Luthier CNC

[cropwell]

I also wanted to have a Z probe which worked without a crocodile clip.

My tool tip has earth continuity, so this type of touch plate works for me.

Even though your spindle body may be earthed, that may not continue to the tool if you have ceramic bearings, so a switch type would have to be used.

Have you metered the resistance between collet and spindle body ?

[Kitwn]

As I've just mentione elswhere, an RCD in your mains supply offers no protection against shocks from the output of your VFD. Don't take risks with the safety earthing of your spindle.

[bluesking]

Don't take risks with the safety earthing of your spindle.

I haven't taken any risks: the spindle is earthed. Thats the reason why I had to introduce a ground loop to make my z probe work how I wanted and still be safe - at the cost of some potential interference...

It's a basic catch 22 - and the reason why many valve amps have a ground lift switch. Always seems a bit dangerous to me to leave it in the hands of the guitarist to decide what is safe! But it's there when you use multiple amps and you know they are all on the same mains circuit yet the ground loop is causing noise to get in the system.

[Kitwn]

We should probaly start a new thread to start talking about multiple amps, Brian May, whether Russian ECC83s are better than the Chinese, using CNC machines to build guitars.....................

Kit

[bluesking]

We should probaly start a new thread to start talking about multiple amps, Brian May, whether Russian ECC83s are better than the Chinese, using CNC machines to build guitars.....................

Kit

For sure. And by the way, the best ECC83s are dutch: amperex bugle boys. They might not be as well known as mullards but they are cracking. You can find them for under £10 each - if you know where to look :)

[bluesking]

My tool tip has earth continuity, so this type of touch plate works for me.

Have you metered the resistance between collet and spindle body ?

I've metered between collet all the way to the BOB, thats what made me think it would work. I then tested the z probe (same idea as the one in your pic), thats how I know it works!

Weirdly my spindle is quoted as having ceramic bearings though so not quite sure why it does work. But I'm happy so far.