DIAMONDS

First, the question of what type of diamond to use, this could be a complex subject to fully explain (I have a choice of six variants) so will try to stick to basics. The first option to consider is whether the diamond is spring loaded, this can be achieved by the mechanism of the machine, the actuation of the tool head, or the actual diamond holder itself. All my diamonds are spring loaded (with a single exception, 100 degree diamonds for stainless steel) and would never consider anything else. Click here for details on the special Kirba sprung diamond.

Having a solid diamond can cause ‘ping marks’ every time the diamond comes down to the surface, which I do not like. You can alleviate this by careful control of the tool head as it comes down towards the metal (this would probably be in the machine execute settings) the downside is that this could result in a lengthy engraving, ok for a single item perhaps, not for a 100 plus though. I would not use a featherlite attachment, whether it is rotating or not.

Ok, so what about the diamond itself, and we are talking pewter/silver plate here. The best option by far is an eight facet tip, but be warned, they have to be custom made, and are not cheap. If you go down this route, then look after them and keep them separate from the others. If you cannot justify the cost, then you will have to buy the taper point variety, these are ok, no problem, and you will still get good results. Remember that a diamond does not remove metal on pewter, it only parts it to one side.

For Silver plate with more than 6 microns use 120 degree, for thinner plate, 150 degree. The reason for this is that using a 120 tip on thin plate can allow the diamond to actually go through the plate to the base metal below, this is not acceptable for three major reasons. It will not look very good, the engraving will go dull over time and finally, it may encourage the plate to start lifting completely, that will definitely make the item a waster. If you are engraving the silver plated items often sourced in China, like credit card cases and handbag accessories then you must use 150 degree tip and preferably an old one i.e. worn/blunt, and for these items wind the pressure back down to 18psi, or equivalent if tool pressure is by mechanical means.

Most silver plated items have copper as the base metal and I use about 24psi. Be extra careful about very cheap silver plated trays, they are probably made out of steel. To check, hold in one hand and flick your other forefinger onto the opposite edge, it will make a ringing sound. I recommend proceeding with caution as regard diamond choice and pressure on these items. If I ran a trophy shop, I would not stock these items, but being based in Sheffield means I am spoilt for choice from actual manufacturers.

For pewter you have a choice, 120 degree will put a burr up, which you would feel with your finger, so the engraving would be slightly rough or coarse in appearance, if you engrave small volumes, do not consider re-finishing on a polishing mop, not only is it a time consuming job it is also a skilled one to do properly. The alternative is 150 degree, which I think gives the best result, I would use about 23psi, a little less, if using the sharper diamond. If you are engraving a badge or design with either hatch or infill, then I would definitely use a 150, the sharper diamond will make a mess of the hatching. To sum up, a 120 will give a deeper engraving, but not quite as good to the eye or touch, a 150 looks better, but is not as deep.

Here is a golden rule, never ever use a pewter/silver diamond for stainless steel. For stainless I use 100 degree taper point at around 18psi, they don’t last long, so I always price the stainless engraving price up quite a lot. Additionally, I warn clients that the final result can be faint. If I had a laser, I suspect that I would never engrave any stainless steel but would go down the Cermark route. I used to use 90 degree for stainless, but found that whilst the initial passes were deep, they lost there edge too quickly, so I now use 100 degree

The rest is down to good old fashioned 'trial and error'    best of luck

 

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