rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Mar 20, 2012 0:38:23 GMT -5
Hot dang, I think I got the problem whupped!! Looks like the problem WAS the shaft slamming up and down. Or, maybe more likely, the entire magnet/winding/commutator assembly. It's a property of used electric motors called "end thrust" or "end play". I'd read that there were old-timers (careful, son - you ain't exactly easter season poultry, yerself!) who used to fix them by adding "wave washers" inside the motor under the top and bottom bearings. I gather that these are sorta potato chip bent washers that can flex. Even brand new motors have a small amount of end play which allows the motor to find its "center" where the electromagnetic fields are balanced and the motor will run smoothly. Over time, the washers in the motor flatten put and the bearing races wear making for an excessive amount of up/down play in the shaft. This is a used original equipment motor i found on ebay - the Grainger/Dayton crapped out after 9 months of nearly constant use. Anyhow, couple that with an inherently unbalanced load on the end of the shaft that you also can't get absolutely perfectly perpendicular and the shaft will bang up and down or at least whack the heck out of the big 3/4" load bearing.
So, since Grainger didn't have - nor had they ever heard of - wave washers when I'd asked them last month, here's what I did: I loosened the set screw that holds the big load bearing to the flat on the motor shaft, grabbed the shaft with a pair of pliers, pulled it up while holding the bearing down, and then re-tightened the set screw effectively keeping the shaft at the upward side of its range of play/slop like a locking collar would. VOI - freaken - LA! I mean this rig is so quiet when it runs that you can hear even the taped rocks clattering against each other! (which, now, bugs me - lol) I have to get really close to the sliding glass door that the lap is only 4ft away from to even hear from inside the house.
I'm still gonna have to keep an eye on it (especially since I can't HEAR it - lol) because I was a little worried that restricting the shaft might cause the motor's bearings - especially the top one - to maybe get hot and wear out sooner than normal. It's been purring right along for over 3 hours but we'll see what happens over the course of a couple of days especially in this unseasonably hot weather down here in Florida right now. I don't even venture out of the house b4 7PM from May-October! And working in the garage is downright brutal hot then. I'd set up on the back lanai but.... moss-kwee-tows!
I'll probably post this "fix" in a new thread after I see if it's gonna hold up as I would imagine that, though most here are tumblers, sawyers, and cabbers, I'm sure it would be of great help to someone with a vibe lab like this Lortone who might be googling like crazy trying to find some info.
C-ya, Rick ("cyborgsam" on ebay)
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Mar 19, 2012 14:58:20 GMT -5
Thanks, rockhound. I'm starting to think that at least part of the noise might be the pan whacking against the pan base. It seems to "modulate" depending on how the 3 thumbscrews are tightened or over-tightened. I had put some rubber sheet in a few strategic looking spots when I saw something on the 'net about it but it wasn't a magic bullet. I used a drill and made a pattern of 3/16" dimples in a grid kinda like a Reciprolap to try to get the rig to flatten rocks faster. Maybe that made the bottom a little wimpier and flexible? Maybe not but I'll look into that. 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 Mar 18, 2012 10:50:00 GMT -5
Thanks - I'd read here that they were the opposite. I tried to call once but the lady couldn't help because the "engineer" took the day off. I'll try again.
The shaft looks ok, though there was a small ding near the end opposite the flat that I had to file down so that the bearing would slide onto the shaft easier - getting it off was a little hard and I certainly needed to take it off a few times whilst tweaking. The bearing on it now is brand new out of the box yesterday.
As I listen today, it IS much quieter than when the last two were going bad. I have no idea how old the one that came with it was; probably years since this is a pretty well used lap. BTW - the sound it makes resembles a diesel truck at idle. Just trying to see if that is the norm for this lap or if I have to dork with it some more. it's like I can get the thing to just purr but only for a short while. The pillow block was quiet for an hour but got louder and the racket was unbearable after a day or two - since the thing had popped loose of the block, I reckon it was slamming up and down. I would have liked to put a much heavier bearing on it but couldn't find a shaft reducer insert bigger than the 3/4" (the bearing's bore size) to 3/8" (the motor shaft size) that's on it now. General duty bearings go no smaller than 1" bore and the heavy duties are even bigger. 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 Mar 18, 2012 2:17:00 GMT -5
Hi, y'all - Ok, so the original bearing (Sealmaster L-12 with 3-bolt stamped flanges) in my 20" Lortone vibe lap bit the dust. I replaced it with a 4-bolt pillow block/mounted bearing that started really quiet but lasted only 12 hours b4 it made 2 much racket (it came loose from the block - too much up/down "end thrust" A locking shaft collar would'a helped but there's really no room on the shaft ) and so I finally found a replacement Sealmaster L-12, spent half a day trying to get the rig to spin without binding and.... quiet as a humming mouse.....for 20 seconds. It's nowhere near as loud as the last 2 failed bearings but the rig makes sort of a hammering sound from the eccentric load attached to the motor shaft. I'm guessing this is - to some extent - to be expected but I'm unsure. Does anyone have or used to an older Lortone vibe lap and could you tell me how much noise one should make? I reckon they aren't super quiet at best. There's a low pitched ringing hum from the pan resonating but the hammering is what worries me. I suppose it *might* be from up-down/in-out vibration due to maybe the chunk of metal not being perfectly perpendicular to the motor shaft. Can't imagine a way to help that, though this bearing shouldn't pop out of the mount like the pillow block did. The reason I'm focusing on end thrust noise is that I had to put washers between the two stamped metal flanges to allow the shaft to spin freely. Any slight misalignment caused by clamping the bearing down super tight without them causes binding, friction, HEAT. Anyhow, the bearing seems to be tight enough and hasn't worked loose but that's the only thing I can think of that might cause a hammering noise. This all said, the rig has hammered since i first got it but I've never liked it. What also helps with the free spin on this setup is to adjust the 4 mounting nuts on the motor. A real p.i.t.a.! I've attached a pic of the bearing/flange mounted on like 1/2in standoffs to the motor plate in case anyone wants to look and maybe tell me if this setup is how the Lortones are really *supposed* to be. The gap between the flanges in the pic is much wider than actual as i tried lock washers first since I didn't have to get up (aaargh - work!!) and go to the garage and find them. :-) I ended up using thin flat washers. When I 1st got this vibe, it didn't have the washers. I was able to adjust the motor screws/nuts to get it level and free. This time around, I did that but adding the washers freed it up a lot extra. Thanks - sorry for such a long post, Rick Attachments:
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Mar 12, 2012 1:28:20 GMT -5
I think that's a Dryhead Agate nodule half... 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 Feb 29, 2012 2:32:24 GMT -5
Ok, I got a smoother polish on the Montana aggies. I only let them go for about 8hr per side. They're "ok". Smoother but they and all the other rocks seem to have a sort of foggy finish even after 16 hours. Especially noticeable with the mahogany lace obsidian. Not sure that the TXP works as well as tin oxide though it sure cleans off of the outside/rinds of agates and t-eggs a LOT better than tin ox.
The wool felt only lasted a day. Since it was so wimpy, I sewed it on top of a Kingsley pad. Stitched around the outside edge. Right away, I noticed little round "wool bunnies" from the wool fuzz being shaved by the heavy nodules and weighted slabs. By morning, it had developed a big hole in the center and the rocks just laid it off to the edges of the pan. I had thought I might use some spray adhesive to hold it down, but I don't think it was robust/durable enough no matter how it was mounted. Ah well, another thing learned. Reckon I'll have to cruise the local carpetiers and hope for some low pile wool rug.
SicksIn Stones - Hey, that lap sounds interesting! I've certainly learned a LOT about repairing vibe laps with this old Lortone and could probably get 'er wigglin' again. If my e-mail is visible/findable here, please send drop me a line and we can talk about it, ok? 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 Feb 24, 2012 19:37:50 GMT -5
Thanks, Sticksinstones. Where can I get a wool pad for my 20" Lortone? I've been using the pads that Kingsley North sells. They do "fair" but seem to flatten out after 24hrs and this causes - I think - my larger nodules and slabs (sometimes 9-10" diameter) to not polish in the center. I'd like to find something a little thicker and more durable than whatever those are. I found, also, that those pads actually shrink like some clothes and I've had to glue them down with contact cement so that they don't start spinning along with the rocks. Does seem to put a really nice finish on the pan after a while, though - lol.
I bought some 100% wool, sorta felt-like stuff at Joann's Fabrics and thought I might try to use a double layer of it. Do you reckon it would work?
You my be right about excessive polish time. I've had a number of agates undercut on me. Especially remember a Demming agate that did. It was nice and smooth after the 600grit stage but, after polishing, it was really shiny but the white matrix had undercut pretty bad. As to the Montana slabs, those have been turning out with a "grainy" finish rather than "orange peel". I ran some using 1000grit Alum. Oxide to see if, maybe, they just needed a "post pre-polish" stage. Reckon I'll find out by Sat or Sun because my "TXP" polish just arrived today. It was recommended on this forum, so I thought I'd try it out since it is 3-4 time cheaper than Tin Oxide.
Hi, Helen - I'm not tumbling; I'm using a vibratory lap. different rock hardnesses don't matter with these. Thanks, though. :-)
C-ya, Rick ( cyborgsam - "CyborgSam" - @ebay)
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Feb 23, 2012 3:28:57 GMT -5
Yeah, I'm putting rocks on top of the smaller ones and also any that are fairly flat even if big. Can't seem to find a tire store that doesn't sell their used weights to the local recycler. Usually quartz "river rocks" from my landscape - as big as will fit without making the smaller nodules top heavy. I, also, load 1 or 2 on top of the Montana agate slabs I'm trying to do. I picked up some slate at the local plant nursery/landscaping shop that works nice for slabs.
This last batch just seemed to take that long to get a good shine. 600 was the last grit before the polish. It might be that the 600 stage might have been too short? It did shine up nice after like 3 days in tin oxide. A caveat, though - I only had less than 1/2lb of SnO and so I started mixing in a bunch of the polish that comes in the Thumler's grit kits because that's all I could get locally without waiting for online stuff to be mailed. Don't know what that stuff is, but it is sure SLOW going with that stuff. Worked great in a tumbler but that was like a week and a half of rolling. 24 hours of that stuff barely affected the dull, 600grit finish on the Montana slabs!
I'm starting to think part of my problem may be the motor I have on my 20" Lortone. (or maybe just impatience!) The original seized up a day and a half after I got it. VERY used. I remember my very first batch rough ground with that motor flattened out in less than 20 hours. Had a real hard time finding out the specs of the motor but did find an old page on the web where the guy said it was 1/15hp, 1500rpm so I picked one up at Grainger. I didn't have a decent amount of time to watch the first motor, but it *seems* that the vibration was less dramatic with the new motor. I've had the new on since summer. Maybe it needs to be slower? The new motor doesn't have an internal fan like the old one, so I had to strap a 6", 12V high velocity rack fan to the bottom of the motor, blowing up thru it and at the temp sensor to get it to not trip the thermal protection in the heat of the Florida summer after 30 minutes. Maybe that is acting as a counter-weight and hosing up the vibe excursion at the pan? Hard to remember my physics after so many (aaargh! lol) years...
I ran everything in this batch for a day in some 1000grit aluminum oxide I had laying around but am still waiting for some TXP polish I ordered last week to show up before I try to re-polish. Cheap price - hope it works! The obsidian was real shiny but not "glassy" smooth before the 1000. And Montana agates I have yet to get a glassy smooth shine on, so I'm hoping they will all shine up more glass-ily when I redo them. Thanks, Rick (cyborgsam at ebay)
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Feb 17, 2012 1:25:37 GMT -5
Thanks - I saw a lapidary site, once, that mentioned it but can't seem to find it amongst the 100s I have. 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 Feb 15, 2012 23:21:42 GMT -5
Hi, y'all - I've been polishing some Montana Agate slabs and a fair sized end slab of Mahogany Obsidian (around 5"' across, square-ish, maybe 3/4' thick) in my 20" Lortone "jiggle pan". I used tin oxide polish. After 2-3 days in the pan, the obsidian was shiny but it has a sort of "orange peel" type texture if you look close at it. Is obsidian a harder rock than most agates and does it, maybe, require a different polish than SnO to get a smooth finish? My sequence is 120/220/600/polish with SnO.
For grins, I ran it and a few other rocks I've not been pleased with for a little under 20 hours using some 1000 grit aluminum oxide I had from when I was tumbling. Haven't gotten a chance to try to rerun it in the tin oxide yet, though, because the big crown bearing that takes alll the abuse when the motor runs just started making way too much racket, so I had to order a new one from Ace along with the flanges it mounts with. Should show up Thurs. 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 Jan 5, 2012 23:46:58 GMT -5
You should wear a respirator - The mist also carries a lot of rock/quartz dust in it and silicosis sounds like no fun at all... 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 Dec 27, 2011 13:37:05 GMT -5
Larry - yeah, actually that does sound like a decent idea. Maybe a sort of "pre-polish" step. I have an 8" Inland lap and a 1200 and a 3000 disk - I'll give that a shot. 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 Dec 22, 2011 0:22:00 GMT -5
Man, I sure have a lot of questions, eh? :-)
About my favorite agate is the Montana Agate. I collect or cut large-ish (4in +) slabs of it for my collection whenever I can avoid the big money "sharks" on ebay.
I have a few that were already polished and am having a hard time getting that glass like finish consistently on the few that I've tried. They seem to be a really hard rock and might take a lot more time on each grit than the usual 16 - 22 hours I typically run. And maybe a super heavy weight on the, as well?
Has anyone vibe lapped these that might know some tricks like which grits/polish and how long they need to jiggle to lose the matted, "micro-pitted" finish? I do 120/220/600 and then tin oxide polish. 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 Dec 22, 2011 0:11:53 GMT -5
Ok, so the two big guys turned out well. The giant Kentucky could maybe wiggle for another 8 hrs but it looks fine. The big, long Maizkoje agate turned out perfect. At least rated against my results - lol.
I used a brand new pad and jiggled them for 2 days. What worked for the 9in long Kazakhistan Maizkoje agate was to crowd the pan so much that he couldn't move far from the orientation I chose for him which was perpendicular to the edge of the pan rather than his usual spot orbiting long ways around the pan.
The 10 or 11" Ky agate is roundish and almost pentagon shaped and maybe 3 1/2' thick tapering to a sharp edge all the way around. All I could do with him was to lift one side every now and then and dump a little extra TiO2 under the middle.
Not sure if it was these things, the new pad, or just a bunch of time in the pan but all's good, now. I would have expected them to take less time than the smaller, lighter rocks but they ended up taking a long time. When this pad wears out, I'll swap in a piece of carpet. Maybe the thickness will help with these monster rocks. I have an even bigger Kazakhistan agate coming that I lucked out on at ebay and I'll see how that one goes.
Thanks y'all and Merry Christmas! 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 Dec 18, 2011 23:25:49 GMT -5
Jack - Thanks. You just reassured me that I wasn't overfilling the pan! lol That said, I DO only fill to maybe 90% and the rocks tend to orbit the pan fairly fast and do a lot of swapping of positions. Except the huge ones that claim their spot and tend not to change orientation very often. I'll experiment with this. I'm thinking maybe it's better to have all the rocks close to the same size, too, because it's the little ones that get shoved around and tipped over by the bigger guys. I just put in lots of different sizes because A) That was my habit from tumbling and B) Well, those were just the ones that were ready for whatever stage.
I'll see if I can't round up enough good size nodules to slow these 3 giants down some. (fixing to be 4 - I just picked up another Kazakh "Maizkhoje" chunk) I'm, also, thinking that I might even rig something to hold the biggies still in the middle of the pan and just dump a teaspoon or so of TiO2 under the dull areas every few hours and see if that doesn't help.
Jake - I think I know, now, what kind of carpet/felt you're talking about. I'd read your tip about it elsewhere here but your description now tells me what the stuff is. Though it's gonna cost me having to get yet another pound of polish, I think I might find some at a van customizing shop or - being in "rockhound hell, Florida" - maybe a boat marina.
Gonna go and reload the pan with the new pad now - I'll let y'all know what happens. Thanks a TON for the help! 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 Dec 18, 2011 0:59:06 GMT -5
All I have is an 8" Inland spinning lap and the 20" Lortone. I grind the nubs off (hate those!!) and try to knock down the saw marks with a 100 grit diamond lap and then do 120, 220, 660, and then tin or cerium oxide. These 3 rocks are/seem WAY too big to do on a belt/expando.
Where can you get lamb's wool carpet? Or how can you tell what it is? I was thinking of using some outdoor pile carpet like is in some boats or like is used on covered porches (not the astro-turf kind). Would that be any good?
I won't get the big guys back into the pan uintil Sunday. Had to do a lot of cleaning and acetone soaking to get the contact cement from the old pad off and I'm letting the new one set up good b4 I try it out. It really does seem like either the centers of rocks over 5-6in wide are either not getting polish like the outsides do or, God forbid, it might be the same "physics" problem that seems to keep anything over cab size from polishing the middle on a spinning lap. Or maybe it's because they are just so darn heavy? Reckon all I can do is keep jiggling them untill the centers shine up. 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 Dec 18, 2011 0:43:24 GMT -5
Thanks, y'all - was hoping I hadn't goofed. BTW - What are "CPP" and "TXP"? $8/lb sounds REALLY interesting! 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 Dec 15, 2011 17:35:36 GMT -5
Oh yeah - The new pad I ordered just showed up so I'll try it out. Might wait and see if I can find a piece of carpet as was recommended since that is thicker. Tin Oxide ain't cheap! BTW - Why the heck is it that just because China was pissed at Japan and raised/limited THEIR supply of rare earths the prices jumped in the US, too? Doesn't sound right as China didn't include us in that bit of nastiness...
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Dec 15, 2011 17:29:22 GMT -5
Yeah, I had already beveled the edges. But some areas were hard to reach - concave - without possibly gouging the rocks with the edge of my spinner lap. I did one and it turned out somewhat better (19hrs) but it still needs more time in the pan. It's about 9" x 5" and point and lighter on the pointy end. Maybe 5-6lbs. It's still a little dull right in the middle.
I put in a Kentucky agate that's roundish and very uniform thichness like 9" and maybe 7-10lbs that had turned out dull in the middle when I first started doing this stuff a few months ago but it didn't improve a whole lot. I had even applied grit to the center agout 3hrs into the vibe.
The other Kazakhistan agate turned out a good bit better. It's *only* 7" and roundy. What I did with it was tape a good size rock over the thin side of it. Might be also because it's not as far from the edge to the center of it, though. The long, pointy Kazakh always gets itself running longways around the edge of the pan, occasionally swapping which end is leading so the center of it is always being starved of polish(?) Maybe I can figure some way to make it go sideways.
More later - and 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 Dec 14, 2011 2:00:47 GMT -5
I have some WAY cool agates from Kazakhstan that I'm trying to polish in my 20" Lortone vibe lap. They are like 8-10" across and probably weigh 2-5lbs each. I'm pretty sure the agates are flat - did the pencil test on all 3 grits, 120, 220, and 600. Problem is that there are areas near the center or to one side that aren't getting as shiny as the rest of the rock. Anybody have any experience with vibing really big agates/t-eggs?
Here are some of my guesses, though they might all be wrong:
1) The matted areas SEEM to correspond to portions of the rock that aren't as thick as the rest. Now, I've done slabs where I had to put more weight on one end because of it being ground down to take out saw marks or those dadgum NUBS(!!!) most sellers leave on them with the usual furrow dug in just before it. Might I have to put some weight atop the thinner part of these 2 nodules to get it all shiny?
2) Might the polish be getting pushed away by the outer edge or the "leading edge" of these guys? These dudes are half again to 3x as big as the rest of the ones in the pan and so they go wherever they want. Eventually, they find their "happy place" and end up always at the edge of the pan and in the same orientation/direction. Might I need to periodically dump a spoon of polish directly under these huge agates so that the light areas don't get "starved"?
3) Might my pad be starting to get kinda thin and these rocks can't sink into it? I'm thinking this might not be the problem because on of the big aggies was in the first batch i did with a brand new Kingsley polish pad.
What do y'all think? Any ideas or tips on doing really big nodules. Hope so because I have some 8-12" slabs I wan't to do, as well. Thanks! Rick
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