Member postings for Jon Duke

Hi, I have made shims in the past using Paul Lousick's method, but for many years I've made shims from shim stock by clamping pieces of the stock, cut into a rectangle using shears, to a flat disc that has a shaft on it, so it can be mounted in the lathe and then cutting the shim out from the stock.

Cutting shims from this is not trivial, but it can be done, and with practice it can be done very quickly. I've used a watchmaker’s graver (difficult to keep it steady), a sharpened up piece of hacksaw blade held in the tool-post (tricky, needs to be very sharp and not to have any top rake or it digs in badly especially when breaking through), and, best of all, a small air die grinder held in the tool-post (using a small cylindrical wheel held at 45 degrees).

I scribe the ID and OD on the piece of shim and then in the lathe I centre it and tighten the clamp screws, which have washers under them, and then start the cutting. You cut out the inside first and then the outside. The cut edges are sharp and I often tidy them up using a small abrasive mounted stone.

I use this device mainly to make shims needed on classic motorcycles, typical shim thicknesses are in the range 3 to 12 thou. The pictures below show the tool used to hold the shim. I tend to drill and thread holes as demanded by the size of shim to be cut. It takes me about a quarter of an hour to make a shim provided that the shum doesn't snag when breaking through (the die grinder method more or less obviates that). I hope that helps.

Thanks for replies so far.

I'm really looking for advice from people who have cut vinyl sheet this way regarding selecting a swivelling head that works ok. I'm also looking for practical advice on setting up the mill to cut vinyl, e.g. downward force needed and how to achieve it, type of backing and how to mount the vinyl sheet, any things to watch out for, would also be very welcome. If I can get a working system then I will have other uses for it, e.g. cutting gaskets or lettering for such as tank badges.

Kind regards,

Jon

I need to cut some backed vinyl sheet to make some bespoke letters and numbers for the number-plate on an old motorcycle. I have a small CNC mill which I drive by making .dxf files from which I make GCODE that I send to Mach3, which then drives the mill.

I’m aware that one can buy small vinyl cutter knives cheaply on eBay and that these operate in swivelling heads which can be fitted to a CNC mill or router. There seem to be quite a variety of heads available, at a very wide range of prices. One of the cheaper ones seems to be:

**LINK**

I would very much welcome advice from people who have cut vinyl sheet this way on selecting a swivelling head that works ok.

Practical advice on setting up the mill to cut vinyl, e.g. downward force needed and how to achieve it, type of backing and how to mount the vinyl sheet, any things to watch out for, would also be very welcome.

Thanks for all help,

Jon