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LORCH Precision Screwcutting Lathes
Models D27 & BIIZ

More information about Lorch Lathes is contained in various Manuals,
Parts Lists and well-illustrated Sales & Technical
Specification Brochures and can be purchased on-line here


A development of the long-established Lorch Model C11 (a type open marketed using the name Lorch Schmidt), the 6" centre height by  40" between centres D27 "Precision Leadscrew Lathe" was one of heaviest-ever Lorch lathes; tipping the scales at 670 kg it was built on a traditional style of open cast-iron stand with a stout pedestal beneath the headstock and the 2-speed motor mounted at the back on an adjustable plate. A cast-iron chip tray, with a single central tool drawer, ran the full length of the non-gap bed ways. The motor drove downwards to an enclosed countershaft - the drive then being transmitted upwards through the pedestal leg by a flat belt to the headstock.
Arranged with three Vees and one flat the bed ways were arranged, in the usual manner, so that the saddle and tailstock were each guided and aligned on separate surfaces. 
Bored through 1
1/16", the headstock spindle was made from high-quality steel and hardened on  its bearing surfaces and nose; it ran in adjustable bronze bearings and was supplied with oil, lifted by felt strips, from cast-in reservoirs situated beneath the spindle line. The 7 : 1 ratio backgear was clustered just behind the front bearing (just like a Myford ML7) with both gears rotating on a shaft below the spindle and its engagement lever positioned just behind the spindle nose. A two-speed electric motor was fitted with the option of ordering normal or "high-speed" versions. The ordinary motor fitted gave spindle speeds of: 41, 66, 82 and 132 rpm in backgear and 285, 465, 570 and 930 r.p.m. in direct drive With the high-speed option fitted speeds were exactly doubled and became: 82, 132, 164, 264 in backgear and 570, 930, 1140 and 1860 r.p.m. in direct drive
Made to the highest possible standards of accuracy, the 5 mm pitch leadscrew was driven not by a full screwcutting gearbox - but though an ordinary tumble reverse mechanism, changewheels and a simple gearbox that gave three sliding and surfacing speeds (and threads) for each setting of the gears. However, a separate power shaft was fitted and, in normal use with the leadscrew disengaged, the sliding and surfacing feeds were driven by that.
A third shaft, parallel and below the powershaft was used to transmit movements of a motor-control lever bracketed to the right-hand side of the apron; this allowed the operator to stop, start and reverse the machine without having to reach back to the headstock. The lever moved in a horizontal plane and was spring loaded to its central position..

Lorch 6" x 40" Model D27 Precision Leadscrew Lathe

Lorch BIIZ Precision  Screwcutting lathe.
The BIIZ "Precision Screw-cutting and Surfacing lathe" was of 120 mm centre height and accommodated 550 mm between centres (4.7" x 21.7"). It was built onto a substantial, vibration absorbing, all cast-iron cabinet stand which housed the three-phase, 3-speed (700/1400/2800 rpm) 3-phase 1.5 HP motor and flat-belt drive countershaft unit. The bed was arranged with two Vees and two flats, one each for the guidance of saddle and tailstock. 
Made from high-quality steel, the 0.79" bore headstock spindle was hardened on  its bearing surfaces equipped with a No. 3 Morse taper nose; it ran in bronze bearings and was supplied with oil from cast-in reservoirs situated beneath the spindle line. The 8 : 1 ratio backgear was clustered just behind the front bearing (like a Myford 7) with both gears rotating on a shaft below the spindle and its engagement lever positioned just behind the spindle nose. Spindle speeds were: 44, 60, 88, 120, 175, 240, 350, 485, 700, 970, 1400 and 1940 rpm.
With its side nearer to the headstock covered by an enclosing bellows, the 5 mm pitch leadscrew was driven by a tumble reverse mechanism, changewheels and a simple gearbox that gave three sliding and surfacing speeds (and threads) for each setting of the screwcutting gears. In normal use the leadscrew was disengaged - by a lever on the face of the three-speed gearbox - and a powershaft provided the sliding and surfacing feeds. .

Lorch BIIZ Precision
Screwcutting Lathe.


Lorch Home Page

Larger lathes branded Lorch, Schmidt & Co.

LAS Precision Screwcutting and LAS, AV1-K, AV11-K, LLRGN,  AVRG, BVIRG, LLRN, AVR  &  BVIR Lathes

Precision Plain Lathes: LLS, LLV,LLK

Precision 50 mm Lorch KD50

Toolmakers' Screwcutting Lathe AVI-L
     
Screwcutting Type AB

Precision Screwcutting Lathe BL27LZ

Toolmakers' Miniature Lathes: LA, LAN, LLN & LLPN Plain and Screwcutting with Leadscrew

Lorch lathes--Newer Accessories

Lorch lathes--Older Accessories

Larger Screwcutting Lathes D27 & BIIZ

Lorch Dividing Apparatus for Watchmakers' Lathes

Lorch COLLETS

Lorch Watchmakers' Lathes

Lorch "Triumph" Watchmakers' Lathe

Lorch Junior Watchmaker's Lathe

Lorch Lathe - a restoration

Early Lorch Model A Lathes

Lorch Milling Machines