Pratt & Whitney 4-40" inside micrometer

[davethorik]

Probably too nerdy for the casual GJ browser...lol...
I believe late 64 or 65 was when Lufkin sold their machinist tool line to P&W. So technically maybe not old enough for vintage. But, there is next to no info on P&W production, like when it stopped. I have seen the occasional catalog on the bay, I should man up and buy one. I'm not sure if they made everything Lufkin offered (not tape measures, that segment was bought by Cooper tools in '67 IIRC). But their machinist tools.

This set looks to have little to no use. I've maybe seen one before...P&W tools arent common, but I've seen mics and scales in the wild. I used to have a similar set of Lufkins that I sold when I got laid off, dead ringers.

Case is beat up but wood looks very nice. I am not sure but it may be mahogany. It looks to have sat in about 3/16" of water at some point on left side, luckily water had not gotten to extensions. However, a foil sticker was there, now mostly gone, you can read C 681 (a Lufkin 4-40" set was a no. 681-K, and C in Lufkin numbers generally denotes a chrome clad finish). And right side of lid looks like someone smacked it with a crowbar. Bottom scratched to hell, latches covered in surface rust. But...tool pieces are mostly beautiful, like hardly used.

The extensions are interesting...one is marked P&W, 2 are Lufkin, and other 7 are unmarked save for size. They are matching, I believe. They are nicely chrome plated with slight rust, which is cosmetic. It could have been cobbled together but I actually think this is how it came brand new.
The mic itself is marked 'P&W Made in USA.' Needs cleaned, has old grease in it.

No size chart sticker on lid, either...under foam looks like no chart was ever there. Perhaps it came as a separate paper.

 

[woody 73]

Very nice set.

 

[MShaw]

Do the rods screw together? If not, which is what it looks like, it is a set of end measures used with a jig borer for positioning the table.

 

[leg17]

The knurled end of the rods have an internal thread for screwing onto the mike head.
It is indeed an inside micrometer, not an end measuring set.

 

[davethorik]

End measure sets look different. They come with 2 mic heads usually, which have a tenths vernier, and don't screw together. The rods are thicker and usually have ground ribs on the OD so they sit evenly in the machine trough.

The mic head on this is only in .001", and the rods do screw together.

 

[MShaw]

I stand corrected. It is a surprise to me as my father worked for Pratt and I worked for another division in the same building and I had not seen an inside mic. by them. Also I have their 1958 gage catalog that does not show an inside mic. It may have been a special order item although a Google search shows a smaller range one for sale on EBay. Total surprise to me.

 

[davethorik]

Did you read my first post, Milt? P&W bought Lufkin's machinist tool line in the mid 60s. They made tools almost identical for a while.

 

[MShaw]

I was aware of that. Here are a 4", 5", 6", mics I bought from them at the time while working for another division of Pratt in the same building in West Hartford. The case for the inside mic. was so typical of the cases Pratt used for their end measures and size blocks that the Lufkin connection escaped me.
Malkin Shaw

 

[Packard V8]

Learn something here every day; that Pratt & Whitney owned Lufkin was news to me. Research found that there was more than one P&W and this one didn't build aircraft engines.

There are conflicting stories on the internet, as there were the Lufkin small consumer measuring tools and larger industrial machinery. Parts of Lufkin seem to have gone in several directions, as did parts of P&W.

At the end of 1966 Lufkin Rule Company sold their precision measuring tool product line, including designs and manufacturing machinery to the Pratt & Whitney Division of Colt Industries. Pratt & Whitney moved the machinery from Saginaw to Hartford and replaced the Lufkin branding with P&W.

P&W's last days as a machine tool builder in Hartford were under Colt ownership, and as Colt was having severe financial problems of their own in the 1980's they sold off the last profitable bit of P&W -- metrological equipment -- and closed down the rest.

Lufkin was acquired in 1967 by Cooper Industries and today Lufkin is a brand of Apex Tool Group. Apex Tool Group is a joint venture of Cooper Industries and Danaher. In October 2012 Danaher and Cooper sold Apex to Bain Capital.

jack vines

 

[davethorik]

I was aware of that. Here are a 4", 5", 6", mics I bought from them at the time while working for another division of Pratt in the same building in West Hartford. The case for the inside mic. was so typical of the cases Pratt used for their end measures and size blocks that the Lufkin connection escaped me.
Malkin Shaw

Don't know why I called you Milt LOL
Those are some nice mics, also bear striking resemblance to Lufkin!

 

[MShaw]

Just to set the record straight, Pratt & Whitney that made machine tools, small tools and gages started in the early 1800s in Hartford. When the infant Pratt & Whitney was looking for manufacturing space and backing the management of Pratt (the former) accommodated them. When they were considering a name they chose Pratt & Whitney as it was a long standing, highly respected name.

That is the summary, there are many more details available.

 

[davethorik]

Do the rods screw together? If not, which is what it looks like, it is a set of end measures used with a jig borer for positioning the table.

I was digging thru stuff and forgot I had these. It is a Lufkin end measure set in box. It has qty 2, 4-5" mic heads. And then qty 2, 1" rods, qty 2, 2" rods, qty 2, 3" rods, qty 2, 6" rods, and a single 10". The last cubby were for Lufkin stamped pin spanners, which I put with other lufkin tools I use so that spot is empty.

The mic heads have fixed caps and a .0001" vernier. They are same size and range as the 681 series ID mic head, so they do appear similar at first glance. But the end measures themselves have raised lapped ends, and are accurate like gage blocks. Nothing threads except mic, they sit together in a groove on jig boring machines for precise measurements.

Mic heads marked patent no. 2,212,910 made in USA

I learned about this on a Devlieg horizontal boring mill, which incidentally was made not far from Lufkin in Michigan. It had factory optional precision scales on X and Y axis that were made by, guess who? Lufkin.

There was a trough covered by a springloaded sheet metal guard on both axes for the end measures. Of course it wasn't used because there was a DRO on the machine, but I took these into work once and tried them. No way I'd want to do that all day, thank God for DRO's. Lol

 

[MShaw]

The company I served my apprenticeship with in the mid 1960s had four end measure P & W jig borers and one numeric in a constant temperature room. The machinists that ran the end measure machines would have an 8 1/2 X 11 ruled pad on the end of the table that was filled with the calculations for each move. Remember this is before anything like hand held calculators. Thus, if the completed operation was at X = 6.875 and the next operation was at .530" farther out you would add .530 to 6.875 equaling 7.405. Next you would reset the mic to .405 and change the end measures from 6" to 7". very labor intensive!!!!!