Bandsaw Vertical Drift! Help!!!

[Todd]

Hi,

So I bought some 8/4 soft maple, with the thought that I could resaw it into 5/8" boards. I've got a 3 TPI 3/4" blade on my 14" Grizzy G0555. I went to resaw, and I found that the blade was cutting further to the left on the bottom of the workpiece (where the blade was exiting) than where it was on top. So I've managed to resaw several tapered pieces.

How do I avoid this? I've never really resawn successfully, or with any intention of getting it perfect. I know that it can be done with this saw, and even cheaper 14inch versions.

Any hints as to what I can check out? Again - I'm following my resaw line up top, perfectly (I've got a single point rip fence that I built for being able to turn the pieces, if needed.) But the bottom of the cut is not at all in line with the top of the cut.

- Thanks in advance,

Todd

[Toller]

If you do a google search you will find more on drift than you could read in a lifetime.

I think it is caused by improper tension. Play around with your tension and see if you can make it go away that way.

I resawed a piece of walnut yesterday. I came in a third of the way on top and bottom on my TS and finished on the BS. It wastes a little wood, requires more planing and makes more dust, but I find it easier than doing it all on the BS.

[Todd]

I think you have a good idea there. I noticed that my spring was fully compressed, and i'm still not tensioned up enough...I realized that I have a stop collar on my tensioning knob. Right now, it sits on TOP of the carriage that contains the spring. I could put it on the tensioning knob BELOW the carriage that contains the spring, and then tension. I think that this will be my next effort. We'll see.

- Thanks for your help.

Todd

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you will find more on drift than you could read in

[Chris Friesen]

Sounds like your table is not perpendicular to the blade.

Chris

[George]

Yep, I think that has possibilities, but if the fence is parallel to the blade, and I assume that's true, won't make a difference, as long as the piece guides on the fence.

I hedge my bets when resawing by getting a flat face and a square edge to reference. Between the two of them, even I can get decent resaws.

Low tension normally shows up as a belly in the board next to the fence. So does overfeeding.

Perhaps a featherboard to make _sure_ the bottom is snug against the bottom of the fence would help.

[damian penney]

I have the same saw/blade setup and can resaw wafer thin pieces so it can definitely be done. My process was to remove any drift by using the tracking knob and then I made sure that the table was exactly square with the blade, after that was dialed in I had no problems at all just using the regular fence to get some nicely resawed boards.

My bet is that you have a bit of a drift problem and that your single point isn't perfectly aligned with the front of the blade.

[damian penney]

Could be because you are using a single point what's happening is that when you are twisting to take drift into account it's pushing the blade away hence the taper (if the point isn't perfectly aligned with the teeth). I'd nix the point, track away any drift, square things up and use the stock fence.

[Andy]

That was my thought - check against a square, and also against a line drawn on the leading edge of your workpiece. If the cut is straight, but just at an angle, I'd play with the table before the tension. Good luck, Andy

[damian penney]

Tension problems usually result in a bowed cut or lots of little ridges. Easiest way to remove drift is to adjust the tracking of the blade so that it goes away.

[damian penney]

I read his post as saying that the issue is that at the beginning of the cut the blade is aligned up with his line (say at 1/8) but by the end of the cut the blade pops out at 1/4 inch?

[damian penney]

Upon re-reading the post Chris got it, the table isn't square to the blade.

[Andy]

Upon re-thinking the post, I think George got it - if the workpiece is guiding against the fence rather than the table, it sounds like the fence isn't parallel to the blade. Ideally, I'd try to make both the fence and the blade exactly perpendicular to the table. Andy

[damian penney]

My assumption was that the fence was square to the table but yup the fence isn't square to the blade.

[Pat Barber]

I would assume that you checked that the table is square to the blade ?

That the blade is tensioned correctly ?

That the material being resawn is flat and square ?

That the blade is up to the task ???

A 3/4" blade is a big blade on a 14" bandsaw and it is very unlikely that you can get it tensioned correctly for this operation.

Change it out for a 1/2" 3tpi and give that a shot.

Todd wrote:

So I've managed to resaw several tapered pieces.

[Peter Huebner]

My old bandsaw did that, never mind what I tried. My solution was after 20 years of frustration to shout myself a new saw :-) Now I can follow the line on top and don't even use a single point fence for ripping ... Bliss!

But anyway, here are some things you might want to check: back off the guides, make sure the blade is riding in the middle of the wheels, then bring the guides back to the blade. Make sure the guides are nice and square to the blade and not worn round or at an angle, and make sure they're set just back from the teeth . You could even try to rip a scrap without guides and see how that goes!

I probably don't need to mention making sure the timber has a solid surface that goes over the table (rather than splintery rough-sawn that can rock) but you may also want to look at the endgrain and see what the grain is doing w.r.t. the deviation you're seeing. It shouldn't throw the blade off everything else being set up right, but ...

h.t.h. -Peter

[Dave Jackson]

I built a taller fence that fits over the stock fence to gain some fence height. Provided the fence is perpendicular to the table and parallel with the blade, I can slice off some pretty thin pieces. Make sure you have a sharp blade, and tension it right. My saw has a indicator that shows where to crank the tension to according to blade size, but I usually run a scrap through to test things before resawing the good stuff. Also, I never did have any luck with the single point attachment that came with the aw. --dave

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[Todd]

Thanks for all of the suggestions.

I actually do believe this is a tension issue, at least partly, since my cuts are experiencing the standard 'bad resawing' traits.

I have a stop collar on the tension bolt, but its on the bolt ABOVE the carriage mechanism that rises and falls with the wheel, not below. As a result, the wheel is starting too low to fully tension it.

I'm going to move the stop collar below the carriage, and I should then be able to properly tension the blade.

I'll try it out and let you know...

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[Billy Smith]

I have found (the hard way) that there are so many variables that affect a band saw that I really had to get some book learning. There's a lot of information you have to know to adjust, use, and troubleshoot a band saw. If you don't know that info, you'll be shooting in the dark. Mark Duginske's book "Band Saw Handbook" is a good place to start and there are lots of good web sites if you go searching.

A band saw may be less dangerous to use than a table saw but it seems that getting it to work right is much more complicated. Resawing is very useful but is especially prone to problems.

[Todd]

Folks,

Thanks a bunch for your help. I'm very grateful for all of your input. However, I have found the solution to my problem.

The solution is buying a GOOD bandsaw blade. I went to my local Woodcraft and bought a Timberwolf blade. I had never used one before, but figured I'd give it a shot. It was pretty amazing. With something like 1/3 of the tension that I was giving the previous blade, I was able to resaw perfectly straight. I couldn't believe it. (ps...I don't work for woodcraft, or timberwolf, or a distributor of them...I'm just a REALLY big fan now.)

The woodcraft guy told me that the rule of thumb (which I had never heard) was buy a blade that is one size SMALLER than the maximum recommended size on your bandsaw. (So I bought a 1/2 inch 3 tpi instead of 3/4. )

So a few things I've learned:

a.) if it feels like you're tensioning a blade too much, you probably are. b.) use a timberwolf blade, which requires less tensioning c.) buy one size smaller than the maximum recommended size.

the saw cut like a champ. I still can't believe it, but I was able to go through 8/4 cherry and ash with dependable accuracy - and STRAIGHT.

I'm interested to know if anyone else has had a similar experience with their bandsaw/resawing efforts.

- Thanks,

Todd

Billy Smith wrote:

[Donna]