Brazing band saw blades

[Bill Swanson]

I have been brazing band saw blades for over 15 years with moderate success. I bought a kit years ago from Woodworkers warehouse. They reccomended the following type of joint.

I have been using a scarf joint of about 5 - 10 degrees, which results in a taper that is about 1/8 of an inch long.

I have been reading that maybe a 45 would work better and that there should be two bevels ground on each side of the blade to strengthen the joint.

I am not sure I understand the two bevels and their placement on the blade.

What do you all do to make the joint strong and no thicker than the blade after brazing?

I have attached a graphic of the scarf joint I have been using.

Thanks

Bill

[Tom Walz]

Looks like you are doing it right to me. The more surface area you have the stronger the join. Your joint should be about 0.002” - 0.003” thick, that is a layer of braze alloy 0.002” - 0.003” thick. Do this then just touch the band a bit to bring it down if you actually need to.

I think this has come up here before and I recall some good discussions on it.

There is brazing info at
http://www.carbideprocessors.com/brazing.htm

Contact me directly if you need more help.

tom

[Paul Atkins]

I have been silver brazing blades for a while and having better luck than with the tool store welding jobs. My band saw has a welder on it, but I haven't perfected that either. I just bevel each end straight across like the first photo. Haven't tried beveled scarf joint yet like photo 2. Seems like the stronger bet, but more time getting angles right. I think I'll try it and maybe set up some kind of grinding jig.

[harry strasil]

Being a Blacksmith, I use an old method, "Brazing Tongs". I used to braze the meat saw blades for a local meat processing place.

Most people get the blades to hot using a torch and the silver solder does not take.

My method was to:

1. bevel the blades, flux the bevels, and clamp in a shop made jig.

2. using a hammer and my anvil, flatten a piece of silver solder and cut it the appropriate length.

3. pry apart the bevel and insert the solder.

4. heat the tong jaws red hot with a torch or the forge .

5. clamp the joint between the hot jaws and apply pressure.

[george wilson]

I used to braze blades when teaching school shop and we had no welder. I just ground a taper about 1/8" wide across the 1/4" blada. They seemed to hold better than a welded joint,which was important to make them boy proof.

I do not like the idea of brazing on an angle across the width of the blade. With the blades bending around the wheels,it looks like an invitation for those sharp corners to gradually crack loose. More surface area can just be had by a thinner bevel as the original post mentioned.

I did not have brazing tongs,but would clamp he blade together with pliers just after the solder melted,to get the thickness of the blade in line with each other. Then,I'd polish,and reheat the blade to blue to restore the spring temper,and lose any brittleness I may have caused by cooling too fast with the pliers. Worked just fine.

[Kent E. Matthew]

Brazing makes me sicker than a dog. I can drink all the milk in the state, and I will still be sicker than a dog.