[How do I?] Replace A Jt33 Locking Collar Chuck With A Keyless Model?

[MetalMuncher]

To the best of my knowledge, you will not find “any” chucks made today that have that threaded collar, especially the keyless ones…Dave

That is what Shars Tools told me when I asked about it.

Perhaps some photos of the knurled rings I am referring to on the back end of keyless chucks will help illuminate my question. I'd really like to know what those are for if someone here can tell me. On ones with the screw on a tangent to the chuck, the ring appears to be split. On the other type, with the setscrew heading radially inward, the ring appears to be solid. See attached.

Edit.......since posting this, I got a reply on Amazon from asking about these rings. The seller said on the chuck they were selling this ring is removable when disassembling the keyless chuck for cleaning or repair. So maybe that's what they are all for?

 

[KenS]

The knurled finish on the the thin rear ring should give you the hint you need. When a keyless chuck is mounted in the tailstock of a lathe, you can simply screw or unscrew the large knurled chuck body to remove at bit because the chuck is is fixed in the tailstock and can't rotate. However, when a keyless chuck is mounted on a drill press or mill, the spindle can rotate. In such cases every once in a while a bit gets locked pretty tightly in the chuck, or conversely needs to be tightened a little to avoid slipping. In such cases you can grip the thin rear knurled ring with one hand to stop the chuck and spindle from rotating, and use the other hand to turn the chuck body to loosen or tighten the bit. Basically the rear ring becomes an instant spindle lock.

Anyone who has ever used a Silver and Deming drill bit in a keyless chuck may have run into this problem trying to loosen the bit. The design of a keyless chuck allows it to self-tighten under power. The torque of a large diameter bit such as a Silver and Deming can cause a keyless chuck to tighten so much that it becomes almost impossible to remove the bit, even using the two-hand opposing-twist action. Save Silver and Deming bits for Jacobs-style keyed chucks. However the smaller bits we typically use in a keyless chuck usually don't present a problem, but every once and a while it is nice to have the leverage provided by the rear ring to tighten or loosen a stubborn bit.

The convenience of using a keyless chuck will spoil you very quickly. But there are times when a keyed chuck is a better choice.

 

[MetalMuncher]

Thanks KenS. I had seen reference to self tightening while looking at keyless chucks, but I was not aware of this issue. I've been using a keyless chuck on my SIEG X2 clone mini mill for awhile, but it has a locking spindle, so never an issue to loosen the chuck. I was hesitant to consider a keyless chuck on the drill press because it lacks a spindle lock. But if it becomes necessary down the road, I'm sure I can find a way to give it that ability. I ran into a similar issue once on a 4 inch angle grinder. The design idiots that made it put a push button lock on it that only worked clockwise to tighten the wheel, but slipped counterclockwise, much like the heads of the one-way security screws used in assembling public bathroom stalls. I had to drill into the side of its spindle so I could insert a rod and hold the spindle from turning while removing the wheel to change it. I suppose something similar could work on the drill press if needed down the road.

Thank you all for the advice! I've decided to order a Grizzly 1/2" JT33 keyless chuck to try in my drill press.

 

[MetalMuncher]

I have the Grizzly G8581 keyless chuck installed, and it works very nicely. I am impressed that for smaller drill bits, the resistance of the belt driven spindle seems to be enough to hold the spindle while I tighten the chuck. And releasing these small bits after using one works the same way.

Today I finally got a reply from Grizzly to the same question I had asked earlier in this thread about locking collars on Jacobs JT33 chucks. This statement in their brief reply is intriguing - "The Jacob’s taper is a self locking taper and as long as side pressure is not applied, it should not release from the arbor."

Exactly what did they mean by "side pressure"?? Perhaps there is some easy way to disengage a Jacobs Taper implied here, such that a bearing press, a threaded ring, or wedges would not be necessary when removing it? Can anyone shed some light on this? Jacobs website says to go with the wedges. They don't offer any other method.

 

[dlane]

Side pressure, if you try useing a end mill in it to cut a slot the side pressure can dislodge the arbor taper in the spindle , the chuck can come out and chase you around the shop . The wedge is used to remove the arbor from the chuck

 

[MetalMuncher]

Aha. Well, not the best option for easy chuck removal then, huh? I'll keep that in mind. I rarely do any mill work like that on the drill press because I have a mill for that kind of work. But if it comes down to needing to do that, I can always put the stock chuck with its locking collar back on the drill press for that job. Thanks.

 

[barrydc1]

Side pressure, if you try useing a end mill in it to cut a slot the side pressure can dislodge the arbor taper in the spindle , the chuck can come out and chase you around the shop . The wedge is used to remove the arbor from the chuck

What I wouldn't give for a video showing that!