Contributing factors to Bandsaw drift?

[jlanciani]

The saw never cut truly parallel to the miter slot...

That's an easy fix, loosen the four bolts that hold the table to the trunions and adjust the table so that the miter slot is parallel to the lead angle of the saw. SOP for bandsaws, I can guarantee that when the saw was assembled at the factory all they did was plunk the table down and tighten the bolts. They don't put blades on the saw just to adjust the table for square, that's the owners responsibility.

[jteneyck]

Put the blade in the center of the upper wheel before adusting the table.  Your owner's manual should describe the procedure. 

If your saw never cut parallel with the miter slot something definitely is wrong.  If my lowly Grizzly was set up perfect from the factory it's hard to imagine that MiniMax would do less considering the MM16 is regarded as one of the best.  In any case, if it's gotten worse in the past couple of years it's unlikely only due to a problem with the table; that wouldn't have changed.  However, you may very well need to adjust the table as part of the fix.  

John

[jlanciani]

Put the blade in the center of the upper wheel before adusting the table.  Your owner's manual should describe the procedure. 

John

MM16 has flat tires, proper procedure on blades 1/2" and wider is to run the teeth off of the front of the wheel, not centered.

 MiniMax owners manuals make every other manual you have ever read look like works of literary brilliance...

ETA, I love my MM20, but it was absolutely not plug and play. Apparently the Italians have decided that every new owner must pay penance before they are deemed worthy of using their machinery.

[jgourlay]

Some findings:

1.  Something about the frame geometry has changed.  When I got it, I measured the tension and made a mark and have been using that mark ever since.  I got out the blade tension gauge and found that I needed to make a new mark, and pretty far up too.

2.  Dial indicator says the blade stable when hand turned.  When running the blade has nominally .005" of wobble.

3.  After tensioning I thought I'd give it another full shot.  So I adjusted the bearings properly and did the exercise you see in the photos.  You'll note just how much drift there is, and this is consistent with what made me do the original post.  You'll also note the gap between fence and work on the resaw.  I was pressing the work to the firmly.  After I braked the saw and let go, that gap is how far the work 'sprang' to the right.  Also, it's a poor resaw--wobbly. 

I took the fence off the base and widened the hole that the clamp bolt goes through.  This let get free swing of the fence past the drift angle.  I readjusted it for drift, and tried a new resaw.  This time on oak instead of ply as that was the next piece close to hand scrap.  This cut, with the fence modified and readjusted.  The result was good.  However the blade could be dull.  Does anyone sharpen carbide bandsaw blades?

Aw....crap.  Well, as you can see below, I now need to start the process of offloading photos from photobucket because....

[mike4244]

Another post correctly mentioned to loosen the table to trunnion bolts and align the slot to the blade.  I use a steel rule placed against the blade and in between teeth so the set does not interfere. You can readily see if the blade has lead. Some saws only have two locking knobs instead of four. You only have to loosen the knobs or nuts slightly. Then tap the table around til the table slots are parallel with the rule. I use a small rectangular magnet to hold the steel rule to the blade, not necessary if you make sure the rule is against the blade before tightening the lock knobs.
As far as sharpening bandsaw blades I do this whenever I need to. I only sharpen blades that have 3 or less TPI.
Finer blades are harder to sharpen and take too much time.Takes about 15/20  minutes to grind 113" blade for a 16" saw. I use a Dremel tool with cylinder shape used for chainsaw blades to grind a blade better than new. Many new blades are stamped out and appear to not be ground.
mike

[Derek Cohen]

One factor that has not been mentioned is the speed at which you push the board through the blade. Too fast, and the blade gullets load up, and the blade deflects and wanders off course. Push slowly - very slowly - and watch the difference.

It also does make a difference when the blade is not vertical, so square up the table.

My resaw blade is 1" wide and has 1-1/2 tpi (on a Hammer N4400). Any more teeth than 3 tpi and I expect deflection.

Regards from Perth

Derek

[jgourlay]

Derek, yes.  Speed is a BIG issue for me.  A great shop day for starts about 5:30 am with a pot full of coffee in a thermos and another brewing.  I've done all the layout from the prior days, and that early Saturday morning is the 'hand-tools'.  Typically if the day involves resawing or what not, I'm a pot and half of coffee into it and like a lab monkey on meth.

Works great with the jointer, thickness planar, chopsaw, and lathe.  I have to put on classical music before resawing on the bandsaw though.

[jgourlay]

Mike...hmm.  You know, I'll have to check that.  I actually don't recall being able to adjust that.

[jgourlay]

So true!  Years back I needed new bearings and that was an absolute NIGHTMARE.  "Nightmare" meaning WEEKS of dealing with customer support, sending pictures, them calling BS, etc.  Finally we figured what had happened.  When I bought this it was 'sight unseen' from a different city, and they give me the discount on the floor model.

What they didn't tell me was that they had southern engineered on the MM16 a set of bearings and bearing mounts from a completely different Centauro saw.  They don't sell those bearing separately, you have to buy the (very expensive) bearings-in-the-mount to replace them, and to get the blade fully adjusted the lower thrust bearing has to have the back 1/2" ground off the back side.

But, overall, I've been very happy with this saw.

[Chipper_Jr]

I wish we could get some pictures. 
How much tension are you putting on your blade?   25,000