Bandsaw - narrow blade tracking at very edge of lower wheel

[Michael Jasper]

Hi folks -

So I have a 9" grizzly 0803 bandsaw. Have been using it with a 3/8" blade for some time, but got a larger BS, so wanted to switch the 9" to a narrow blade.
I've tried putting on a 1/4" and a 1/8" blade, and I'm having the same problem with both.


I can get the blade to track in the center on the top wheel, but it ends up on the very forward edge of the lower wheel - with the teeth actually starting to go past the edge - so it looks like it could fall off in a second.


I checked the alignment - I can get both wheels parallel but the bottom one seems to be about 1/8" farther out. I tried shimming the top wheel to get it coplanar - that seemed to make things worse. I tried shimming the bottom wheel even more - reasoning that since the blade was at the forward edge, moving it forward might put it closer to center. What's weird is that depending on how much I shimmed it - it either stayed at the front edge or went to the back edge. Nothing I did seemed to put anywhere close to center. I couldn't even get it so it was entirely on the tire.

I've tried it with different amounts of tension on the blades, in case that made a difference - but it didn't.


I'm not entirely sure I ever checked tracking on the bottom with the 3/8" - but it never fell off for sure.

The other thing - which may or may not be related - is that the quick release tension lever has always been a little flaky. Sometimes it does exactly what it should. Other times, moving it to the release position seems to do almost nothing. It seems worst when there is the most tension. Using the deflection method on these blades, I ended up having to turn the tension up almost to the max - and when I tried to use the release bar, there's almost no change. Since the plate that angles the top wheel is part of the same mechanism, I wondered if there could be any relationship.

One last thing -- with no blade on there, the plate that angles the top wheel is floppy. It rests against the tracking screw but there is no force pulling it back against the screw. Maybe that's normal, but I wondered.


I've been doing lots of reading but so far, haven't gotten any clues. I know there are some bandsaw experts out there, so any help would be appreciated.



Thanks!

[John K Jordan]

It's difficult to diagnose without seeing the saw. If you know someone locally with experience perhaps they would be willing to take a look.

Checking for coplanar should be done with the saw under tension. How are you setting the tension? (The tension indicators in most or all bandsaws cannot be trusted - I use a tension gauge) All checks, of course, should be done with the guides backed off.

Assuming the tires are good AND the blades are properly tensioned, that it doesn't ride in the center indicates one wheel is angled somewhat. Some bandsaws have an adjustment for the angle of the lower wheel. On one of my saws without an adjustment I had to shim the lower wheel significantly to get the blade to track where I wanted it.

Is the tensioning spring good? Keep in mind a narrow blade will need less force for the same blade tension compared to a wider blade of the same thickness. The design of your tensioner might be angling the wheel differently for blades of different widths.

That the quick tension release does not behave consistently is worrying - I'd probably disassemble and check the parts and to understand how they work and convince myself that things are right or identify the problem. Maybe there is a worn or bent part.

What you are describing for the top wheel without a tensioned blade is probably normal but I've never seen a saw of that model.

Oh, BTW, I worked on a saw for someone once that had a clearance problem in the tensioning mechanism, for some reason causing some binding. (Perhaps the saw was abused at one time, I don't know.) I had to spend some quality time with a file to get things working properly.

[Curt Harms]

Hello Michael

I went thru this with a different brand saw. Adjusting the 'tilt' of the lower blade is what was required. In your case, the manual for your saw is available if you don't have it. It looks like page 45 of the online manual details wheel alignment.

https://www.grizzly.com/products/gri...r-guide/g0803z
Manual is under the 'Documents' tab.

[Michael Jasper]

Yes, I saw that page in the manual - also that it says not to do that except as a last resort because if you make a mistake, it's hard to correct!
I just spoke to their customer support. I'm pretty sure my tension spring is shot - they're sending a new one. (Part is $1.00, shipping is $6).

They also suggested going back and shimming top to get it coplanar even though that seemed to make things worse when I tried it.
One I get the new spring, I'm going to start from scratch and see how it goes.

[Curt Harms]

Yes, I saw that page in the manual - also that it says not to do that except as a last resort because if you make a mistake, it's hard to correct!
I just spoke to their customer support. I'm pretty sure my tension spring is shot - they're sending a new one. (Part is $1.00, shipping is $6).

They also suggested going back and shimming top to get it coplanar even though that seemed to make things worse when I tried it.
One I get the new spring, I'm going to start from scratch and see how it goes.

Not messing with the lower wheel positioning is generally recommended. I did, but first drew a line on the bolt heads so I knew how many turns on which bolts I made and could reverse them if needed. So far so good.