What's the best way to Mark the Home Location on a Fixture?

[777funk]

I have several machining fixtures for my processes. They are located to the table of my machine. I'm looking for a way to permanently (well as permanently as possible) mark the home location on my fixture plates. That way if something ever goes off in either the fixture or machine I can adjust.

What brought this about is that I had to remove the servos on my machine today and when I put them back on my indexing position home was of course no longer the same since the motors were removed and the encoders or ball-screws had turned. Back together and... no line up. Home was off in the X and Y directions.

So I'd like to avoid this in the future. I want to have a sure fire way to ALWAYS make sure I can get my home back every time.

I have a home spot plunged into my fixture plate but when I re-aligned the ball-screws and encoders I just did it by eyeballing the tool and rotating the ballscrew until the tool matchd my home plunge. I'd like to have a more precise or standard way of doing this in the future if/when I have to work on my machine again.

Any suggestions?

[777funk]

bumped to Wednesday.
thanks!

[Bwana Don]

Put a precision hole in the fixture. This becomes your datum. Swing the hole to set or verify position. Everything comes off the datum for machining. We also set "Z" datum to table top on the machines.

If you ever move the fixture off the table just swing the hole when setting up and set datums from it.

Hope this helps.