Yes , the blades will hold firmly together when brazed , but if you don’t
spend most of the time in setting up the weld , you will end up with a
temporary blade only. I first tried the butt end method , while concerned
about not getting too much bronze on the blade itself. Once done and
satisfied that the weld was smooth enough to go through the guides , I
started my bandsaw / dropsaw. I cut a few pieces of wood , then increased
the cutting piece thickness , only to have the blade break again , as you said
in a different spot. This is because the strength of the blade changes at the
points on either side of the actual welded area.

So , I tried another way. I set the blade into a vise , extending the blade
end about 3/8″ . I ground a square slot into each end of the blade , leaving
a rectangular square when the pieces are brough together. Then I made a
very small block , from scrap metal , measuring about , 3/8″ long x 1/4″
wide. This allowed me to change the angle of the stiffness of the weld.

So , instead of having just a straight line weld across the blade , no matter
what the blade’s width , you would have more angles. You would have a
straight angle across the blade , 2 angles along the blade , reinforced by 2
end welds , across the blade.

This worked and cut alot of pieces before it too , gave to the same principals
as the straight across method. So . I decided to try a different type of metal
and found a small piece of bimetalic metal. The type of metal that has what
you call memory. This worked best. To get a good blade out of the deal ,
you have to weld the blade when it is in it’s memory position , or you are
welding the blade in an unnatural positon , causing stress on the weld during
it’s bending operation. Mocking this position is the answer.

The main problem with welding any bandsaw blade is you have to take into
consideration that the blade is bent throughout the operation at the machine.
The blade is always bending. It even twists it’s way off the drive wheels and
through the guides. Which don’t allow much tolerance to imperfection in the
weld area.

My next theory is to consider welding blades in a jig setup that takes the
blade’s actual position on the wheels into consideration. After all , who would
expect a blade that is bending during operation , to be welded straight and
flat. So , I think if you set up a mock blade setup at your weld jig , you
might be able to weld the blade in position more characteristic to it’s actual
intended position , as I am sure manufacturers do.

What I mean is , you need to stretch the blade completely out and have the
blade resting in it’s natural operating position , before you weld the joint.
That way , there is no force pulling on the weld from any angle. Thus , it
has no choice but to just follow repeatedly. How did I figure this , you ask.

Well , we know most blades are bimetalic , springy like. But the problem is
we are trying to weld that very position , which you can’t achieve unless you
put the blade into it’s natural position before you join the metal at that point.
At what point , is the answer to the problem. We are welding at the wrong
point throughout the metal’s structure , and we all know that if you bend a
piece of metal back and forth , what happens ? It breaks.

I hope you can understand what I mean. Placing the blade in a setup that
mocks the operation position , putting tension on the blade itself , then being
able to weld it , right there , makes the blade follow properly , structurally.
Thus , it just goes , round and round , without any stress on the weld or the
blade itself.

In other words , an adjustable , mock , jig is necessary. Where there is no
change in the position of the welded area during operation. Just hanging the
remainder of the blade , doesn’t position the blade properly for welding or
joining. I guess you could say , welding the blade right on the machine
could be an idea , as I have seen this done once when there were no new
blades available in a shop I worked at , after the supervisor got tired of
trying to keep the blade on the machine , he welded several other used ones
only to go directly to the machine because the blades kept breaking.

Sure , he clamped a prepared blade at the joint , while it was on the machine
under tension even. It worked , if I remember correctly , but he was mad
by that time , so I stayed away from him , especially while he was holding
a hot torch , I’m not dumb you know , (lol).

There is also much to be said about the actual molecular structure of the
steel , it requires consideration , as metal sheeting will break if bend over
repeatedly.

Hope this helps

Brian

OK I’ll give a description of what I do to braze a blade together here. Make the loop you need, overlap the blade so you can cut the blade across at a 30 degree angle. Cut the overlapped part of the loop you have wrapped with shears. Now with a grinder chamfer the facing angled cuts. Then I have a clamp jig that holds the blades together. Here is a picture of my clamp jig:

http://home.comcast.net/~pcf1/BladeClamp.png

You can buy these too, but I made mine out of a piece of 3 inch channel. Now just lay in a braze bead with your torch. Grind the joint smooth to width, and you’re ready to run. The braze I use has a tensile strength of 70,000 PSI, which is typical for the material. In use it is more than strong enough for my needs.

When I first did this I didn’t have a whole lot of faith in the method, but having done it I don’t even think about my braze failing anymore. They don’t, I’ve snapped blades again in other places. It took me longer to type this up I think than it does to actually do. And, although I’ve never done it, my method would work on enclosed hole cutting too. Cut the blade, pass it through a hole, then braze it back together.

Everyone that has a bandsaw should be able to put blades together. It isn’t that hard, and it works better than I ever expected it to.