bandsaw questions

[Lee Alkureishi]

Hi all,

Last year I did some minor restoration work on an old 12" craftsman bandsaw - cleaning up rust, urethane tires, new blade. I fitted it with a 1/2" 4tpi resaw blade, and have used that with no problems until last night.

I was cutting some bowl blanks, and the motor kept stalling. I figured the blade got too dull, as I was also having to push harder in the cut. I switched out the blade for the only other one i had handy, a 1/8" 14tpi blade.

Now, I know that blade is not designed for heavy cuts, but figured i'd get by with it until my replacement resaw blade arrives. But, I'm having a lot of trouble with even light cuts.

- The blade deflects severely when I try to enter the cut - almost 90 degrees sometimes! I've adjusted the guides (which are original - cool blocks are in my to-do list), but it ddn't help.
- in the cut, my blade keeps popping off, usually if I try to back up any. Never had that problem with the bigger blade. The rear bearing stops it popping off the back, but how can I stop it coming off the front? More tension doesn't seem to help, and the blade is otherwise tracking correctly.

Are thinner blades known for being more finicky? I can't wait for my resaw replacement!

Thanks in advance,

Lee

[Prashun Patel]

What kind of bowl blanks are you cutting? If they are thick, you're probably just bogging down your motor on the 4tpi.

If they are green, then in addition to this, the blade choice becomes critical:

A resaw blade is typically designed for minimal waste and a decent finish face. Green wood, though, requires a raker set to keep the kerf wide, and low tpi - I prefer 3tpi. You want a blade that'll move those wet shards down and out of the kerf. If anything binds in there, you'll start seeing deflection, stalling, resistance...

I used to cut a fair amount of green bowl blanks on a 14" 1hp saw. It was slightly underpowered, but I was able to make it work fairly well with a 3/8" 3tpi blade. I also lowered the speed from ~3000 to ~1750. If yr saw has dual speeds, try using the lower one. I can't recall ever needing the higher speed; but I didn't use my bandsaw for finished-quality cuts...

[Lee Alkureishi]

Hi Prashun,
Thanks for the quick response. The bowl blanks are green, and are about 5"deep, and it was definitely bogging down before I made the blade change. But, it wasn't a problem before the blade got dull. Thanks for the info about the Raker teeth for green wood.

That said, the problems with the smaller blade persisted even with light cuts 1-2" deep. No bogging down, but then I couldn't get the blade to cut for more than a couple of seconds before either deflecting or popping off.

Thanks again

[Howard Acheson]

A 1/8 x 14 tpi blade is totally inappropriate for cutting thick stock. Blades designed for thick stocks not lots of space in the blade gullets to remove the sawdust being produced. When used on thick stock they just fill with sawdust almost immediately and stop cutting. I'm surprised that the blade has not destroyed itself.

Buy a new 1/2 x 2-3 tpi blade and all should be good.

[Prashun Patel]

To point a fine point on it, it's not raker 'teeth', it's raker 'set', which means the teeth are staggered. This results in a wider kerf that helps with chip ejection. Howard's point about bigger gullets is also well taken; the lower the tpi, the bigger the gullets between the teeth with also helps clear chips.

On a 12" saw, I'm not sure you'll be getting the best tension on a 1/2" blade. If it were me, I'd go for a 3/8" blade. I use a 3/8" 3tpi blade on my 19" bandsaw and it works great. A 3/8" blade will also be a *little* better at cutting curves than a 1/2".

[Lee Alkureishi]

I appreciate the advice, thanks again

[Van Huskey]

First, I think the 1/2" blade got dull. The 1/8" blade with 14TPI standard tooth pattern is about as far from a green wood blade as one can get the problems there are no ability to clear the chips. The "standard" green bowl blank blade is a 3/8" 3 or 4 TPI blade with a LOT of set. There are plenty of places to source them but in the effort to make life easy Highland Woodwork sells what thay call a turners blade which meets all the criteria.

BTW a 1/2" blade unless it is a very thin gauge is pushing the limits of that saws tension ability anyway, add to that not cutting straight lines with the half inch blade is REALLY taxing the motor as well, get the right blade for the job and you and your saw will be much happier.