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.

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

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