horacefarrow
off to a rocking start
Member since March 2010
Posts: 2
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Post by horacefarrow on Mar 21, 2010 10:55:24 GMT -5
I have a Covington 10 " slab saw when I put a rock in the vice it cuts a short way into the rock then it binds and locks the blade and burns the belt. anyone have a sugestion on what I can do to stop this. I am using mobil home antifreeze for a coolent. I use this in my six inch saw that I cut by hand and have no problem .Can this be the cause of the binding
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Post by deb193redux on Mar 21, 2010 13:02:46 GMT -5
You could try oil and see if the problem goes away.
What kind of blade? For non-oil coolant, you need a blade where the kerf is a bit wider than the core to avoid too mich friction.
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Post by Bikerrandy on Mar 21, 2010 17:14:18 GMT -5
Does it have a screw-type auto feed? The binding is a very common problem for screw-type auto feeds, everyone around here is converting those saws to gravity feeds. When cutting the harder stones (like Brazilian agates), the blade doesn't keep up with the hardness but the auto feed continues at the same speed, forcing the rock into the blade. I burned up 2 belts on my 16 inch Covington last month. I don't cut any agates on it now, not until I convert it. The gravity feed will put the vice past the blade without forcing it. This allows the blade to cut the stone at it's own pace, and not the pace of the auto feed.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,484
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Post by Sabre52 on Mar 21, 2010 17:52:15 GMT -5
Yeah, coolant might not be the problem either. Your blade may be dished or have it's edge so rounded that the cut it's making is sort of wedge shaped causing the blade to bind or the coolant may be too full of sludge so it gets gooey in the cut making it bind. As Randy has said, power feeds often force hard rocks into the stone too fast too. I've even had that happen with gravity feed as you are still pulling the stone against the blade with weight. Sad fact is, most diamond blades only cut for a hundred hours or so before they get so they bind in the cut. Even with all the various types of resharpening, my record for a 20" blade ( MK303) was 135 hours before it started screwing up when cutting larger agates. My old Beacon Star 10" does better but it's way overpowered with a very fast running blade and a very very slow screw feed...Mel
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Post by freeformcabs on Mar 21, 2010 20:48:48 GMT -5
Is it a new problem, specific to the rock you are cutting? Not fimilure with the saw, but it could be a simple losse screw on the feeder than cuase the vise to lift or become out of algnment with the blade when the rock starts really cutting.
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horacefarrow
off to a rocking start
Member since March 2010
Posts: 2
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Post by horacefarrow on Mar 21, 2010 20:51:47 GMT -5
I Replaced the blade with a new on. I saw nothing wrong with the blade that came with the saw it has only cut 3 to 4 stones. New blade had same problem. the saw was purchased ned about a year ago. and has a screw feed Where can I find information on converting to gravity feed.
any other information will be a big help
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,484
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Post by Sabre52 on Mar 21, 2010 21:27:57 GMT -5
OK, if a brand new blade is binding in the cut you probably have a misalignment problem or something other than a feed problem. I don't really know how you'd misalign the vice and blade on my saw as position is pretty much fixed but maybe yours has something loose so the blade is not parallel to the vice. A brand new blade running straight should keep up with a screw feed. Does your motor have pulley with various wheel sizes? Mine has three pulley sizes on one pulley so you can speed up the blade and sometimes cut more effectively. I fear changing the feed type will not solve your problem as both weight feed and power feed both still drive the rock against the blade....Mel
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Post by freeformcabs on Mar 21, 2010 21:30:58 GMT -5
Mine is homemade, but i bought it used. it has a screw feed, but its on a slip pulley. The feed is driven by a rotistire motor, bought new at homedepot for $15. Its a 1inch pulley on the motor and a 1.75 inch pully on the screw feed. The belt is i beliee a 4inch belt.
The motor is mounted on a pin and spring, that allows it to kick in either driection depending on the tension on the vise and how fast the rock is cutting. The only problem with this method is it requires a step to insure the motor is spinning the right driection to feed the screw, so to cut the rock and not back off the blade. But its a good idea too becasue ive never had any binding in this saw ever, either the rock pops out of the vise, or the motor swtiches driection and backs the rock off the balde.
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Mudshark
fully equipped rock polisher
Diplomacy is the art of saying 'Nice doggie' until you can find a rock. Will Rogers
Member since December 2008
Posts: 1,083
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Post by Mudshark on Mar 22, 2010 15:50:13 GMT -5
I have the same saw with the same problem.I don't believe the power feed is the problem because it feeds very slowly.Check the alignment of the vise,I use a dial indicator in the vise and adjust the screws on the side of the saw.I use baby oil for coolant and when it starts to turn to mud it will start to bind.After cleaning the saw and changing the oil run a piece of brick or Obsidian through to expose fresh diamond on the blade.The belt seemed to be a loose fit even when the saw was brand new so I added some washers under the motor mounting bolts to tighten it up a bit.After doing all this it still binds after a while so I am going to take a closer look at the vise itself and how it mounts to the rail.I have a feeling that the vise mount needs to be beefed up a little.It usually only binds up when I cut a lot of very hard Agate but always goes back to normal after cleaning and sharpening.
Mike
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jimrbto
noticing nice landscape pebbles
Member since April 2007
Posts: 94
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Post by jimrbto on Mar 22, 2010 21:52:29 GMT -5
Really sounds like an alignment problem. I had a similar problem a few years ago. Is the vise and motor feed assembly attached to the saw table and is it necessary to remove the table to replace the blade? If so- there might be enough rotational play in the hardware holding the table in place to cause a severe misalignment between blade and vise. When a blade STOPS in a cut (assuming the motor is powerful enough) almost always the cause is feed rate way too high or alignment/lubricant problem. Verify vise/blade alignment as the vise passes from the edge (behind the diamond area) of the blade to the center. Good luck Jim
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