Bandsaw Blade Bottom Doesn't Follow Top!

[Dan Hunter]

I just recently set up a Jet 14" bandsaw (the blue one) and I'm having trouble getting it to cut straight. For example, if I want to cut a big O out of something two inches thick, after being cut, the O at the top of where the blade cuts is 3" in diameter, but the O where blade exits the wood is only 2.5" It seems like the bottom of the blade isn't following the top. From what I can tell, I have the guides set up properly. My suspicion is maybe the tensioning or blade choice? Any help would be greatly appreciated.

[glenn bradley]

My experience with bandsaws is that they are pretty basic but, there is a lot of voodoo floating around them. 2" thick material would make me choose a 6TPI blade or less, depending on horsepower. With the saw properly aligned I run my blades using the flutter method (http://www.suffolkmachinery.com/six_rules.asp) for tension which runs looser than a lot of folks prefer. Works well for me but some folks like their blades really tight.

[Jacob Mac]

Sounds like your table might not be square to the blade.

Or maybe not. I'm far from an expert. But it is something to check

[Bob Barkto]

First check the table to be sure it is square to the blade.
Then check your tension and then the guides.

[Dan Hunter]

Ah, thanks for the tips. I did not even think that my table might not be square to the blade.

[William Falberg]

"My suspicion is maybe the tensioning or blade choice?'

Bingo! I assume you're using a skinny blade? 1/4" or so? What kind of set angle does it have? Set angle is just as important with 1/4" blades as it is with 1" blades, but harder to measure. Have you seen the video where I cut a 3/4" plug 15" deep with a 1/2" blade? There was no variation in diameter from top-to-bottom. It was done with little tension and a wide gap between the blade guides. Trying tapping out just a few of the teeth very gently to widen the set, even slightly, and try that again.

[Myk Rian]

It's possible you're putting side force on the workpiece.
+1 on the flutter method to set tension.

[mickey cassiba]

FWIW...I read , years ago, that a careful stoning of the back of the ribbon(non-cutting edge) would remove the burr left during manufacture. Bear in mind that I'm not a real woodworker yet. Been repairing and working on, and collecting WW machines for a long time.

[Howard Acheson]

What blade are you using and how new is it?

[Prashun Patel]

My money's on the blade. I think the table'd have to be tilted at about 11 deg to get a 1/2 taper on 2 1/2 stock.

Blade tension's fairly forgiving for most cuts: I have a great blade that cuts fine 4" oak no matter (within limits) how I tension it. I had a crappy stock blade that wouldn't cut a curve in 3/4" pine.

Also, are you using a circle cutting jig to cut the circle? If so, then are you feeding the piece too quickly? If you do that, the chips won't eject fast enough, which can cause blade lean.

[george wilson]

A 1/4" blade is just fine. It may not be tensioned right,or,like he said,the table might not be square. That is a very severe error in 2" of cut. Is the blade sharp? Does it leave burns? Do you have to really push the wood hard to make it cut? If any answers are yes,get a new blade.

[phil harold]

these couple articles improved my 14" delta

I also needed to replace my bandsaw wheel tires, but I opted just to turn them inside out (cost nothing to try) worked great with all the other tweaks


http://www.ccwwa.org/NEWSITE/plans/BandsawTuneup2.pdf

http://www.owwm.com/files/PDF/FAQ/110124076.pdf

http://team358.org/files/mechanical/BandsawTuneUp.pdf

http://eberhardt.bz/GME_Wood_Land/GME_Woodworking_Stuff/2_Tool_Tune_Ups/5_Tuneup_Bandsaw.pdf

[Stephen Edwards]

I would suggest that you also check to be sure that the lower blade guide assembly is parallel to the trunion support piece that's mounted on the lower arm of the saw. Tuning that on my BS made a world of difference.

[Dan Hunter]

Turns out I went to check the table with the square and it was off by about 4-5 degrees. First lesson learned: "Never trust the built in angle guide!" The guide said it was on 0 degrees, but it obviously was not. I also tried using a different blade with fewer TPI and rechecking and adjusting the guides, and retensioning according the the instructions above. I think that might have also contributed to the poor results of my cuts. Thanks for all the help.

[Stephen Edwards]

Glad that your problem is solved! Your saw may have an adjustable positive stop under the table. If so, once you have the table 90 degrees to the blade, you can set that stop (usually a bolt with a lock nut or two).

I never the trust the degree markings on machines, either. I was pleasantly surprised, however, when I recently squared my new DP table to the quill on my Grizzly DP. That degree gauge was dead on the money.

Again, glad that you got your problem solved. One positive thing about having such problems is that it helps us to become more acquainted with our machines.

[Jacob Mac]

Turns out I went to check the table with the square and it was off by about 4-5 degrees. First lesson learned: "Never trust the built in angle guide!" The guide said it was on 0 degrees, but it obviously was not. I also tried using a different blade with fewer TPI and rechecking and adjusting the guides, and retensioning according the the instructions above. I think that might have also contributed to the poor results of my cuts. Thanks for all the help.


Glad it is fixed. Bandsaws are so mysterious to me. I have been working on my new bandsaw for almost 10 months now, and I still can't get a good quality cut. And I have been through everything. Glad you had a simple fix.

[george wilson]

Most of at least the older machines had an adjustable pointer on then. They are seldom accurately positioned,and NEVER to be trusted,even if you have adjusted them. Use a square !!!!!!!!!!!

[phil harold]

Glad it is fixed. Bandsaws are so mysterious to me. I have been working on my new bandsaw for almost 10 months now, and I still can't get a good quality cut. And I have been through everything. Glad you had a simple fix.

I was like that too until I followed the first 2 links I posted above now it runs like a charm

Once I shimmed the upper wheel to be even with the bottom made all the difference in the world

[Stephen Edwards]

I was like that too until I followed the first 2 links I posted above now it runs like a charm

Once I shimmed the upper wheel to be even with the bottom made all the difference in the world


Phil, Thanks for posting those links. I've saved them on my computer for future reference.