Friday, January 13, 2017


As you all know, I'm spending a lot of time playing with CFDA shooting, acquiring equipment, learning shortcuts, and having a lot of fun.

I want to expand my personal range, and we're making some changes at our club range, and I'm experimenting.  When we use the CFDA timing equipment (and that's about all that's available right now) it requires that you drill holes in your target to install a hit sensor on the back of the mild steel target.  It's a simple piezo switch that hooks to the back of the target.  It wiggles when the target is hit, and it trips the timer.  It looks just exactly like this:

The description on the CFDA webstore page says:
These sensors are constructed with highly dependable piezo transducers, they also have a foam box filler which nearly eliminates false hits recorded on the timer.Comes with 2-10/32 screws, with lock nuts, for secure attachment.
There may be a good reason to screw them to the target, but I don't see it.  I'm thinking that putting a faceplate on them, and affixing them to the back of the target (which is, again, mild steel) with magnets ought to work just fine.  To that end, I started looking for suitable, inexpensive magnets this week.

Talking to a tech at work, over coffee, it turns out that every hard-drive has two magnets installed inside.  And, with thousands of computers in active service at any time, there are a certain number of hard drives that go defunct (ask Lois Lerner).  So, I was able to scrounge a couple of old, defunct hard drives, with the understanding that as I salvaged the magnets, the remainder of the drive would be completely destroyed.

I did, in fact, destroy the hard drives.  And, after destruction, I mailed them to the IRS for their attention. (just kidding).  Yeah, they've been destroyed.  A half-inch drill bit run through them, then a session with a propane torch had rendered them warped, holed, and completely defunct.  But I digress.

One thing that I learned is that all hard-drive magnets are not created equal.  Some are very strong, some only marginally strong.   But, they all come with cool little mounting brackets.

So, I've ordered some spare switches to experiment with, and I have some freebie magnets to experiment with.  Hopefully, the switches will be in next week and we can begin experimenting with vigor.

The journey continues.


Anonymous said...

Just for giggles, take one of the really strong magnets, and use it to hold some annoying notice on your refrigerator; then watch your wife try to pull it off...........LOL

Old NFO said...

Seagate magnets are usually pretty good... :-)