3/8" drill chuck replacement

I put a Jacobs that looks like this one on my battery drill several years ago. I don't use it a lot but it works really well for me. I like it better than the keyless chuck that came on the Dewalt 3/8 inch corded drill. It clicks down when you tighten it. Price is similar to what I paid (~$20) over 5 years ago at a local Menards store. They don't seem to have it anymore...

I have a bunch of chucks (mostly imports), but its surprising to hear you didn't have like the Jacob's. Usually genuine Jacob's chucks are quite good. I wonder if Makita licensed the name.

Thanks for the tip. The price seems surprisingly low. Added to my list if things needed to make a free shipping order.

bob prohaska

I was surprised also, Jacobs has always been the premier builder of hand drill chucks, at least to my mind. It could have been made under license.

I did notice the chuck seemed to lack lubrication, so for the moment I've oiled it a little. Maybe that'll help. Still, the convenience of not needing a key is very tempting. It's amazing it took me this long to lose the original key...guess I didn't use it much.

Thanks for writing,

bob prohaska

Tangent... I've always been a fan of Milwaukee for drills and recip saws. Particularly recip saws. However the quite durable steel shell keyless chucks that came on the Milwaukee cordless drills I have owned are hard to grip, and always seemed to need the help of some slip joint pliers to tighten well, and by extension to loosen. As as Joe Pi would say, "to unloosen."

I had decided not to get more Milwaukee Cordless for my shop due to the price of batteries and went to Bauer. Bauer is okay for very occasional use, but for even regularly occasional use I wasn't as happy as I hoped. The batteries are cheaper, and the batteries are decent with bigger batteries performing better than smaller batteries just like other brands. I just wasn't thrilled over all. After my dad passed I gave all my Bauer stuff to my son and took over my dad's DeWalt cordless stuff. One thing I noticed about the DeWalt keyless chucks is its very easy to get a good grip, and I can reef down on them easily by hand. Further the drill only turns a short distance before coming up on a firm stop to reef against when tightening or unloosening a chuck by hand.

To give an idea. I use my one remaining Milwaukee cordless almost exclusively for tapping 1/4-20 blind holes. I tightened it with slip joint pliers and never take the tap out. I have a bottoming tap to finish the last few threads in a DeWalt cordless right next to it, and I was able to tighten by hand enough that the clutch slips when I hit the bottom of the hole, but the tap doesn't. The DeWalt plastic shell keyless chuck looks and feels cheap, but it works really well. I have three DeWalt cordless drills now. Very useful.

Further afield. I was replacing all the locks on my dad's commercial property yesterday. Well, my mom's property now I guess. I took my DeWalt cordless stuff with me and used the cordless angler grinder (I bought that one) with the 8AH batteries I bought. I continued to be impressed with how well it performs for a high power cordless tool with those batteries. Several double cylinder deadbolts had to be cut off. I sliced right through them in order to cut through the screws I didn't know how to expose without the key. Big batteries continue to be worth the price. More longevity for light work, and more current for heavy work.

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 .

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

--------------------------------- 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.

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

I normally tighten key chucks with just one of the three holes but... when slipping problems occur I'll go around and tighten the bit with all three holes which usually stops it from slipping. Maybe you already know this but a lot of people don't. Chuck instructions often tell you to use all three holes but who reads instructions😄️

That chuck I suggested cost 2/3rds the price of the drill I put it on. The keyless chuck it replaced was miserable junk so it was a huge improvement in my case...

Bob, I'd read the one-star reviews first.

Joe

Point taken. I usually check bad reviews but didn't this time. the "wrong thread" complaints are quite surprising.

Still, in-person transactions aren't foolproof, at least when I'm the fool. Went to a local Ace store and asked for a chuck key to fit a

It's a nice bike ride to return it and I don't think they'll give me much pushback if i want to exchange it for the right part, but that was a one star deal too.

Thanks for writing!

bob prohaska

Still, in-person transactions aren't foolproof, at least when I'm the fool. Went to a local Ace store and asked for a chuck key to fit a

It's a nice bike ride to return it and I don't think they'll give me much pushback if i want to exchange it for the right part, but that was a one star deal too.

Thanks for writing!

bob prohaska

-------------------------- Is the K number of the key stamped in tiny letters on the chuck?

If you find one with the right gear but too small a pilot you could sleeve it with hobby store brass tubing, stretched to almost fit and pressed on.

It's marked SM4G61, with capacity in millimeters and inches. It also has the spindle thread stamped on it. There's no K number visible.

I don't think it'll be a problem to get the right key. I just wasn't paying enough attention. In fact, "hobby store brass tubing" will be considerably harder to find, at least around here.

It would have been smarter to take the chuck with me.

bob prohaska

I don't think it'll be a problem to get the right key. I just wasn't paying enough attention. In fact, "hobby store brass tubing" will be considerably harder to find, at least around here.

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I'm seeing that too, all techie DIY stuff that requires manual skills is disappearing.

In the 1950's PopSci and PM carried projects "for the man who can weld" or owns a lathe. They faded away in the 60's.

"Boys' Life" had scalable patterns for a paper hot air balloon, which I built. The "UFO" in the Exeter Incident seems to me very much like one. Paper hot air balloons carrying enough fuel to first inflate them were initially too heavy to rise like a Helium balloon and tended to stay low and move randomly in ground turbulence. Road flares were a source of powder that burned bright red as the falling fuel level exposed it, lighting up the whole envelope like a Japanese lantern. Rocking back and forth and rising as they lighten are typical of model hot air balloons.

The Physics professor from Phillips Exeter Academy lived nearby and build toy gizmos, and my guess is some students were trying to impress him.

This was usually when they tried to buy a chuck that fit named kind of drill. There may have been wrong-item-shipped problems.

The key comment is that the new chucks are imprecisely made, and so the chuck cannot grip firmly no matter what you do.

Llambrich makes very good chucks. Their JK Industrial line seems most suitable. About USD 200.

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Röhm is also very good.

These hand-tightening chucks will all open if rotated in reverse. Does this matter?

Yeah, chuck keys have two parameters, not just one.

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Joe

Interesting that the page is footnoted "Quality made in Spain" They do look nice, but rather an overkill for a hand drill.

Again, 1-star reviews are not encouraging, prompt breakage

Usually, no. In some cases yes. Best to avoid, I think.

The table makes me scratch my head. The key I have which seems to fit is a 15/64" pilot with 11 teeth on a 1/2" pinion, from a 1/4" Makita drill. Not in the table, far as I can tell.

The key I mistakenly bought has a 15/64" pilot with 10 teeth on a roughly 0.665" pinion. 30825, but with a D suffix.

Looks like maybe I need a "gotcha" key. I'll take the chuck with me when trying to exchange the key I bought by mistake.

Thanks for writing!

bob prohaska

There are adapters available, so you may be able to standardize on the

Röhm is not a good as Llambrich , but both are far better than what you currently have.

Keyed chucks are also cheaper.

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Not everybody follows Jacobs, even when selling "Jacobs chucks". Patents ran out a generation ago, and the name became generic as well.

Bringing the chuck is the best way.

Joe