Singing Turn-Pro Bandsaw

[MMurphy]

The band saw is a 7X12 turn Pro. The blade I'm using is a 6 tooth per inch, standard rake, hard back morse. Cutting AL 2-3 inches square.

A soon as the blade engages, the singing begins. If a vary the feed rate I can modify the sound, and sometimes, eliminate the sound. The cut finish is a little rough. I have also varied the sfm, slower is better. At 260 sfm the sound was loud enough to make my ears ache before I stopped the cut.

It seems to be some form of chatter. What do you think causes it, and more importantly, how do I stop it. I'm sure it's not good for the blade (and my ears).

Thanks

Mike

[3 Phase Lightbulb]

What are you cutting? Is the stock flimbsy? When it's singing, start grabbing things (except the blade of course) and see if you can find exactly where the noise is comming from. If you can dampen the sound by touching the stock then it's probably not clamped securely enough, or it's flimbsy and the end of the stock is chattering.

-Adrian

[Forrest Addy]

Damn double posts!!

The "singing: accompanied by an ordered appearance of roughness in the cut is from "harmonics." The band is like a stretched string and can vibrate in a number of ways. The material sets up a stick/slip behavior that excites resonance in the band. The vibraation can be heard and it often manifests itself in the appearance of the sawed surface.

The vari-tooth band design is intended to eliminate singing (harmonics.) The band tooth pitch ranges from larger to smaller and back over several inches. It breaks up resonance as it tries to establish itself.

I strongly suggest you move to a vari-pitch bi-metal band. Bi-metal bands have HSS teeth and are twice as espensive but they last 4 to 5 times longer; a definite deal. Never buy factory saw bands until you check local sources and prices. Your local saw shop will sell you bands; what ever you need often at a 5 for the price of 4 deal. You can mix the pitch in yur order so long as it's the same material width and band length.

I seem to prefer Lenox "Super" a basic HSS bi-metal band. It's what my local pro-level saw shop sells. I think I paid $21 apiece and got 5 bands for the price of 4 ($84). Lenox, Starrett, whatever; the band stock they sell is very competitive and very good. So don't feel married to a particular stock if you find a deal in brand "X."

Don't forget to use a rich coolant mix for aluminum.

[MMurphy]

3 Phase Lightbulb, Forrest...

Thanks for your posts.

Three phase... the stock I'm cutting right now is 3x3 square 6061 AL. Its clamped good and tight.

Forrest...Sorry, I usually post to both forums as I have noticed that there is a few folks who only seem to visit one or the other, not both. I will heed your advice about the vari-pitch bi-metal. Alas, there is no one here in my little town who I can purchase blades from.

I turned up the tension a 1/4 turn or so with a rubber strap wrench and nearly all of the "singing" is gone. Just a little at the begining of the cut.

Next I'll try to go back to 260 SFM and see if it stays OK. As soon as I break the morse blade I will replace it with the vari-pitch, bi-metal. I never seem to wear out a blade there's always an AW S^%$#%.

Thanks again

Mike

[Boomer]

I have the same saw and the same problem sometimes. I just got two variable pitch Morse blades from Enco, a 6-10P and a 10-14P. They are bi-metal and on sale at least to the end of November @ $21.99.

http://www.use-enco.com/CGI/INSRIT?PMAKA=DM371-0410

The other one is DM371-0412.
I always had trouble finding a bi-metal blade the right length in 3/4" before.
I haven't tried them yet, waiting for a howler.

[wierdscience]

Try dropping the speed and making a cut in steel to joint the set.The condition might be an irregular set,making a cut or two in steel will sometimes correct this,another metod is running the saw at it's lowest speed and holding an oil stone to each side of the blade to joint the tooth set.

Stay away from Morse blades,I have had loads of trouble with them being inconsistant.I use Sandvik and Lennox with no troubles.