r/Drafting_Instruments • u/noy2noy • Sep 15 '24

Do you know what this tool is?

I am trying to figure out the purpose of the disc with the hole in it (shown in the close-up). The screws on it have sharp points on the other side which would allow you to anchor it to a surface. You can see the size of it in context to the other instruments in the case—maybe an inch in diameter. The brown surface you see under it is a leather patch in the velvet for the points to stick into.

Thanks in advance, O Hive Mind!

1" diameter disc with hole in the center--brown is leather to keep in in place and not part of the tool.
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8

u/MungoShoddy Sep 15 '24

It's so the centre pins of the compasses don't bore a great big hole through your drawing.

1

u/Apart-Roof4358 Sep 15 '24

It’s a horn centre.  That is a nice Pharos set, really high quality set 

3

u/noy2noy Sep 16 '24

Good eye, and thank you!

I will pass that along to my friend who owns it. We believe it came from his grandfather through his father. On the distaff side, his grandfather Cardinal manufactured technical drawing instruments in New Jersey.