How to make Lead Screws work

[Dad1279]

Originally Posted by Bruceb

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The JVN calculator is not usable for this as far as I can tell.......

For an approximation** I use the Linear Mechanism tab, and adjust pulley diameter and gear ratio for the turns per inch of the leadscrew.

For pulley diameter I use 1/pi (.318) (forces the spreadsheet to 1 unit of revolution to 1 inch of travel)

Then in addition to whatever gear/sprocket/belt ratios you are using to drive the shaft, add a gear ratio (Drivingriven) of 1:[tpi of screw] (1:5 for a 5 tpi acme screw)

**This does not take into consideration friction/loss of the leadscrew, which could be very high (steel screw/nut needing lubrication) or low (ballscrews, etc) so design conservatively.