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LORCH - Watchmakers' Lathe
Dividing Apparatus
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

Lorch Home Page  Lorch Schmidt
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 Restoration

Early Lorch Model A Lathes
Lorch Milling Machines


A unique design of dividing head was offered by Lorch for their WW and LL lathes that allowed all divisions from 2 to 400 to be created without the use of changewheels. The special head is shown below mounted on a LL lathe made during the 1920s. 
The unit consisted of a wormwheel located on the lathe spindle with its division plate over a friction clutch. The wormwheel had 200 teeth and the scale ring 500 marks - hence one turn of the lathe's spindle gave 200 revolutions of the worm and so (200 x 500=10000) 10000 marks on the division ring. As an example, to cut an 83 tooth wheel it was necessary to calculate a ratio of 200/83 with an accuracy of 4 decimal places, to give 2.4096. This was 2 full turns plus 4096/10000 turn. As the division ring had only 500 division marks it was necessary to divide the decimal fraction by 2 . Now you had 2 full turns and 204.8 marks on the scale ring. To aid repetitive resetting, an adjustable stop was provided under the division ring. An example: to cut a gear with 127 teeth:  200/127 = 1.5748. The decimal-place numbers were halved to give one full turn and 287.4 marks on the division plate. First the stop-ratchet was set in position 3 and adjusted with a magnifying glass to exactly 287.4 - and the stop locked. Next, in position 1 of the stop-ratchet, the division plate was set to zero, the fixing screw of the worm spindle locked and the first cut taken. The fixing screw was then loosened, the stop ratchet brought into position 2 and the worm spindle turned once. The stop-ratchet was then brought into position 3, the worm spindle turned (for the additional 287,4 marks) to the stop, the fixing screw locked to bring the stop into position 1, the dividing plate turned back to zero - and the next cut made. For divisions without decimal fractions only full turns of worm spindle were needed. Priced in 1937 at 175 Reichsmark - when a complete Lorch LL lathe with a compound slide rest was 170 Reichsmark - very few of these units were sold and are consequently rare. 

Lorch "Triumph" Geneva Type lathe fitted with the special dividing apparatus



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LORCH - Watchmakers' Lathe Dividing Apparatus
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

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 Restoration

Early Lorch Model A Lathes

Lorch Milling Machines