In following up certain leads about the origins of the firms "Boley" and "Boley & Leinen" the following information came to light through the good offices of one of the American personel drafted in to help restart German industry at the end of the Second World war. He writes:
The basic story, regarding the two Esslingen firms, I got either from Gunther Leinen, the grandson of the founder or from Fritz Carl Mahr, who was a good friend of Gunther's. I also knew the son (Gunther's father) who was owner and manager of the firm at the end of the war, when I had my first contact with Boley and Leinen - and with the firm of G.Boley.
F. Carl Mahr is the principal owner of the big measuring instrument firm of Carl Mahr. In any event, I was told that the manner by which Boley and Leinen got the Boley part of the name was a matter of acute embarrassment to the Leinen family. The founder of the firm, Gunther's grandfather, had been employed by G. Holey, and left them, initially, to manufacture the bench vise of his design. This vise was always marked "Leinen" even though it was manufactured by Boley & Leinen.  G. Boley also made an exact copy of this very popular pattern. My understanding is that Leinen was quite successful with the vise and decided to go into the watchmaker's lathe business in direct competition with G. Boley - an already well established name. Supposedly he searched the town directory and located a not particularly well-of widow named Boley and persuaded her to become a partner in his firm. His firm thus became "Boley & Leinen". This is really all that I know of the matter. It would, of course be very interesting to know what relation the widow's husband had been to the G. Boley of the pioneer lathe firm. Unfortunately 1 have more or less lost touch with Carl Mahr and everyone else in the Esslingen region.
I am sorry I can't be more helpful regarding Boley et al. Maybe the Esslingen chamber of commerce has a web site which might lead to a local history site …….

Leinen MLZ4S & LZ4S  5.1" x 19.7"  circa 1950s
With pre-WW2 origins as the Model L4Z, by the 1950s two models of this very serious-quality toolroom lathe were available, the MLZ4S with a "Multiplicator" screwcutting gearbox (where by rotating three knobs, 27 different metric screwcutting pitches from 0.1 to 6mm were produced as well as 35 longitudinal feeds from 0.017 to 1.16mm per rev.) and the LZ 4S which used changewheels and a simple feed box which gave 6 sliding and surfacing feeds for each setting of the changewheels.
The spindle bore was 0.98 inches and the main spindle drive pulley, as on all high-class lathes, ran on its own bearings and drove the spindle through a peg, so removing any chance of the drive belt's pull transmitting vibration or spoiling the machine's accuracy.
The drive system was contained within the very heavily-built, sheet-metal cabinet stand and consisted of a 3-speed, three-phase motor driving a two-speed gearbox. Combined with the single-lever selected, oil-immersed backgear this gave twelve speeds which could be configured for the MLZ 4S as either 13.5 to 1515 rpm or 23 to 2220 rpm - and for the LZ 4S as 13.5 to 3030 rpm. Later configurations, with two-step pulleys on the motor and gearbox-input shaft produced 24-speed drives, again with a choice of three speed ranges:
Range A 13 to 1567 rpm - both lathes
Range B 23 to 2170 rpm - both lathes
Range C 13 to 3135 rpm - LZ 4S
Limit stops, fitted with trips, were fitted to both the sliding and surfacing feeds, with those for sliding being provided with micrometer-adjustment collars. The lowest of the three shafts along the front of the bed operated an electrical-reverse mechanism with the operating lever was attached to the right-hand side of apron.
Besides the backgear, each headstock bearing, the apron, screwcutting gearbox and speed-change gearbox all ran in their own oil bath.
In the 1960s, although these lathes were commonly advertised with the maker's name "Boley Leinen", each model had the word "Leinen" before its type descriptor.
Spares and service for these lathes are available from:
P&Z Engineering
Anton-Ditt-Bogen 3
80939 München
Tel: 089/31857-370

If any reader has catalogue pictures of the Leinen range of machine tools, of any age, I would be very interested to hear from them.