Sunday, February 20, 2011

Metering Your Tools

Awhile ago, I blogged about finally changing the oil on my planer.  Oh, my, that stuff was treacle not oil!  I want a way to track my planer's hours so I can plan to change the oil after 35 hours of use, but how?!  Many tools could use metering.  I could see any industrial tools like this PM-20 planer having oil that needs changing or maybe put a timer on a DC unit to know when to rince the canister filter.  Or maybe just out of curiosity like an odometer; might be interesting for shop owners wanting to know what gets used and for how long.

Anyway, my quest to put an hour-meter on my planer lead to McMaster-Carr.  There, I found the perfect digital hour timer with 1/10th hour resolution.  It tracks the time that voltage is applied to two pins.  The best thing is that it works with AC or DC input (75-270 VAC, 36-185 VDC). Perfect for a 220V planer!
I'll describe how I connected this to my planer.  Mine has been out of warranty for, oh, a decade. Yours is likely different, this may void the warranty, you might mess something (you?) up.  It's easy, but understand everything before taking it on.  I'll explain enough (i.e., "babble") that you should be able to easily adapt it to your tools.
Here you can see the cover of the planer power switch opened.  The push buttons on the front push buttons on the relay unit with all the wires; that is, the push buttons you touch have no power.
This is the wiring of my power switch (yours very likely will differ).  The key is to know: a) the timer needs voltage to pins 1 and 2 (the documentation explains this), and, b) we only want that voltage when the switch is on.  So where do we tap the voltage?  Well the voltage is connected to the motor when you power up the planer so the easiest thing to do is see where the wires from the motor come up.  For mine, the motor is the black cable coming up on the right side of the box.  The two 'hots' for it go to two terminals just to the left of the round red 'off' push-button.  That's my target.
The timer will fit on the side of the box near the top; plenty of clearance inside for it and it's a convenient place.  Here I taped a pattern for the hole I need to cut out.  Used a knife to score the ABS plastic then drilled a hole in the corners.  From there... was all fretsaw work and a little touch-up with a file.
Here, I connected it to the motor terminals with the motor disconnected.  I want to try out the timer.  Powered up, didn't smell anything 'funny', and left it while putting on some CPES (that smells funny!) for a sharpening pond I'm making.  After that was done, I logged 0.4 hours (~25 minutes) on the timer and I verified that after disconnecting it for an hour from power and re-running it, the accumulated hours were stored.  Wahoo!
Here it is installed.  Note that the timer display is normally off; once voltage is applied for 5 seconds, it shows the hours of use.

Now all I need is to 'borrow' an oil-change sticker next time I get my car done so I can mark my planer as due at 35 hours of run-time.