Lapidary / Gemstone Community Forum

I built a new cabbing machine from a shaft that a rockhound in Oregon sent me. Thanks, Mike! I've been using it for several months & am finally posting some pix.

I started with a platform built of plywood & 2 x 4s. It sits on a wheeled cart. I mounted a 1/3 HP, 1725 RPM motor that I picked up at a pawn shop for $20. The risers are blocks of hardwood - Maple.
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I made trays & hoods out of Sintra - a 1/4" PVC sheet used to print & mount signs. I got a bunch of reject signs from a local sign shop. They were happy for me to take them off their hands. I cut out the pieces on a table saw & glued them together with medium thick superglue. I did a test of 3 different glues & this one worked best. So well, that I couldn't break the bond without breaking the plastic. The trays are held down by 8 screws into the threaded inserts - the kind that have 4 prongs to bite into the wood so I didn't have to deal with a bolt and a nut under the platform. Sorry, no picture of them.
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Mike made me a 46" x 1" shaft with the ends drilled & tapped. This length with this many wheels gives me 2" of space between each wheel. Eat your heart out Genie owners! I still manage to nick my knuckles, though. I may cut down the shaft by 2" so nothing protrudes out the ends of the hoods. I'll have to re-tap the right hand threads. I bought cheap Chinese diamond hard wheels & Nova type soft wheels. The spacers between wheels are lengths of PVC tubing. It was hard to determine the sizes of the spacers since the inner hub of the wheels isn't as wide as the outside of the wheel & that dimension differs between hard & soft wheels & between brands. I assembled the wheels, spacers, bearings, & pulley in order & tightened down the bolts on each end, then I tightened the set screws on the bearings.

I bought 2 pillow block bearings. 4 bolts through the bearings & riser blocks into threaded inserts holds it down.
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Here it is with hoods installed. They just sit inside the trays. I glued cotton belt material from a thrift store in front of each wheel under the front lip to spread the water evenly over each wheel. It also helps cut down on stray spray. The material has to drag on the wheel, or you still get water spraying you. I added extra belt to the sides of each hood to keep water from spraying from the side of the end wheels. Instead of a complex system of tubes & shutoff valves for each wheel, I just have a single hose running from my water supply (a 5 gallon bucket suspended higher than the machine). I move the tubing from one wheel to the next. It takes about 2 seconds. It's so much easier than shutting off a valve & turning on another one. This was in the garage & I was going to hook the water supply up to the hot water under my sink, but I just moved this indoors. It's so cold in the garage that I wasn't doing any cabbing on cold days.
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Here's an oblique view of the machine. I've added foam pipe insulation as padding to the front edges of the trays, but I forgot them when I took these pictures.
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Here's a closeup.
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I'm running 3 hard wheels - 80, 220, & 360, 6 soft wheels - 300, 600, 1200, 3000, 8000, 14000 & a hard felt wheel on the left end for polishing. Sometimes 14000 is good enough & I don't need to do any further polishing. The Chinese 280 soft wheel only lasted about 6 weeks before it couldn't even remove the scratches from the 360. I refurbished it with 300 diamond powder. I highly recommend refurbing your own wheels. It'll probably last a year or more. & I do a lot of cabs! There are several threads here about refurbishing your Nova wheels. Here's the original - http://gemstone.smfforfree4.com/index.php/topic,4184.0.html

Excluding the wheels, I have only about $150 into this machine. It's a sweet machine. I don't have to switch belts or have more than one machine. I went with 6" wheels because I like to do tight inside curves on some of my cabs. Otherwise, I'd have made an 8" machine. I could adapt it to 8" with taller risers & new hoods.

Right now I'm using a desk lamp on top of the center hood, but  bought some 12V LED strip lights  will see how those work in illuminating the cab.

If you have any Qs, post them here or PM me.

Lynn

Lynn..gotta tell you this is the coolest, best design grinder, polisher, cabber I have seen to date.  Bar none just the best ..... wow.... double wow.   ura12

TOG

Ditto and a triple wow!

That is just way too cool !!!

The two pillow blocks were enough and no vibrations ??

Really a super great setup !!  yes16

Wow!  Thats a great set up.

That is sooooo amazing.  What a creative approach to cabbing and saving $$$$$.  Keep giving us feedback, please, on how it works and if you'd change anything.

what does it take to get one of those shafts?

 Nice, only changes I would recommend would to add 1 more pillow block on each end and upgrade to a more powerful motor with a step pulley. Great work, must be nice to have all those grits right before you on one machine.

Christopher,

Look up spicerm (Mike Spicer) on RTH. He made a 34" shaft with left hand threads on the left end & a bolt to match, and right hand threads on the right with a matching bolt. Shipped to from Oregon to Utah in a PVC tube it cost $68 total. Check a local bearing store or machinist friend who can cut & tap a steel shaft. Perhaps it will be cheaper since shipping was probably expensive. The left hand tap & bolt are costly though.

Lynn

Patrick,

I thought about having additional bearings on the ends, but I think it's fine without them. I've had stepped pulleys on other machines & never used anything but 1:1 to get the shaft spinning at the motor's native speed. By having a single speed pulley on the shaft, I save space. If I do need to slow it down, I can put a smaller pulley on the motor. If the motor burns out, it's no great loss. I have a 1/2 HP Baldor waiting to take its place.

Lynn

Thanks Lynn

Wow that thing is awesome!...its just what I was dreaming of building, but couldnt find the shaft. So  yes16I just bought a used genie...:>)

Nice Lynn, I like your style.......and the pvc wheel spacers.

 I'm like you with the water hose as I just move mine from slot to slot without having to adjust the water. Much easyier and cheaper.

Correct me if I'm wrong but you said Mike had drilled and tapped the shaft ends?????

That would be easier than having to either chase the treads on a lathe or using a hand die for theads. Just drill and tap 2 holes. Super!!!!!!

The major cost with a shaft that long and 1" OD would be the shipping and metal cost. Machining time shouldn't be that expensive.

Don

That's AWESOME!  Thanks for sharing that!

Lynn..

Would you have any interest in building another one ? Would be willing to pay for materials, your time and shipping.

I don't have the means to fabricate something like this. Even if I did, don't believe I could make it turn out as nice !

I really do like having all those wheels on one unit.  yes16 

Thought it might not hurt to ask ? Of course I completely understand if you have no interest. The only real motivation would be getting paid for your time....dunno28

George,

I just might. PM me with your phone # & we can talk.

Lynn

This looks like a very nice machine.  Do you mind if I attempt to make one that is similar?

Doug,
Go for it! And please post your pictures of your progress. Everyone will approach it differently & we'll end up with a combination of the best ideas.
Lynn

Silly question...  What keeps the tension on those wheels in the center so they don't freewheel? Do those bearings offer a little play in the tolerance?

Hi There, I"m  interested in making the grinding/polishing machine, But when searching for the diamond wheels/Nova wheels all i can find are ones costing $75 each and up??..was wondering where You purchased Yours.
Thank You in advance for your reply..

Regards.
Steve.

That is about the most bad-ass cabber I have ever seen! I'd love to make one myself but there's enough wheels on that thing to break my bank!  shuffle08

Sweet job - I'm in awe!

Go big or go home right Lynn?
Love it:)

Great job Lynn, great idea to set 10 different grid in just one axis and one 1/2 hp mechine, so efficient to work by those unit.


 yes16

Hi Lynn,

I am curious, you have had this machine together for over a year now. How do you like it? Is there anything you would change in your construction?

I had Mike make me one last winter. He also made me a metal frame with mounts for my bearing and motor. I have yet to collect all the wheels I need (10). I think there will be 2" in between my wheels. I still need to make a hood for it.

Can't find the words.... yes16 yes16 yes16 yes16 yes16 yes16 yes16

 shocked30

Awesomely ingenious!  I'm also curious how it is working our for you.  Also, what is the purpose of tapping the ends of the axle?  For a bolt to hold the end spacers on?

Tim

It's a wonderful machine. I've made a couple hundred cabs on it. I've now made an 8"  version of it, so the 6" arbor is for sale. http://gemstone.smfforfree4.com/index.php/topic,10157.0.html

I have a potential buyer, but he's living from hand-to-mouth & may take months to come up with the $.

To answer 2 questions above - the shaft ends are tapped so I can tighten everything up with a bolt on each end. That keeps the wheels from free-wheeling.  It works so much better than collars with setscrews. It's really hard to get enough pressure on collars to keep the wheels from free-wheeling.

Lynn

You have inspired me!!!!! Where did you get the wheels from? the hard diamond Chinese ones? That thing is great!!

This is one of the post that made me join this forum ! Thankyou for posting this as this is the unit I am going to be building.
I have a couple of questions.
#1 What size did the shaft get drilled and tapped in the pics it looks to be 1/2" or maybe 5/8" (going by the bolt head size)
#2  Is the pulley keyed and set screwed to the shaft, or just set screwed with no key.

Thank you for any help on this.

Ernie   

So the shaft is metal, but the spacers are PVC? And the ends are drilled and tapped so you can tighten down everything?  Cool!
In the past year, did you experience any negative effects like vibration,  slippage, etc?
I like that material you made the box from.... will have to see if any local signage shops have any waste!
Thanks!
Phil

Wow - it was neat to see this post pop up again. First time around I had not fully appreciated what it could do. Not only a start to finish setup minus the saw (and I see zero drawback to that) but with options on grit that would really help with the variety of stones put through it.

Anyway, this pup should be on the cover of rocket science magazine, lol... way cool!

Really nice build - So many projects, so little time  dunno28

That is Awesome  yippie24
Very creative, friend~!!
I'll try my hand at making a similar 8 wheel setup when my tools are out of storage soon.

This is an interesting project.  My question is how do the wheels between the bearings keep from freewheeling?  I'm guessing there is a little play in the bearings that allows the end screw compression to transfer all the way to the center section via pvc sleeves?  Thanks.

What do you folks feel is the optimum space between 8" wheels?  Everyone please chime in.  All insights appreciated.  Thanks. 

no set measurement, but enough space so I don't grind or polish my fingers and etc  on the neighboring wheels when working the bezels on a dop stick.

Superb stuff, inspired so I am.
Bought my bar today, got two pieces, one for sort of the same as your build, it's rather longer @ 60", also got another @ 40" for a flat lap, the bars are 25 mm, was surprised as they only cost me the equal to $18, the threading cost me $5 and a bottle of vino.
Now for the pillow blocks, looking to get them here in Spain, will  be much cheaper than from the UK, where they are $10 each + shipping, I reckon about $8 a piece, my amigo is on the case, will post pics when it's looking like a machine.
Still looking for flat grinding pads for hand work.
This blog is superb, the info is second to none.
Thanks from the cave.
Keith.

People ask about how to keep all the wheels tight without them free wheeling. I tighten the bolts on each end. An oversized washer under each bolt puts pressure on the assembly of PVC spacers, wheels, pulley & bearings. After tightening the bolts, I tighten the bearing setscrews, then bolt the bearings to the risers.

I sold this 6" machine & built an 8" version with just 8 wheels. I'm using a sintered 60 grit wheel for my coarse grind. It weighs 14 lbs or so, & the new machine has 4 8" x 3" rubber drums, so I have extra bearings on each end of the shaft. I have the motor mounted below the bench. It's a pretty loud machine. I'm not sure if I could reduce that noise by better balancing the wheels. I can't listen to music while grinding because of the noise.

I'm working on a new design that has just 2 trays instead of 3. The shaft is a little shorter. It's designed for 3 bearings.

I'm happy to see people making their own machines. Please post your project here or in a new thread. If creating a new thread, post a link to it in this thread.

Lynn

Hi Lynn,
Show us some photo's of you new machines????????????? Please........
Don

How to you drain your trays? Did you setup a plug in the bottom or do they lift out to empty?