Tightening jacobs chucks

[Martin KyteParticipant @martinkyte99762]

Are you sure you have the correct chuck key?

Martin

[SillyOldDufferModerator @sillyoldduffer]

Posted by Martin Kyte on 27/01/2017 12:18:47:

Are you sure you have the correct chuck key?

Martin

Now that's a cracking good question! I'm pretty sure the answer is yes but I can't guarantee it. As far as I know, it's the key that came with the drill and, until the fitting broke, it was kept clipped to the drill where the cable enters the handle. The drill and it's accessories are kept in their own box which makes a mix-up unlikely, not impossible.

So your point is well taken. The possibility that the wrong key has been used certainly rains on my parade!

Perhaps chucks come with 3-holes just in case a nitwit wants to violate it with the wrong key…

Oh dear.

Dave

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Dave, at the risk of being shot down and no offence intended, but even if you use one hole or three, the best way for the key to engage the ring gear is to turn it in a fashion that forces the key into the ring gear and not out of it, i.e. with the key lever moving towards the ring gear and not away from it. This applies to tightening and loosening the chuck. Turning in an outward fashion does tend to put the forces on the chuck that have produced the gouging effect that you have in the body of the chuck.

Regards Nick.

[peak4Participant @peak4]

I'll take a wild guess at this Dave. Does your chuck key have a cross handle with sides of equal length, or is it one of the ones with a longer handle and a swaged out thumb section?

I've found that the latter type works better, with a proviso.

Imagine holding an electric drill with the chuck end facing away from you, and a key hole on the top.

Set the key such that the longer handle is to the right at 90 degrees, facing due east if you consider the drill to be pointing north.

That way, when you tighten up, you effectively pull the key towards you, and force the gear teeth into a tighter mesh, rather than away from you as the second photo shows.

Are you left handed, as that might mean you normally use the key 180 degrees different to me?

 

p.s. took too long typing, Nick beat me to it. 

Also I sent a message to Jacobs earlier on asking this very question. i.e. one hole or three. If I ever get a reply I'll update this thread

Edited By peak4 on 27/01/2017 14:41:34

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Peak4, you mention left handed and this is not meant to be derogative, but I have seen this in left handed workmates who F and Blind when their key keeps jumping out of the ring gear. I do understand that it's difficult for left handed people to work the same as right handed people, as my younger brother is left handed and he used to get all manner of frustrations using some tools and other things when we were youngsters.

Regards Nick.

[Martin KyteParticipant @martinkyte99762]

Am I the only one who used to tighten mains portable drill chucks without using a key. Just grab the ring and sort of flick the wrists. The momentum of the drill body did the rest. Generally worked for undoing too. Don't need to do it anymore with the battery drills.

Martin

[EmgeeParticipant @emgee]

SillyOldDuffer

I like your thinking but it must now be time to retire that chuck !!!!!

Emgee

[Sam Longley 1Participant @samlongley1]

The pin of the key should fit the holes fairly tightly to prevent "key rock" & the teeth should engage the teeth of the chuck correctly with the key at 90 degrees to the chuck. I have a dozen chuck keys collected over the years & all have a variety of gear diameters & pin sizes.. Some for chucks of the same capacity

The key in the picture is clearly wrong for the chuck

May I suggest that the user takes the chuck to a decent tool supplier & gets a chuck key to fit the chuck & his experience will improve no end.

I would also wonder if the term "Jacobs chuck" is a bit like " Hoover" & is being used to describe some inferior chucks which may distort the debate somewhat

[SillyOldDufferModerator @sillyoldduffer]

Posted by Sam Longley 1 on 27/01/2017 15:26:05:

…

The key in the picture is clearly wrong for the chuck

…

I would also wonder if the term "Jacobs chuck" is a bit like " Hoover" & is being used to describe some inferior chucks which may distort the debate somewhat

I photographed the wrong key! It's actually for the newish vertex chuck in the tapping stand I made in 2015. Somehow it had ended up in the Drill Box and I carelessly picked it out for the photo. You can't be too careful.

The correct key was also in the box so I've not been inadvertently using the wrong key for years, phew. I'm pleased to say that despite being a much better fit, the chuck still exhibits the faults I enumerated earlier. Now I don't feel quite so foolish. The chuck is worn.

As for the manufacturer, it's marked 'Jacobs, 'Made in England'. Came fitted to my Black and Decker Drill at least 25 years ago so I'm not complaining.

Dave

[Ian S CParticipant @iansc]

Dave, I'm sure that chuck has a pressed steel sleeve on it, I remember many years ago going to the Black & Decker agents here to get a new electric drill, the old one had a burnt out armature, I took the old one in, and the salesman took the chuck off the new one and gave it to me, he then put the chuck off the old drill onto the new one, the old chuck was of the type with the solid machined steel sleeve, his coment was "these cheap pressed metal sleeves won't hold anything, complete waist of time".

Ian S C

[MWParticipant @mw27036]

Posted by Ian S C on 28/01/2017 10:10:59:

he then put the chuck off the old drill onto the new one, the old chuck was of the type with the solid machined steel sleeve, his coment was "these cheap pressed metal sleeves won't hold anything, complete waist of time".

Ian S C

Hi Ian,

If you buy the official Jacobs ones, they are still fully machined sleeves. They just cost a fair bit more, like £40 rather than £15-20 of the far eastern equivalent. I got mine from Cromwell tools in the UK. The only tricky thing is, they aren't usually sold with an MT taper, so you have to match up the Jacobs taper, to the corresponding adapter, which takes a little bit of fiddly working out.

I've still got a few of the chinesium variety but I don't mind them, When i'm using my lathe though I want a decent drill chuck hence the purchase.

One thing that really struck me is how precise the jaws are;

You can see how the Chinese chuck on the left has very rounded rubbed jaws whereas the Jacobs has very sharp, to a point jaws, this allows you to hold drills to 1mm shank accurately. The pinion teeth are wider, heavier duty too.

Michael W

Edited By Michael-w on 28/01/2017 18:07:57

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Michael-w on 28/01/2017 18:04:02:

If you buy the official Jacobs ones, they are still fully machined sleeves.

.

Except for the 'economy' ones … **LINK**

http://www.jacobschuck.com/keyed-chucks/jacobs-30243d-1-4-multi-craft-drill-chuck.html

MichaelG.

[Sam Longley 1Participant @samlongley1]

delete

Edited By Sam Longley 1 on 28/01/2017 20:04:01

[larry PhelanParticipant @larryphelan54019]

We were always told to"Tighten on three,open on one" Full Stop ! What,s the big deal about it?,it,s not going to start World War Three.

I can think of much better things to post on the Forum .

[Neil WyattModerator @neilwyatt]

I have a few Jacobs brand chucks. They are variously totally worn out, cheap and cheerful and rather nice…

The cheap and cheerful one came off a small portable drill, actually it does feel a bit smoother than most such, I don't know about accuracy but I will stick it on an arbor some time. I think the others were dirt cheap boot sale gambles, one paid off and another was demoted to a handle for a deburring tool!

[Mick B1Participant @mickb1]

Blimey, how many of you have worked in real dog-end machine shops where everything's worn by decades of neglect and abuse?

The real reason is because the teeth in the ring gear get locally worn and blunted, and you might get a better purchase on another part of the gear that didn't get buggered some other time someone was trying to tighten a lumpy, scored drill shank enough to stop it spinning, just like you are now!

That, plus one or more of the jaws might have some swarf trapped between it and its taper, or be hindered by a long-standing burr left over from the last time that happened.

Having said that, and noted Harry W's comments, I'll play around using all holes on mine and see whether I can detect a difference.

[HopperParticipant @hopper]

I've been using the "tighten on all three" method since reading this thread earlier in the year and it does seem to give a better grip than just tightening one one hole. The outer ring does move that extra half a tooth or so on the second and third holes, so it must be gripping tighter that it was originally off the first hole.

I have really noticed it because I replaced my worn out vintage keyless tailstock chuck with a low cost eBay keyed chuck, which worked well for a few weeks but then seemed to lose it's grip a bit, until using the three hole method. Nice new Rohm keyless precision chuck is in the mail as we speak so it will all soon be moot.

[SillyOldDufferModerator @sillyoldduffer]

I've always tightened the 3-jaw chuck in my lathe moving round all three key-holes in sequence. Although tightening the first hole gives a good grip I can still feel slight movement tightening the second and a hint of movement on the third. Possibly the sign of a cheap chuck? I don't know if 3 hole tightening adds anything to the chuck's actual holding power but it sure feels as if it does.

Dave

[Sam Longley 1Participant @samlongley1]

Posted by larry Phelan on 20/08/2017 08:26:42:

We were always told to"Tighten on three,open on one" Full Stop ! What,s the big deal about it?,it,s not going to start World War Three.

I can think of much better things to post on the Forum .

But you have not said why you were told. You just blindly followed -do you never stop & ask why? when told to do something.

[Dod MoleParticipant @georgeclarihew]

Never try to stop ask why you should pull the ripcord when voluntarily exiting a flying vehicle,

[HopperParticipant @hopper]

Posted by George Clarihew on 21/08/2017 21:56:24:

Never try to stop ask why you should pull the ripcord when voluntarily exiting a flying vehicle,

But you might ask why you are exiting a perfectly good flying vehicle in the first place.

[Author]

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