rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 12, 2014 4:30:59 GMT -5
I could shine 'er up with my 20" Lortone jiggle pan if you want to send it to me. How crumbly is the matrix rock on the "bad" side? Would it have to be sealed to keep bits from popping off? I've found that 99.99999% of all squiggly scratches come from little bits coming off either the edges or a druse in the same rock that was scratched rather than from "contamination". They all do it to themselves. The bits pulverize under the slabs and never get a chance to scratch any other rocks in the pan. Let me know. C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 12, 2014 4:18:06 GMT -5
I think "alundum" is some combination of aluminum oxide and corundum. Just a guess. I went ahead and cut a slice of my 4-5" aluminum oxide wheel with my black Covington blade. While it was cutting, I worked on straightening out an old - not much used - gold Covington blade I had. Got it so straight that I just removed the black one, made a quick cut through the wheel with the gold blade and just used that one. Cut the Parral just fine!
A couple of months ago I'd had a problem with the same black blade not cutting Polka Dot agate. I switched to the gold one and it cut it just fine. Left some nasty saw marks, so I just took it back off and went with the black blade until my recent problems cutting Parral Agate with it. The gold blade is one of those notched jobs and cuts a thinner kerf than the black, sintered one. Now that it's fairly straight, I probably won't use the black one until I'm cutting something softer.
This is my second black Covington 14". The last one wouldn't cut Polka Dot worth carp and I ruined it "sharpening" it by cutting a silicon carbide "diamond wheel dresser" stick. I, also, scrubbed every last diamond off of my 10" push through saw's blade with the same stick. The black Covington blade *seemed* to make a smoother cut but the darn things are just plain dull right out of the box! I want to get a 16" segmented 303 or 301 MK(?) blade like everyone here recommends but my Ebay rock selling has dropped off a lot in the last 3 weeks and my Paypal balance is precariously low. Since I'm out of work long term, I only let myself buy supplies with whatever I make selling slabs on Ebay. Sure wish I could get the prices some of the "big boys" there do! If anybody wants to help me get a decent blade, just look for "rykksROX" in the Lapidary Materials pages and make some crazy high bids - LOL The slabs I'm selling were almost all bought from the 4 or 5 "big" sellers there and I'm lucky to even get $9.99 for them. C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 11, 2014 2:15:51 GMT -5
Niiiiiiiiiiiiiiice! Where can I get a chunk like that and not have to go into hock for it? Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 11, 2014 2:07:45 GMT -5
Well, from what little I can find out, (the numbers on the wheels are, apparently, obsolete) these 3 wheels are aluminum oxide. Apparently there is a numbering convention for grinding wheels and these are "A180" and "A60" which should mean that the two small, brown ones are 180 grit AlO2 and the bigger one is 60 grit. The big fat grey one I can't tell because all of the labeling/markings are gone. I'm going to try to force this slab through to the end by rotating it to cut thinner/shorter sections of the rock and then make a cut or two in one of these wheels. Sure hope it helps/works! C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 11, 2014 1:10:30 GMT -5
I agree about the obsidian. I completely slabbed a fair sized chunk and it didn't make the slightest difference. I found a few small Norton wheels - 2 of them about 2.5" and brown, and the other is dark gray and very coarse. Says it's a 6" but I measure 4.25. There are part numbers on them. I;ll google and see if I can find out what they are. Thanks, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 10, 2014 19:54:14 GMT -5
Hi, all - I'm in the process of cutting some Parral Agate and am finding it VERY slow going. This material, along with Polka Dot Agate, is the hardest agate I've ever cut. My saw gets to a fairly thick spot and then the feed stops. It's the slip clutch in the motor. Actually, the gear in the motor just slips when it encounters a lot of resistance. I've run the feed rate down to below 4in/hr and it still won't cut.
Anyhow, the rock starts to ride up on the blade and this is what eventually stops the feed. I've run into trouble like this, before, with the blade I use. It's a 14" Covington "Black" sintered, continuous rim blade. It's a pretty stout blade and is fairly thick. And it's fairly new, as well. Might have like 20-30 slabs on it. It strikes me that the blade is just plain dull. It cuts other rocks, like Graveyard Point Agate, just fine.
I have a grinding wheel a friend sent me and have heard here that cutting one can "sharpen" a blade by exposing new/more diamonds. I don't know what the wheel is made of, however, and don't want to make the same mistake I made with my last blade (cut a very coarse diamond wheel dressing stick) and cut the wrong material. This wheel appears to be around 100 grit and is grey in color. I've seen different colors of grinding wheels - brown, green, and grey/black - and I think the color can determine what the wheel's composition is. Can anyone tell me the right wheel to use and if this light grey one is correct to use? And how much, if any, damage cutting one of these wheels might do to a diamond blade? Thanks, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 8, 2014 23:07:47 GMT -5
Both - you'll have to trim the bottom of the left one and then reshape the top of the right one to match. Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 7, 2014 22:33:28 GMT -5
bassackwards motor rotation - whodathunkit?? Glad yer up and slabbin'! Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 6, 2014 22:22:49 GMT -5
The first two might be Amethyst Sage Agate or maybe Sheep Creek Plume Agate or Mexican Dendritic Agate.
#3/4 is Cripple Creek Picture Jasper.
#5/6 Looks looks like one of the Mexican Crazy Lace varieties.
The last one is Agua Nueva Agate, from Mexico.
Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 6, 2014 21:41:48 GMT -5
Feeding too fast can cause saw marks and can warp the blade. The larger blades don't spin as fast and need a slower feed rate. And the rocks are usually bigger which calls for a slower rate of feed, as well. I get impatient with my rig, too, and am often tempted to increase my feed rate. My saw (self built) has a digitally variable feed rate. Nifty little whiz bang thing and I love my digital readouts and LEDs but the only time it's advisable to change the rate is if I swap in a different size blade. I've warped/dished a couple of blades by getting too cocky and feeding too fast when cutting very hard rocks... C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 6, 2014 21:31:05 GMT -5
Now THERE's a good idea - crud on the threads would definitely cause problems with the split nut slipping. Nice shot, Tim! Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 6, 2014 21:27:57 GMT -5
Ok, so it *appears* that the threaded rod shaft is all one piece and the ring gear is just mounted to the thin part of the shaft outside the bulkhead. So, there's no coupler needed in this design. Mine has a coupler because I drive a separate threaded rod coupled directly to the shaft of a gear motor. Cheaper and what I had at hand. So, reckon the only way the vise carriage wouldn't advance would have to be a problem with the feed dogs not engaging the threaded rod tightly enough or the threaded split nut inserts need the mounting screws to be tightened to the feed dogs or the threads are totally stripped out. Maybe the spring on the feed dog split nut assembly is old and too weak? See if you can squeeze the split nut together more tightly and now the carriage moves. HP sells the spring and it's only like $9.00. It's also possible that the feed dog mechanism is just gummed up if the saw has sat dormant for a good while and that might prevent the dogs from clamping tight enough. See if you can uninstall the feed dog assembly and soak it in some acetone to dissolve the gummy snot/oil. If it's the threads on the split nut, that's an expensive fix because it doesn't appear that HP sells the inserts separately and you have to buy the whole "pliers" assembly. Try shoving real hard on the vise and see if it slips along the rod with the feed dogs engaged. Try sliding the vise to different areas farther down or up the rod and see if the carriage advances when the split nut is on a different section of the threaded rod. That would tell you if the rod, itself, has an area of its threads that have worn down. If you have to replace the rod, it could be $40-$70 from HP's site. Make very sure that the worm gear and ring gear are meshing properly as they wear out, too, and that the shaft is definitely turning and doesn't stop or change in the rate of rotation. If it does, maybe the gears are either worn and slipping or are spinning on their shafts and need tightening. Make sure that the shaft doesn't move back and forth and the vise doesn't move with it. That would mean that the feed dogs' threaded inserts are either loose or stripped out. I''l check back later. C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 6, 2014 20:45:41 GMT -5
Ok, I should read things more closely b4 I spout off - lol. If the shaft can be moved back and forth with the split nut engaged, do you do this my pushing the vise back and forth or do you just grab hold of the shaft, itself, and push that back and forth? I guess I can see it being a non problem if the entire mechanism - shaft and vise carriage together - moves but if the shaft moves back and forth and the vise and split nut stay still, then you have something loose and need to see if there is some sort of coupler attaching the pictured worm gear shaft to the threaded rod shaft that is slipping and needs its set screws tightened back up.
I'll go and look for some diagrams of the assembly of HP saws and see if I can figure out where the problem is. I built my own saw, so my direct experience might not match what's in this one since, of course, *my* design is so much better than theirs - lol C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 6, 2014 20:24:42 GMT -5
If there's a set screw in the bushing (or collet?), it might be that you either need to tighten it or loosen it then push it flush with the bearing and re-tighten the set screw. If it is an actual bushing - brass or bronze - that is supposed to extend well into the bearing, then it might either be broken or need to be hammered back in.
From what I can see, the "bushing" is actually a collet or sleeve meant to keep the shaft from ramming into the worm gear on the outside of the bulkhead while cutting and/or might connect the gear shaft to the threaded rod that advances the vise carriage. In operation, I don't think a little slop away from the worm gear would pose any problems because the pressure of the blade against the rock in the moving vise would prevent any forward movement of the shaft like you've shown.
If this "bushing" is also what couples the gear shaft to the threaded rod, then there should be a set screw on it or, possibly, a metal key that makes the worm gear shaft turn the threaded rod. If there's no set screw, look for a slot on the shaft that extends under the bushing/collet. There should be a rectangular steel key hammered in to couple it. If it's gone, you just need to get a new one. If there's a threaded hole in the side of the bushing, you'd just need a new set screw.
The more I look, I don't think this sleeve is the coupler and is just to keep the worm gears from getting jammed. Maybe somewhere under the vise there is another coupler sleeve that needs its set screw(s) tightened. If it's not any of the above, then maybe the split nut's threads are very worn and stripped out and that is what needs fixing/replacing. There is some pretty hefty pressure being applied against the rock and just trying to push the carriage back and forth with the split nut engaged wouldn't be strong enough to tell if the threads are worn out. However, if the carriage will not advance even with no rock being cut, then the split nut probably isn't your problem.
When you engage the feed, does the pictured bit of the shaft turn while the vise carriage doesn't advance? If so, the problem is further up the shaft/threaded rod under the vise carriage. (Edit - I reread and it seems that the shaft *is* turning, so the rest of this is probably moot) Does the worm gear shaft going across, laterally, outside the bulkhead turn but the shaft doesn't? That could mean that the worm gears are worn out - a more expensive fix. Check to see that the two gears' threads mesh properly with the shaft pushed back toward the bulkhead. If the lateral shaft isn't turning, then the problem probably lies in the feed pulley/belt adjustment or the feed motor if it has a separate motor for the feed. Just throwing a lot of ideas against the wall to see what might stick and start us a brainstorming session here... C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 6, 2014 19:51:55 GMT -5
Might be that, if these are thin blades, the rings might be for added stiffness or tensioning... just a guess. Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 6, 2014 4:38:21 GMT -5
LEDs can be kinda tricky. You have to select the right color or "bin" temperature for them to make the rocks look right. Warm white would tend to give a more yellowish tinge, I think. What you really want are full spectrum "daylight" binned LEDs... if such a thing exists. I use a full spectrum daylight bulb made by Ott to light pictures of my rocks and they look great. The colors really pop. I'm not sure if LEDs are capable of broad spectrum light, though. I used to work for a company that built hardened computers and displays for the Army and have a bunch of LED strips from flat displays that I was going to try to use to light a display case but haven't gotten motivated to wire them all up, yet, or I'd be able to tell you more. C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on May 5, 2014 2:53:24 GMT -5
I never had any trouble with my 20" Lortone walking. It did just fine with the rubber pads on the feet. I do, however, have to pile heavy rocks on 2 opposing sides of the rig now that I've mounted the pan on shock mounts and gone to a quasi-reciprocal motion using an offset shaft.
What is the purpose behind separating the pan into 4 sections? I'm sure there's a reason, but I can't figure out what it is. How do you keep it from impeding the rotation of the rocks around the pan? I've been thinking of how I might install a 2-4in pvc pipe in the center of the pan to try to prevent dishing of the pan - do you think it would be worth doing?
Most of the slabs I jiggle are too big to fit into a 6" circle and I've found that rubber rings around the rocks doesn't work because nodules with sharp-ish edges and a low slope tend to just work under the rings and toss them aside. So I don't do either and feel like the wood cross and rings eat up a good bit of valuable space in the pan. I've gotten up to 30 rocks into my 20" once by just taping them and don't have any problems in the grinding phases with tape coming off as long as I don't let the water/slurry get too deep. Too much water lessens the grind, anyhow. Typically I can do 20-25 at a time unless I'm doing some really big slabs or nodules for display. The only time I go to super sticky tape is when doing the second side of a slab. The polished side is really slick, so outdoor rated duct tape is a must. Plus, I tend to end up with my polish pan on the wet side from constantly spraying tin oxide off the sides of the rocks to save $$.
I never tried glue on slabs because it seeps into softer rocks, like jasper, and discolors them. Taping isn't as time consuming as it sounds - you get real good at it real fast. You do need to be careful pulling it off but it's usually pretty wet and, as long as you don't try to pull it UP off the slab, you're pretty safe. Some of the stick-um gets left behind, but that comes off easy by just taking one of the rolled up pieces of tape from the bottom of the weight and rubbing the leftovers off. Tape loves to stick to itself.
I only have one jiggler and 2 pans, so I wash out the grind pan after every batch/side. Too much grit or old grit more than 20 hours old doesn't do much of anything even if you add more new grit. The old stuff just gums it up. I only add grit once and only about 2 hours into the 60/90 grind. Just 2 or 3 tbsp. The 600 phase is the only one where you want the grit to wear down as fine as possible and might run it a long time or, better yet, repeat it.
I hear you about using the attached weights as "handles" when working the slabs on a wheel. Works great! With tape, though, I've found that there's always some fine grit dust left between the folds no matter how much you spray it off and it will pollute your polishing wheel leather/felt. Found that out the hard way.
The 4-bolt pillow blocks they use are the wrong bearing for the job. What you want is one of those 3-bolt stamped flange farm equipment bearings like came stock on the older Lortones. They are made for tough side to side stress like spinning an eccentrically weighted shaft. Found that out on my modified rig. The 4-bolt on the bottom of the pan base and also the 2-bolt one nearest my counterweight very soon developed a lot of slop. The rig was quiet as a mouse - not counting the low, hissing sound of the rocks sliding on the grit and the cooling fan for the motor - for a few days. Now, it sounds like someone idling a Harley on my back porch 24/7! Still works fine, so I'm taking my time on replacing the bearings. Not only is it a gritty job, but getting everything plumb and perpendicular was a real pita and I'm not in a hurry to be doing that again. C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Apr 30, 2014 18:52:22 GMT -5
Can you add some closer pix of the red/white stuff y'all found piled at Last Chance? I have a big chunk of plumey moss agate that I got un-named on Ebay that I thought might be Carey Ranch, but it looks a lot like the two pieces in the very bottom right corner of the pic you already have. I've slabbed it out and tried to sell a couple of the slabs listed as Carey Ranch Plume with no luck - maybe because it's not from there? If it's from Last Chance, I think it would actually be rarer than the Carey. The piece I have is some incredibly nice stuff. Thanks, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Apr 29, 2014 23:42:08 GMT -5
No prob, man. The only thing not pictured is the 4-bolt 3/4" pillow block bearing I installed to the bottom of the pan holder pan. I had to drill 4 holes and mounted it dead center.... ish. You don't need the set screw in the bearing because you want the offset shaft to be able to spin freely in it. Good thing, too, because I have no idea how the heck I would have gone about tightening it! C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Apr 28, 2014 20:55:52 GMT -5
1nickthegreek - Here's a link showing how I modified my 20" Lortone to be like a Reciprolap. Got rid of the orange peel texture on some rock species, though it seems to work slower. That may be due to the motor running at around 1050rpm or so rather than the 1550rpm of the stock motor. Might also be because I need to anchor the rig down better to stop the base from jiggling so that only the pan jiggles. forum.rocktumblinghobby.com/thread/62688/presenting-reciprotoneC-ya, Rick
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