Bandsaw blade drift : how much is too much?

[radhak]

I've always cut freehand on the bandsaw so never noticed this, but today when I paid attention, I see that the blade drift on my bandsaw is almost 30° !

I am sure I could set my fence at that angle and cut, but doesn't that indicate something wrong with my bandsaw? What?

(And yes, if you think it also indicates something wrong about me because I never noticed this before, well, that's me : I'm pretty sharp about these things )

And while at that, what could I use to push the wood while resawing? Methinks my fingers might not be a good idea... I was thinking a block of wood with a small heel.

[Habe]

Try aligning the blade forward or back on the wheel. This will change the drift angle.

[mpc]

Drift is usually only a few degrees on a properly tuned/running saw. Most bandsaws (other than the very inexpensive ones) have adjustments on the fence to align the fence with whatever drift is present. If your bandsaw's drift is outside the adjustment range of the fence, it's likely abnormally large.

Drift sources:
* blade not centered on the crown of the tires - or the crown itself is mis-shapen and isn't a smooth curve.

* blade teeth set damaged - if one side has more set than the other, the blade will drift a lot.

* Blade tires not vertically aligned ("co-planar" in the bandsaw books). When this is the case, the blade doesn't ride the crown properly after you adjust the blade tracking control to keep the blade on the wheels. If you could hold a straightedge to the top and bottom lip of the lower wheel (6 and 12 o'clock) that straightedge should just touch the top and bottom lip of the upper wheel too. A straight board with a 4 dowels or screws is a quick alignment tool: uses screws/dowels long enough to "reach" around the wheel houses and other obstructions. Make sure the 4 protruding dowel/screw lengths are identical so their tips are a good reference edge. Removing the bandsaw table is usually necessary for this check.

* wheel axles not straight - if they're aimed left/right (i.e. not parallel to the fence) then the wheels and tire crowns will also be non-parallel to the fence's neutral adjustment. Easy to check/test: with the blade installed, tensioned normally, and tracking adjusted to keep the blade on the wheels bring the fence next to the blade (saw OFF!) and see if the face of the fence is parallel to the blade body. You can't quite touch the fence to the blade due to the tooth set... but get really close so you can eyeball.

* table that's not installed properly causing the fence mounting rail to not be straight relative to the blade & saw wheels.

* blade not tensioned enough, letting it wander too much.

* blade over-tensioned (or just too big for the saw) leading to the saw body deforming a bit.

My little Craftsman 10" bandsaw has virtually no drift at all - I can use the fence at its centered adjustment and get a consistent thickness resaw. My Rikon 14" is similar.

mpc

[warrenp]

When I purchased my Ridgid 14", it has close to a 30 deg drift. It was almost impossible to cut a straight line.

After a month or so, I replaced it with a Timber Wolf blade and it tracks almost perfectly straight. Same width, only slight adjustments.

Just my experience.

Warren

[cwsmith]

I think "MPC" posted some excellent points for you to consider. These are the things that I watch out for with my little Ryobi BS902, and about the only time I experience erractic drift, is when I've seriously dulled my blade.

I also make it a habit of adjusting the upper guide down for minimum clearance above the piece that I'm cutting. The closer you can keep the upper and lower guides to each other, the better will be the support to the blade area that is cutting.

Also, you should not that many of the less expensive blades are not finished well during manufacturing and thus may have a burred "back-edge". When installing a new blade, I always run an emory board or small sharpening stone against both side of the back edge, in an effort to remove any possible burr or ragged edge.

As far as using some kind of "push block" when working with the band saw, ABSOLUTELY! While my personal opinion is that there's hardly a safer power cutting tool, you still risk a serious injury, should you slip or something. I especially use a piece of scrap when cutting small stuff or when having to "push" at a position when my fingers may be directly in line with the blade.

I hope this helps,

CWS

[radhak]

Wow, lotsa good info there! Thanks, gentlemen! I now need to examine my bandsaw closely to fix this. Mpc, your steps are detailed enough that I won't have to look elsewhere for the how-to; thanks!

This is the bandsaw I mentioned here, and I would not be surprised if the table is not well seated - I did it myself .

I did find awhile back that the blade was making a whole lot of noise when passing thru the yellow blade guard, so I removed it. I am pretty sure that was also caused by whatever is the reason for the drift.

I should change blades - haven't yet, at all. In my attempt to be frugal, did not order another 1/2" blade from Grizzly, just a 1/4" one; silly mistake - now I'll have to pay shipping again. At 103", I can't buy it local.

[Cochese]

I haven't even checked mine. Ignorance is not having a fence.

[LCHIEN]

i think those are all factors. BUt probably one of the best things is a super quality blade.
Don't order the Grizzly blade, get a Woodslicer blade from Highland or a Timberwolf blade from Suffolk Machinery, as a starting point.

[radhak]

Ok - I checked, and the prices for those blades are not too much higher, so I might as well try them; but that Timberwolf page boggles my mind - too many parameters to worry about. That woodslicer seems simple - just select the blade width, length, and order!

Any preferences between them?

(Now that I'm buying, I might as well go for the cat's whiskers, right?)

[LCHIEN]

Ok - I checked, and the prices for those blades are not too much higher, so I might as well try them; but that Timberwolf page boggles my mind - too many parameters to worry about. That woodslicer seems simple - just select the blade width, length, and order!

Any preferences between them?

(Now that I'm buying, I might as well go for the cat's whiskers, right?)

woodslicer

[wardprobst]

I highly recommend Iturra Design, his catalog is one of the best books on the band saw, IMO. He doesn't have a website but here is the contact info I have:
Iturra Design
4636 Fulton Road
Jacksonville, FL 32225-1332
Phone: (904) 642-2802
He's a great guy to talk to so the phone call is worth the dime.
DP

[radhak]

Thanks DP, that was helpful.

Before I called, I googled. And Louis Iturra seems to have a great reputation around. Looks like he has not gotten around to making a website for himself, but still attracts a loyal clientele.

So I called, and had a very nice chat with Louis. He sells regular Lennox and Woodslicer blades, and also Bimetal and Carbide tipped blades.

The 1/2" woodslicer would cost me about $20, which is much less than what I saw at Highland! He also told me that the BiMetal blades last 10 times longer, and cost around $37, while the Carbide tipped blades last 40 times longer but cost around $128. For my needs, I went with woodslicer, particularly because he mentioned that FWW had tested, and found Woodslicer cut cleaner than any other blade. Cheap enough for me to try it out!

He told me ceramic blocks for the bandsaw come only in square shape; since I need round, he suggested cool-blocks at $14 for a set of 4. Order is in, expected delivery within a couple of days. Neat, I say!

I did ask him to send me his catalog; he says the web-site is coming soon; but I hear that's what he's been saying for years now ! Maybe I'll scan his catalog and put it up for others to look up; might even help him get some business.

Now to tune up my band-saw this weekend!