Mazanec
spending too much on rocks
Member since March 2004
Posts: 355
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Post by Mazanec on Oct 10, 2004 5:01:44 GMT -5
Anybody have experience with these? How much do they cost? What are the pros and cons? Any other comments?
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llanago
fully equipped rock polisher
Member since January 2004
Posts: 1,714
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Post by llanago on Oct 10, 2004 9:47:03 GMT -5
Well, first ya'got to have a grinder to put it on. ;D Seriously,I can't think of any cons, except I have to wear a plastic garbage bag to keep from getting soaked! I found the best price on green 100 grit grinding wheels at Dad's Rock Shop. They are really nice folks and I am sure can and will answer any questions you might have. Of course, there are folks on the forum that can answer any question better than me - I haven't had my grinder very long. Here's the link to Dad's www.dadsrockshop.com/llana
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Mazanec
spending too much on rocks
Member since March 2004
Posts: 355
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Post by Mazanec on Oct 10, 2004 11:54:47 GMT -5
Thanks. I believe in getting stuff like equipment locally, as I can easier get it back if there is a problem, so I would probably use my local rock shop. Am I a senior now? YEP!
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Post by docone31 on Oct 10, 2004 18:29:06 GMT -5
Grinding wheels. The ordinary wheels that come with conventional bench grinders work fairly well. I use a Benchmate grinder. A Walmart special. 6". I still use it. I replaced the second wheel with a rubber drum, 6" It takes three inch belts, width, and it works very well. The RPM is a little too high. I got a router speed control and toned it down. Works very well. I used a coffee cup with water to cool the stone. Once I wore down the 36 wheel, and the 60wheel, I replaced the grinding wheel with a 100 grit diamond wheel. I stlll use the rubber drum. The rubber drum uses a leather buff as well as the conventional belts. What I saved over purchasing a lapidary unit was phenominal! With the diamond wheel, I added a water drip. I fabricated a shield from flashing material, added a spigot drip. Bingo. Without the diamond wheel, we are still under $100! To feed the water, I use two techniques. One is a screw on tap for the kitchen sink spigot. The second is a portable pump unit I got from Rio Grande for 80$. It comes with a bucket, pump, hoses, is refillable, the runoff goes back into the bucket. Bingo! Nothing fancy, nothing high tech, it just works, and works predictably. I was worried about water entering the grinder. It does not. It grinds, it sands, it polishes, it does not make sandwiches however. I have to do that. It does not, and will not cut. I could use the motor for a stationary arbor but I was given a trim saw. It is that easy. All you are doing is grinding stones. Go slow, watch heat, always grind from the border to the top of the stone. Less chipping. Does that help? A grinder spins at 2250, you need 1750 for lapidary. Instead of a spinning dresser for the wheel, I got a diamond point dresser, and made an acme thread feed arbor for it. I get square wheels. I find that important. I like sharp tools to start.
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birdseed
starting to spend too much on rocks
Member since September 2004
Posts: 167
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Post by birdseed on Oct 11, 2004 13:18:17 GMT -5
I have even used a high speed metal grinder--lots of sparks(dry) and wears down the wheel real quick-but, it works very well to prep stones....A 6 inch wheel only cost about $6.00--Unless you are using the grinding for cab or refined work--Get a cheep(Home Depot) 6" sharping wheel---Watch out for your fingers!! I have lot's of scars......
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Mazanec
spending too much on rocks
Member since March 2004
Posts: 355
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Post by Mazanec on Oct 12, 2004 6:06:54 GMT -5
Birdseed, are you trying to convince me to buy one or not? ;D When you look up "clumsy" in a dictionary, they show my picture. I spoke with the local rock shop. They do not carry grinders, but they can order one from a catalog. I will think about it some more, maybe get out there in awhile and get myself a Christmas present? Thanks.
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WilliamC
spending too much on rocks
Member since August 2003
Posts: 416
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Post by WilliamC on Oct 12, 2004 18:05:14 GMT -5
Greetings All, Hey Doc, why is it important to have a slower rpm for lapidary work than a normal benchtop grinder runs at? There's a 6-inch $40 grinder from homedepot that runs at 3450 rpm, and an $80 variable speed model that adjusts from 2000 to 3450 rpm www.homedepot.com/prel80/HDUS/EN_US/diy_main/pg_diy.jsp?CNTTYPE=PROD_META&CNTKEY=Products_2%2fPower+Tools%2fGrinders%2fBench+Top+Grinders&BV_SessionID=@@@@0024506674.1097621449@@@@&BV_EngineID=ccckadcmkikdgljcgelceffdfgidgnl.0&MID=9876 Is the higher rpm just too agressive for grinding rocks or too dangerous in that it makes it difficult to hold onto? Would 2000 rpm be close enough to 1750 rpm that it wouldn't make any difference? You mentioned replacing the grinding wheels that came with your unit with a lapidary wheel; aside from getting the correct diameter for the arbor shaft (3/4-inch for the variable speed above), are there any special considerations or will any grinding wheel do? Like, if I get a 3/4-inch shaft diameter grinding wheel from Dad's www.dadsrockshop.com/wheels.htmlit should fit? Any feedback will be greatly appreciated. I've got some big 'ole (fist-size) jasper rocks I'm trying to tumble and after putting them through multiple 60/90 stages I begin to see the value in preshaping. Of course a rock saw is what I really need but it will be a while before I can save up for one of those. I could spring for a grinder much sooner though. WilliamC
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Post by docone31 on Oct 12, 2004 19:21:48 GMT -5
William. How did you fare in the storms? The RPM of a conventional grinder I have found when cutting, grinding, polishing, is just too much for stone work. 2000 should work well. The rubber drum, if the belt comes off and it runs 3200 runs the risk of exploding. I have also found out, conventional grinding wheels do not hold their flat like lapidary wheels. Also, the grit combinations on grinding wheels clog faster than lapidary wheels. If it were me, and it was, I would go with a speed control and one speed grinder. That is applying a rheostat with old technology. The new grinders, if they stall lose power. Just my way.
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WilliamC
spending too much on rocks
Member since August 2003
Posts: 416
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Post by WilliamC on Oct 13, 2004 17:09:03 GMT -5
Greetings All,
Thanks for the feedback Doc. I dunno about me trying to rewire a grinder, I suppose I could try, but something tells me (past experience that is) once I get it apart it won't go back together again. All I really want to do is preshape rocks for tumbling, I'm not ready to get into cabbing yet. I'll take a look at what WalMart has tonight and maybe get one this weekend. Darned if I haven't gotten downright miserly when it comes to spending money lately, the wife and I are actually on a written budget now so I have to account for every dollar I spend. Makes me think before I buy it does.
Up here in Northwest Mississippi we didn't see any weather from any of the four Florida hurricanes, although we finally got some much needed rain from tropical depression Matthew last weekend.
Later...
WilliamC
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Post by docone31 on Oct 13, 2004 20:23:12 GMT -5
William, it is not a rewire, the router control unit is a plug in. It plugs into the wall, and the grinder plugs into it. I really love the unit I got from Walmart. It is just a good basic grinder. I took the guards off the wheels and it cuts really well. Glad you escaped the mess we had down here. We went to close on an home in Lakeland, but it blew away the day before the closing. We went to close on an home in West Palm beach, and it got blown away the day before the closing. We went to close on an home here, in New Port Richey, and the power was lost but the title company opened up for us. Maybe this is where we are supposed to be, my wife loves it here. Glad you are ok there.
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WilliamC
spending too much on rocks
Member since August 2003
Posts: 416
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Post by WilliamC on Oct 14, 2004 9:27:22 GMT -5
Greetings All, Ah, I completely misunderstood you Doc, when you said something about a "router speed control" I envisioned something that one had to hardwire into the grinder, but I see now that something like this: www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=43060is what you were talking about? Just an electronic device that plugs into the wall outlet and the grinder plugs into it, then you can dial the speed up or down? Much easier than what I had envisioned. Even I can plug things into a wallsocket, why the other day I actually replaced the wall socket in the back room that my tumblers are plugged into. I had finally gotten tired of the broken one with the wires exposed that came with the house. But I do sort of miss the colorful sparks, it always added a bit of excitement when I plugged in the tumblers. Thanks much for the advice Doc. WilliamC
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Post by Cher on Oct 14, 2004 11:01:52 GMT -5
Doc, just curious as to how long you've been using that grinder with the router control. Was telling hubby about it and he thought that lowering the voltage to the grinder could cause the motor to burn out. (Kind of like in a brown-out situation, they always tell you to shut off anything with motors because you can burn them out if your experiencing brownouts.)
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Post by Cher on Oct 14, 2004 11:22:58 GMT -5
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Post by docone31 on Oct 14, 2004 17:32:16 GMT -5
William, you found it. That is what I use, and I have used it for a long time. I understand brown out condition, the ampherage drops. THis unit drops both voltage, and ampherage. Theoritically, you are slowing down about 1/3 this should make the unit last 25% longer unless high loads are placed on the machine. Electronic grinders, I do not reccomend for this. They are indeed voltage and ampherage sensitive.
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Mazanec
spending too much on rocks
Member since March 2004
Posts: 355
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Post by Mazanec on Oct 25, 2004 8:57:00 GMT -5
Any websites I can use to research grinders which would be good for our hobby, what is involved, and so forth? I tried google but kept getting stuff like coffee grinders, etc.
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Post by docone31 on Oct 25, 2004 11:11:52 GMT -5
You won't find much on the internet. I found out by accidently stumbling on old lapidary books in a used book store. Basically the grinding wheels, bench grinders, are used as an arbor and shields are made up for the water splash. I like using a 100 grit diamond wheel and a rubber drum with sanding belts for grinding/polishing. It sure is a lot less expensive that way.
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Post by Cher on Oct 25, 2004 13:20:54 GMT -5
I looked all over in Wally world yesteday for grinders, could not find one anywhere. Could find hand grinders, but not the kind to mount on a bench. Cher
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Post by docone31 on Oct 25, 2004 14:04:37 GMT -5
Ace, Walmart, Home Depot, Lowe's, etc. They cost about 40$ come with two grinding wheels. They can be adapted to buff, grind and the brave souls can mount saw blades. I do not reccomend that without building a guard and rest however. I run my grinder without guards as I use both the face, and side of the wheel.
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Post by docone31 on Oct 25, 2004 14:05:41 GMT -5
Oh, yeah, they are called Bench Grinders.
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Post by Cher on Oct 25, 2004 14:23:33 GMT -5
;D There's my DOH! for the day. I know they are called Bench Grinders ... and that's what I asked for at Walnut. Don't have a Lowes, have Ace, but they are very expensive in this town. Home Depot, something like 85 miles away. AAArrrgggg I was in Home Depot last Wednesday looking for a lightbulb, totally forgot about the grinders at that time.
Cher
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