cutting sheet aluminum on 12 inch wood bandsaw

As a electronic guy I often need to cut 1/16-3/16" & sometimes 1/2 small pieces of Aluminum, I have a Craftsman cast iorn 12" bandsaw. They sell metal cutting
blades for these all the time however I know I will have to drop the rpm. One blade has 9 tpi the other 14 tpi but neither say what rpm to run. The stock saw has 1725rpm motor 2/1 pully for 862 rpm of the 12" wheel. If i figure it right thats around 2700 fpm, again this is for wood cutting. What would be a good fpm to go for when cutting aluminum. Another thing is both say for non ferrous metals but will also cut thin ferrous metals, one 9tpi and ones 14tpi both fit the same model saw, I guessing the 9tpi could run a faster fpm?
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N4aeq wrote:

If you have the space, you'd be better off just to get one of these when they are on sale...
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber762
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14TPI is good, and AFAIK wood speeds are OK for aluminum although I like slower settings, only because then I can risk cutting closer to the line and have less cleanup.
If you cut steel (ferrous) the speed needs to be way down around 100 - 200 FPM even for thin sheet. Otherwise the tips of the teeth will overheat and soften almost instantly.
Break's over, back to cutting & bending aluminum. Jim Wilkins
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In general, I've considered that alumimum should be sawed at about 1000 surface feet per minute, about 1/3 the speed of wood band sawing. And steel at about 1/10th the speed of aluminum, or somewhere between 80 and 150 SFM. Another general rule is to have at least 2 teeth in the work at any given time. At 14 tpi, you'd not quite have 2 teeth in 1/16" thick stock. a 9tpi blade would be even worse, at about .110 between teeth. I wouldn't run it any faster just because it has less teeth. To me that would just mean that the teeth hit the work harder. I use either 14 tpi blades in my band saws or the 10-14 tooth type. When I do occasionally cut 14 or 16 ga steel stock, I just take it easy on the blade. With high quality blades, I have only ever lost one or two teeth in a blade, over 25 or 30 years.
One neat way to slow down a machine like yours is to go get a used gearmotor, one that goes a lot slower than your current motor. Install that motor below or farther away from the saw pulley than the current motor. Get the proper belt. Then just change belt and engergize the appropriate motor for the speed you need to run.
Pete Stanaitis ------------------------------------
N4aeq wrote:

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wrote:

Take a look here for an idea on using a speed reduction unit to slow down your bandsaw.
http://neme-s.org/Oshkosh_2007/Carlstedt/DSC02356.JPG
Errol Groff
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500 fpm on HSS bands is more like it if my various charts are right, so you are going too fast. Got a table saw? Carbide tipped blades work well on aluminum. I cut 2" dia aluminum rounds on my chopsaw often.
Wes
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N4aeq wrote:

I'm an electronic guy also but I have been volunteering at a local high school metal shop for 6 or 7 years. We have two vertical band saws, 20 in.or more, one set up for steel and the other for Aluminium. The Aluminium one is running in 2000+ fpm with a 4 tpi blade and I've cut everything from 1" down to 1/16" with it. When cutting thin stuff just feed slowly and keep it down solid against the table. Sure it would be some better to have a higher tooth count for the thinner material but changing blades is a PAIN. :-) The only problem we have is when students try to cut off the risers on the castings and let it cock over and either break or badly bend the blade. ...lew...
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wrote:

Oh, about 2700fpm would be good.<g> The chart on my DoAll says 1500fpm, but only because that's the saw's highest speed. Machinery's Handboook says 1000 to 3000fpm. I used to cut aluminum at around 5500fpm on a 36" saw I owned, but softer alloys are more prone to gumming the blade at that speed. A bar of stick wax, made for metal cutting, will help prevent that.
A 6 TPI hook tooth, same as for wood, is a good all-around blade for aluminum, a somewhat finer blade might be better at the low end of your thickness range. The usual 3 teeth in the work rule for cutting metals at low speed does not apply to soft materials at high speed; you'd have to be feeding your material at 16 inches per second to take a .003 chip per tooth with the above setup. If you don't already have something close, most small cities will have a saw shop that will make up any blade you want.
--
Ned Simmons

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wrote:
Make that,

--
Ned Simmons

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Ned Simmons wrote:

Another way to cut the thin stuff is to sandwich it btween a couple of pieces of scrap laywood. This gives it support and holds it in place.
Jim
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For me, the cheapest way and often the most accurate to cut all kinds metals is to use a variable speed fixed base jig saw, my preference is a Porter Cable. I was dubious at first. Not the best tool for squares and rounds(it will cut them though if pieces are properly held), but great for flats. I cut 1/4" steel with it no problem, use saw wax that is available at Home Depot and similar. Put cutting oil or wax along the line to be cut, it is pain to keep stopping to lube but a necessity. I can cut a notch in a piece of 1/8" angle iron within a 1/16", a real time saver. Also when cutting wear long sleeves, long pants and face shield- hot chips fly around. I clamp on a straight edge to make excellent cuts in 1/8" steel plate finish with a file and it looks factory made. I used to have a plasma cutter and preferred the jigsaw in many instances because of the precision. You will go through blades, maybe spend $2-3 dollars on a 24" cut in 1/8" ferrous, totally worth it for me. If want to get real fancy mount a coolant mister on the saw and be sure to use a GFI.
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You will have much better success to use wood blades and wood speeds with aluminum. Stick wax or appropriate coolant to prevent galling the blade. Wood working carbide table and chop saw are fast, sage, and efficient. Bandsaw and router for curves, etc.
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for what it's worth, I have a wood cutting bandsaw and when I need to cut aluminum I cut it just fine, same coarse blade, etc - just feed slowly so you don't damage the blade - I'm sure a metal cutting fine toothed blade would be better
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One problem is that the rubber tires pick up the aluminum swarf, particularly if you use cutting wax sticks.. When you switch back to wood, this will come loose and embed itself in your project just at the worst possible spot to remove it before finishing. DAMHIK. In my shop, thin aluminum sheet gets either sheared or whacked out with a saber saw and a fine blade. Sandwiching it with scrap door skins makes it a lot easier to cut, I used to get mine from a lumber yard that usually had a few than the pallet bands messed up and could be had cheap.
Stan
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I cut aluminum of any thickness with a 14TPI, 1/4" blade on my 14" Delta wood/metal band saw at full speed, 3000FPM. This is the recommended speed in the manual and I have never had a problem with short blade life, gumming, etc. You have to slow down the feed rate as the thickness increases. 1/16" thickness cuts as fast as I can feed it and follow a line. My saw has polyurethane tires and I get a little embedment of metal chips, but they remove easily with a stiff brush. In fact, I never bother unless I am changing blades which very rarely happens. I find that a 14 TPI, 1/4" blade makes a very good general purpose(mostly metal) blade. I cut ferrous metals at 110FPM with the same blade.
Randal
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N4aeq wrote:

Run the wood blade, at wood speeds. If the aluminum is really thin, put a backer under the sheet (some scrap ply or mdf)
It works fine, and wont hurt anything. Just dont ram the material into the blade (good advice, no matter what you are cutting!)
Cheers Trev
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