aperture elevation scale redo?

[RJW NZ]

Howdy,
I have a couple of aperture sights missing the elevation scale plate, that thin piece of steel or aluminium depending on the maker with the graduations on it that attaches and adjusts with two little screws. (one central and one ph5a) I've got samples of what should be there and have been going through the yellow pages looking for people such as trophy engravers who might be able to make me a couple. So far no such luck, the trophy guys have said they couldn't stay that accurate in the graduations.
Any thoughts from anyone a) what would be a good type of tradesman to approach to copy and reproduce the plates I have b) perhaps any other sources for replacement plates?
cheers and thanks Roger

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[KimW]

All you really need - as well as the two little screws to fit the arm - is a plate with scribed lines. Many years ago - when I had access to a good quality lathe - I reproduced a "Good Enough" scale plate for NRA use. A HSS tool bit was ground to give a 90 degree very sharp point and put into a boring bar and into a lathe chuck - the lathe was never turned on. The scale plate was mounted on the toolpost at a height just enough for the tool to scribe a line across the plate. The divisions were manually set by advancing the toolpost a set number of thou consistent with the machined divisions on the arm - a number found by trial and error.

Peter may note that , ' So this is what RNZEME Workshop Officers do with their lunch hours', turning a perfectly good lathe into a poor quality Ruling Engine.

Complicated to describe but if you have a friend with a lathe and the time ?.

[Patrick Chadwick]

RJWT32, get in touch with the nearest model engineering club!

As KimW has described, you can use a lathe. But a better tool is a hand shaper, and only MEs have such outdated equipment these days. Using a hand shaper with the scribing tool mounted in the clapper box (does anyone out there know what I am talking about in these CNC days?) is a doddle, as you don't have to keep on backing off and advancing the scriber. I did this a couple of weeks ago to scribe a scale for a long-range sight for my Sharps.

The lathe, of course, had been set up to calibrate the bullets....

(The screwdriver is used for stirring the tea...because the spoon is used for removing the dross from the molten lead.)

Patrick