old question from different pt of view - saw blade wobble

Forum for people who are new to woodworking. Feel free to ask questions or contribute.

Moderator: admin

gk777
Gold Member
Posts: 52
Joined: Sun Apr 06, 2008 4:03 pm
Location: Delaware

Post by gk777 »

Hmm, wonder if that is why I had so many burrs, maybe the guy I got it from removed the blade and then put it together to show it for sale and did this or maybe I did it. But this actually may be the direct cause. I think my arbor is ok, but maybe someone can tell me for sure. Since I had it tapped out. I think its working great so far. That would also explain why the ends were the biggest issues. I did have a few tuff spots in the middle but the ends were very bad.
User avatar
RobertTaylor
Platinum Member
Posts: 569
Joined: Mon Sep 03, 2007 9:28 am
Location: North Canton, Ohio

Post by RobertTaylor »

my experience is the same as Bill's. if the arbor nut does not come off with your fingers once it has been loosened with the wrench, do yourself a favor and look at the setscrew instead of using the wrench to force it over the setscrew thus boogering up the threads. just one more reason to buy new arbors from shopsmith instead of on "the" bay. i learned the hard way. hope you may save the frustration.
Bob
1954 greenie, 1963 anniversary edition now a mini,
1984 500, 1985 510, 1987 510, pro-planer, bandsaw, dust collector
User avatar
Nick
Platinum Member
Posts: 808
Joined: Mon Aug 28, 2006 4:04 pm
Location: Dayton, Ohio
Contact:

Post by Nick »

"If the high low spots remain the same I would remove the blade from the arbor and lay it flat on the sturdy table and smack it."

Ed, I respect your know-how but I have to caution against anyone doing this to today's blades.

Back in the good ol' days, before bi-metal saw blades and carbide teeth, blades were made from tool steel and they could be "tuned." Tuning a blade was procedure meant to reduce the runout. The sharpener measured the runout in a blade then hammered it on a special anvil. Each blow of the hammer caused the metal in that area to spread slightly and introduced tension in that spot. The sharpener aimed his blows to create tension that would counteract the runout and cause the blade to bend in the opposite direction. This is no simple thing; tuning was a highly refined art and I would be surprised if there are 50 professional sharpeners left in the whole country who know how to do this proficiently.

There is little need for tuning today. Most blade bodies are made from "tonnage" steel that can't be tuned effectively. Teeth are made from carbide or a thin rim of tool steel that is welded to the less brittle steel in the body. However, whacking the body with a hammer still has the effect of spreading the steel in the immediate area of the whack. It still intruduces a tension that wasn't there before, and this tension will cause the blade to bend one way or the other. Even if you lay the blade on workbench instead of a harder surface, the blow will tension one side and compress the other, bending the blade if only slightly. Unless the whacker knows precisely what he/she is doing, this could easily make the problem worse rather than better.

Personally, I would opt to send the unwhacked blade back to the retailer for a replacement.

With all good wishes,
User avatar
Ed in Tampa
Platinum Member
Posts: 5834
Joined: Fri Jul 21, 2006 12:45 am
Location: North Tampa Bay area Florida

Post by Ed in Tampa »

Nick wrote:...However, whacking the body with a hammer still has the effect of spreading the steel in the immediate area of the whack. It still intruduces a tension that wasn't there before, and this tension will cause the blade to bend one way or the other. Even if you lay the blade on workbench instead of a harder surface, the blow will tension one side and compress the other, bending the blade if only slightly. Unless the whacker knows precisely what he/she is doing, this could easily make the problem worse rather than better.

Personally, I would opt to send the unwhacked blade back to the retailer for a replacement.

With all good wishes,
Nick
I very definitely agree I would not hit it with a hammer. When I said smack it, I meant with the palm of the hand in case there was a spring introduced in the blade from a bent arbor.

I have seen more than one steel plate that immediately popped back to perfect flatness after being smacked with an open palm, While I never did this with a blade I can't see why the same conditions couldn't be possible and the same remedy wouldn't work.

If blades are different than I stand corrected however I do know my blade sharpen does rap every blade I bring to him before he checks for runout. Kind of like a tuning fork, I thought he said it relieved tension but I will check with him to make sure the next time I take a blade to be sharpened.
Ed
gregf
Gold Member
Posts: 178
Joined: Mon Mar 17, 2008 2:19 pm
Location: Richwood, OH

Post by gregf »

" I thought he said it relieved tension "

Maybe it was his tension, not the blades. ;) Some days you just want to hit something.
Richwood, OH
There is no such thing as an unsafe tool, only unsafe owners. If you make a machine idiot-proof, God will invent a better idiot.
Post Reply