mystery Table top mill

[bukowski1981]

Hi

Ive searched the internet and still cant identify this mini mill. Seems like it maybe be a lathe head added to a milling table. This seems like the place for answers. no makers marks. it is definitely missing the table.

thanks

 

[Screwmachine]

Looks like a lot of small machines that were used in watch factories in the U.S. (and Switzerland). Usually set up with fixtures for repetitive production work. I wouldn't be surprised if it was out of Waltham or Elgin.

 

[L Vanice]

I suspect the mill was made by one of the circa 1900 bench lathe makers. The best way to identify the maker, assuming you thoroughly examined the machine for marks, is to look at pictures of the many different lathes made back then. Use Cope's lathe book and Tony's website. The basic design of the head is very generic. I would concentrate on the brass covers at each end of the spindle because they will be different for different makers.

A second thing to figure out is to identify what collet fits the head. Most of the lathes back then had proprietary collet designs. The chart from an old Hardinge catalog is helpful, but not complete.

To get you started, it is not a Hardinge Brothers Cataract mill. And Sloan and Chace beds are a different shape, so eliminate that one.

Larry

 

[Screwmachine]

Nice charts Larry- my Hardinge #6 catalog from 1913 has most of that info but not all, now I finally see in print where the bastard 1.666mm thread on the Schaublin W20 collet comes from, the Whitcomb 1898 model 4 (and Schaublin bumped it to 20mm diameter). Still have to wonder why Whitcomb went with 15.24 tpi (what does the T mean?)...

A handwritten note on the cover of mine says "bill and letter of 11-7-21 say prices of #6 catalog are advanced 100% or just Double" with double capitalized and underlined, ha.

 

[L Vanice]

Nice charts Larry- my Hardinge #6 catalog from 1913 has most of that info but not all, now I finally see in print where the bastard 1.666mm thread on the Schaublin W20 collet comes from, the Whitcomb 1898 model 4 (and Schaublin bumped it to 20mm diameter). Still have to wonder why Whitcomb went with 15.24 tpi (what does the T mean?)...

A handwritten note on the cover of mine says "bill and letter of 11-7-21 say prices of #6 catalog are advanced 100% or just Double" with double capitalized and underlined, ha.

I don't have an answer for the "T." There is an old Swiss Thury thread standard, but the diameters of the big Thury threads do not agree with those Whitcomb collet threads.

The American watch factories used a seemingly random mix of measuring units, inches, centimeters, lignes and such. The factories employed mechanical geniuses to design and build their machines, and those people generally did not have engineering degrees or extensive educations in international and modern trends in units of measures. They were just smart people who had come up as apprentices from gun makers and the like and knew how to make things that did what was wanted. Some of them went on to start their own machine factories near the watch factories, seeing the advantages of being their own boss and knowing where to find customers. Whitcomb was one such person, who became a partner in American Watch Tool Co., Waltham, MA.

As for the M1.6666 or 15.24 TPI, consider that metric thread pitches were sometimes specified as threads per centimeter and those apparently odd numbers resolve to a very round 6 threads per centimeter. Pull out your Levins' Practical Benchwork for Horologists and look for the Table of Gears for Use with Metric Slide Rest (for screwcutting in the watch lathe) and you will see that they gave the pitches as threads per centimeter, which can make some pretty odd mm per thread numbers. Similarly, those "Met." pitches in the Hardinge catalog are kind of puzzling, even if you know that 63 Met. is about 40 TPI or .63 mm per thread.

Larry

 

[Screwmachine]

Oh wow- that makes so much sense now! I never really looked at the thread info in the Levin book as I never had the attachment.

I always found it odd that Schaublin specs the thread for B8 collets at 0.625 mm, while 40tpi is exactly 0.635mm, and Whitcomb specs 0.63mm. I use a 40tpi tap and die to make tooling and it fits my Swiss drawbars and male tooling, and German stuff too (which should be 40tpi, like I'm pretty sure Levin uses for their collets). But there's a lot of "should be" in watch size machinery.

 

[bukowski1981]

well according to the chart it would be a watch factory whit. no 2. number match perfect for the collet size.

 

[L Vanice]

well according to the chart it would be a watch factory whit. no 2. number match perfect for the collet size.

John E. Whitcomb worked at the American Watch Co. of Waltham, MA until 1872. He was a mechanic and probably designed and built some of the watch factory machines. In 1872, he started his own machine building business in nearby Boston in partnership with another mechanic from the watch factory. He changed partners a couple more times and moved back to Waltham. The final company name was American Watch Tool Co. His most successful lathe was the Webster Whitcomb and that collet type is still made, along with machines to use them.

American Watch Tool Company - ProQuest

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www.proquest.com

Machines built in the watch factories would not have a manufacturer's name on them. That mill could have been used in the American Waltham Watch Co. or one of the other Waltham/Boston area clock and watch factories which were in business for many years.

Larry