A new Diamond Cabochon machine part 1

A new addition to our stable of homemade Lapidary machines, this one will be a 4 wheel cabochon machine using for rubber expanding drums fitted with REZ belts which will be charged with diamond paste of different mesh.

Details view of cabing machine shaft showing threaded end with nut
The Cabing Machine shaft full view
Full view of shaft

Just thought I would let you all know that we are building a new cab machine, this one will be a lot different to our first creation of a few years ago as it will only use diamond as the cutting medium.

It will have four rubber expanding drums which are 8” diameter and 3” wide, these will be fitted with REZ belts, to all intents and purposes they are the same as the silicone carbide belts that you would use, except they are impregnated with resin instead of silicone carbide. The resin “holds” the diamond onto the belt which is applied as a paste and you use lapping fluid to thin the paste to help spread it over the surface of the belt.

Details view of cabing machine shaft showing threaded end with nut
End view of shaft

We have found this very cost effective when compared to buying a set of diamond wheels simply because when the cutting action becomes dulled, you just recharge the belt and don’t have to change an expensive diamond wheel.

As out original machine will do all the rough work through to 600 grit silicone carbide, the new machine will follow on from there and in many cases I don’t think that polish will be required, it certainly wasn’t on some Lapis we did as we got a mirror finish straight off the Rez belt.

Cabing machine shaft showing flanges in detail
View of the flanges

This will also be a “clean” machine as does not require water, instead you occasionally give the wheels a burst of lapping fluid to keep things lubricated and as you don’t hold the stone against the wheel for as long as you would with a wet machine, things don’t get too hot.

The stage we find ourselves at right now is that we have a shaft which is 24” long and 1” diameter. It has a left hand thread on one end and right hand thread on the other, a 2,3,4 pulley fitted, two ball bearing sealed pillow blocks and 4 pars of 3” flanges, so it’s just about ready for assembly. This assembly was machined and supplied by Andrew at ABC Polishing so thanks Andrew a great job.

Cabing machine shaft showing 2,3,4 pulley and bearings
View of the 2,3,4 pulley

We have just received the four expanding drums from the USA and we already have the REZ belts and diamond paste.

Next job is to make the supports for the bearing blocks and a base for it all to sit on. This machine doesn’t need hoods over the wheels and pans to catch the water as there will be none, so we plan to sit it on a base and make a cover to go over the whole machine for when it’s not in use to keep dust out.

I also had a single phase motor that I was going to use for this machine, but it died so have to order a new one soon.

I will keep updating as the machine progresses through the build and report on its performance once it’s operational.

Cheers

Dave

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