Gem'n I
freely admits to licking rocks
Member since March 2008
Posts: 980
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Post by Gem'n I on Nov 5, 2008 23:19:40 GMT -5
I guess looking and hoping for some tech advice...How much run out is allowed in a saw blade before it has to be straightened?? And after reviewing some past threads I could find nothing on how anyone trues up a blade...I know most of the manufacturers do not do this anymore so I was hoping some direction could lead me to the best ways to true up a blade and what kind of tolerance do I need for a blade to perform well. I just don't want to start whacking away at the blade with a hammer...this was covered somewhere before but I couldn't find anything??? Thanks!!
Larry
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Post by bobby1 on Nov 6, 2008 10:06:29 GMT -5
Larry, If you have a divot in your blade caused by the rock slipping and the blade jamming up you can do a fairly good job straightening it with a hammer. I lay the blade on a flat surface like my garage floor and whack it with a plastic faced dead blow hammer. Dont use a steel hammer or it will add dents. Here is a picture of the hammer that I use. If the blade is dished in the center and you whack it and it springs back, you're out of luck. In that case you can't straighten it without annealing and retempering it. Those steps require an annealing oven and professional help. If the blade is wobbling slightly and the bearings are OK and the blade is properly gripped in the flanges you might be able to grab the blade and flex it a little and help it. Bob
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spicer m
spending too much on rocks
Member since October 2008
Posts: 337
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Post by spicer m on Nov 6, 2008 20:53:01 GMT -5
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Gem'n I
freely admits to licking rocks
Member since March 2008
Posts: 980
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Post by Gem'n I on Nov 6, 2008 21:10:46 GMT -5
Bob, Thanks for the pic of the hammer...I really hope I can find out what run out is allowed on a blade..I figured I would have to start smacking it on a flat surface to true it up but I need to discover that threshold point of wobble is .010" allowable or is .025 out of luck?? The bearings are fine and the blade is locked in the flanges. My plan was to take a piece of channel stock and true it up by moving it in a clockwise around the blade tapping as I move around the 360' surface...there is no ding in the blade and it's an 18"...so before I start this exhumation...I need to find out if I am just picky or my runout is beyond acceptable standards. Somebody should know I am hoping. Larry
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Gem'n I
freely admits to licking rocks
Member since March 2008
Posts: 980
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Post by Gem'n I on Nov 6, 2008 21:27:25 GMT -5
Mike, Thanks... lots of good info in that article and I think that will put me on the right track. I just knew someone had crossed this bridge before!! Larry
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Post by johnjsgems on Nov 28, 2008 20:41:34 GMT -5
One problem that is pretty common is overtightening blade nuts. The nut should be snug enough to prevent slipping. Overtightening can dish the blade. If the blade wobbles a little but cuts smooth I wouldn't worry about it.
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rallyrocks
fully equipped rock polisher
Member since November 2005
Posts: 1,507
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Post by rallyrocks on Nov 28, 2008 20:50:21 GMT -5
If the blade wobbles a little but cuts smooth I wouldn't worry about it. That was what I was going to say, at the same time I think you'd find that it is somewhat dependent on the kerf for the blade you are using. Run-out on the order of 1/4 - 1/2 the blade width or so would be about the max that I'd think will not cause too much problem, but much more than that and I'd think you run the danger of the blade binding up or kinking and getting ruined. So a thin blade like a gem slicer will be a lot less forgiving than say an MK 303.
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Gem'n I
freely admits to licking rocks
Member since March 2008
Posts: 980
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Post by Gem'n I on Nov 30, 2008 16:27:02 GMT -5
Well guys here's the story...I used a dial indicator on a mag base to check the runout...it proved to be TIR of less than .015" which seemed like a lot but proved to be not so bad. This is a blade that I had been using for a couple of years. I then took a smooth faced ballpeen hammer to the lead of the kerf pretty much whacking it with good force every 1/8" or so squaring the lead edge which was pretty rounded...this was with some trepidation because of diamonds are not good friends with hammers and I feared knocking some out or to smitherines at worst case...well my fears are gone..the blade works better now than it has before and my cuts are smooth as a babies behind!! I am not suggesting everyone needs to do this but after hanging this blade up a couple of times and tripping the motor out...this was a solution for me...no more tripping, hanging or messing up!! Ballpeen hammers serve some purpose....imagine that it only took 30 years to find out!! So John, Spicerm, Bobby and Rally thanks!
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Post by mohs on Jan 21, 2009 23:02:37 GMT -5
That's great that you were able to make the blade run true. Hammering is an art, and I dying one at that! That article was very informative and right on.
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