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Post by Jugglerguy on Nov 4, 2013 19:46:02 GMT -5
This summer I bought a 10 inch FranTom saw. I've already asked some questions about it, but I'm still having a problem with it. My first problem was that the vice track was not parallel with the blade, so rocks would bind as they went through the saw. I fixed that by shimming the arbor. There was also a piece of wire missing that the vice rides on to keep it off the table. I added that. I was also using the depth guide as a fence which I've stopped doing. All these things were helpful, but I'm still having a problem of the rock riding up the blade. The vice has a single rod that it rides along. The vice can be pivoted up on this rod to move out of the way. I'm assuming this is both for cleaning and also so that the saw can be used as a trim saw. It's a gravity feed vice and I've been careful to not add too much weight so the rock moves slowly. I haven't actually timed it, but my goal is five minutes per inch. Rocks start out going faster than that, but slow down as they move through. I'm sure that's partly due to the rock getting thicker and causing more friction as it moves, but they eventually almost stop. They also ride up the saw so that the vice pivots up off the table. I'm not sure if the pivoting is causing more friction or if more friction causes the pivoting. The blade is turning toward the table. I have given up on the saw and I'm just hand feeding the rocks. The saw seems to work fine this way, but I'd rather be doing something else while the rocks cut themselves. I have two possible sources for my problem, but maybe it's something else. First, I bought a cheap blade. I bought the economy green blade from Color Wright. It cuts well when hand feeding. The other possible problem is that I've been using water with RV antifreeze as a lubricant. I'd rather not use oil. I'm going to order some Gem Lube from Kingsley North, but so far I'm using 50% water and 50% antifreeze. Am I missing some other cause for the rock riding up? Would a better blade or lubrication help? (Edited to correct "an inch a minute" to "five minutes per inch")
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Thunder69
Cave Dweller
Thunder 2000-2015
Member since January 2009
Posts: 3,104
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Post by Thunder69 on Nov 4, 2013 20:31:32 GMT -5
IF it is a friction problem why not try mineral oil...cuts really well ..not as bad as saw oil to clean up....Little dawn and water ..Plus you can get it anywhere for cheap..As far as blades go I got one.. name brand Rigid .continuos rim..from the hardware store and use it on my 10 inch and with the mineral oil it cuts like a charm....John
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Nov 4, 2013 21:50:18 GMT -5
An inch a minute seems pretty fast. I believe my saw cuts at five inches in twenty five minutes and that is a factory set speed drive motor. Jim
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Post by Jugglerguy on Nov 4, 2013 22:03:30 GMT -5
Oops, I just corrected that to say "an inch every five minutes". I was thinking one thing and typing another!
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,559
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Post by jamesp on Nov 4, 2013 22:22:07 GMT -5
1-dull blade 2-poor lubricant 3 1 inch every 5 minutes sounds fine.
Try dressing w/AO grinding wheel
try it w/mineral oil
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Post by Peruano on Nov 5, 2013 8:12:28 GMT -5
The problem is indeed that your specimen is moving faster than the saw is cutting, but the real culprit to work on is that vice. Because the vice can lift up (as I understand it only on the blade side), the pressure of moving forward causes it to lift up as the specimen rides against the blade. Try running the saw and keeping a hand on the vice to make sure it stays on the table. This is the only fix unless you can devise a way to lock the vice in the horizontal position. Not having the rock firmly gripped in the vice causes rocks to ride up in other situations (even with saw vices that can't ride up). Many others deal with a vice table that can twist slightly due to loose fit on rails (usually turning away from the blade (again due to pressure) and that causes the blade slot to be misaligned and binding or at least excessive saw marks on one end of the slab. I hope this helps. The other factors mentioned are also important. Tom
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Post by nowyo on Nov 5, 2013 9:32:39 GMT -5
I have the same saw and experienced some of the same problems. When I first got the thing, i wasn't sure how much I really wanted to put into it so I bought the cheapest blade I could find, and used water for lube. It cut slow, the rock tried to ride up the blade, vise wanted to rotate on the one guide rod. Finally a rock rode up, bound up on the blade and wrecked the blade. Bought a BD 303 blade and started using mineral oil (horse laxative from Tractor Supply). Seems to have solved most of the problem. The only real difference I see between your saw and mine is the position of the pulley for the weight cable. Mine is about halfway between the vise guide rod and the blade, and attaches at about the midpoint on the vise. I'm thinking that arrangement would help it keep pulling in a straight line better. I can try to get a picture later if you'd like.
How much weight are you using? I've never really seen anyone say how much weight to use on these gravity feed saws, and I'm still playing around with that part of it. Really is dependent on the rock type being cut, too. Slower cuts seem to work better.
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Post by 1dave on Nov 5, 2013 9:56:57 GMT -5
I think the problem is the attachment of the weight cable. It is attached too high and too far to the left, lifting the arm up and the arc of the swing is binding the blade. Try moving the attachment point to the bottom of the eye-bolt.
Better yet, drill a hole low in the back of the vice near the blade and attach the weight cable there. If that doesn't work, like the President, I never made any of these remarks.
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panamark
fully equipped rock polisher
Member since September 2012
Posts: 1,343
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Post by panamark on Nov 5, 2013 10:06:59 GMT -5
Hi Rob,
Just a thought, have you dressed the blade lately? I mention this because I use 50% RV antifreeze on my 10" saw. Well the other day I got forgetful and used virtually straight water (with borax) and within 2 rocks the blade was shot. Not ruined, but it will take me quite a while with a firebrick to get the blade back working. It was really surprising how quick it glazed over with just water! Made me a real believer in the antifreeze. (I, like you, don't want the mess of oil in this small saw). In the past (and for the first stone this time) the saw would cut very nice and fast, but now it really is ineffective and all kinds of binding and other problems are occurring. As I remember you have run this saw blade quite a bit with just plain water.
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Post by Jugglerguy on Nov 5, 2013 16:14:43 GMT -5
Mark - I did try dressing the blade with a firebrick. I only cut through it once (about 4 inches). Maybe I have to cut more brick to get the job done. I have always run with antifreeze.
Everyone else - Thanks for all the tips. I'm going to continue to attempt to use this without oil until that's the last thing to try. The eye that the cable attaches to does not look like an original part. However, the pulley does seem to be original. So I think the attachment point should be in the same place, but maybe lower. I'll try lowering it. Attaching closer to the blade seems like it would make the vice bind on the rod. I'll give it a try if lowering doesn't work.
I'm also going to get a different blade for the saw to see if that makes a difference, and get some Gem Lube.
Nowyo, I'd love a picture of where your pulley is. Is it the original pulley? I don't know how much weight I'm using, but it's a couple of fist sized rocks in a bucket. I've tried more and less also.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Nov 5, 2013 18:30:28 GMT -5
I am wondering if sitting a large rock or other heavy object on top of the vice would help any. Jim
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panamark
fully equipped rock polisher
Member since September 2012
Posts: 1,343
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Post by panamark on Nov 5, 2013 18:54:33 GMT -5
The physics are that when you cut a thin rock the saw blade cutting portion is almost perpendicular to the rock. But if you are cutting a thick piece of rock, instead of perpendicular, now the saw acts like a wedge on the top portion of the rock to lift it up. In other words, rather than strict cutting, the rock is riding up on top of the saw blade. The problem seems to be the saw is not cutting well/fast enough to keep the rock from riding up. I think you need either a sharper saw blade or a slower feed rate, or both. Also, more force pushing down on the rock may be the simple fix as Jim mentioned. The new blades are relatively cheap (i.e. relative to a 24" or 30", ha!) so that would be the next step. Hope this helps
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Post by Jugglerguy on Nov 5, 2013 19:08:40 GMT -5
Mark, that's a great explanation of the cause of the problem. I hadn't thought of the blade acting as a wedge or ramp. The blade is moving toward the table (in the front), so I couldn't figure out why the rock would lift up.
Jim, I tried putting a large rock on top of the vice and it did help some, but not enough.
I just ordered a BD 303 blade and some Gem Lube, along with 100 lbs of grit from Kingsley North. Thanks for the tip on the grit sale, Mark! Hopefully with all the advice, I'll get this thing working better.
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Post by johnjsgems on Nov 5, 2013 19:37:36 GMT -5
Covington supplies a fish scale with their gravity feed saws. I think if you use the fish scale to measure the weight required to pull the vise through by hand you can determine the weight needed. I've owned two of those saws over the years. The pulley looks right but the eye bolt doesn't. Been a long time and I only hand fed mine. With a good blade you can feed really fast if you want so you may not need the gravity feed. Best approach is to really listen to the saw when hand feeding. You can easily hear when you go too fast. Use just enough weight to maintain the right sound without worrying about the time. The slower the cut the smoother the cut, the less amount of glazing, and the longer the blade life.
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Post by nowyo on Nov 6, 2013 19:24:58 GMT -5
Rob, finally got a picture this afternoon. I see another difference between your saw and mine-yours is clean. The pulley mount is original. Hope this helps. Johnjsgems - thanks. Kind of what I had figured, been going by when the saw sounded happy. Russ
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Post by Jugglerguy on Nov 6, 2013 19:46:13 GMT -5
Thanks Russ. My vice is slightly different and my pulley also appears to be original. My vice has a set screw on the vice where it pivots to keep it from sliding while I'm loading it. Yours seems to have a tall replacement bolt there. My vice also has the eye that will screw down to tighten the vice to the rod that I have my cable tied to. It looks like they changed the design somewhere along the line. Now I'm wondering which one is the new and improved model! John, thanks for the info on the blade sound. I haven't noticed the sound changing much, but I'll have to listen more closely.
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Post by johnjsgems on Nov 6, 2013 20:11:23 GMT -5
I rebuilt my first Frantom. The vise rod bushings were found at Ace Hardware in the pull out hardware drawers. You might want to check those too. Mine were worn enough to cause the vise to not slide easily. When you put the 303C blade on you can speed up the blade a few hundred rpm's. They cut better at 2000-2200 rpm.
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Post by Jugglerguy on Nov 6, 2013 20:16:54 GMT -5
Thanks for the info, John. My vice slides easily, so I don't think that needs replacement parts yet. I didn't know about the saw blade speed. I think one pulley is slightly larger than the other, so I'll have to switch them or replace one. Ace has those too.
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jollyrockhound
spending too much on rocks
Member since March 2013
Posts: 409
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Post by jollyrockhound on Nov 6, 2013 21:24:19 GMT -5
Hello, yes I agree with everyone saw blade speed is the issue most of the time, sometimes its because the rock is not clamped tight enough check that too. usually if the saw is slow it will still cut but leave multiple saw marks.
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ash
spending too much on rocks
Prairieville, Louisiana
Member since July 2012
Posts: 361
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Post by ash on Nov 6, 2013 22:09:18 GMT -5
New blade and probably less weight would do the trick. I would say change the oil, but you're not using any lol so don't change the oil.
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