The Home Machinist!

magnetic reed switches are the last thing that I would consider for this application.

adding the 'pulse' as described above is exactly what we do on more 'industrial' applications and will give you want you want long-term.

There is nothing more annoying than setting up a job, having all the tools 'where you want them' and having to start over the next morning.

Bill, I still agree with you but it is not all that bad for those of us who do not have pulse homing. Mach 3 uses a master tool table setup so you don't lose you tool offsets on power down. All I have to do is touch off my master tool to the stock, set zero's and go. Of course I'm working on a lathe and setting Z zero to the end of the stock is easy as I set a bump stop in the program to start which lets me get a repeat on the next part. The X is a little harder as you really need to take a test cut in a scrap piece, measure it and enter the measurement into the DRO.

Not ideal, but it is accurate!

Dave C.

That's cool....but I still would not use those magnetic reed switches for that application.

Don't you also generally use them for limit switches?

The problem with magnetic switches is that they can accumulate 'magnetic trash' on the magnet, and before long they are tripping (or not tripping) at odd times.

I would recommend (what I use industrially) a proximity switch that is non-magnetic.

http://www.omega.com/googlebase/product ... 0wodyc0NRw

You can get them for $10 or so today and are industrial grade.

Bill,

It seems your link is just for the mounting bracket. The actual sensor is $255.

http://www.omega.com/pptst/LD701.html

Hmm, proximity sensors, my airplane has tons of those all over the airframe, for the gear doors, the landing gear, the cargo doors, main passenger door, etc. Anything that opens and closes and is considered either structural or safety oriented.
I'd hate to know how much the FAA approved version costs!