Cordless drill with a cord

[mklotz]

Probably one of the most frustrating tools in the hobbyist's arsenal is the cordless electric drill. It's undeniably handy but, if you're like me, dealing with the batteries is enough to make you wish that Maxwell and Faraday had just kept their discoveries to themselves.

I wanted to drill a single hole out on the patio. Not wishing to deal with stringing an extension cord through a window, etc., I reached for the Craftsman 12V drill my daughter gave me a few years ago. No the battery wasn't dead - it managed to revolve the chuck at a stately 33-1/3 rpm for about ten seconds. Then it was dead. The backup battery that came with the drill hasn't been able to hold a charge since its second recharge. I reached for the backup cheapy drill from HF and it could spin its chuck but only if I didn't hold on to it. I hadn't used it in about a month so, of course, the battery had run down.

After exhausting my repertoire of curse words in three languages I started thinking about the problem. The real advantage (at least to me, an occasional user) is not that they're cordless but that one doesn't have to string (110 VAC) extension cords to use them. (Sounds confusing but stick with me.) I wouldn't mind if the thing had a short cord attached to a battery if that battery was more dependable than the ones supplied with these drills.

The typical NiCd supplied has all sorts of "memory" problems that can interfere with it taking and holding a decent charge. The manufacturers don't supply charging instructions and the chargers they supply have no "smarts".

But 12V Sealed Lead Acid (SLA) are widely available in small size packages, have decent capacity, and can hold a charge.

So, I opened up the drill and found the battery contacts...

Attached a hunk of speaker cable with some brass screws...

and, voila, a corded cordless drill...

Now the thing spins like a banshee and has torque to spare. The drill draws about 1.5 A at top speed and the battery is a 5 A-hr so it should last for at least an hour or two of use. I've never done anything with a cordless that took longer than a few minutes of drill run time so I think I'm in good shape there.

Lead-acid technology is well understood and smart chargers are widely available and inexpensive. Mine delivers 0.75A so it should be able to recharge the battery in 6+ hours. I intend to leave it on trickle charge most of the time so it's always ready to go.

The voltage on more modern drill batteries has gotten higher than 12 volts but I expect a 12 v battery will still run most drills. Before investing any money in this scheme, try your drill with the car battery. (Ignore that last if your car is a Tesla :-)

[DIYer]

Thanks mklotz! We've added your Cordless Drill Extension to our Drilling and Drill Presses category, as well as to your builder page: mklotz's Homemade Tools. Your receipt:

Cordless Drill Extension by mklotz

tags: battery, cordless, electrical

[PJs]

Thanks Marv, that rung a bell for a lead acid I have for my 2 axis equatorial mount that's been sitting...a while and a 12V Ryobi drill I picked up at Restore for $8 (batteries are $25+ ). I had built a 12ga wire cage around it with a handle then put it in an old camera bag that was just the right size...portable and handy with pockets. I've seen these hacks before but this one hit home with your writing style!

These cordless drill/tool batteries are like Printer Ink...3 uses and the ink cost more than the printer. My C3 stuff I use all the time and finally got a 18V 4ah Li-ion for them at a price I didn't have to indenture my first born for. A world of difference to what it came with (1.5ah). I picked up one of those mini C3 vac/blowers and after 15 minute of use it blew the fusible link in the one of the 2 original batteries I had. Some engineer cacked on the current draw/heat load calcs. Li-ion has its pluses, but over heating danger and the link are the bane of them IMHO. I think you can push Lead acids a bit harder and they recover much better, plus capacities are reasonable, just larger typically.

Also wanted to say thanks for your gear ratio tutorial...definitely confirming to what I came up with for a solar powered music box I'm making for my grandson. Had to go from 2400 to about 60rpm with 2 singles and a double (8-50/8-56=~55rpm).

Thanks!! ~PJ

[Jon]

These cordless drill/tool batteries are like Printer Ink...3 uses and the ink cost more than the printer.

Exactly: Razors and blades marketing. My printer does it with toner. It prematurely throws a "low on toner" error, and refuses to print. Reinstalling the printer driver makes it work again.

[PJs]

Exactly: Razors and blades marketing. My printer does it with toner. It prematurely throws a "low on toner" error, and refuses to print. Reinstalling the printer driver makes it work again.

Good Read on the link and something we shouldn't stand for at some level, IMHO. I'm all right with a proprietary design having higher cost at the git go but down the road with innovation in mfg, pass on the savings and promote some good will instead of milking every last drop and bad will, plus adding to the waste stream. Wondering now whether that was an engineering error with the C3 vac/blower because they had some issues with their reciprocating saws too. Life Cycle Planning or Planned Obsolescent...Oh My, what happened life time engineering. ~PJ

P.S. I have 2 Epson Ink Jets B-size and an all in one and it takes an hour and a half to reload on 5 machines.

[Ed Weldon]

Marv - You did it again. Reminded me of what should have been obvious, not to mention a bunch of add-on hints. I have two old Skill 12volt drills, batteries long dead, that I just can't to throw away. I think I'll try setting one of them up to be a small drill press with a fuse/switch/cable box/battery box. Perhaps the other will run a jeweler's lathe that will live with a battery in a little carry bag if I can get the speed up high enough.
Thanks, Ed Weldon

[mklotz]

Marv - You did it again. Reminded me of what should have been obvious, not to mention a bunch of add-on hints. I have two old Skill 12volt drills, batteries long dead, that I just can't to throw away. I think I'll try setting one of them up to be a small drill press with a fuse/switch/cable box/battery box. Perhaps the other will run a jeweler's lathe that will live with a battery in a little carry bag if I can get the speed up high enough.
Thanks, Ed Weldon

Drills with dead batteries spark many ideas for new applications. Dedicating what was meant to be a multipurpose tool to a single application doesn't seem so bad when the tool would have been discarded for lack of batteries.

My latest idea, for a long-dead Harbor Freight drill, is to somehow lash it to a length of pipe or closet rod, fit it with a scrub brush, drive it with a battery or 12V battery charger and use it to scrub the lower reaches of the shower tile. At my age bending over for extended periods of time or kneeling on hard tile are not pleasant activities.

[MasterMaker]

Drills with dead batteries spark many ideas for new applications.

Milling-machine power-feed....

[kbalch]

Same here. My HP color laser printer started squawking about low toner levels a month or so ago. A little investigation revealed that the black is down to about 30%, while the colors are just fine. Replacing the black cartridge alone is going to be ~$80. A full set of cartridges is over $200 - for a sub-$200 printer!

Madness.

[Elizabeth Greene]

My HP color laser printer started squawking about low toner levels a month or so ago. A little investigation revealed that the black is down to about 30%, while the colors are just fine. Replacing the black cartridge alone is going to be ~$80. A full set of cartridges is over $200 - for a sub-$200 printer!

Back in the 90s HP laser printers were rock solid workhorses. They would print reams of paper without so much as a blip. The brand has declined, i.e. "value engineered", significantly. Today Brother is making the good laser printers. I'm 4 years into mine and my only complaint is I didn't drop the extra $100 to get one with a sheetfed scanner on it.

Edit: I didn't realize I was replying to a 4-year-old post. apologies