Lathe Gear Layouts for cutting screws

This is mostly intended for a 8x16 mini lathe that has a fixed headstock gear of 56 teeth. Other min Lathe gear calculators on line assume that the headstock gear can be changed to anything. On a 8x16 it cant, which is why this page exists.

Gears on the same row are joined. h means a hub connected to the gear on the row but no other. G is the headstock gear (56 on a 8x16, cant be changed).

Set the leadscrew pitch (2mm on a 8x16), the desired pitch, the head gear (G) teeth, and the available gears. Press calculate and a list of options will be found, with the closest match first. These will in in one of the 4 layouts. Try and select a set of gears where the ratio between gears is as close to 1 as possible to avoid over stressing the gear train. All code is on this page.

If you have 2 gears of the same size, then list both gears in the available gears list. The code will assume it can only use a physical gear once in the layout.

Not all gear combinations will fit. They must have centers less than the mounting which is the distance between centers for A and the leadscrew. And the total distance betwene centers must be greater than the headstock to leadscrew center for the years to be able mesh at all. On a 8x16 the maximum A to leadscrew center measurment is 130mm, and the minimum headsctock to leadscrew measurement is 170mm. In addtion layout 1, gear B must have clearance with the headstock gear and in layout3 gear A must have clearance with gear C. A quick check is to add up the number of teeth in a pair, the smaller sum will mesh. Results that dont meet these criteria are not show.

LeadScrew Pitch: Desired Pitch: Head Gear: Available Gears: Gear Pitch: Distance been headstock and leadscrew centers: Distance been A and leadscrew centers:

Layouts

    

Short form
==G,A-B,D,F--- Headstock (===) gear G meshes (,) with A connected (-) to  B meshes (,) with D meshes (,) with F connected to leadscrew (---)

Long Form
==G   <--- headstock input
  A-B  <--- A and B are on the same shaft conected together.
  C-D  <-- B meshes with D, or A with C, but never both at the same time. a h indicates a hub with no gear teath.
  E-F ----   <--- leadscrew output

Layout 1          Layout 2         Layout 3           Layout 4
==G,A-B,D,F---    ==G,A,C-D,F---   ==G,A-B,D-C,E---   ==G,A,C,E---
==G               ==G              ==G                ==G
  A-B               A-h              A-B                A-h
  h D               C-D              C-D                C-h
  h F---            h-F---           E-h---             E-h---