Issue bandsawing a 10" circle, what went wrong?

[Randall J Cox]

Have a circle cutting jig that I just adapted from my 14" Delta bandsaw to my recently purchased new used MiniMax 18" S45 bandsaw. I used the jig very successfully many times on my Delta (with a 3/8" blade). Tried to cut a 10" circle with it in 3/4" wood on my S45 and it pulled the blade out from the center of the circle as it turned, had to stop. Didn't get very far into the turn. I'm using a 1/2" Lenox Diemaster 2, wavy 6-10 variable spaced blade on the MiniMax. After I took off my jig, I was able to freehand cut the circle with no problem. After thinking about why it did what it did, maybe I didn't have the wood pivot point lined up correctly with the front of the blade or maybe there is not enough set to the blade teeth or maybe I had too wide of blade. Any expertise on why I had this issue would be very welcome. Thanks. Randy PS I checked all the settings on the bandsaw afterward such as blade alignment, tension, etc and it was all correct.

[Grant Wilkinson]

I think you hit on the answer, Randall. It seems to be that your pivot point was not in line with the gullet of the blade. Certainly, that blade is easily capable of turning a 10" circle.

[Charles Lent]

A 10" circle with a 1/2" blade seems to me to be too tight of a turn. I would go with a much smaller blade, like maybe 3/16-1/4". Also, your jig should be set so the pivot point is in line with the teeth of your blade, not ahead of or behind, and this position of your blade is also centered on the band saw tires. Once adjusted this way, then move the blade back guides of the saw up to just touch the rear of the blade.

I usually get better results using one of my routers and a circle jig, but I have made many arc shaped pieces using my band saw.

Charley

[Yonak Hawkins]

A 1/2" band saw blade should cut a curve twice that tight. I'd check the alignment of the pivot point with the front edge of the blade and the condition of the blade itself for culpability.

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[Alan Schwabacher]

A wavy tooth blade with 6-10 teeth per inch sounds to me more like a metal cutting blade than the more usual 3 TPI for a 1/2" wood cutting blade. It is possible it does not have sufficient set to make a curve that is easy with other 1/2" blades. That said, if you were able to freehand cut the same circle size with that blade, it must be that the cut direction was not appropriate, so you should be able to fix it by moving the circle center point. With a wider set you would have more leeway in terms of center position, but you should be able to get this blade dialed in.

With no drift, the center point should be even with the blade, front to back on the table. If for some reason your cut drifts left or right and you don't fix that first, your center point would need to move forward or back a bit to match your best cutting direction.

[glenn bradley]

Another vote for pivot point to gullet alignment.

[Randall J Cox]

Yes, I think pivot point center was not in line with front of blade. Looking back on it I just threw on the circle cutting jig and just kind of eyeballed it. Next time I get the ruler out and make sure its right. A dumb move on my part.... Randy