convert wood band saw to metal saw
So, I picked up a Craftsman 12" bandsaw for a few bucks at a garage sale. I gave it a little TLC and it is running great. But, it's a wood bandsaw and I really want it for cutting metal. Right now it runs the blade about 2280 fpm with a 1752 rpm, 1/3 horse motor. I need to get the blade speed down to about, what, 250 fpm to use it for cutting metal?
I've done some figuring with the gear ratio and figure I need to get it down to a 1:23 ratio to get the blade fpm down into metal cutting speed. I just can't figure out how to get it running that slow without at least two intermediate pulleys between the drive and final driven pulley. (The motor is mounted outboard of the saw itself and transfers power via V-belt.) Right now the belt runs on a 2.5" drive pulley and a 5" driven pulley. There's not enough room to mount a much bigger driven pulley.
Any ideas on how to get the bandsaw RPM down to 77rpm? Can you get electric motors that turn fewer rpm? Is the whole idea a waste of time?
I'm in the process as well (see my post about capacitors). You will need a gear reduction motor, or a bunch of pulleys. I got a 20:1 85rpm 1/3 hp motor for $80 bucks off ebay. You'll want roughly 100 fpm for steel, and around 300 for Al. I'm trying to keep my original sheet metal belt guard, so worked backwards from what diameter pulleys would fit inside of that to get an rpm.
A surplus C-mount motor with a gear reduction could get you close. Years ago I had such a motor hooked up to a 14" Delta bandsaw that way and it worked well enough.
That said, the 12" Craftsman bandsaw isn't all that rigid to begin with -- you'd be better off in my opinion finding a cheap old import horizontal bandsaw and tinkering to get it to cut straight.
I know (knew) a guy that wanted his saw for wood and metal. What He did was to keep the original belt/motor setup and added a gear head motor with a two step pully on it . One for steel and one for aluminum. He would take off the belt from the motor He was not using and put it on the other motor. He had it layed out so one belt would work with either motor. Each motor was on it's own gravity motor plate for belt tension.
No I don't have pics but wish I did it was a real slick set up.
I have an old and very solid Walker-Turner vertical woodcutting bandsaw that a previous owner converted to metalcutting using a large sheave. It works really well and is one of the most useful tools I have. The guy also installed a large (about 4 feet square or so) steel plate table that is very useful. However, I'm kind of in agreement with PeteM that you'd be better off waiting and finding a more rigid saw before investing much effort and money in the Craftsman machine.
Craftsman made two-speed bandsaws, with an separate speed reducer module. Of course, chances of finding one, or just the reducer, are pretty slim, but you could hit some surplus places for gear reduction units, and integrate what you find with some pulleys that fit, and at least get close.
I've often thought of doing the two-motor thing for the occasional slow speed use, but using a large variable speed drill, in a cradle, with a pulley on a mandrel in the chuck. Of course, it's not a long-term solution, because the side loads imposed would eat a modern drill's bearings, but it could get you through the occasional evening's cutting ok. If you find a old ball-bearing drill, it would last longer. Single speed may even work, because some of the bigger ones are 600 or 800 RPM, wide open throttle.
Using a drill would defeat my favorite aspect of using a bandsaw, though... it's gotta be the quietest machine in the shop.
Check out TSC or HVAC places for big pulleys.
Have you seen the horizontal band saws that have an attachable table to use them as a vertical? I saw one, I think it may have been a Rigid, that was real nice.
Joe at Plaza has all kinds of bsaw goodies... gear boxes, motors, etc.
my wood band saw came already metal ready its a delta 15 inch i think it is any how it came with a balde for wood and aluim and i can get blades for doing SS and other metals as well,, guess my dad bought right when he picked this one up at home hardware,
takinga straight wood saw and going metal your going to have to slow it down a bit speed wise other htne that get some metal cutting blades and you shouldbe set to go and slice and dice metal..
I have the same "problem" - a Jet 14 inch bandsaw I want to use for metal. It seems to me that the 3 pulley arrangment used on the head of many drill presses would work fine. That way you can easily change from wood to metal and back.