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Post by rockpickerforever on Jul 27, 2012 17:20:36 GMT -5
I had posted this on a different thread "What material is hardest on your equipment?" but moved it here because it's a more appropriate location. Hope that's okay...
I've got a 10" MK303 blade (sintered) that is almost a year and a half old. Somehow, it has worn out of round, causing vibrations that separate the rocks from the wood blocks holding them in the vise. Is it possible that cutting with it with a bend in the blade changed the outer circumference for it to wear that way? Then when I changed the oil last time, I straightened the blade, making the problem become apparent? We've checked the center hole, and the problem is not there. You can actually see the difference in the width of the sintering around the edge of blade.
It still has plenty of diamond left, but just can't use it how it is. Would cutting an old 220 carbide wheel round it up? Bought a couple like Carleton has (crimped), but they wear out really fast, and won't even touch the hard stuff.
Thanks for any suggestions. Jean
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Steve
has rocks in the head
Member since June 2005
Posts: 506
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Post by Steve on Jul 27, 2012 17:49:37 GMT -5
I'm having a hard time coming up with a way that this could happen other than a defective blade. Maybe you should contact the blade's manufacturer.
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Post by 3rdrockfromthefun on Jul 27, 2012 19:24:16 GMT -5
Cutting with a bend most definitely could change the diameter on the in-line cutting plane (and make a larger swath through the rock I should think).
To get an idea just take a CD between your index finger and thumb, give it a little bend and look at against a black background - it's no longer round.
It may have re-dressed itself as it bent, not being so noticeable as it may have bent slowly and also because it's pulled most of the way in-line while going through rock.
I bet if you'd looked at a profile in silhouette before straightening it it would have looked round. After straightening it's now no longer round AND in-line by itself - double whammy.
No clue how to fix this I'm afraid.
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Post by Bikerrandy on Jul 27, 2012 19:57:16 GMT -5
Out of round blades is usually caused by worn out shaft bearings. This causes the shaft the bounce around, wearing the blade more in some spots than others. The only fix is to replace bearings and get a new blade.
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Post by Pat on Jul 27, 2012 22:30:34 GMT -5
Is working with the bent blade dangerous to the user?
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Post by bobby1 on Jul 28, 2012 0:23:08 GMT -5
It could also be because the round washer that fits in the hole on the blade to match the diameter of the shaft popped out when you were working on the blade and you didn't notice it being missing or shifted out of the hole as you pushed the blade flange up against the blade. This would allow the blade to shift to an out of round position. This would be the most likely situation for the blade running out of round. I don't recall ever having a blade wear out of round. Bob
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Post by deb193redux on Jul 28, 2012 1:57:46 GMT -5
I had blades get slightly out of round when hand feeding. It made for bump-bump as I cut. I did fix it by very slowly feeding 220 carbide. But it was only slightly out of round.
Try the 220, but a new 303c is <$60, and you got 1.5 years use. Too much time spend would be a waste.
Good advice on bearings. check to see if there is any play.
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Post by 3rdrockfromthefun on Jul 28, 2012 7:03:11 GMT -5
I had blades get slightly out of round when hand feeding. It made for bump-bump as I cut. I did fix it by very slowly feeding 220 carbide. But it was only slightly out of round. Try the 220, but a new 303c is <$60, and you got 1.5 years use. Too much time spend would be a waste. Good advice on bearings. check to see if there is any play. I paid over 80 bucks for my 303C (bought direct from barranca) - where do you get 10" 303C blades for under 60 bucks!? I happen to need a new one.
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Post by Drummond Island Rocks on Jul 28, 2012 7:21:05 GMT -5
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Post by rockpickerforever on Jul 28, 2012 9:21:17 GMT -5
Thank you all for your responses.
Steve - The blade was fine when we got it, and we had no problems until recently. I don't know how it could have been defective.
Frank - You totally grasp what I'm saying about the diameter of the blade changing. You could see the slight wobble (I'm talking very slight) in one spot when you rotated it by hand, but it wasn't noticeable when turning at operating speed. And the cuts were good.
Randy - My husband thinks we replaced the spindle bearings in the saw before this blade was installed (but maybe not). We checked for wobble or end play when we took the blade off, and there was none.
Pat - Unless the blade were to shatter into pieces, I don't think it would be unsafe. As long as the cuts were good, I was okay to use it. It actually wasn't until I straightened the blade that the out of round became a problem.
Bob - This blade doesn't use any spacers on the shaft. And we checked both the diameter of the shaft, and the hole on blade, and everything was good.
Daniel - I do a lot of hand feeding (and holding!) since a lot of my rough is too small and irregular to put in the vice. At this point in time, I have more time than money, so I think I'll try the 220 carbide. I've really got nothing to lose, right? If that doesn't work, well, since the problem appeared when I straightened the blade, so maybe I need to put the bend back into it in the same position...
Chuck - Thanks for the info about a new blade. When all else fails... Jean
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Post by deb193redux on Jul 28, 2012 11:13:39 GMT -5
ditto on John. I get my 303c from him.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Jul 28, 2012 11:55:27 GMT -5
I have the same problem on my trim saw blade that i hand feed especially if I really push it to the limit. When it happens I cut an old grinding wheel until it stops and go on about my cutting. Just feed it slow so the high part of the blade is the only part that is hitting the stone. It usually does not take very long to get it to quit bouncing. Jim
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Post by rockpickerforever on Jul 28, 2012 15:45:30 GMT -5
Thanks, Jim, I think I'm gonna give that a try. But if I do have to buy a new one - The MK-303 blade I have is .050" thick, and it got bent. The blades John sells are only .040" so since I tend to do a lot of hand cutting, it would probably get bent easier. It doesn't look like John sells 10" x 050" blades. Got any ideas on where to look? Thanks! Jean
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Post by deb193redux on Jul 28, 2012 16:23:25 GMT -5
ask if he can get the .050. that one will cost a little more.
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Post by rockpickerforever on Jul 28, 2012 16:48:09 GMT -5
That's okay. I paid $73.50 plus $11.15 shipping and handling for this one in February 2011. I'm just looking for sources for if this one won't true up, and when I can afford a new one. Jean
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Jul 28, 2012 20:27:49 GMT -5
You can usually find thick blades at most any hardware store. A 10 inch tile saw blade here costs $34.00 but that is the blade that has gotten out of round a few times. Pretty tough to bend it though. If mine has a wobble I whack it one side then the other with a piece of two by four to get it back straight and it takes a pretty good whack. Part of my problem is that I just have flat washers instead of the cupped washers that are generally used with saw blades. If you over tighten you can get wobble also. If your cupped washers are not cupped any more that could be part of your wobble problem. They are pushing harder on one side than the other. Jim
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QuailRiver
fully equipped rock polisher
Member since May 2008
Posts: 1,632
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Post by QuailRiver on Jul 28, 2012 20:41:16 GMT -5
I agree with bikerrandy. It sounds like your bearings have too much wear and play in them. If you continue to use a saw with bad bearings, the shaft will very soon begin to wear where it makes contact with the inside of bad bearings collar. Most saw's bearings can be bought at a much lower price at local Industrial supply houses or online than they can be from the saw manufacturer. But arbors are a different matter. Who manufactured your saw?
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Deleted
Deleted Member
Member since January 1970
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Post by Deleted on Jul 28, 2012 21:41:41 GMT -5
I should have mentioned the bearings also. My saw started sounding different so I checked the bearings and I was too late. the shaft had worn down some. Luckily I could slide the shaft inward enough so I could get onto good shaft when I put in the new bearings. If it happens again I will have to replace the shaft so I am watching it pretty close. I bought bearings at the auto parts store. Jim
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Post by rockpickerforever on Jul 28, 2012 22:07:59 GMT -5
Quailriver - The saw is a Highland Park. We can't feel any slop or play in the shaft. And I would definitely buy bearings online, rather than a saw manufacturer. We also have an old 6 inch trim saw, that we replaced bearings on. My husband is a machinist, with a full machine shop in the garage. I'm not sure of the make of the saw (it didn't have any identification on it), but it had loose ball bearings in a groove on each side, not a regular bearing. He made a new arbor that would accept standard bearings for it.
Jim - I understand about the shaft wearing undersize. My old Ranger is on the driveway, with the rear on jacks, the differential cover, brakes, drums, axles, bearings and grease seals all removed, while I wait for new axles to arrive next week. Would've been a lot cheaper and easier to replace them BEFORE they got so bad, wore into the axle shaft, wiped out the grease seal, and ruined the shoes. A LOT cheaper, and a LOT easier. But when money is tight, you tend to let things slip. Seems when an emergency arises, you find a way.
I'll let you know what happens with the blade. Jean
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Post by phil on Jul 29, 2012 18:30:54 GMT -5
We've had excellent results using the gold series blades from Covington....
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