Blimey!

Its rather sad that Myfords are pricing themselves out of business. At one time their quality made them a better proposition than what was foreign tat.

Sadly Jonny Foreigner has started to get his act together and stealing our markets.

Bit like Rover/MG.

May well be true, but what's the connection with Nigel's Chipmaster?

Cheers Tim

Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

Absolutely nothing.

I was having a blonde moment.

Did she enjoy it??

Peter

-- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk

She probably can't remember it

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

I have one of those VFD devices on my lathe, very handy. One day I keep meaning to rig something up to the cross slide so it keeps a constant cutting speed at the tip as you face off for example.

Stephen.

One of the projects I keep intending to get around to is a tachometer with an approximate measurement of cross-slide position so it can display cutting speed in feet per minute. This seems like an obvious thing to do, but I haven't ever seen one. Do they already exist ?

It would be fairly easy to add an analogue output to a device like this to do the VFD control that you suggest. The advantage of doing it through a control box rather than with a pot coupled direct to the VFD is that it would be easy to reset the centre position, and set limits to the demanded speed.

-adrian

The fly in the ointment is that to calculate the cutting speed it's not the cross slide position you need, it's the cutting radius..... this will change in relation to the cross slide every time you change tool.

It might be possible to have a " tool ofset " to set the "at centre" position for the tool.....

I had assumed it would need zeroing - fairly easy to set it when you check centre height. But some other fixed position like the outer diameter of a favourite chuck would be a good idea too. It just needs more messing around and extra buttons to set a non-zero value.

Or should I just try to get more experience so I can tell the right speed without having to think about rpm and radius ?

-adrian

OK for meausurement, but I'd agree it's a problem for control.

I think a VFD will do 10 to 1, but probably lose torque at the low end. However, I don't think you'd want such a large change done automatically anyway. You certainly wouldn't want the speed approaching infinity as you got towards the centre while facing off ! You'd need to set upper and lower limits.

-adrian