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Post by Rockoonz on Sept 7, 2014 20:09:32 GMT -5
I spent the last week at the NW Rockhound retreat. Had a conversation with the intarsia instructor about slab saws. Her husband, a brilliant engineer who designed several experiments that went up in space shuttle missions has been studying slab saws for many years. He has determined that the best feed rate for minimum blade wear and best quality cut is between 3 and 4 inches per hour. He changed all the feeds over to variable speed and used test equipment that can measure to 0.0001" to determine the rate of blade wear plus looking at micro inches of surface finish on the cut faces.
Amazingly (insert sarcasm symbol here) he discovered that the feed speed of the original manufacturers (you know, the same ones who sell you new blades too) seems to be ideal for the fastest blade wear.
Food for thought. It is not always easy or cheap to modify saws, and certainly beyond the technical abilities of some, but if you have a saw with a feed you can slow down it may be in your interest to do so.
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polishedball
noticing nice landscape pebbles
Member since August 2014
Posts: 89
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Post by polishedball on Sept 7, 2014 21:18:21 GMT -5
I'll go with blade wear and save the time personally.
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Post by parfive on Sept 7, 2014 22:09:49 GMT -5
Gravity rules - easily adjustable, maintenance free and never breaks down. : )
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QuailRiver
fully equipped rock polisher
Member since May 2008
Posts: 1,640
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Post by QuailRiver on Sept 8, 2014 0:13:48 GMT -5
Was there any discussion about blade speed as it relates to feed speed? Larry C.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Sept 8, 2014 6:41:00 GMT -5
Was there any discussion about blade speed as it relates to feed speed? Larry C. i was thinking the same thing.like in cutting or drilling metal,the faster you go the faster the tool wears out.
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Post by Rockoonz on Sept 8, 2014 23:30:36 GMT -5
Was there any discussion about blade speed as it relates to feed speed? Larry C. I didn't consider that during the conversation, but it's something to think about. Blade RPM recomendations are based on the surface speed of the cutting surface, and should not be exceeded, but I think staying towards the upper end of the RPM range also helps with the surface of the slabs. polishedball if as your name implies you are into sphere making a fast cut may be more cost effective, the sphere machine will take care of nasty saw marks rapidly. If the goal is polished slabs, wood , geodes and the like, then a surface with a poor surface will lose you much more time removing saw marks than you could ever gain in saw cut speed, plus add more wear and tear to the tools you use to clean them up. The people who suggested this to me cut slabs exclusively for intarsia out of nothing but high quality material. In intarsia all surfaces must match perfectly.
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Post by Rockoonz on Sept 8, 2014 23:32:47 GMT -5
Gravity rules - easily adjustable, maintenance free and never breaks down. : )Hydraulic is better
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electricmonk
spending too much on rocks
Member since August 2011
Posts: 281
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Post by electricmonk on Sept 9, 2014 0:18:40 GMT -5
Lee, that is mighty interesting and not really that surprising. I can't imagine having the patience to run a saw that slow but still will consider significantly slowing down the two that I have which are pulley dependent. My Covington might be another matter, and given the issues I have with blade marks when it slabs it is probably my prime candidate for "should be slowed down".
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Post by phil on Sept 9, 2014 12:05:26 GMT -5
Gravity rules - easily adjustable, maintenance free and never breaks down. : )Hydraulic is better So how do I modify a gravity drop saw to a hydraulic feed saw? Thanks!
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deserthound
spending too much on rocks
Member since December 2013
Posts: 390
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Post by deserthound on Sept 9, 2014 12:30:37 GMT -5
That some great info..That confirms my theory also..i have had nothing but problems with my new 18" its factory feed speed was set at 12" per hr..yeah...i brought this up on another post and it was suggested i increase my blade speed via pulley change....i never did understand how that would work, as feed speed was set at 12 "and it needed to be around 5" per hr... i came uo with this figure with some other research on slab saws..i have replaced the feed speed motor to a slower one and so far so good. hydraulic drop saw now there's a cool idea...
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Post by Rockoonz on Sept 10, 2014 19:46:53 GMT -5
Hydraulic is better So how do I modify a gravity drop saw to a hydraulic feed saw? Thanks!. I have seen drop saws with dampers on them like on a screen door only more adjustable. A cylinder with a flow control to limit the drop speed would probably work on any gravity feed, it wouldn't need to be powered if the flow control was directional like the cylinders on large horizontal band saws.
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Post by phil on Sept 10, 2014 20:28:39 GMT -5
So how do I modify a gravity drop saw to a hydraulic feed saw? Thanks!. I have seen drop saws with dampers on them like on a screen door only more adjustable. A cylinder with a flow control to limit the drop speed would probably work on any gravity feed, it wouldn't need to be powered if the flow control was directional like the cylinders on large horizontal band saws. SO I need to find a directional flow control hydraulic cylinder, by weight capacity, somewhere?
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Post by Rockoonz on Sept 10, 2014 21:09:08 GMT -5
Yep phil here's a whole bunch of PITA involved in that modification. You should just get one of these...
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Post by phil on Sept 10, 2014 23:34:08 GMT -5
Yeah, me the bank and mortgage company for a property where I can use one.. grin
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