brunomoki
off to a rocking start
Member since December 2010
Posts: 10
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Post by brunomoki on Jan 25, 2012 0:38:57 GMT -5
I just got my first saw on Christmas it is a frantom 10" combo unit. It needed a new blade so I ordered a covington gold series. The first few cuts have been trial and error. To much weight, not enough weight. Today I had a rock come out of the holder and put a bend in my 5 day old blade. Is there any way to straight out the bend? Is there a rule of thumb for how much weight to use, I cut mostly agate and geodes that I have collected? Thanks for any and all advice about cutting.
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Post by johnjsgems on Jan 25, 2012 9:03:44 GMT -5
The best thing is cut slow. You may need to hand feed and listen to the saw. Set up the weight feed to just ease the rock through listening to the sound. As far as straightening it can be tricky. Lay the blade on a solid surface and tap it straight without stretching the metal. I think someone posted a how to a long time ago but don't know how to search for it.
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Post by paulshiroma on Jan 25, 2012 10:18:23 GMT -5
One thing I did to learn how to use my saw was to spend an afternoon with my local rock club in the shop. I dragged some samples along with me and the gang there showed me how to hand-cut the rocks. And John is right - much of what they talked about was "feel" and listening to the saw. They gave me a good reference point with which to start. Maybe you've got a local club who can help you out?
Paul
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Post by jakesrocks on Jan 25, 2012 11:21:13 GMT -5
Hate to say it, but your first mistake was ordering the Covington gold blade. They're ok for cutting soft material, but garbage when it comes to cutting hard stuff. Suggest that you invest in a BD-303 blade. John from jsgems will give our members a real good price on them.
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Post by Hard Rock Cafe on Jan 25, 2012 11:24:41 GMT -5
Some advice given to me was tighten the vise to the point where you can't move the rock when you try to pull it out. Sorry to hear about the blade.
Chuck
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Post by deb193redux on Jan 25, 2012 11:44:06 GMT -5
I second the 303 recommendation - and go for the wider option; it is stronger.
I second the advice about getting more hand-feed experience before relying on the weight system. You need to know the "sound" of your saw.
The time an effort to somewhat straighten a 10" blade versus the cost of replacement is a tricky formula. Most "straightening" does not work really well - unless it is just a little dishing. I did manage to sufficiently straighten a bent 7" blade I was using on an angle grinder to permit me to keep using it - but an angle grinder operation is more hacking then cutting.
The most important thing is to become an expert at clamping. Also, don't let wanting to cut a rock make you relax clamping standards. You can always glue it to a block, or use a slab-grabber - or just make a preliminary cut to improve the way the rock clamps up. Be careful and patient.
Have fun cutting!
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meta99
has rocks in the head
Ohio Flint Ridge flint
Member since October 2010
Posts: 540
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Post by meta99 on Jan 25, 2012 13:35:22 GMT -5
I second (third?) what everyone said! I have the Frantom unit and didn't cut nice slabs until I bought a 303 from john (johnjsgems). Save the bent blade to play with in the future unless you are out of $$$ and don't care what your slabs look like. Your cabs will take twice as long if you have lousy slabs (I know!).
As for "How slow?", there is a guideline that says you should not cut any faster than an inch every 5 to 6 minutes but if you are cutting really hard stuff (Ohio flint for me) I get an inch every 30 minutes sometimes! That explains why slabs can cost a pretty penny online or at shows. Makes you appreciate when you see someones pictures of the tens to hundreds of slabs they've cut!
Sue
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herchenx
Cave Dweller
Member since January 2012
Posts: 3,360
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Post by herchenx on Jan 25, 2012 18:11:11 GMT -5
I bent my 6" doing a freehand, I was able to straighten it out.
It took me about 20 minutes of fiddling to straighten it. I ended up just laying it on a flat surface, noting where the bends were, placing my thumb on the side opposite the direction of the bend, right on the bend, and pulling the bend out carefully. I repeated this until it laid pretty flat and re-attached it to my machine. I've been cutting a lot since and it is working fine. The noise and flutter are all gone.
Don't know if this works for everyone or on every blade, but it worked on my 6"
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Post by deb193redux on Jan 25, 2012 18:46:09 GMT -5
I bent my 6" doing a freehand, I was able to straighten it out. It took me about 20 minutes of fiddling to straighten it. I ended up just laying it on a flat surface, noting where the bends were, placing my thumb on the side opposite the direction of the bend, right on the bend, and pulling the bend out carefully. I repeated this until it laid pretty flat and re-attached it to my machine. I've been cutting a lot since and it is working fine. The noise and flutter are all gone. Don't know if this works for everyone or on every blade, but it worked on my 6" yes, but what thickness was the blade? Some 6" are quite thin. I don't think I could bend a .032" much less a .040" with my thumbs/
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Steve
has rocks in the head
Member since June 2005
Posts: 506
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Post by Steve on Jan 26, 2012 11:09:55 GMT -5
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LarryS
freely admits to licking rocks
SoCal desert rats
Member since August 2010
Posts: 781
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Post by LarryS on Jan 26, 2012 20:01:41 GMT -5
I 4th the 303 blade from JSGems. The Covington Gold Blade is only good for cutting plywood! John also sells these nice 60 grit aluminum oxide sharpening blocks.
My 10" Covington is 1 year old and I was having drive belt issues when it was only a couple months old. Replaced the original industrial light duty 4L240 belt with a upgraded Gates PoweRated belt which are green in color. O'Reilly Auto and Napa Auto Parts sell them. These are medium duty belts and make less noise and last longer. The original belt was making all kinds of noise when under a load plus spitting out rubber dust all over the place.
My power feed runs at 8 minutes per inch, which I think that's too fast for cutting hard rocks above 2" in size. I need to swing on my Covington and see what the weight drive system looks like and copy it. That should cure a lot of problems when cutting larger and very hard rocks. I only cut super hard jasp-ag.
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Post by Rockoonz on Jan 27, 2012 0:21:41 GMT -5
Larry 8 minutes an inch is fine for anything you want to cut in a 10 inch saw. Did you increase your blade RPM with the 303 blade, for a 10 inch blade it should be 1720-2290 RPM. www.barrancadiamond.com/home/tec_speed.htmlLee
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LarryS
freely admits to licking rocks
SoCal desert rats
Member since August 2010
Posts: 781
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Post by LarryS on Jan 27, 2012 1:13:17 GMT -5
Lee,
The Dayton/Covington motor is 1725 rpm. Material I cut is extremely hard. I've stalled/locked up the motor on rocks only 1 1/2" in diameter. Yes the blade is sharp & vice is aligned. Think the motor is on it's last leg. I still would like to set it up for gravity feed on the larger rocks where I can slow it down.
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Post by johnjsgems on Jan 27, 2012 9:16:17 GMT -5
He was referring to speeding up blade speed by changing pulleys, not motor. The 303C and new style 301 blades perform better a little faster than "normal". Barranca saws run 1" in 5 minutes for 10" and 14". Slow feed rate results in smoother cuts and is kinder to the blade.
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LarryS
freely admits to licking rocks
SoCal desert rats
Member since August 2010
Posts: 781
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Post by LarryS on Jan 27, 2012 11:16:13 GMT -5
Thanks for clarifying John. Guess my operational speed is a little slow!
That's interesting. My saw struggles most of the time feeding at 8 min per inch. At 5 min, think I'd smoke the motor for sure. I never did like the itty bitty 1 1/2" pulleys Covington uses. Those are a little rough on the belt. I should kick up the rpms a bit and see how it runs through the hard rock. I'd still like to experiment with the gravity feed. I'm in no hurry. If it's easier on the blade, it's that much better.
2" motor pulley with the stock 1 1/2" arbor pulley would increase the blade rpm to 2290. I'll give that a try.
Why doesn't someone design a 2 speed power feed?
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Post by Hard Rock Cafe on Jan 28, 2012 10:09:40 GMT -5
Hi Larry,
My Great Western saw has gravity feed with an hydraulic cylinder to regulate the speed. I can adjust it from full stop to very fast. It's a nice set-up. I don't know whether there are saws currently made that have that feature.
Chuck
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Post by jakesrocks on Jan 28, 2012 10:27:58 GMT -5
Larry, they used to. The old HP saws for one had a 3 step pulley on the power feed. Now everyone seems to want to save money building saws, and use the single speed power feed motor. Older technology was better when it comes to saws. Don
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brunomoki
off to a rocking start
Member since December 2010
Posts: 10
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Post by brunomoki on Feb 6, 2012 0:24:29 GMT -5
Thanks for all the info. I tried fixing the blade to no avail. I am going to but a new blade, and would really know the right one to buy. I cut mostly agates, jasper, petrified wood and geodes. I searched 303 blades and got alot of results. Should I buy the thickest one or one with the notches in it, also has anyone heard about the 301 series, it is supposed to be a agate eater. Thanks for all of the help.
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Post by deb193redux on Feb 6, 2012 0:52:41 GMT -5
301 did not perform well for me. I love my 303C - both the 10" ans 12"
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