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Post by sitnwrap on Nov 12, 2008 16:28:54 GMT -5
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Nov 12, 2008 18:11:41 GMT -5
Alright! Your on your way now!!!
The wheels look like Aluminum Oxide (which doesn't grind stone well at all).
If you don't know it or if you do I'll still repeat it...Use caution when using SiC (or any other porous wheel)
1) If they get chipped badly or cracked, DO NOT USE IT! Remove it from the grinder immediately! (Save it for dressing your saw blades).
2) This is important for every time you use the unit...Leave the grinder running while you shut the water off and let the wheels spin dry! Porous wheels will let the water drain to the bottom of the wheel and will be off balance when you restart the grinder. Wheels can separate (in essence explode!) when this far out of round as they basically shake themselves to death. This MUST be done every time you shut the grinder off. If your only going to step away for a few seconds, it's better (shudder) to leave the machine running if you are the only one around it.
3) These wheels can grab cloth and clothing alot faster than other wheels (expanding and nova style), so naturally no loose clothing around it.
Take the side cover off and remove the wheel and measure the shaft size / length you have to work with.
Your going to have to make a water shield too (cut down bucket etc.).
Dr Joe
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Post by sitnwrap on Nov 12, 2008 18:46:37 GMT -5
ok. Be reassured I will take all safety precautions. will be back when I have the shaft length.
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Post by sitnwrap on Nov 12, 2008 20:50:02 GMT -5
I took off the side cover. There is a ridge that the back plate for the wheel rests up against. From the ridge to the end is 2 inches. the first inch is smooth steel. the second inch is threaded in order to accept a nut. I also measured from the way back for a total length of 3" I also did some research. Based on the model # of the grinder, this baby dates back to the 60's or 70's. Boy it's in good shape for the age. more pics. ok, now what do I do?
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Post by johnjsgems on Nov 12, 2008 22:53:26 GMT -5
Be careful of maximum rpm's on any wheels you use. Expando's are made for slower speeds. You'ld have to check diamond wheel specs. I think most silicon carbide wheels would be ok. Rig up a guard with water feed and like someone said turn off the water after use and let the wheel turn for 5-10 minutes to sling excess water and avoid out of ballance unsafe operation. When the wheel wears down to the label you will need to replace it.
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Post by bobby1 on Nov 12, 2008 23:49:36 GMT -5
I would be concerned with running lapidary grinding or sanding wheels at 3450 rpm. Most are designed ( or at least intended) to run at about 1/2 that speed, or less. Bob
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Post by sitnwrap on Nov 13, 2008 5:41:27 GMT -5
After John posted the concern about the rpm, I went digging in the old homemade threads to see about that and also to see if there already was a tutorial to make a cabber from a grinder. I found a couple of tutorials that I can kind of use as a guide line but it looks like I should first see if there is a way to slow it down.
I'll be back when I figure it out.
drjo thanks for your help and your initial list of what is needed to make your own cabber.
John and bobby, thanks for your replies.
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Gem'n I
freely admits to licking rocks
Member since March 2008
Posts: 980
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Post by Gem'n I on Nov 13, 2008 22:20:47 GMT -5
All of the info I have on my expando and diamond grinding wheels say 1750 max rpms..so I guess what has been said is very accurate...you may need to go to plan B
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Post by sitnwrap on Nov 13, 2008 23:38:18 GMT -5
yup, plan B is just keep saving . I did go online and as John said, the silicon carbide wheels are in the 4000 rpm max.
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UtahRockHound
spending too much on rocks
Sometimes your the Windshield, sometimes your the Rock.
Member since May 2008
Posts: 301
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Post by UtahRockHound on Nov 14, 2008 3:27:37 GMT -5
I have a 6" grinder I mounted some Silicone Carbide wheels on one side, and a stack of diamond blades on the other. A couple of things I noted right off.
I placed a washer on each shaft just out from the bearing. On each side of the washer is a O-Ring. This holds the washer in one place. It acts as a water slinger and helps keep water and grit from getting in the bearing.
I was very happy at how fast the stacked diamond blades (Rock Hog) took down a hard stone.
I was very un-happy with how fast Quartz and similar stone would wear down the Carbide Wheels. The courser the Carbide wheel, the quicker it would wear down. Chances are I ended up getting a low quality stone, but it was twice the price as the Aluminum Oxide wheel. After about 20 Cabs, the wheel was shot and needed replacing. At $30 to $40 a wheel, this becomes expensive real quick. There are people here much more versed in this then I am. I would guess they can point you to a better quality wheel then I am getting.
I only use the Rock Hog now. If I replace the stones, it will be with a Diamond Sintered Wheel. On ebay, a seller named Rocklady1 sells sintered wheels for $65.
Your on the right track, keep going. :-)
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Post by sitnwrap on Nov 17, 2008 13:20:37 GMT -5
Thanks for the info.
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Wolfden
fully equipped rock polisher
Member since November 2007
Posts: 1,368
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Post by Wolfden on Nov 18, 2008 1:21:56 GMT -5
could you use a router speed control to slow it down ? Harbor freight sells one
Dennis
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Nov 18, 2008 7:45:59 GMT -5
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Post by sitnwrap on Nov 18, 2008 11:13:26 GMT -5
Hey, maybe this will work. Thanks wolfden and drjo for the idea and the link. It looks like the unit is just a plug in and I can do that. Kind of on my own on this project as homefront interest to help is less than enthusiastic.
Thanks again, will check it out.
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Post by akansan on Nov 18, 2008 21:08:19 GMT -5
Sitnwrap - talk with Bikerrandy. When he first started his pendants, he was using a similar type of grinder with SiC wheels. I don't know how much wear he was experiencing on them, but he was turning out large amounts of pendants!
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Nov 18, 2008 22:10:45 GMT -5
Your grinder should be an induction type motor and not a brush type motor
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Post by connrock on Nov 25, 2008 6:24:50 GMT -5
Mixing water and electricity is a big no no but it can be made safe. A bench grinder is not designed for use with water so as with any lapidary equipment it should have a ground fault interrupter. This can save you life. I have a separate 100 amp service in my shop and all of the circuit breakers are GFI. You DO NOT have to go that far with it but a GFI outlet,adapter or extension cord is a must in my opinion!
(you wouldn't take a hair drier in the shower,,,,would ya?)
Good luck with the cabber!
connrock
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Nov 25, 2008 8:04:43 GMT -5
"(you wouldn't take a hair drier in the shower,,,,would ya?)"
Now that's just silly!!!!! You'll never get your hair dry that way! ;D
Dr Joe
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Post by sitnwrap on Nov 25, 2008 12:06:07 GMT -5
connrock, bejewelme sent me a GFI as soon as she saw my post indicating that my saw may be zapping me. What a sweetheart! I installed the GFI in the bathroom and used the hairdryer to make more bubbles in the bath. it didn't work ;D..j/k anyone reading this DO NOT DO THAT!!!!! I'm going to be putting this project on hold til after the holidays but I'll be back to pick everyone's brain. Akansan, thanks. I'll bug Randy also when I'm ready to get back to it.
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Post by Bikerrandy on Nov 25, 2008 21:50:58 GMT -5
Bug who? Me? About what? Hmmmmmm, I used a bench grinder very simular to yours for almost two years before my wife finally got off the cash and bought me the machine. I did all of my grinding dry, but dust control was the biggest issue. To remedy this, I purchase a Shopvac and duct taped the hose to the exhaust hole in the back of the grinding wheel housing. Also, you gotta take it easy with the rough that you're grinding, stuff get's hot!! The grinding wheels usually lasted me a few weeks. At $25 a pop, you'll want to purchase 4 or 5 at a time. Also, the speed on my grinder was 3,500 rpm's. I didn't do anything to slow it down, I used it "as is". Today I started converting this very same grinder into a trim saw. (honest) ;D And yes, I'm taking pics. Anyhow, here's the grinder as I used it....... For your viewing pleasure, here are some pre-shaped rocks. ;D
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