gh
off to a rocking start
Member since June 2015
Posts: 4
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Post by gh on Jun 24, 2015 7:05:07 GMT -5
Built a rock saw to cut field rock and it works great but hard granite seams to be a problem. It is a reciprotating blade 48 in long with diamond segments and will cut limestone at 5 in / hr but hard rock at 3/4 in per hr will cut for the first 6-8 in then the blade no longer cuts, Ive seen some mention that diamonds can only cut granite unidirectionaly not bi directionaly is this so==is there a simple way to get arround this or do I have to find a way to lift the saw every stroke (60 in/min.) or only cut soffter rock--also what is a good way to classify== Scratch test seems rather hard to interperet and one hard rock ruins the blade. My home built works very well but very disapointing in this regard as most of my rock is granite that i want to cut. I managed to get through a few rock 2o in deep x 30 in long but some were a struggle --any help would be appreciated --I did see a photograph on your forum of someone else with a reciprotating saw. Most of my reserch has been on comercial frame saws but not a lot of info available. Have cut lots of granite with circular blades no prob so thought this would be the answer for large rock but apparently an oversite on my part---who new --they say diamond gets pulled out and torn away in hard rock going back and forth (ok on soffter rock however} It has been mentiond that there is a supper diamond segment that will withstand granite---does anyone know about this subject
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Post by woodman on Jun 24, 2015 8:59:14 GMT -5
I use a drag saw and on hard materials I had to use diesel as a lube. Would not cut using water. Diamond segments are two inches long. I don't know how hard granite is compare to agate but using diesel on agate it cuts good. With water it would cut for a short time and then I would have to dress the segments. Still have to dress the segments using diesel but not nearly as often.
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,711
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Post by Fossilman on Jun 24, 2015 9:40:20 GMT -5
I have cut granite on my 14"..........Took a bit longer,but did a great job....Using mineral oil as a coolant.Sounds like your blade is what is giving you problems,switch it out and try something else... PS: Welcome to the board...
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gh
off to a rocking start
Member since June 2015
Posts: 4
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Post by gh on Jun 24, 2015 13:33:50 GMT -5
Problem is reciprotating bi directional rather than unidirectional---diamonds only work in one direction such as in a circular saw on hard granite, ok on softer rock, I cut limestone and marble no prob at 5 in/hr. The diamonds get raked by going in one direction and then when they go the other direction they are like a barb catching on the hard granite and get riped out of the segment.
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Post by woodman on Jun 24, 2015 13:59:36 GMT -5
Problem is reciprotating bi directional rather than unidirectional---diamonds only work in one direction such as in a circular saw on hard granite, ok on softer rock, I cut limestone and marble no prob at 5 in/hr. The diamonds get raked by going in one direction and then when they go the other direction they are like a barb catching on the hard granite and get riped out of the segment. If I had a piece of granite, I would give it a try. I am not an expert by any means but my saw cuts fine in both directions when cutting hard agate. What are you using for coolant/lube? I find that granite is 6 to 7 on the mohs scale and agate is the same, so you should be able to cut it. Where did you get the diamond inserts that you are using?
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Post by deb193redux on Jun 24, 2015 22:38:33 GMT -5
your segments may not be in the right metal matrix. if the metal is too hard,new diamond does not get exposed fast enough on harder rock
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Post by Rockoonz on Jun 24, 2015 22:58:43 GMT -5
I think Daniel gets the prize for this one, It makes sense that the segment matrix is important. If diamonds are somehow ripped out of the matrix it's a kerf problem, not a directional problem. Cutting with oil and not water is critical.
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gh
off to a rocking start
Member since June 2015
Posts: 4
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Post by gh on Jun 25, 2015 2:03:55 GMT -5
certaintly merit in what you say---Yes I'm only using water but lots of it. May be I should try mineral oil but will have to make changes to keep it contained Currently I run a little giant submersable pump that drops water into a funnel that then directs the water to the curff and I use duck seal to constrain or dam the water if needed like on a pointed rock but there is lots of overspray and splash-which I catch most of with cloroplast skirts or curtains but the short fall is made up with a float to a garden hose. Grass is a little greener arround the saw lol so will have to make some sort of curtain that is quick to put up and yet 100 % eficient.-- I have spaced 2x4s making a deck for the rock to sit and can easily screw blocking to this to restrain the rock. My reservoir , 3'x3'x1' h is supporting the deck. Its important that I can use a fork lift and tongs to load and unload as some rocks Ive cut are 500 lbs. or so. Heat would not be an issue as I'm only running 60-70 strokes / min but the lubrication could be what i need, just have to re design tank and recovery and give it a try. WHAT WOULD BE BEST DEISEL OR CHEAP MINERAL OIL? Do you wash the rock with ? after etc. Lots to learn. Made my first blade with 14 ga steel but the next one will be 12 ga. so will be cutting a wider curf but hope to have less flex and more tension on blade by reinforcing the frame. Will appreciate all advice and ideas from the forum. Gary H. .
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Post by woodman on Jun 25, 2015 2:33:49 GMT -5
Cheap mineral oil is still prettly costly, that is one reason I use diesel. I built a pan to set rock in to recover the diesel. I think it is more of a case of lube rather than cooling. the inserts i use are centered onto a 1/8 inch thick tool steel blade ten inches wide that has a stiffener on it that comes off when the cut is 8 inches deep. When I was cutting soft materials, water worked fairly well but had to dress the diamond often, but after cutting with diesel I would never go back to water. Diesel in time will evaporate but not mineral oil.
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gh
off to a rocking start
Member since June 2015
Posts: 4
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Post by gh on Jun 25, 2015 6:06:29 GMT -5
How do you post photos I am not in sync with this hard to use (probably me ) board and find it hard to navigate as well .
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Post by woodman on Jun 25, 2015 9:27:27 GMT -5
How do you post photos I am not in sync with this hard to use (probably me ) board and find it hard to navigate as well . At the top of the page, click on help, then under the user guide click on Threads, Posts, Polls, and Attachments, then click on Adding an image to your posts.Have a good read, it explains it all. The add attachment way does not work. This picture was posted for photobucket using the direct link method. Once you do it a few times is works real good. I tried using the add attachment function but got an error saying this board has used all the attachment space allowed, what ever that means. Hope this helps
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Post by woodman on Jul 4, 2015 11:14:57 GMT -5
Glad to hear that you got it cutting better using the water soluble biodegradable oil.
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Post by johnjsgems on Jul 17, 2015 14:06:23 GMT -5
Diesel is a lot cheaper than mineral oil. I've met two different cutters at Tucson show that lost their shops using diesel in their saws on hot days. Spontaneous combustion. Also I think carcinogenic (but that might be the exhaust fumes). Doesn't smell like perfume either.
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Post by Rockoonz on Jul 17, 2015 23:09:52 GMT -5
Lots of nasty additives in the modern clean burning diesel and the flash point is also lower. Looked at the aftermath of one of those fires, piles of formerly nice limb casts covered in melted asphalt roofing. The guy said they would clean up, I said no thanks.
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Post by roy on Jul 18, 2015 9:27:28 GMT -5
i ad more oil in the summer to my diesel it will help with that problem in the winter i run it straight it makes clean up real easy for me
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