There have been several people writing about the Omni Transfer Jig not being accurate and introducing transfer alignment errors. I too am experiencing these problems, but I have been able to isolate the cause and reduce its effects during transfer.
Look at these photos of the Transfer Jig and you will see that the sliding block is only constrained in one dimension, and that there is significant play in the block even when the single adjustment screw is tightened. In these pictures I’ve done my best to tighen everything so there is as little play as possible, but the mis-alignment that you can see was caused by merely touching the top of the sliding block.
To mitigate this problem, I am careful to press down on the top of the sliding transfer block near the dop end. And since I use glue rather than wax, I don’t have to worry about thermal expansion.
If you examine the rest of the Transfer Jig photos you can see how the sliding block is only being pulled against the back part of the transfer rail, not against the bottom. You’ll also note that neither the rail nor the blocks have been machined to be accurate against each other – they appear to be stock material that has been cut and anodized.
While it may be possible to modify the jig to work better, I will be shopping around for a Transfer Jig of a proven design. I have been told that the Polymetric Transfer Jig may work with a slight modification, though it will not be keyed.
This type of jig (ie. not one piece with bore aligned grove for dops) has inherent design flaws. My Omni jig (blue) is made from one piece. the only moving parts are the two clamps to hold down the dops.
I have the flat keyed dops not the newer end key, so I use a Facetron transfer device. I never enven tried the one provided wiht my machine.
I inserted a small nylon washer in the end opposite the “V” to accomodate the increased dia of my .300 dops vs .250 Facetron’s. The small washer evens out the bar and sorta aligns it better.
“W”
Hello. I just purchased the Omni and am relatively new to facetting, being a cabber. Can someone please tell me a how to use the Omni transfer jig. I know how to us the jig as far as lining up the dops goes, but I have problems getting the wax to stick to the gem during the transfer process. Any advise would be greatly appreciated. Thanks, Willy
Hi Willy – two things come to mind.
1) Make sure your stone is absolutely clean. Wash with soap and warm water, and I often will wipe the stone with a paper towel dipped in methyl alcohol to take off any oils and fingerprints – especially if I’m polishing with diamond and oil/WD40. Dry it, then paint the stone with a thin layer of shellac (flake or stick shellac dissolved in methyl alcohol works) and let it dry. This will give the wax something to stick to.
2) Make sure both the stone and the wax are hot enough. If you don’t heat the stone, the wax will not stick to it. Be careful not to over-heat the stone though, and also be careful with anything that’s heat sensitive. Some people use one of those mini Butane torches, others use an alcohol lamp. The alcohol lamp is slower and more controllable in my opinion.
Good luck!
-Allan
Thanks Alan. I will try this. Can the shellac be what I would use on wood, like at Home depot or lowes? After cutting would the stone then be cleaned in mineral spirits to dissolve the shellac. Thanks so much.
Hi Willy – yes, any sort of shellac will work. I use stick or flake shellac that I dissolve myself in alcohol. But pre-mixed shellac will work as well.
Most faceting waxes are made of shellac in some proportion. By painting a thin coat on your stone you are giving the wax a very sticky surface to adhere to. The shellac also sticks very well to the polished stone – some adhesives will not stick to a highly-polished surface (some brands of superglue come to mind).
-Allan