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Post by BuiltonRock on Nov 21, 2009 15:46:58 GMT -5
I have a 14 inch gravity feed Texas saw. I just put a new blade on it. I made 6 cuts great each taking about 10 minutes. On the 5th it started to slow down and the 6th it just spins half way through the cut. I am cutting Owyhee Jasper, the oil is mineral oil from a feed store and was just cleaned before the cutting with the new blade. The guides are not new, but I cleaned them and the carriage slides free. I am at a loss to know what else to do. I added some weight, cleaned the guides and that did not help.
Amy ideas are appreciated.
John
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Post by rockmanken on Nov 21, 2009 16:39:23 GMT -5
Give it to me and I'll take care of it. ;D ;D Seriously, cut a fire brick in it to dress the blade. Really shouldn't need it, though. Also, when mine does that I turn the blade over. That helps. I think jaspers clog up the blade. I have had the same thing happen. Agates seem to 'glaze' over the blade. Have to cut a fire brick to clean it. Ken
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Post by catmandewe on Nov 21, 2009 19:05:56 GMT -5
turn the blade around first, if that doesnt speed it up then try cutting a thin slice off of a fire brick or an old SC grinding wheel (the main ingredient in fire bricks is silicone carbide). If that doesn't work let me know.
Tony
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Post by johnjsgems on Nov 21, 2009 19:27:20 GMT -5
If it is an old style notched rim or crimp blade you can reverse it. Sintered blades are directional. Try the dressing first.
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Post by johnjsgems on Nov 21, 2009 19:31:15 GMT -5
Also, check the feed rate. Too fast will dull the blade. If you have a sintered blade check for directional arrow and make sure it is correct. Sintered blades will make a few cuts then stop if running backwards.
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rockhound97058
freely admits to licking rocks
Thundereggs - Oregons Official State Rock!
Member since January 2006
Posts: 760
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Post by rockhound97058 on Nov 21, 2009 20:00:08 GMT -5
Another trick that works well besides the brick/stone trick is take a bastard file (really that's what their called) - and use the edge of it and tap the leading edge of your blade with it... Do this the complete edge of the blade. This mashes away metal exposing new Diamond and is much cleaner than cutting brick... This was a old machinist trick from a Very high profile rockhound in my area!
Also you mentioned about adding weight? By doing this your increasing the feed speed. Picture Jasper is a hard stone and I would think eliminating some weight might help... This would slow your feed rate and allow the blade to clean the kerf much better before taking another bite.
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Post by catmandewe on Nov 21, 2009 20:14:53 GMT -5
This is a 10-20 year old lapidary blade, and it has no directional arrows on it. It had never been used, so it is essentially a brand new blade. I got two of them in an estate sale and one had "MK" and a number stamped on it, and the other one only had a number stamped into it but no MK, but they looked to be identical blades except for the stamping on them, same box, same finish, everything. The bastard file trick works if your leading kerf is getting thinner than your actual blade, but I can't see that happening right off the bat on a brand new blade.
Could possibly be too much weight and it is glazing the blade, try less weight and slow the cut down. Those jaspers are pretty hard, so a slower cut may be needed.
Let us know what works and what doesn't work.
Tony
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,471
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Post by Sabre52 on Nov 21, 2009 22:07:05 GMT -5
John: I guess I'm a little confused by your description. If the blade is still spinning halfway through your cut but not cutting further into the stone, it sounds as if you've stripped the diamond from the blade or glazed the blade so the steel just spins against the stone because there's no diamond to remove rock. That's the only reason I can think of where a gravity feed blade would just sit and spin against the rock. Usually what happens is the blade itself binds in the cut and stops period. In that case, the suggestions others have made might work. Also in that instance, oil viscosity can be to blame as more viscous oils just pick up too much sludge and bind in the cut. Picture jaspers are very good at that. Good luck solving the problem. I pretty much hate all rock saws as they're all pretty friggin cranky and troublesome....Mel
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jimrbto
noticing nice landscape pebbles
Member since April 2007
Posts: 94
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Post by jimrbto on Nov 21, 2009 22:14:26 GMT -5
Don't keep reversing the blade or beating on it with anything unless you like to waste a lot of money buying new blades. Every time you reverse a blade or beat on it you lose diamond that you paid good money for. First look to see that the blade is not binding in the cut and that the carriage is moving absolutely parallel with the blade at the point where the cutting stopped. If everything checks out o.k. THEN slowly and carefully cut through a piece of old fire brick, some obsidian, a piece of grinding wheel or blade sharpening stick. Then take a hard look at how much weight you are using as gravity feed, don't be in a hurry - use only enough weight to make a clean cut. Too much weight will be forcing the blade to glaze over. good luck Jim
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Post by BuiltonRock on Nov 21, 2009 22:24:50 GMT -5
Wow! We had friends over for dinner and when I get back to this post a couple hours later all the experts have given help. Thanks guys!!
I had the same thought that some blades are directional. After dinner I did sneak down and turn the blade around. I did not see an arrow, but it cut much better. I was using light weight at first and added weight as it slowed down, probably made it worse.
Tomorrow I will dress it and lighten the weight and see if we have it perfect. I am using mineral oil which is pretty thin, but still a lot of sludge in it.
I am going to the Rams game (big deal) after church tomorrow so won't be much time, but this is a short work week and I will be home all Thanksgiving weekend and will hopefully give you all an update with pics. The Owyhee I am cutting is fantastic!!
Thanks again All! John
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Post by BuiltonRock on Nov 21, 2009 23:05:17 GMT -5
I dressed the blade with an old SC wheel I had. Lightened up the weight and seems to be cutting steady. Slow and steady. I think it would be good to replace these old guides. They are rusted in spots and although I have sanded them I think it could slide better.
John
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Post by texaswoodie on Nov 22, 2009 7:03:25 GMT -5
John About every 3 or 4 cuts take a dry cloth and wipe the front of carriage where it meets the guides. Wipe it good and as close as you can get to the carriage. Put a little light grease on the guides.
Curt
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elegantcabs
starting to spend too much on rocks
"Oh make no mistake, it?s not revenge he?s after?It?s a reckoning"
Member since November 2009
Posts: 164
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Post by elegantcabs on Nov 22, 2009 8:08:00 GMT -5
The one thing Ive encountered with Owyhee Jasper is the hardeness and the fact that the rock itself likes to shift in the vise IF the feed rate is a tad excessive......that stuff needs to have a hardness rating of 9!...LOL.....but well worth it when your done
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Post by catmandewe on Nov 22, 2009 16:24:23 GMT -5
Slice up a chunk of obsidian in between chunks of jasper, it will make things a whole lot easier.
If turning it around made it work better, then it was glazing over. Too fast of a feed rate will cause that.
Have a good day.................Tony
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rockdewd
has rocks in the head
Member since October 2007
Posts: 605
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Post by rockdewd on Nov 27, 2009 12:19:43 GMT -5
This sounds like the problem I had with an HP 10 inch gravity feed when I was trying to use water as the coolant. The blade would glaze over. You didn't indicate if you were cutting with water or oil as coolant. If you are using water switch to mineral oil. Go to WalMart and buy their generic Equate brand baby oil.
I would lighten the weight you are using and take an old file and beat on the edge of the blade with the sharp corner of the file edge. You don't have to be overly brutal about it. Just give it a firm hit and do it every 1/4 inch or so on the edge of the blade.
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