Bandsaw silver soldering fixture

[thehomeengineer]

Hi All

I was able to purchase two coils of bandsaw blade from a local scrapyard for my Startrite bandsaw at a great price (£10 each coil). My bandsaw is fitted with a blade welder but for some reason I have never been able to get it to work well. So, I have always silver solder the blades together which works really well.

As a treat to myself.

I knocked up a new soldering fixture to aid the alignment of the two ends. Once the blade is cut to length I grind the two ends at approximately 45 degrees to increase the surface area of the joint rather than just butt the ends together. I have used this technique for years and have never had one break yet. The photos below show the fixture. Two M6 penny washers are bent to clamp/hold blade in place


Fixture with welded bar to enable it to be held in the vice so the heat source can be placed beneath the blade.


Ready for silver solder NOTE the splice to increase the mating face surface area and bent M6 clamp washers.


Silver soldered together. Another advantage for silver soldering the blade doesn’t require annealing

Thank you for viewing
The Home Engineer

[mrehmus]

Nice job,

I was taught to flip one of the blade ends over and then grind the ends at the same time. That way the resulting joint will be straight. Of course we were using a blade welder, not a brazed joint. The annealing process was to first hold the lever on the welder down until the weld was made and then pulse it in decreasing amounts to anneal the weld. Never had one break.
Too bad the stand-alone welders are in the $600 and up prices here in the U.S.

Fortunately, a good braze job is stronger than the metal being joined.

[thehomeengineer]

Nice job,

I was taught to flip one of the blade ends over and then grind the ends at the same time.

Hi mrehmus
Every day is a school day. That is a great tip which I was unaware of thank you for the reply and I will be trying this tip next time I make a blade.
The Home Engineer

[uv8452]

"I was taught to flip one of the blade ends over and then grind the ends at the same time." Let me add: one end <1mm offset; and grinding both 45° angles at the same time. Then the exact angle doesn't matter.
The clamping spots should be at a greater distance, say, 2"; to give room for a generous flame >> brazing time just a few seconds
What saves a lot of adjusting: precisely aligned shoulders for both backs of the blade. Like one sees it on pfredX1's photograph.

[pfredX1]

When I brazed bandsaw blades I double scarfed the joint. Someplace I have a picture of the jig I made. It is similar to what's here. http://i.imgur.com/7SrdP.jpg

Yeah I was certainly in the mood to mill that day.

[thehomeengineer]

When I brazed bandsaw blades I double scarfed the joint. Someplace I have a picture of the jig I made. It is similar to what's here. http://i.imgur.com/7SrdP.jpg

Yeah I was certainly in the mood to mill that day.

Hi pfredX1
I would be very interested to see the joint if you are able to find the photo. Anything to make improvements to what I do is very welcome. Thank you for taking the time to view and reply to my post.

[Ralphxyz]

I thought the jig should be made from wood so that the heat is not dissipated quickly.

I like to see the actual brazing.

Ralph

[thehomeengineer]

I thought the jig should be made from wood so that the heat is not dissipated quickly.

I like to see the actual brazing.

Ralph

Hi Ralph
I will do a video on silver soldering very soon and post. The temperature of the silver solder I use melts at 720-degree C so very hot and the wood could cause a fire. I hope this has answered your question and thank you for taking the time to view the post.
The Home Engineer

[wizard69]

Hi Ralph
I will do a video on silver soldering very soon and post. The temperature of the silver solder I use melts at 720-degree C so very hot and the wood could cause a fire. I hope this has answered your question and thank you for taking the time to view the post.
The Home Engineer

That would be most welcomed, a picture is worth a 1000 a movie millions.

This appears to be a simple fixture to make, so all I really need is likely some silver solder. I must ask though do you believe a propane torch could heat the band fast enough to do a silver solder joint properly? Also preferences for solder and flux would be appreciated.

[mrehmus]

Propane is probably not hot enough and you need to be careful that you don't take the temper out of a large section of the blade with a large flame. MAPP gas would probably work using on of those small torches with the small flame.