screw cutting on a chester db10 lathe

confused by the instructions in the lathe hand book for setting up the gears on the db10 lathe

You got a hand book with your DB10, wow they've raised their game.

If you let us know what thread you are trying to cut it will help in deciding what gears you need to use, below is a picture of the gear settings on my DB10.

Depends on which DB10 there's Ian's as above or there's the older DB10G like mine. Imperial or Metric machine? Mine had some kind of "manual" which was less than useless, threading section was a waste of ink, no explanations whatsoever.

Easy enough if you follow the plate, I've only done metric threads on my imperial machine, you have to leave the carriage feed engaged for metric with an imperial machine not use the thread dial, others will say there is a way round this but it's no real problem to leave it engaged..Left hand set up figure is for metric, right hand for imperial. Picture was right way up, the album has put it on it's side...sorry

Edited By Mick Berrisford on 21/08/2019 23:30:15

If you know the pitch of your Leadscrew,it should be fairly easy to work out what gears you need to set up for a 1.5 mm pitch thread.

Just picking numbers out of the air. Unless my arithmetic or logic, is wrong.

If your Leadscrew is 1.5 mm pitch you set up a 1:1 train, such as 60 - Idler - 60 (i e The same Driver as Driven)

For a 1.0 mm pitch Leadscrew, you need to turn the Leadscrew faster than the Mandrel so set up 60 - Idler - 40

For a 2 mm pitch Leadscrew, you would set 30 - Idler - 40

For a 3 mm pitch leadscrew, you would set 40 - Idler - 80

Brian Wood's Book "Gearing of Lathes for Screwcutting" will explain this in detail, and give gear train set ups for a variety of Leadscrews and thread pitches that can be cut.

Howard

Kind of you to say so Howard, but the chapter on mini lathes in my book with the various pitch leadscrews does not go into gearbox machines like the DB 10. There were way too many combinations over the range of models to begin to make any progress on trying to unravel all those.

I principle I agree with what you say, but I'm afraid I look at these machine plates with wonder, the guidance is really quite dreadful and to send them out without a handbook is even worse.

Regards

Brian

If you can confirm which model you have and whether it is imperial or metric that will make it easier to help, ideally post a photo of the manual page or chart on the machine cover.

Once you know what the diagram is showing it is quite simple, must be as I seem to manage OK with my similar machine.

J

Posting photos

Thanks for your replies and have sorted the gears out