rockbrain
Cave Dweller 
Member since January 2022
Posts: 3,167
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Post by rockbrain on Nov 20, 2022 10:05:20 GMT -5
Son Of Beach an expanding drum is a rubber wheel that is designed so it stretches or expands from centrifugal force when it's spun. You buy belts that are just big enough to slide on the wheel. When the wheel is spinning the belt is held in place by the expansion. This allows you to have multiple grits with one wheel. You would typically grind and shape on 80 and 220 hard wheels and then switch to 280 on the expanding drum then change the belt to 400 on the drum and keep going through the grits. SIC (silicon carbide) belts don't cut as quickly as diamond and wear out a lot quicker. SIC belts for a 6" wheel can be purchased for about $1.50. You can also buy diamond resin wheels which basically turns it into a soft wheel like a Nova. Those will set you back about $45 each. It was nice going from changing out belts to a machine with all the wheels but it's a way to get into a cab machine for less money and you can spread it out buy starting with SIC and then changing to diamond one or two at a time. I started with a 1000 and a 3000 because I couldn't find any SIC belts higher than 1000. My 6" machine is on semi-permanent loan to my sun in law but I have an 8" machine with an expanding drum that I still like to get on. The drums are typically wider than a standard wheel. A 6" is usually 2.5" wide and my 8" is 3" wide. Sometimes that extra real estate is really nice to have. An 8x3 seems huge after you're on a 6x1.5.
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Post by stardiamond on Nov 23, 2022 17:45:11 GMT -5
link $195 and they will ship.
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wampidytoo
has rocks in the head
Add 5016 to my post count.
Member since June 2013
Posts: 709
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Post by wampidytoo on Jan 16, 2024 5:08:42 GMT -5
I was on here before the rocks you play with turned to dirt but I don't come on here much anymore and I have all the necessary excuses for it but just happened to see your post and had to reply.
I have only used one home made machine but I have made thousands of pendants and polished about as many slabs. Ask any of the old timers on here and they will tell you that I can make some happy sh-t that keeps the ladies coming back for more.
I am talking about a machine made with a drill press, bench grinder, 6 inch counter top diamond impregnated polishing pads with Velcro backing and a backing pad to spin them. Oh yeah, and a plastic tub to keep the water off of me. The time it takes me to change grits is about five seconds longer than it takes the drill press to stop spinning.
Almost forgot, I did have a two wheel machine with a trim saw once but only used the trim saw. It takes two hands to use a wheel machine but on my flat pads I can polish with one hand and eat or smoke with the other hand. Plus, on big cabs with a flat back it is simple to keep the back flat or use the edge to do concaves way tighter than the curve on a wheel.
If you are still trying to get started let me know and I will get some photos to you somehow. I have learned and forgotten the new photo thing here but I heard of an easier to remember way to do it that I need to check out.
Jim
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vwfence
has rocks in the head
Member since January 2013
Posts: 566
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Post by vwfence on Jan 16, 2024 12:51:15 GMT -5
For a starting machine take a look at a rock rascal . it gives you a saw and a 6 inch wheel . with an expando drum and belts it gives you the full range of grits , its just slower
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realrockhound
Cave Dweller
Chucking leaverite at tweekers
Member since June 2020
Posts: 4,483
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Post by realrockhound on Jan 19, 2024 19:04:54 GMT -5
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Post by Son Of Beach on Jan 19, 2024 20:52:22 GMT -5
I'll give him a shout  |
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realrockhound
Cave Dweller
Chucking leaverite at tweekers
Member since June 2020
Posts: 4,483
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Post by realrockhound on Jan 19, 2024 22:02:48 GMT -5
I'll give him a shout I noticed they had other prices listed. Didn’t see a price on that. If they want over $1000 then I personally believe he’s asking too much. But that’s just me |
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Post by Son Of Beach on Jan 19, 2024 22:11:20 GMT -5
I'll give him a shout  I noticed they had other prices listed. Didn’t see a price on that. If they want over $1000 then I personally believe he’s asking too much. But that’s just me You really are a Lapidary Yoda, eh? |
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dshanpnw
fully equipped rock polisher
Member since December 2020
Posts: 1,157
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Post by dshanpnw on Jan 23, 2024 8:41:59 GMT -5
I know someone from our club that makes all his cabs on a flat lap and they are pretty spectacular. He's been doing it for a long time. It's all he's ever used. I saved enough to buy a cabbing machine, I can relate to having a tight budget, but before I managed to get that I was going to go with the Hi-Tech slant lap that Jason has.
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Post by Son Of Beach on Jan 23, 2024 19:15:46 GMT -5
I know someone from our club that makes all his cabs on a flat lap and they are pretty spectacular. He's been doing it for a long time. It's all he's ever used. I saved enough to buy a cabbing machine, I can relate to having a tight budget, but before I managed to get that I was going to go with the Hi-Tech slant lap that Jason has. Not like I'm cranking out cabs, but I have a flat lap as well and I really do think I can get by with this for a while now.
My only issue is not have a saw, but I'll figure it out in time...
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Post by Rockoonz on Jan 24, 2024 10:59:03 GMT -5
For a starting machine take a look at a rock rascal . it gives you a saw and a 6 inch wheel . with an expando drum and belts it gives you the full range of grits , its just slower What a coinkydink, I just picked one up at a living estate sale. They are pretty good for a starter unit. |
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Post by 1dave on Jan 31, 2024 12:07:53 GMT -5
Expando Wheels - buy two wheeels, an arbor & motor, Large bottles to catch the water and DIY. The wheels give with pressure and naturally curve the stone.  |
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realrockhound
Cave Dweller
Chucking leaverite at tweekers
Member since June 2020
Posts: 4,483
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Post by realrockhound on Jan 31, 2024 12:18:28 GMT -5
Expando Wheels - buy two wheeels, an arbor & motor, Large bottles to catch the water and DIY. The wheels give with pressure and naturally curve the stone. I have something similar. Pretty nice for polishing large slabs and stones. |
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docharber
has rocks in the head
Member since October 2008
Posts: 716
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Post by docharber on Mar 13, 2024 1:44:08 GMT -5
I have an Ameritool 8" flat lap and I find it easy to use, but a bit slow grinding (you can always add a more aggressive grinding disk than the 180 grit it comes with). They also offer a 6" machine. I can sit and watch TV with the machine on a sturdy TV tray and sand /polish away. Grinding is a little too noisy, though. I do have some gripes about my AMeritool, however. I had to replace one of the four rectifiers early on and more recently, the rheostat rotary switch is getting gimpy. They gouge you for parts (the switch is $30). The water drip bucket tends to vibrate a lot if the wheel isn't perfectly balanced which is hard to accomplish, and if the bucket is low. The replacement PSA abrasive disks are a little pricey, too, at $40 each though the 325 is the most perishable by far. It is fairly clean for indoor use and does a nice job overall. The grinding stage is the most time consuming, but I can do a cab in about a minute each subsequent stage. I have an 8" Diamond Pacific monster in the garage if I want to preform material quickly, but I find the Ameritool meets most of my needs. I understand opal cutters like this and similar machines for the very reason that they are not too aggressive, and less likely to grind away color in a heartbeat.
Our club has both an 8" All-U-Need and a 6" slant cabber, the latter being used mainly for intarsia. They seem to be pretty good machines, and are made by Hi-Tech, a respected manufacturer.
In the same size, all these machines are priced pretty much the same, being about $600 complete with laps (they're sold without laps for considerably less, if you have compatible laps- see the Kingsley North Catalog online). If you can find a used machine, check it out thoroughly including assessment of lap wear, and is it's sound at a good price, BUY IT. The problem with your budget is that good used machines are in short supply and go for premium prices. It is entirely feasible, however, to build your own machine if you have some basic skills. There's nothing precise about these machines. You need an AC motor of about 1/4 HP max, capable of turning the disk at at least 600 RPM. An AC motor is fine, but less efficient than a DC motor, but the advantage is that the AC motor doesn't need a rectifier/ diode circuit. You also need a rotary speed control switch, a housing that will keep water away from the electricals, a drip bowl, and a water supply with adjustable drip rate. Add a cord and there you have it. The most difficult part to fabricate would be the arbor assembly to hold the disk well-centered to minimize vibration.
As an aside, I didn't like the hold-down screw on my Ameritool and substituted a stainless steel chair glide with a 1/4"-20 screw that works great in my machine. Just make sure the screw isn't too long. I tried to fit one to the All-U-Need at the club but it was too long. These furniture glides are about an inch in diameter and have an integrated rubber washer that eliminates lap disk chatter on start-up. It's easy to loosen, too.
Good luck finding a machine. I know you'll enjoy it, whatever you find.
Take Care,
Mark H.
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