bpjack wrote on Oct 30^th, 2018 at 4:10pm:

Jack,

Back when Parson's was making the Long Scope, and the Super Targetspot repro, black delrin was used for both the micrometer knob buttons and the opposing plungers in the  4-point and 3-point mounts.



Frank and Wayne,

The Centennial Journal by Lyman is a good source of info about this. Strobel's later scope book duplicates a lot of the Lyman Centennial info.
Way too much to type here, but some highlights are...

5A and 438:
Lyman 5A scope first sold in Feb, 1929
Lyman 438 scope first appeared in Lyman catalog No. 18 published in 1930
Originally scope bases and mounts were interchangeable for the 5A and 438 scopes
Early rear mount had the plunger opposing the horizontal micrometer knob, and the "grasshopper" spring opposing the vertical.
The 4-point rear mount (shown in Frank's photo) with the bottom plunger opposing the vertical micrometer knob, first shown in catalog No. 21, had taken place by 1932.
Early clicks were 1/2 minute, by 1933 the rear mount had 1/4 minute clicks (using the 7.2" base spacing). This mount was discontinued by 1938, when a new 3-point mount was developed.

Targetspot, Jr, and Super:
Targetspot introduced in Lyman catalog No. 22 published in 1934, using a 4-point mount with 1/4 minute clicks.
Jr and Super introduced in Lyman catalog No. 25 published in 1937, using the new 3-point mount with 1/4 minute clicks.
Some people preferred the earlier 4-point to the newer 3-point, so the earlier 4-point wasn't discontinued until 1949.
Note that Lyman wrote that the 4-point mount that was used with the 5A and 438 was discontinued in 1938, 11 years before the 4-point mount used with the Targetspot series was discontinued.
There's been a lot of mount (and mount parts) swapping going on from scope to scope since then. 

Thanks BP.  Just ordered 5 pieces 1/4” by 12” off eBay for under $8 shipped.  Nothing like a lifetime supply!

Jack

bpjack wrote on Oct 30^th, 2018 at 5:12pm:


     I have come to realize that a "lifetime supply" is not as big a deal as it used to be.

CHRIS
RGChristensen

(bad) weather permitting, I hope to make some steel inserts this weekend (or I will be dealing with a ton of maple leaves). Then I will try the Delrin when it shows up.  Have some other plans for that Delrin anyway.

Thanks

Jack

JLouis wrote on Oct 30^th, 2018 at 5:54pm:

John,

Aren't your mounts already micrometer mounts with the appropriate graduations across the designed vertical and horizontal adjustment ranges?

Turned out nice but I think you would be better served by not having the radius and please do not take that wrong.

BP the Mount on the one I repared is shown in Reply #29.

JLouis