Colt 1921 actuator checkering pattern

[choppero]

Can anyone tell me, with certainty, the actuator checkering pattern LPI and angle. I have two style checkering wheels 36 LPI @ 90 degrees and 35 LPI @ 60 degrees.

[bob241]

This is taken from a post by Reconbob a few months ago, it may help. at that time he was considering mfg the 1921 actuator.

(The knurl is no problem, other than you can,t get the  original 32 lines per inch, so have to use 36 lines per inch, even the 36 line knurls are $850.00 per set). I think I read somewhere (do not hold me to it) that the knurl were at 60 degrees (diamond out) 

 

 

 

[bob241]

4 hours ago, bob241 said:

This is taken from a post by Reconbob a few months ago, it may help. at that time he was considering mfg the 1921 actuator.

(The knurl is no problem, other than you can,t get the  original 32 lines per inch, so have to use 36 lines per inch, even the 36 line knurls are $850.00 per set). I think I read somewhere (do not hold me to it) that the knurl were at 90 degrees (diamond out) (Degree corrected)

 

 

 

 

[reconbob]

I am away from the shop, but I brought some actuator drawings with me. One is a copy of the original Colt drawing of the M1921 actuator. On this drawing for whatever reason the location and width of the knurl is called out, but the diamond pattern is not. The width of the knurl is 0.30” +/- 0.01” and is centered on the ball which is 0.680” diameter.

From Doug Richardson’s drawing of the M1921 actuator he specifies the knurl as 32 TPI, 45 degree LH/RH concave pattern knurl.

The actuators Doug made were perfect except he either could not get, or did not want to pay for the correct 32 TPI knurls. He used 36 TPI. Knowing Doug 32 TPI must not be available because he was a fanatic about details. The 36TPI must be a standard because it is available off the shelf, but as noted last I checked was $850 a set. 

i wonder about the 90 degree knurl. If I understand correctly, that would not create a diamond knurl, but a box. 
 

Bob

[choppero]

I have 36 LPI @90 deg pictured on the left. And 35 LPI @ 60 deg on the right.

 

[Colt Chopper]

Without getting an actuator out to compare, the one on the right looks more correct to me.

[bob241]

this may help.

 

 

[choppero]

I'm going to make the rest of my 1927A1 '21 knobs with the 60 deg pattern. Thanks for the feedback.

[TD.]

choppero,

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