jspencer
freely admits to licking rocks
Member since March 2011
Posts: 929
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Post by jspencer on Mar 21, 2012 0:28:03 GMT -5
I have seen threads here that have stated a rate of about 1 inch per 5 mins for a good rate of feed on a saw. Would that be the travel distance on the carriage for a rock using the full blade depth or does it matter? In other words if I`m cutting a 2"x2" rock would I expect the same rate? I first put a 6lb. weight for the pull and it cut nice and smooth and was cutting fairly fast. I have now found that using a 3lb. weight gives me about 1" per 5 mins. but it seems to barely make any noise at all when cutting. Is it possible to cut too slow and cause any excess wear or damage to the blade? Both weights cut smooth and the heavier weight does not seem to use much of the saws capacity as far as I can tell by listening. I`ve used since I was a kid and was a carpenter by trade so I have used every saw imaginable between that and welding school and machine shop work. It helped to be raised by a mechanic too. I laerned to build my own hotrods when i was a kid.
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Post by Woodyrock on Mar 21, 2012 1:40:29 GMT -5
With a weight driven feed, your hearing is the best judge of how much weight you need for each different stone. A big rocks needs to be fed a wee bit slower than a wee one. Soft ones faster, and hard ones slower. If you put your weight in a can that drops into a bucket of water, you can have a self stopping feed. This will help the longevity of the blade by now allowing it to run past the end of the cut, and have the wee broken bit at the break point from running against the saw blade. a query on the net about weight fed saws will come up with an illustration of this to make it clearer. Woody
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Post by johnjsgems on Mar 21, 2012 14:35:14 GMT -5
I don't think you can feed too slow. On my tile saw if I shove soft rocks through fast the cut is never as smooth as feeding hard rocks slower. The slower feed is less pressure of the rock against the blade so it can only be better to feed slowly it seems to me. On my HP 24 I set the belt on the slowest pulley choice when I bought the saw some 15 years ago. I have never moved it since.
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jspencer
freely admits to licking rocks
Member since March 2011
Posts: 929
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Post by jspencer on Mar 23, 2012 0:29:37 GMT -5
Ok thanks guys. I actually am using a pad made of foam rubber at the bottom of the drop. This saw almost feeds itself and with just 3 lbs. on it the carriage stops when it is cut through. I have had hardly any of those bits left from a cut coming out of the rock. I don`t know howI got it to work so perfect on my first attempt. I think it feeds better than most motor driven auto feed saws I have seen used. I cut mostly all agates, jaspers, and petwoods so I am cutting a lot of hard stones. I think I`ll just leave the lesser weight on it since I`m in no hurry. I have a lot of material to cab now from last weeks cuts. I`m filtering my oil before I run again. I am also going to go diamond on my cabber soon and can then finish the cabs off on the spool polisher.
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Mar 23, 2012 4:01:09 GMT -5
The numbers I've read at blade and saw manufactureres' sites are more on the order of like 7-10 inches per HOUR...
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QuailRiver
fully equipped rock polisher
Member since May 2008
Posts: 1,640
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Post by QuailRiver on Mar 23, 2012 13:13:53 GMT -5
Different manufactured saws have different feed rates according to the saw's design and intended usage. For example, most 14" saws are designed for a top feed rate of around 13" to14" per hour, but the Lortone 14" Panther is designed for a fixed rate of 19" per hour. Lortone's 18" saw has a variable feed rate that ranges from 9-12" to 19-1/4" per hour. I've had two Lortone fixed rate 10" slab saws that were manufactured about a decade apart, one cut 10" per hour and one 8" per hour. The proper feed rate is relative to the surface feet per second that the blade is traveling, the hardness of the rock you are sawing, the size of the rock you are sawing, the type or condition of the blade you are using, and the coolant you are using. Obviously a hard Brazilian agate will cut slower than a Jasper of the same size under the same saw conditions. And a well dressed blade cuts faster than a dull blade. A thin kerfed blade cuts faster than a thick kerfed blade. An oil cooled blade can safely cut faster than the same blade being cooled with water. Some of the more expensive saws have a built in clutch system that will adjust the feed rate automatically as needed. But gravity fed saws are more challenging. As Woody mentioned, hearing the sound of the saw while cutting is the best way to judge if you are using the proper weight. But this takes experience and unfortunately a blade or two can get ruined in the learning curve, so you might want to start out with an inexpensive blade.
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hope
spending too much on rocks
Member since May 2008
Posts: 477
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Post by hope on Mar 24, 2012 12:59:05 GMT -5
The sound of the saw is definitely very important and it does take some time to get use to. You will, after a while, realize that the "harder", louder sound means that your saw is traveling to fast for the rock and/or your blade needs "dressed". Another very important sign of a saw traveling too fast or a blade that needs "dressed" is the temperature buildup of the blade and the rock. I always pay attention to how hot my blade and the rock I am cutting is getting. If they are more than just a little warm, you probably need to slow down or "dress" the blade, or both.
I remember posting on this site a while back about glueing my partially slabbed rocks to a block of wood to finish them with interior wood glue. The great think about the wood glue is you can just throw the last slab in a bucket of water and the glue will come loose in a few days. The one comment I got was that someone said they could not use the glue as they had had the glue melt and the rock come loose. That person was evidently running to fast, or had a dull blade to melt wood glue. I have never had a rock come loose that was glued with interior wood glue because the rock never gets hot. So, again, run slow enough and keep the blade in good shape and you will always be a happy camper.
Hope
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