>Are these realy Starrett? I picked up a pair just like them today at a sale only they are missing the points them selves just pencils sticking in them:<( the only markings I can find is F31 only things at the sale were them and a #12 rip saw with the largest hang hole I have ever seen had to be 1/2" or bigger
>According to my uncle's Starrett catalogue, they look like they are, although neither my uncle's catalogue nor the current listing at Starrett shows copper coating.
>The same attachment was available on their No. 85 Universal Dividers, which I inherited from my revered uncle - another neat tool. I use the dividers, with their outside points, inside points, divider points, or one of the above and a pencil, regularly. I have yet to use the measuring-from-a-hole ball attachment, but it's nice to know that, when I have a problem to solve that can't be solved any other way, they'll be sitting there waiting.
They appear to be available from Starrett still, although I've learned that it's a good idea to be sitting down when you call their helpful toll-free number for a price (I own a No. 245 engineers' combined taper feeler gage, from the same revered uncle, and somehow the tip of the taper gage got snapped off - $65, as I recall). I imagine the fittings for the trammel points are also available.
The engineering on the attachment is nifty - the shaft on which the balls fit is tapered at the ball end, like a tiny Morse or similar taper, with just the perfect taper to hold the ball in place with a little pressure, but remove easily with a twist on the ball.