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WTB All Things JT Slocomb Co

Differential mics use two screws of very slightly different pitch. When rotated together you get the equivalent of a pitch that's the difference between the two. That can be darn close to zero. The downside is concentricity and thread errors limit the resolution somewhat. Newport is typical, but a Google search will turn up others- https://www.newport.com/p/DM-13

Don't know how long it might be there, but here's the Burleigh one- https://www.ebay.com/itm/325888648088
I worked for Burleigh and can confirm it was made by Slocomb. https://www.conradhoffman.com/BI/BI_history.htm
 
Differential mics use two screws of very slightly different pitch. When rotated together you get the equivalent of a pitch that's the difference between the two. That can be darn close to zero. The downside is concentricity and thread errors limit the resolution somewhat. Newport is typical, but a Google search will turn up others- https://www.newport.com/p/DM-13

Don't know how long it might be there, but here's the Burleigh one- https://www.ebay.com/itm/325888648088
I worked for Burleigh and can confirm it was made by Slocomb. https://www.conradhoffman.com/BI/BI_history.htm
Wow! Thank you for that information!

DO you know the time period that Slocomb made them?

Or any other information to be honest!

Have a wonderful day,


---Spyke
 
Old guy with bad memory, but here's what I remember. There was company in Ithaca NY that made mirror mounts and other stuff, Lansing, a competitor. They sold a differential micrometer that was made for them by Starrett. We wanted to sell a diff mic, but since Lansing used Starrett as a supplier, we had to find somebody else. That somebody was Slocomb. I don't remember the year but it was probably in the late '70s or early '80s. To give you an idea of what a good diff mic can to, and the Slocomb was definitely not at the top of the heap due to the rolled threads, I found this excerpt in a research paper from the time-

9. Micrometers and Mirror Mounts
Extraordinary stability and adjustment precision are necessary for TEM00 passively mode-locked Nd:Glass laser alignment. These requirements are met by a Burleigh Star-Gimbal stainless steel mirror mount [39] with Lansing differential screw micrometers [40] on the front mirror, and Starrett precision stainless steel micrometers with Delrin knobs [41] on the back mirror stainless steel dye cell assembly. The differential screw micrometers can make translations as small as a millionth of an inch. Experience has shown that, using the Star-Gimbal mirror mount, alignment for TEM00 operation must be accurate to within approx. 40 millionths of an inch on the front horizontal Lansing differential screw micrometer, i.e. 0.4 seconds of arc, for stable, reproducible behavior at the minimum lasing threshold.
 
Hello TowersMetalworks,
My best friend in high school's dad was an engineer. By "engineer" I mean in the real old school sense. He knew his way around the machine shop. He would have been born in about 1910 or so. He always referred to micrometers as "Slocombs", have you ever heard of that before? I've been curious about this for a LONG time. If it adds helps the story any he grew up and first worked in Meadville, PA and the later at several places in Cleveland, including TRW.
 
Hello TowersMetalworks,
My best friend in high school's dad was an engineer. By "engineer" I mean in the real old school sense. He knew his way around the machine shop. He would have been born in about 1910 or so. He always referred to micrometers as "Slocombs", have you ever heard of that before? I've been curious about this for a LONG time. If it adds helps the story any he grew up and first worked in Meadville, PA and the later at several places in Cleveland, including TRW.


I've seen Slocomb mics referred to as that in a couple of trade publications from around the 1910'sm to the late 20's or so.

It all depends on where you grew up, and who you learned from.

Slocomb has their "Combination Center Drills" as well as their "Bell Type Center Drill", while I grew up calling them hole starters, or countersink starters.
 








 
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