Re: Re: Engraving and engine turning

Hi Ian,
I know what you mean with the springs anchored up i the air but I do not think it is that bad.

If we assumes a 30 mm quill movement on a very small system and accept a 10% max. change in compensating force error the springs would
only have to be 150 mm long. We would design for a perfect balance in the middle of the 30 mm, therefor only +/- 15 mm movement.

You mention an air turbine. I built a gantry type machine some years ago and I mainly used it to drill PCB. It uses a small air
turbine, about 15 mm in diameter and it has a chuck for 1/8" bits. It turns at about 55,000 RPM. Harbor freight sells them here in
the USA for about $60. It worked great and was very simple.

Talking about watch making. A very close friend was an old retired watchmaker and he gave me his watchmakers lathe which is one of my
priced possessions. It is in very good condition and I have built a nice varnished wood display base for it. One of my other
interests are precision pendulums but I have not built any clocks, just reading and thinking.

Best Regards

Bertho Boman
===============================================
"Ian W. Wright" wrote:

> From: "Ian W. Wright" <Ian@...>
>
> Hi Bertho,
> I could do this but to use a long spring, it would have to be anchored
> quite a way up in the air whereas weights can be pretty much within the
> boundaries of the actual machine. The machine I am making is quite
> small, being intended mainly for watchmaking work and I am intending to
> use it in my indoor workshop where space is a little linited and so the
> more compact it is the better. In actual fact, I could probably design
> it to dispense with the need for a counterbalance on the quill by
> mounting the motor remotely and driving through a flexible shaft but my
> design hasn't progressed this far yet - I make it up as I go along!
> While I laid for two hours yesterday in the dentist's chair, I was
> actually contemplating the possibility of an air turbine for some of the
> small engraving-type jobs! I must try to research their technology.
>
> Best wishes
>
> Ian