Using a wood saw to cut metal

Too often, a homeowner or hobbiest tries to cut metal with the wood cutting bandsaw they have. Woodworking saws typically run much faster than metalworking saws, and bimetal blades have issues when they are run too fast. Here is a perfect example of a recent situation from a future customer named Dennis:

Joe,
My saw is a Craftsman 12” band saw. It has a 1725 rpm motor. The motor pulley is a 2-1/2” dia. and the machines pulley is a 5” dia. The saw blade mounts on two 12-1/2” wheels.
The saw is mainly used for wood but on occasion I cut metal. The heaviest I’ve cut is ½” thick stainless, but that’s very rare. Usually it’s just like 1/8” steel and nickel plated steel.
When I cut the stainless, I don’t force it, I take my time.
Of course my son has used it too, so you know how that goes.
So, was the blade I was using from McMaster Carr the right one? Bimetal 6’8”L., ½” wide, .025” thk., 10-14 Tpi.
Thanks for your help,
Dennis

Yes and no. I would recommend our M42 dieband blade over the blade McMaster Carr has sold you, but yes you were using a bimetal blade and that would be the right blade. However, I think your saw is running too fast for cutting stainless and that is part of the problem you are having. I do not know for sure the speed in feet per minute based on your response, but stainless should be cut at around 100 surface feet per minute. My guess is you are cutting at a wood cutting speed, and burning up the blades prematurely.



You are probably right about the wood cutting speed. Is your M42 a better blade then the bimetal I was using? If worst comes to worst, I can change drive pulleys to metal cutting speeds and that shouldn’t really bother the wood cutting.
What do you think?
Dennis

Yes, it has a harder tooth. About 69 rockwell. If you can slow it down, it will last longer Dennis. Make a mark on the blade and count how many times it goes around in one minute. Multiply that by the length and that will give you a ballpark of how fast you are going – feet per minute. Shoot for 100 f.p.m. for stainless, 250-300 for mild steel. The harder it is, the slower you need to go. Also the cut ease lubrication stick would help as well.

Let me know if we can help you.

According to the site I sent you for calculating SFPM, my saw runs at 2,821. A little fast to say the least.

As you can see above, the reason for his inablility to cut stainless had nothing to do with the blade, but everything to do with the saw. For a complete line of metal and wood cutting bandsaws, visit www.detroitbandsaw.com
We are here to help, thank you for looking!
Joe Bandsaw