Because I want to do more with threading I wanted a TDI (Thread Dial Indicator) for my Huvema lathe.
I realized a TDI is really only a cog to follows the longitudinal guide. You link the longitudinal guide at the moment the dial has a predetermined position. After disconnecting and moving the longitudinal guide you can reconnecting when the dial has returned to the same predetermined position.
My spindle has a pitch of 1.5mm. After a little math, I decided on a 30 mm circumference so 20 teeth. It allows me to use it for threading of 0.75 1.0 1.25 1.5 and 2 because each of these has a multiple that is exactly 1 time the circumference of my gear (30 mm)
So using an existing reduction and improvised a 4th axis and machined the sprocket. This can also be done without CNC router by using a tap with the correct pitch.
CNC was getting a bit sloppy (inaccuracy of about 0.5 mm) so I had to do some rebuilding because my current solution doesn’t have any adjustment possibilities.
Just made this on the lathe. Shaft is now 7mm so I can make my own collars and the end is 6.5 for the shaft coupler.
I’ve tested the direct drive setup and it allows speeds about 3-4 times compared to the old setup. That’s good because I’ll need that speed with one of my other projects:
This should be a part of my extruder. Already has a 3mm hole for 3mm filament. Most of the metal will be removed to create cooling ribs. Bottom will probably have an M8 thread to attach a couple so I can attach various nozzles.