Re: 3/8" drill chuck replacement

"Snag"  wrote in message news:vt7jam$2a1a9$1@dont-email.me...
   My cordless are ALL DeWalt . Got a plastic tub full of 18v stuff at a
yard sale , all the batteries were junk . Neighbor gave me some more
including a recip and a circular saw , but no batteries . Got 2 3.6 A/Hr
Ni-MH batteries on eBay and I'm good to go for around the house . Shop
drill is a 20V also from a yard sale . Came with a charger and one good
battery ... so I bought 2 more bigger ones  .
Snag
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When the NiCads for my 14.4V Dewalt DC730 drill died I bought aftermarket NiMH batteries. The original charger appeared to be rated only for NiCads and its peak charge voltage approached don't-go-there land for NiMH, so I bought an inexpensive aftermarket charger for both types that stops short of the red zone, at around 22V. The combo has been fine for my relatively light use, if you consider deep 3/8" holes in steel "light". I use a corded Magnum Holeshooter for larger holes.
I measured the voltage by tacking wires to the base of the battery socket inside the charger. The third connection is a variable resistance temperature sensor.
A meter that reads to 1 millivolt above 20V shows the small voltage drops as each individual cell reaches full charge and shifts to generating oxygen, but the charger seemed to end the charge based on total pack voltage which isn't the fastest way. The sensor detects the temperature rise when the generated oxygen recombines and heats the cell. I think it's a backup Stop signal for a pack with a shorted cell that won't reach full voltage.
The meter is a UT61E that can graph its readings on a computer, so I could see the drop after it happened instead of watching closely.
https://lygte-info.dk/info/batteryChargingNiMH%20UK.html
"-dv/dt" is Calculus for a voltage drop.
This drill has the automatic spindle lock that allows firmly tightening the keyless chuck. A screw inside the chuck retains it. Another marked down store-brand drill was missing its #12-24 left handed chuck retaining screw which I made on the lathe because I can, dammit.
jsw