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Post by HankRocks on Jan 11, 2020 8:22:05 GMT -5
Well, the worst thing that can happen in a Lapidary Shop has happened to me. The blade on my 24 inch saw is bent, or more exactly, has developed a wobble. The wobble looks to be at least an 1/8 of an inch. All I can figure is one of the "slipped" rocks is the culprit. It is an MK-303 24 inch segmented blade.
I did check and there is no looseness in the shaft or the bearings, it's definitely a bent blade. Anyway of getting these fixed or am I looking at a new blade. I did find a Youtube video about straightening a bent blade. Mine does not seem to be bendable as the one in the video. I was going to call MK Diamond on Monday to see if they have any suggestions.
Thanks
Henry
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whyofquartz
spending too much on rocks
So, Africa is smaller than I expected...
Member since December 2019
Posts: 318
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Post by whyofquartz on Jan 11, 2020 9:05:19 GMT -5
It being a circular blade it would be hard to get flat again without heating it and heating it will effect the temper and other molecular properties. If you have access to two ~26" square, thick(1/2 inch thick or thicker) steel plates and a screw press you could mash it for several hours but it being tool-steel it has probably "taken a set" and the only way to "reset" it is to get it very hot.
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Fossilman
Cave Dweller 
Member since January 2009
Posts: 20,723 
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Post by Fossilman on Jan 11, 2020 9:13:06 GMT -5
Give it a try (As stated), but I think a new blade is in order! That sucks!!
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Post by HankRocks on Jan 11, 2020 9:23:55 GMT -5
It being a circular blade it would be hard to get flat again without heating it and heating it will effect the temper and other molecular properties. If you have access to two ~26" square, thick(1/2 inch thick or thicker) steel plates and a screw press you could mash it for several hours but it being tool-steel it has probably "taken a set" and the only way to "reset" it is to get it very hot. It sounds like that might work. On the other hand finding the required plates, not to mention lifting said plates and a screw press are the show stoppers. I will call MK on Monday and see if they do flattening. Thanks |
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Post by hummingbirdstones on Jan 11, 2020 11:01:52 GMT -5
Oh man, that sucks. Sorry that happened to you, especially on a 24" blade.
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Post by stonemon on Jan 11, 2020 13:10:20 GMT -5
My experience with 24" blades is that even when they get a wobble or as the case with my last new one which came with a wobble, is that you can still get a nice smooth cut with them as once they get embedded into the cut they will not flop back and forth.
I would suggest loading up a piece of hard, low grade material and running a few slabs to see what they look like on completion.
It may be you will find the saw still will give you an acceptable slab even with a bit of wiggle.
Hope you find a way to make it work. Buying new blades for that size of saw is never any fun! Good luck with it.
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Post by HankRocks on Jan 11, 2020 16:39:27 GMT -5
My experience with 24" blades is that even when they get a wobble or as the case with my last new one which came with a wobble, is that you can still get a nice smooth cut with them as once they get embedded into the cut they will not flop back and forth. I would suggest loading up a piece of hard, low grade material and running a few slabs to see what they look like on completion. It may be you will find the saw still will give you an acceptable slab even with a bit of wiggle. Hope you find a way to make it work. Buying new blades for that size of saw is never any fun! Good luck with it. I am going to give it a try tomorrow. The only downside I see is that the cut will not be as smooth and for those pieces I wish to lap polish it presents a much longer first stage. We will see what it does. I am wondering if there's any reason to buy the expensive blade. Did see some that are about $230 less than what I paid for the first blade. If the dang blade is going to develop a wobble at some point, maybe I am better off going cheaper. The video on youtube indicated that some blade can be "bent" back in shape by hand. Something to do with the type of core. And they are cheaper. It appears that more research is in order Henry |
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Post by hummingbirdstones2 on Jan 11, 2020 23:01:17 GMT -5
Have used the method in the video on blades. It can work. If you have a problem closer to the center of the blade, sometimes a 3 lb. deadblow with the blade lying on a piece of plywood works. If you find the center of a warp closer to the center just hold the blade down against the plywood and apply a little persuasion there.
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Post by toiv0 on Jan 11, 2020 23:46:07 GMT -5
I would lay it down on something you know is true flat, then peen it with a hammer and if its close to the diamond switch to the dead blow. I have straightened a couple like that. Never tried it on a segmented blade though.
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Post by HankRocks on Mar 1, 2020 20:46:49 GMT -5
Finally got around to replacing the "bent" 24" blade with one of the cheap replacements I bought. The plan was for the cheap blade to do the cutting while original blade could hopefully be repaired. Right away we noticed that the new blade had a wobble!! now what!! We removed it and decided to check both blades on a piece of thick plywood laying on garage floor. Both were flat!! It could not be a bent shaft as that would not create a wobble, just a slight off parallel. Plus the idea that the 1 inch shaft could have gotten bent is very unlikely. A bit more investigation showed a small burr(ding) on the blade side of the back flange. We sanded out the burr, mounted the original expensive blade and it ran true!! It made sense as tightening the nut against the front flange would have bent the blade around the dinged burr on the back side flange. Bottom line, the original expensive blade is still good. Did a test cut and it was smooth!! That is a nice day!!!  Henry |
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Post by knave on Mar 1, 2020 20:56:11 GMT -5
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agatemaggot
Cave Dweller
Member since August 2006
Posts: 2,195
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Post by agatemaggot on Mar 1, 2020 21:08:34 GMT -5
There used to be a shop that could straighten bent blades, you might try calling Minnesota lapidary supply and ask Val Carver if he knows anyone that does that sort of work.
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Post by hummingbirdstones2 on Mar 2, 2020 8:23:51 GMT -5
HankRocks - glad you found that problem. It must've felt like finding money when the re-mounted blade ran true, eh? I just ordered an 18", and saw the prices for the 24" blades while I was shopping around. Good for you.
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