Need info on the Graves Preformer

[Unikite]

  I would like some information on the Graves Preformer.  The description says it can be used on most vertical grinders and comes with several pre-shaped patterns.  I would like to know if I can use this on a Genie type grinder with the coarse wheel on the left side. And especially want to know how small a cab I can form on the performer.  Also, does it grind the domes? I make cabochon jewelry and want to speed the process of grinding cabs for ear rings in the 4 to 6 mm range.  None of the descriptions list the size range of the preformer and what patterns they list are larger ovals. Has anyone used the Graves Preformer and what are the opinions do you have?  Also is it worth the extra $ to buy the motorized version?  I have found a good price for the whole setup but don't know if it will fit my needs.

[jakesrocks]

Try contacting Graves directly. http://gravescompany.com/

[finegemdesigns]

It doesn't do domes just the perimeters.

If you can get it to work by hand then the motor should also work.

Are you cutting 4mm and 6mm rounds or are you cutting ovals? Also very small cabs are tricky since you will need very small dops. 4mm might be borderline small unless they are rounds. Rounds are the easiest to do.

Post a photo of your Genie machine. My unit works and I can clamp it to my Covington 4 wheel vertical machine.
There is a mounting bracket that comes with the preformer but there has to somewhere on the cabbing machine frame to clamp or attach to.

Note: This preformer will not cut symmetrical ovals when mounted to a HORIZONTAL lap. But this doesn't appear to apply to your situation.

Also there is a limit to how elongated a cab you can cut in some dimensions. Very long thin cabs might not work on this machine.

[Debbie K]

I recently acquired an old one a few weeks ago on a Graves Cabmate. Mine holds the standard 1/4" dop, but I don't see any reason why you couldn't machine either 1/4" dowel or copper rod down to the desired diameter at one end for the stone. Mine is set up to use on the right side on a 100 grit hard diamond wheel. If I remember correctly, you could probably use it on the other side.

I haven't had the opportunity to really try it out, and I won't be able to for the next few days. But it appears to me that if you shift the platform off perpendicular and move in a little you could do a little more than just cut the perimeter. You can make your own patterns out of plexiglass.

I'm having a roof put on my house today, but after I sort things out a little I'll try to take a picture and post the attachment and maybe you can determine if it'll work on your Genie. It appears to be a really sweet machine, especially the attachment. I wanted to figure out how to use it on my expando wheels. I couldn't find any information about the actual mechanics of it either, and posted an inquiry here but didn't get any replies.

Debbie K

P.S. Mine is the manual, not motorized version
P.S.S. Just checked the gadget, it can be mounted on either left or right hand side of the grinding wheel. However, if you want to do something smaller than 1/4" you're going to have to make an extension for both the plate that the pattern rolls on and the pattern holder.

[Unikite]

Thanks for the helpful info and speedy replies.  I cut mostly 4-6 mm round cabs but occasionally cut ovals.  I own a Smithy metal lathe/milling machine so making small dops should be no problem.  My cabbing machine is similar to the Genie but is made of a very hard stainless steel ( a Chinese copy of a Kingsly North grinding machine).  I tried drilling holes in it and ruined three drill bits before I gave up. Due to the toughness of the steel, I think I will have to resort to clamps. I believe the preformer will reduce the time spent in shaping the cabs so I think I'll try it out and post my results after initial set-up and possible modifications.

[Debbie K]

I had the same issue trying to drill a drain hole in my mystery grinder. Ended up using diamond bits and stones, which worked a heck of a lot better.

Debbie K

[Unikite]

Thanks for the tip Debbie.  I will try the diamond bits on the water holes since they never lined up correctly with the wheels.  If I elongate them, I will be able to adjust the water so they drip on the middle of the wheel. The manufacturer punched several holes for each wheel but the spacers between the wheels offset the wheels from the holes.

[Back]

Hi and welcome.

Preformers is something that intrests me. I am guessing that you are cutting calibrated rounds? I cut a lot of calibrated cabs and most of them wont fit in the setting because of the shrinkage of the setting. What kind/grit your first wheel?

Very interesting

Bless
Shawn

[Debbie K]

I haven't really used mine yet for trying calibrated cabs, but the Cabmate came with a 100 grit Cystalite hard diamond wheel.

Debbie K

where the roofing job is still ongoing....

[Unikite]

I start on an 80 grit hard wheel and then progress down to a 250 grit hard for final sizing. I'm sure it will take some adjusting to get the sizes down to an acceptable dimension.  Currently I am using Dop wax for the dops, but with a brass Dop, I expect to be using epoxy for the small cabs and was wondering if there is a good method of releasing the cabs from the Dops.  I plan to be using heat, either boiling or a torch first but would like to know of any reliable method as a plan "B".

[Debbie K]

Most of the faceters I know either use faceter's dop wax or thick super glue. They use an alcohol lamp to heat the wax to either transfer or release or set a stone and acetone for the super glue. They sell an activator for super glue which helps to set the glue pretty quickly and it works pretty good. I found some at Woodcraft, I believe. http://www.kingsleynorth.com/skshop/product.php?id=98052&catID=1125

Faceters use the same brass dops as this unit uses. Thank goodness the Graves units don't require a keyed dop, so we can make our own.

Debbie K

[slabbercabber]

They sell an activator for super glue which helps to set the glue pretty quickly and it works pretty good. I found some at Woodcraft, I believe. http://www.kingsleynorth.com/skshop/product.php?id=98052&catID=1125

Activator for super glue is water.

[Unikite]

I just received my Graves Preformer in todays mail.  After inspecting it, I am slightly disappointed in the motor assembly.  I purchased the motor since it was almost half the list price and if I would buy it later the shipping was almost $20.00.  I assembled the preformer and attached the motor.  After turning on the motor I found the motor shaft unscrews off of the dop shaft, an easy fix with a setscrew but I would have thought this should have been corrected way before this. Also the on/off switch is flaky, not a crisp switching. The spring clip used to hold the cam against the stop is too small to easily attach to the motor pin.  Also, if using the motor, you have to completely disassemble the unit to change cams.

The performer itself seems well made although it does not easily lend itself to being mounted on the left side of a verticle wheel.  The cam engagement is set up for operating on the right side and if you mount it on the left side you will not be able to adjust the pressure down into the wheel during the grinding process.

My recommendation, if you plan to purchase the performer, don't invest in the motor unit unless you plan to make the same shape cab in quantity.  If you plan to change the cams for different shape cabs, you are better off using the manual version.

[finegemdesigns]

I start on an 80 grit hard wheel and then progress down to a 250 grit hard for final sizing. I'm sure it will take some adjusting to get the sizes down to an acceptable dimension.  Currently I am using Dop wax for the dops, but with a brass Dop, I expect to be using epoxy for the small cabs and was wondering if there is a good method of releasing the cabs from the Dops.  I plan to be using heat, either boiling or a torch first but would like to know of any reliable method as a plan "B".

http://www.finegemdesigns.com/doppingmethod-fgd.htm

[finegemdesigns]

I just received my Graves Preformer in todays mail.  After inspecting it, I am slightly disappointed in the motor assembly.  I purchased the motor since it was almost half the list price and if I would buy it later the shipping was almost $20.00.  I assembled the preformer and attached the motor.  After turning on the motor I found the motor shaft unscrews off of the dop shaft, an easy fix with a setscrew but I would have thought this should have been corrected way before this. Also the on/off switch is flaky, not a crisp switching. The spring clip used to hold the cam against the stop is too small to easily attach to the motor pin.  Also, if using the motor, you have to completely disassemble the unit to change cams.

The performer itself seems well made although it does not easily lend itself to being mounted on the left side of a verticle wheel.  The cam engagement is set up for operating on the right side and if you mount it on the left side you will not be able to adjust the pressure down into the wheel during the grinding process.

My recommendation, if you plan to purchase the performer, don't invest in the motor unit unless you plan to make the same shape cab in quantity.  If you plan to change the cams for different shape cabs, you are better off using the manual version.

Since the assembly is mounted on the right side of the wheel and your wheels rotate top down they use a motor with a clockwise rotation. The idea is to have the motor rotation running against the cutting wheel rotation. If the rotation is going WITH the wheel rotation then your cutting will be drastically slower.

The problem of course is when the threading on the shaft adapter is incorrect and allows the spindle to unscrew.
To fix this I use a set screw (like you mentioned) to prevent it from unscrewing.