zarguy
fully equipped rock polisher
Cedar City, Utah - rockhound heaven!
Member since December 2005
Posts: 1,791
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Post by zarguy on May 6, 2014 20:40:41 GMT -5
Our club shop has a 20" Highland Park slab saw. It seems to feed extremely slow. I have an HP 14" at home & it feeds much quicker. I think the small drive pulley is 2". The shaft is 1", so that looks about right. Not sure about the motor, but probably 1725 RPM. I'm driving the smallest of the 3 pulleys at the front of the saw. I'm just wondering of I should replace the 2" pulley with a 3". That would multiply the speed by 1.5. I should have done my homework & gotten specifics. I'll check tomorrow. What kind of feed rates are recommended for this setup? Lynn
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QuailRiver
fully equipped rock polisher
Member since May 2008
Posts: 1,634
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Post by QuailRiver on May 6, 2014 21:26:39 GMT -5
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 6, 2014 21:41:48 GMT -5
Feeding too fast can cause saw marks and can warp the blade. The larger blades don't spin as fast and need a slower feed rate. And the rocks are usually bigger which calls for a slower rate of feed, as well. I get impatient with my rig, too, and am often tempted to increase my feed rate. My saw (self built) has a digitally variable feed rate. Nifty little whiz bang thing and I love my digital readouts and LEDs but the only time it's advisable to change the rate is if I swap in a different size blade. I've warped/dished a couple of blades by getting too cocky and feeding too fast when cutting very hard rocks... C-ya, Rick
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zarguy
fully equipped rock polisher
Cedar City, Utah - rockhound heaven!
Member since December 2005
Posts: 1,791
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Post by zarguy on May 6, 2014 21:50:53 GMT -5
Thanks,Larry & Rick. I'll do the math next time I'm at the shop. Lynn
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rockpowell
having dreams about rocks
Have been rock hunting most of my life, love cutting rocks, have tons of slabs, just haven't posted
Member since February 2013
Posts: 73
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Post by rockpowell on May 6, 2014 22:47:10 GMT -5
FROM ROCKPOWELL That's an OLD machine in the first place if you noticed there is 3 sizes of wheels on the drive feed-- fast smallest med for med feed and the large wheel for slow when cutting very large rocks, If you have a PROBLEM WITH MY SAWS PLEASE TALK TO ME FIRST after all, I AM the shop foreman, this going behind my back does not get it as you have gone and under cut my deal on the Indian blanket. That was my deal !!!!! And by the way thats a 1/2 horse motor on it. and its getting old and wore out. I have a broken trim saw to show for people messing with the equipment.
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Post by Rockoonz on May 6, 2014 23:04:51 GMT -5
I will have to agree, Don't start "fixing" your clubs machines. These are shared machines, not your personal saw. Powell has the job for a reason, and I'll bet that he saves the rock club a lot of cash by dialing everything in for long life. I do the same thing for my club and when the phone rings and it's a certain member I know I have something to fix.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on May 6, 2014 23:25:53 GMT -5
I would think that it would not be a good idea to alter a specifically engineered machine.and it would suck to be responsible for a blade that pricey.just my 2 cents.
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zarguy
fully equipped rock polisher
Cedar City, Utah - rockhound heaven!
Member since December 2005
Posts: 1,791
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Post by zarguy on May 6, 2014 23:28:12 GMT -5
I was only asking. I wasn't ready to change anything. If the pulleys on the machine aren't original, I wanted to find out what should be on there. Does anyone know what sizes should be on a HP 20" Lynn
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Post by Rockoonz on May 6, 2014 23:56:37 GMT -5
zarguyHere's a better idea, find out how fast it is really traveling. When it's set up to cut a slab before the lid is closed measure the distance from the vice to the front of the saw box and write down the number. Start the stopwatch on your cell phone when the saw starts, and when the cut is done note the time and write it down. Before the vice is moved take a measurement from the same points and subtract the original measurement to get distance traveled. If the number of minutes it took to make the cut is more than 8 times the distance traveled in inches then you might bring up your findings to Rockpowell. Correct cutting speed for a slab saw is 5-8 minutes for every inch of travel, and the bigger the saw gets the slower it should be. The type of blade the saw has is a factor as well. if your club has a lap shop it's a rare thing, worth working to keep. I am sure the shop could probably use some help, ask your shop foreman how you can help. I'm sure he spends a lot of time taking care of things to give the club members an enjoyable experience.
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Post by 1dave on May 7, 2014 10:03:03 GMT -5
It would be good to know your feed rate options. On a slow day pull the vise all the way back and turn the saw on for 10 minutes and measure the travel. Do the same for the other pulley sizes and make a chart for others in the shop.
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