I recently acquired a bandsaw that will cut wood or metal (aluminium at 3000 fpm and steel at ~100 fpm). It always cut at an angle with the original cheapo blade. Tightened and adjusted. No dice. Gave it a 5/8 inch wide 10-12 tpi bimetal blade. Much better, but still crooked. The bandsaw books in effect say that this is to be expected, and describe various ways to cope with the tendency, but I could not see why.The mitre guage that came with the saw is pretty flimsy, but even that didn't seem to explain the degree of crookedness. Now, on table saws, the greatest accuracy is obtained by use of a sled that carries the stock past the blade.So, I made a sled out of a 3/8 by 3/4 by 12 inch cold rolled mild steel bar (that slides in the mitre slot in the table), a piece of 1/4 inch 6061 T6 aluminium plate about 6x8 inches that I had laying around, and a piece of 3/8 by 3/4 inch aluminium bar (set vertical and accurately perpendicular to the steel bar and thus mitre slot). The pieces are held together with some large flat head socket cap screws. The sled reaches to within 1/16th inch of the blade, so the stock is well supported.In use, the stock is held in the sled against the aluminium bar, and the sled is pushed past the blade. On wood, this works quite well, but on metal it still drifts a bit, the stock being held in the sled by hand. So I drilled another hole in the sled to accept a 1/4-20 flathead socket cap screw, and attached a small strap clamp. This allows the metal to be clamped firmly to the sled. This works: the cuts are now perpendicular.So, the lesson seems to be that a significant cause of crooked cuts is the stock drifting sideways while being cut. I don't know the source of the sideways force, but it cannot be that large. It may be nothing more than the vibration of the saw causing imperceptible walking.Joe Gwinn

Apparantly it is not 'el-cheapo blades or a cheap saw that generates off-angle cuts.(or at least I assume that *this* outfit uses quality equipment)I recently got some half inch thick 6061-T6 al. plate from Online Metals.One side of a six inch square of this material has a milled and square surface. The other three sides were off by as much as 1/32" over the HALF INCH!Moral?If you really need a six inch square +?/-0 order at least 6 1/4.Also - don't assume any band saw cuts straight.Ken.

How to make a bandsaw cut straight

May 31, 2005 21 Replies

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Brian Lawson 21 years ago

Hey Gunner,

I've sent you a couple of cute cat pictures lately, but I get a "bounce" on the e-mail address I have. If you care to, send along a current useable to:

Lawson at ciaccess.com

ALL CAPS, no caps, miXed uPPer and LoWeR....no matter.

Take care.

Brian Lawson, Bothwell, Ontario.

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Gunner 21 years ago

try gunnerasch At gmail.com or gunner at lightspeed. dot net. I may have set up the spam blockers too stiff.

Gunner

"Considering the events of recent years, the world has a long way to go to regain its credibility and reputation with the US." unknown

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