i feel pretty dumb (bandsaw box question)

[betacrash]

I am feeling pretty dumb because I am have issues cutting thick stock with my bandsaw.

I have had not trouble resawing though. My issue is with cutting with a .25" timberwolf blade through some 6" cedar. The cut is way uneven. It is right on the line at the top and it slants out about .25" at the bottom. I have cool blocks and I also have the harbor freight bearings. I was using the cool blocks. Do I need to put the blade at the heart of the cool blocks? The way I have it now is that just the flat part of the blade (not the teeth) are between the blocks. Is that right. My table is totally level and sqauare. Any comments/suggestions are welcome. Thanks.

[Russianwolf]

is it a relatively straight line, but going in the wrong direction or a wavey line?

If it's straight but not in the right direction, it's probably blade drift. Each blade will drift differently so there is no one setting fix for the saw. It will have to be adjusted for each blade every time you change.

If it's a wavey line, then it could be the blade tension being too loose. letting the blade flex from side to side as it cuts.

Since Cedar is a pretty soft wood, it won't take much for the blade to go where it pleases. But I think your guides are set correctly as far as staying off the teeth.

A picture of the setup and bad cut might help diagnos the problem better.

[Ken Weaver]

I'm no expert but is it common to use a 1/4" blade through 6" material? Wouldn't that make drift more likely? Wouldn't a 1/2" or 5/8" blade work better and still get the curves you need?

[LCHIEN]

if I understand correctly, the problem is that the blade is not staying vertical through the block of wood. As much as .25" off vertical from top to bottom.

OK, I've not yet attempted band saw boxes or thin blade cuts through thick pieces but I'll take a few shots based upon theoretical knowledge:

1. I assume .25" is the correct blade width based upon the curves you want to cut; for 6" think you need to be using fewer teeth per inch, like a 4 tpi skip tooth configuration so that the gullets have enough space to carry away the cuttings. Most .25" blades have like 10-12 tpi and are designed for curves but in thinner pieces of wood (like 3/4 or 1/2" thick wood, not 6").

2. Placing the teeth just forward of the cool block is correct.

3. I assume you have correctly set the top guide as close to the workpiece as possible (and not have it at 12" because you have a riser-
That would be a serious contributor to your problem).

4. You have the cool blocks set with .003" clearance to the blade (about a dollar bill thickness) both top and bottom guides.

5. Proper tension - if the tension is too loose then the blade can wander right and left.

6. Feed slowly - this is a thick piece and you have to allow for cutting removal. pushing too hard will cause the blade to deflect to the right or left giving your problem, esp. if you have too many teeth. Allow the blade tension to do the cutting; you'll have to take your time.

7. Lower blade guides are farther away from the workpiece than the properly set upper guide, due to the table and other hardware. Make sure that the thrust bearings turn and cool blocks are set right as the uppers. Clean the dust off.

8. Don't assume the lower is off and the upper is right because you observed the top is right on the cut line. Its right on the cut line because you steered it that way and the top cut line was all you could see. the errors are cumulative.

HTH
Good luck!

[Ken Massingale]

If your upper guides are set just above the piece, cool blocks as Loring stated, I suspect the tension.
I normally use 3/16 10 TPI blades as Lois Ventura suggest. If I can't find the 10 TPI locally I use 6 TPI, no less. Any wider than 3/16 will have issues with tight curves. The 10 TPI needs to be fed slower but will save a lot of sanding time due to a smoother cut.
HTH
k

[betacrash]

Im starting to think that the blade tension is the culprit. Its the one thing that I just kinda guessed and didnt have a way of actually measuring. The only instructions that I ever see say to "tighten the blade until it makes a musical note". I kinda feel like that is bunk since it always rattles and sounds like crap. Another reason that I think I didnt give it enough tension is due to being afraid of the blade being thin and possibly breaking. Thanks for all of the advice and suggestions thus far.

[drumpriest]

Timberwolf are low tension, as are some Olsen pro blades. I play with the deflection of my blade to see if I feel that it's tight enough for the cut I am making. I just finshed my first bandsaw box not long ago, and I made good cuts with a 3/16" blade. So it can be done with proper guide setup.

http://www.bt3central.com/showthread.php?t=19773

[gerti]

Timberwolf are low tension, as are some Olsen pro blades. I play with the deflection of my blade to see if I feel that it's tight enough for the cut I am making.

I am having a hard time with blade tensioning myself too. Could you give me a rough ballpark on what kind of deflection to expect with Timberwolf blades? Something along the line of 'Medium hard push with 1 finger deflects the blade x/y inches?'

The tensioning method coming with the Timberwolf doesn't really seem to work on my G0555...

Thanks

Gerd

[Wood_workur]

Im starting to think that the blade tension is the culprit. Its the one thing that I just kinda guessed and didnt have a way of actually measuring. The only instructions that I ever see say to "tighten the blade until it makes a musical note". I kinda feel like that is bunk since it always rattles and sounds like crap. Another reason that I think I didnt give it enough tension is due to being afraid of the blade being thin and possibly breaking. Thanks for all of the advice and suggestions thus far.

there are how many musical notes? Oh yeah, infinite!!! That method is a bunch of bs . Here is the correct method:

1. Remove guides--you CANNOT run this test if the band saw blade is restricted in any lateral movement.
2. Make sure tire surfaces are in good condition--they cannot be hard, flattened out, cracked or brittle. On mills with loose fitting V-belts, replace them with the next size down so they are tight fitting. This will eliminate over 80% of the vibration in your mill and the blade.
3. Mount the blade on the machine and apply the tension to the band that the manufacturer recommends for other steels.
4. Close all covers for safety purposes.
5. Start the machine, engage the clutch into the high speed cutting mode. NOTE: You will not be cutting any wood.
6. Stand at the head of the machine, with your hand on the turn screw tensioner and your eyes on the band saw blade. Very slowly start detensioning by half turns at a time, keeping your eyes on the band saw blade. The object is to bring the tension of the blade down to a point that the blade starts to flutter. TAKE YOUR TIME.
7. When you see the band start to flutter, you have hit ground "ZERO". Now start ADDING quarter turns of tension, SLOWLY, until the band stops fluttering and is running stable again. At this point ADD one-eight to one-quarter turn of tension.
8. You have now tensioned our blade correctly. Shut off the machine and put your guides back in place. You are now ready to start sawing.
9. ALWAYS DETENSION YOUR BAND SAW BLADES. Since you do not know exactly where the proper tension is, it will be easier to remember if you take off 8, 9, or 10 full turns of tension until the band is completely relaxed. The next time you use our bands, add the same amount of turns of tension that were taken off. At this point, you will only have to run the flutter test one time.

(Thanks Timberwolf for posting this method on their website (http://www.timberwolfblades.com/six_rules.asp))

[drumpriest]

I agree with Gerti. For completeness it is good that this information has been included in this discussion, however as Gerti referenced the flutter test, I would assume that he knew of it.

" The tensioning method coming with the Timberwolf doesn't really seem to work on my G0555..."

The truth is that the flutter method isn't very effective on my saw either. As following it results in a tension that is still far too loose. I'm talking about loose when compared to the gauge, as I understand that Timberwolf blades are low tension.

Gerti, I basically tension it so that I can deflect it about 1/8" with ease with my finger. I know that is still subjective, but that's what I do. If you over tension a timberwolf, you run the risk of breaking it at the weld.

[gerti]

The truth is that the flutter method isn't very effective on my saw either. As following it results in a tension that is still far too loose. I'm talking about loose when compared to the gauge, as I understand that Timberwolf blades are low tension.

Gerti, I basically tension it so that I can deflect it about 1/8" with ease with my finger. I know that is still subjective, but that's what I do. If you over tension a timberwolf, you run the risk of breaking it at the weld.

Thanks, that helps a lot. I had that problem too that the flutter method would result in a blade that was too lose. But having no prior experience with band saws I just didn't quite know what to expect. Having a rough idea of the deflection at least lets me know if I am in the ballpark. Thanks again!

Gerd

[betacrash]

well, i found out that it was the blade tension. My second bandsaw box came out like a champ. I am eager to finally get to post something in the finished projects section.