Hi!

Today was the second time I broke an endmill because of this   and it's time to find out out what's going on.

I have a simple setup, with the spindle relay controlled by a PP pin which works fine, no hardware issues here. The problem is software related.

After starting Mach3, loading a program etc., I always have to manually start the spindle (then turn it off) by clicking the Start Spindle button, before running the program; otherwise the M03 command is ignored completely, no matter how many times I try. There are absolutely no issues with subsequent runs, different files, resets or anything else as long as I don't quit Mach3. Again, I only have to do the spindle start once and everything's cool thereafter.

Additional observation: interestingly enough, looking at the G-Code scrolling up during a run, the program doesn't pause at the M3 command at all, whereas it should do so for 1 second (which it does, after the quick fix.) This makes me believe that Mach3 somehow does not execute the command at all.

So the question is... WHY?  

What version of Mach are you using as I seem to recall a similar issue a few versions back.
Hood

I just recently set up this spindle relay but it's been a few months since I checked for software updates... anyway, my version is 3.042.033

And now that you brought it up, I went to the changelog page and the very next entry after my version is:

Jan 05/2010
Release 3.042.034
-- Driver Frequency locking in at proper Hz
-- Spindle not turning on bug fixed
-- new Driver test added to show Rev of Driver

"Very funny!" he said, cringing at his broken endmill. 

Upgrading will hopefully save you some endmills
Hood

That's right, what other benefit could an upgrade bring? Authentic Scotsman!

How's the v4 coming, dude?

V4 is coming along, been a few weeks since Brian sent an update as he is reworking a few things to do with the way FeedHold works but its looking good so far.
Hood

Your are not alone as my spindle starts if I stop and start again. Sometimes it starts first go. Using latest version.

Noel