[Lowfer] Looking for thumb-screw(s)

[KD7JYK DM09]

A local OM has an old key of the following description:

J.H. BUNNELL &CO.   NEW YORK
PATENTED FEB. 15. 1881
IT IS ALL BRASS EXCEPT FOR THE ARM WITH THE BUTTON ON IT.

It is missing one of the two knurled thumb screws, I'd like to find one, if
it is a common type or a matched pair so that he can get this key on the
air.  The OM has shown the key to me several times, I think he really wants
to restore and use it, I'd like to help him out.

Here is a picture of the key:

http://jhbunnell.com/pix-Bunnellearlykey.jpg

http://jhbunnell.com/pix-BunnellKeyAdr.jpg

Please let me know what you have available and for what price.

Kurt