mikeinsjc
spending too much on rocks
Member since June 2010
Posts: 329
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Post by mikeinsjc on Nov 20, 2011 18:50:01 GMT -5
I have an 18" Covington saw. Much to my chagrin, inattention on my part led to the destruction of an original Covington US-made blade that cut thousands of square inches of material without ever needing dressing. I took a chance and purchased another 18" (Chinese) blade from Covington. It was junk from the get-go, with over .025" runout in about twenty degrees of rotation. Rocks cut with this blade were unpolishable, the gouges were so deep. So I bought a MK303.
My problem is the blade won't cut. It bogs down the motor to the point I have to shut it off. The blade runs true. I am using the slowest feed rate. I dressed it, and it's doing it again. Are all blades today bad, or could it be my motor?
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Post by deb193redux on Nov 20, 2011 19:51:25 GMT -5
I thought my 301 was binding and slowing the motor, but it turned out to be the belt slipping. I tensioned it and used some belt dressing and it is cutting a lot better.
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rocpup
spending too much on rocks
Pink Limb Iris
Member since March 2011
Posts: 465
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Post by rocpup on Nov 22, 2011 8:21:04 GMT -5
Like you I very seldom if ever dress my blades. I cut a variety of material and the old saws just keep putting out slices. BUT once in awhile I have run across a rock that is very tough on the diamonds in the blade. I have one local rock that will take the diamond right off the saw in the first cut and jam the saw in the cut. When this happens it is very difficult to get it to cut again and a lot of dressing to expose new diamond. I keep some softer rocks and old grind stones around for just that. If you run your thumb nail across the edge of the blade you should feel the diamond catching on it. If I would check the run out on my old saws it would scare us all but they do give me a slab and that is what I want. My Chinese blade on my 14 inch saw has a kink in it from a jam but it still cuts. I don't polish slabs and for cabbing a few saw marks makes little difference. If the belt is slipping you will hear the blade slowing down and a little more tension should improve the sound. I keep just enough tension on my belts to turn the saw blade but loose enough that when it jams it will burn the belt off and not burn the motor or completely destroy the blade. Belts are much cheaper. Don
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Post by johnjsgems on Nov 22, 2011 9:35:06 GMT -5
Make sure the rotation is correct. The 303 and new style 301 blades are single directional. There is a sometimes hard to find arrow in the blade core usually on side opposite the label. I found 3 blades last year with label on wrong side so always go by stamped arrow. They cut better with a little faster speed than the old charts recommend. Also make sure the carriage is alligned properly.
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Post by catmandewe on Nov 22, 2011 21:13:19 GMT -5
John covered everything I was gonna say. Make sure you are going in the right direction and speed it up 25%.
Tony
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