Bandsaw won't cut straight

[Pilot]

No matter what I am cutting the cut line always wanders off to one side--the same direction each time. Doesn't matter if I am using a guide or not, still does the same thing. Almost like the blade is dull on one side, but I have changed the blade and no change.

It's an old Jet brand & I have no manual for it.

Any ideas why it does this?


A second hand store has a great buy on a like new Rigid unit of about the same size and I am tempted. Half price sale because the store owner is retiring. I'm tempted.

 

[BigBoyToys]

Depending on what material you're cutting and thickness you have to have the correct size blade or it will wander on you.
I have a 14" enclosed Delta bandsaw I bought new about 25 years ago and it has been a solid machine. I only use it for cutting wood as I have a dedicated horizontal saw I use for metal. Jet makes nice stuff. Check and see if they have a manual here...JET Tools | Manuals

This might help...How to Choose the Right Bandsaw Blade

 

[George2615]

I have a similar bandsaw. Check your guide rollers If the bearings are worn it will cause the blade to wander off center. Another thing that will cause it to not cut straight is a floating vise that is not square. Not sure if yours has a floating vise. Counterbalance spring tension will also cause it to not cut straight if not set right. Click on the site provided by BBT for your manual. It should tell you how to check the squaring of the blade to the table and may provide other answers why it isn't cutting straight.
Here's a section from one of the manuals on crooked cuts.

 

[Egon]

Find a tune up video on YouTube and then tune yours up. Go thru it step by step.

Make sure the fence and blade are parallel.

 

[Fossil Farm]

As George said, be sure your guide roller is properly set behind the blade, mine is to be 1/32 of an inch behind. Too far back or on the blade messes it up. Blade tension is also very important so the blade is firm but not too firm as to easily break it. Tighten until it just starts to "ping" when you pluck it. A few trial cuts and you will find the correct tension. Also be sure the blade is tracking in the middle of the wheel. There should be an adjustment for that also. Just move the upper wheel by hand to watch it track.

 

[Pilot]

Thanks for the info, I'll try those ideas.

Unfortunately, they don't have the manual for my BS. Probably too old.

 

[the old grind]

Some difference between cutting wood vs metal, but not all that much. Make sure your guide adjustments aren't destroying the kerf of the blade(s). Set all 'block type' guides ~1/16" back from 'top' of teeth if pitch is 14TPI or more, further back if fewer (~3/32"-1/8" for 8-12TPI, ~1/8"-3/16" for 4-6TPI, YMMV), and keep the gap narrow. As said, keep thrust roller(s) close. (IMO 1/32" clearance is max)

Also adjust guide bars for/per workpiece size. Too far apart along the blade almost assures poor tracking in the cut, as does excess pressure, too high SFM, or too skinny a blade (front to back). Square to 1/16" per inch cut depth is a reasonable goal. btw, HFT blades are OK ... and proven when all is adjusted well. Let us know how it's going, ok?

 

[Billrog]

Not unusual what you describe is called drift , run a straight piece of wood through the saw a ft. or so then set your fence accordingly you may have to do this every time you change blades then don't all cut the same.
Google band saw drift and get a more concise answer than I've given there must be one there I've never checked.

 

[Egon]

One of many set up videos. There may be more than a couple of things needing adjustment for good cutting performance.

 

[Mysfyt]

Two things can cause this. One is the blade itself not having the proper 'set' in the teeth. Cheaper blades are notorious for this, but I've seen it on expensive name brands also. Over the years, I have probably purchased every name there is in saw blades and sooner or later there will be a bad batch. I cut mostly metal and I always buy the bimetal or M42 blades because these tend to cut straight until they break as opposed to the carbon blades that will cut crooked. Currently using Wikus brand blades and they have been pretty consistent.
The second thing that comes into play is the force on the blade. Too much pressure will cause crooked cutting and shorten the life of the blade. On a horizontal band saw, I want to see the blade continue down at the same rate after it's cut through the metal. If it 'lurches' when it breaks through, that's a sign there is too much down force on the blade. High end saws are adjustable for feed (and some like Amada are even micro adjustable), but on less expensive saws it's usually counterbalanced with spring pressure or weights. Years ago I had a Jet that required a total revamp on the counterbalance to get it right, but that saw cut a LOT of metal for years and was still cutting good when I upgraded to a bigger saw.

 

[teejk]

Don't think I've ever seen a mid-priced band saw make a straight line (I have a Delta that I'm sure came from the same factory as your Jet). From what I have read it is "random" as to which side it will want to "drift". My Delta came with a pivot pin that can be attached to the fence to try to keep things on the mark (that in itself tells me that they know it probably won't cut straight with the fence). I have a decent table saw for most things and only use the band-saw for re-sawing and small cuts when my alarms go off. Back to the re-saw part...I saw a "hint" somewhere that suggested doing a shallow kerf cut on the table saw (top and bottom of the board). It works! The blade has little chance of going anywhere other than to follow that kerf.

 

[jix]

I have had that problem with successive new blades. It is caused by the way the blades are made..not enough set on one side of the blade... Change blade suppliers.. And the defective blades back for a refund.

 

[teejk]

I have had that problem with successive new blades. It is caused by the way the blades are made..not enough set on one side of the blade... Change blade suppliers.. And the defective blades back for a refund.

I've used several different brands and notice no difference. I think it's strictly a function of the wheel alignment (explaining why each saw is different). A mere fraction in tolerance gets magnified a lot on the cut. As somebody noted, google "band saw drift" and you'll see it is not uncommon. You'll also see how some people correct for it (sleds, shims, etc.). I usually just accept it and leave pieces a tad large and true up at the table saw or miter saw.