PM
That is the unit that uses a car battery for the power source I believe, and I'm a little nervous when it comes to using a battery in that application.
Without a load limiting device, wet cell batterys can disintigrate when shorted.
07-16-2005, 05:50 PM
Do you use Eutectic 680 or equivalent or just mild steel filler rod and I assume you anneal it after welding.
07-16-2005, 11:41 PM
I had high school students silver braze the shop bandsaw blades together over thirty years ago. Easy Flo 45 or similar silver solder works well. The jig I used was considerable less complicated. I used a piece of flat bar about two inches wide and on that I tack welded a square cold finished bar. If the bars were at least six inches long it assured the straightness of the joint. Two pincer style Vise Grips held the ends together. The back of the blade sat against the cold finish bar and the tips of the grips were no more than an inch from the joint on each side.
Cut your blade to length, put one twist in it and match the ends so that you can lightly grind the ends square while sandwiched together. That way if your end grind is out of square the ends will match when the twist is released and the ends butted. Grind your scarf ends then clamp it in the jig.
I don't like a gap in the jig. You lose support, and the bar under prevents you from overheating with your torch. Put flux on the low side of the scarf joint then heat to a dull red. Touch the silver solder to the edge of the lap and it should suck in. Using any more than one eighth of an inch of solder is a waste. You will be grinding the lump off.
We used oxy acetlyene , Victor torch with a number one tip. Your first couple of attempts will fail but you will gain skill. It was a sort of macho thing going after awhile in the class and having the same blade last for weeks was a bragging right. The side benefit was that if anyone abused the bandsaw blade they got heckled by someone other than myself. :'))) Starret blade stock is definitely the way to go. One year I was talked into purchasing a cheaper brand. It was a major mistake as the teeth were wearing out after only a few days of use.
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