Quote:
Originally Posted by GeoffW1
My word,
I would like to send my applause and appreciation. I started my working life as a Fitting & Machining apprentice, so I can see what this involves.
Cheers
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Indeed, thanks Geoff, but the hard work has all been done by others.
A few really good articles on the web about this subject.
I thought I'd dive in and have a go myself.
Progress:
Tried the first test blank today. Old Hard disk platter, aluminium
mounted to the spindle flange.
M12 test cutter with splines cut with a Dremel.
(Makes it cut better just like a thread tap).
With the lathe on lowest gear I wound the platter in until it just
made contact with the cutter.
The cutter immediately began to drive it's way around the blank.
Nice cutting action. When it had driven all the way around the blank
and made a nice initial set of cuts, it didn't exactly meet up with the
first cut.
This is to be expected.
Unless I had made the blank an exact circumference to match a
theoretical thread pitch, this was never going to meet up.
All of the web articles I have read mention this.
What I then did was to just continue and watch it attempt to
'self index' by cutting deeper.
Eventually, a second set of 'mountains and valleys' appear as the
cutter made it's way around several dozen orbits.
The second set are eventually eroded away until the main set
sort of 'take control'.
The trick is to stop adding depth to the cut once the self index finds
exactly the right circumference for the start to meet the end.
It went better than I expected!
Pics attached.
Steve