Metal cutting blade on wood band saw?

Railrider1920 · Jan 1, 2011

Hey Folks,
I have a working 12 inch craftsman band saw and a 14 inch harbor freight band saw that is not in working order right now. All I would have to do is mount it to a stand and put a motor on it. The 12" takes an 80"(I think) blade and the 14" takes a 93 1/4" blade.

I am thinking about using the HF 14" for metal so I will also have the 12" ready for wood, if it will work.

While in one of the big box stores today, I saw that they have metal cutting blades for band saws. The sign there recommends a 3/8" wide 18 TPI blade for metal. Would one of these types of blades work for cutting the metal used for blades?

I don't have any blade metal yet, but I'm thinking about trying some 1080 up to 1095 tool steel and some of the easier to cut / work stainless.

Thanks for your opinions,
Rob

Salem Straub · Jan 2, 2011

Typically if you run a metal blade on a wood bandsaw the excessive speed (2000 sfpm+) of the wood saw will knock the teeth off of your metal cutting blade in a hurry. You could make it work, but you would have to slow the blade drive wheel way down. Think 250 sfpm to 80 sfpm. There are saws on the market with variable speed that use higher ranges to cut wood, lower ranges to cut metal. See if you can use pulleys, David Boye talks about this in "How to Make Knives." You might retrofit a 3 phase motor and VFD onto the saw if it's worth it to you, this is the technology used now by the variable wood/metal saws.

The exception: a technique called "friction cutting" in which a metal cutting blade is subjected to high speeds, I think higher than 3000 sfpm, and the work (carbon steel, titanium, stainless) is forced into the blade. The heat generated by the friction creates an orange-hot spot right in front of the cutting action, and the hot metal is then carried out of the kerf by the by-now-blunted teeth. I've done this at other shops, it works pretty well but is kind of low finesse in my experience. You get a lot of life out of a blade.

Miles Undercut · Jan 2, 2011

I have an ancient (c. 1930) Delta 12-inch bandsaw that I built a step-down pulley arrangement for in order to slow the blade speed down, works great with metal-cutting blades for cutting brass up to 1/8-inch. Dunno yet how it will behave with my new bi-metal blades on steel knife blade stock.

Patrickknives · Jan 2, 2011

Waste of time and money, wood saws run much too fast for metal you will just burn up your blade.

Miles Undercut · Jan 2, 2011

Hence the step-down pulley.

Patrickknives · Jan 2, 2011

The step down will work if you can get the right pulley set up, a band saw working at 2000 fpm needs to be slowed to 200 so a pulley 10x less in diameter will be needed if only the driven pulley is changed, typically you will need to fit a small drive pulley (one on the motor) to a larger driven pulley. I just saw the HF metal cutting bandsaw that many makers use us on sale.

Good luck

Railrider1920 · Jan 2, 2011

Thank you guys for your replies. I do have a couple of motors around and some pulleys of different sizes, I think one or two are step down. I think one of the motors is actually variable speed. I hope so. I may pull everything out and see what I can come up with. It would be kind of fun trying it anyway.

Thanks for the reminder about the metal cutting saw at HF. I'll stop by and check it out.

Wandering Thinker · Jan 2, 2011

I use something like what has been suggested here. We have a wood band saw that my dad turned the motor around on years ago and added one medium size pulley connected to the small motor one, a drive shaft, and a small pulley on the other end connected to the large main pulley. It works well for us, if we could only afford some decent saw blades that didn't dull up after two D2 knives.

If you want some pics of it to help give you an idea, let me know.

Just my 2 cents; DON'T buy the cheap blades (ours were $20 from Grainger, waste of money), get the absolute best you possible can or you'll be standing there all night cutting out a blank.

As long as its 16 tpi or higher they will be fine, I've even gotten away with 14 tpi but it's recommended that you have at least two teeth in the metal at all times, so it really depends on how thick it is. I've only used 1/4 in blades but I put a 1/2 in on last night, the 1/2 cuts well so far but I would recommend something smaller. The shorter/narrower your blade is the sharper the turns you can make. 1/4 in. can give some pretty sharp turns if you take is slow and don't twist up the blade.

Good Luck!

GrizzlyBear · Jan 3, 2011

I received a variable speed Skil 10" bandsaw for Christmas. Wonder if the lower speeds would be slow enough to cut metal (and then would it have enough 'oomph' to do so)

Patrickknives · Jan 3, 2011

Thinker, you may want to revisit you speed, I have used the $20 from grainger as well and they cut alot, I easily get 10 blades, nothing really big but alot of cutting for $20, I can pick them up when I forget to order good blades. If your saw is running too fast you are probably just burning them up, you could be cutting thicker steel than me as well. My bandsaw has 3 speeds 80, 120 and 200 fpm, I use the 120 since I thought the 200 was wearing our my blades to quickly, I am typically cutting 1/8 and 3/16 1084, CPM 154, a2 and ATS 34.

Most of the variable wood bandsaws go down to about 600 fpm, still pretty fast for metal cutting. I looked up the skil and it looks to be a direct drive, if its a pulley drive you may be able to get a new pulley set to slow it down a bit.

GrizzlyBear · Jan 3, 2011

it's a switched variable speed direct drive

Wandering Thinker · Jan 5, 2011

Patrickknives, Your right. I checked out mine today and its running around 200; I had no idea it was that fast, so I guess that's whats going on here. I have a pulley system to slow mine down, so I'll have to try to find one that will fit sometime. I'm really glad you said something! Thanks!