bandsaw weirdness - what am I missing?

[rudy de haas]

I have a Craftex cx104 "ultimate" 14" bandsaw (same as the grizzly circa 2014). Normally it works well... however two weeks ago the 3/8th" blade broke in use, so I replaced it.

Unfortunately the only 3/8th x 101" blade Windsor Plywood had in stock has 3 teeth per inch and is "quite aggressive" - nice when cutting a softwood but terrible when you're cutting something hard like Jatoba - two days ago I was holding a 6" long, 4" high, 1" thick piece edge down and cutting into the 4" side when a tooth caught, slamming the wood down forward. Not fun, so I got the 6 teeth per inch, 1/4" blade I knew Windsor had in stock.

It won't stay on - I've adjusted the guides and retensioned twice, but it persists in moving to the front of the top wheel and therefore out of the upper guides. The wheel alignment has not changed - when I put a 3/4" blade on it stays where it should, as did the 3/8th. So what am I missing? Does a narrower blade need different wheel alignment or tensioning?

[Lee Schierer]

Your previous jam could have damaged something on the upper wheel support, which has caused the wheel to get out of alignment.

[daryl moses]

I know nothing about the Craftex bandsaw but I assume it has a tracking adjustment knob [wheel tilt] have you tried adjusting that?

[rudy de haas]

Your previous jam could have damaged something on the upper wheel support, which has caused the wheel to get out of alignment.

I wondered about that -but the 3/8th didn't break and continued to work. After I could not get the 1/4" to stay on, I put a 3/4 on and that stayed just as it should.

[Doug Garson]

Did you use a 1/4" blade before the 3/4" blade broke? If you did that supports the theory that something went out of adjustment when the 3/4" blade broke. If not, maybe your wheel alignment has always been out and I'm guessing that if your wheels aren't coplaner it may be harder to track a narrower blade than a wider blade. I'm sure the band saw experts will chime in soon, I'm not one of them.

[rudy de haas]

Did you use a 1/4" blade before the 3/4" blade broke? If you did that supports the theory that something went out of adjustment when the 3/4" blade broke. If not, maybe your wheel alignment has always been out and I'm guessing that if your wheels aren't coplaner it may be harder to track a narrower blade than a wider blade. I'm sure the band saw experts will chime in soon, I'm not one of them.

That is possible - this is the 1st 1/4" blade I've tried.

[Alan Schwabacher]

It is possible that when you tension a 3/4" blade, that flexes the frame enough to affect tracking and alignment. If so, when you use a smaller blade, the tension does not deflect the frame as much, so the tracking needs to be adjusted.

Duginske advises adjusting wheels to be coplanar with your widest blade installed and properly tensioned, assuming it will change with other blades but that it's most important for wider blades. The tracking adjustment then serves to make other blades run properly.

[rudy de haas]

It is possible that when you tension a 3/4" blade, that flexes the frame enough to affect tracking and alignment. If so, when you use a smaller blade, the tension does not deflect the frame as much, so the tracking needs to be adjusted.

Duginske advises adjusting wheels to be coplanar with your widest blade installed and properly tensioned, assuming it will change with other blades but that it's most important for wider blades. The tracking adjustment then serves to make other blades run properly.


Makes sense - thank you for the explanation.
.
After seeing Doug Garson's note (above) yesterday, I tilted the upper wheel a bit and that seems to have worked. I have yet to put a bigger blade back on, when I do I imagine I'm going to have to untilt but now at least I have some idea why.