Another Fobco Chuck

[spencerd72Participant @spencerd72]

Dear all,

 

I have no idea how to remove the chuck from my recently acquired Fobco Star 9see pics below).

I have seen an old post in this parish where there was a knurled ring that unscrewed and pushed the chuck off. My drill does not seem to have this. Any ideas?

Many thanks in advance,

Dominic.

[noel shelleyParticipant @noelshelley55608]

Extend the quill and see if there is a slot in it – if so then it will be 2MT and need a tapered drift to push the 2MT shank out of the quill shaft. If not then a Jacobs Taper in the chuck, the chuck may have this fact marked on it. Gentle heating and a forked drift should get it off, patience is needed. Good Luck. Noel.

[spencerd72Participant @spencerd72]

Many thanks Noel,

There isn’t a slot, even with the quill extended, so I suppose it’s a case of getting a good forked wedge and tapping with some heat.

I can’t see any markings on the chuck to describe the taper. It says it’s British made, in Sheffield, shows the capacity and says it’s a Jacobs number 34.

Thanks again from the reply.

Dominic.

[noel shelleyParticipant @noelshelley55608]

Dominic, whilst I would expect it to be a JT I have seen ones with an internal thread, I bought one in the early 70s to fit a Myford, but it told me the thread – you say yours has no info. Noel.

[spencerd72]

On spencerd72 Said:

Many thanks Noel,

There isn’t a slot, even with the quill extended, so I suppose it’s a case of getting a good forked wedge and tapping with some heat.

I can’t see any markings on the chuck to describe the taper. It says it’s British made, in Sheffield, shows the capacity and says it’s a Jacobs number 34.

Thanks again from the reply.

Dominic.

As far as I can see, all Jacobs 34 are all tapered fit, in the current range anyway.
http://www.jacobschuck.com/plain-bearing-keyed/17.html

Really, I believe you should uses opposed tapered wedges, specifically for the purpose, rather than just hitting on one side with the likes of a ball joint splitter.
http://www.jacobschuck.com/uploads/ueditor/file/20200604/1591240204146153.pdf

They are available, but come at a cost.
http://www.jacobschuck.com/search/index/tag/id/97.html

Bill

[spencerd72]

.

On spencerd72 Said:

It says it’s British made, in Sheffield, shows the capacity and says it’s a Jacobs number 34.

Thanks again from the reply.

Dominic.

No. 34 indicates a chuck with a J6 taper IIRC. If it were screwed it would be 34B.

A long time ago I removed my taper mount Fobco chuck very quickly by trying to use the machine as a vertical mill!

 

[spencerd72Participant @spencerd72]

May thanks for all the replies.

I’ll have another look and let you all know how it goes.

 

[spencerd72Participant @spencerd72]

Dear all,

I thought I’d update on my progress. I bought some wedges, but using these just seemed to pull the spindle further downwards in the quill. I eventually realised that you are supposed to use the wedges against the slightly wider diameter ring just above the Jacobs taper on the end of the spindle, not against the body of the drill as I was. (see pictures below). In the end, I removed the body of the drill off the pillar, turned it upside down and drilled and tapped an M8 thread in the back of the chuck body, which allowed me to easily remove the chuck. Now I can take the chuck off easily whenever I like. Unfortunately, after a clean and rebuild the chuck is still not holding drills true (one of the jaws looks to be worn on the side it grips the drill. i wonder if filing the other two down to suit would improve this?

EDIT: I noticed that when the spindle had been pulled down further by the action of the wedges, this introduced some play into the spindle (disaster!). However, the spindle was easily moved back up by exerting some downwards pressure on the re-installed chuck against the table.

An better way of drilling the hole would have been to mount the drill bit in a machine vice rather than taking the body off and using a hand drill. The machine vice is in the post!

[Chris CrewParticipant @chriscrew66644]

I would be buying a new keyless chuck for around fifteen quid from a well-known auction site. That’s what I did for my Union pillar drill when I refurbished it and it runs truer than the Jacobs chuck I removed ever did. Keyless chucks are far more convenient to use in any event and it’s not like you will be removing a chuck regularly. The other far eastern bench drill I have has never had the keyed chuck removed in the last 42 years and it still runs as true as it did when I bought the machine.

[PeteParticipant @pete41194]

Most would consider any drill press with the chuck taper integral with the quill as something your not going to be changing drill chucks very often. Yes it can be done but is it really worth it? And given the age, condition and amount of use that chuck seems to have had, it’s highly doubtful much can be done to improve it’s run out. It’s not just jaw wear, it’s also the internal wear on the ground internal surfaces most have no way of correcting or regrinding.

While I own some very expensive key less drill chucks, there most definitely not for everything that might be used as a cutting tool on a drill press due to there built in self tightening design. Albrecht are quite specific about never using any cutting tool with a larger diameter than the shank size the chuck was designed to accept. S & D reduced shank drills, hole saws etc are not to be used for very good reason. As the cutting diameter increases so does the torque. As that goes higher, a key less chuck self tightens to prevent any slip between the chuck jaws and the tool shank. If the torque on the tool gets high enough, the chuck will continue to self tighten to the point of starting to temporarily or permanently cause deformation within the chucks internals. There’s even a few older posts on the Practical Machinist forums mentioning this exact issue, and with some admitting to permanently locking up even high end Albrecht chucks to where no amount of force will open the chuck again. Turning a $300+ chuck into scrap makes a pretty expensive day. I use key less chucks on both my lathe and mill, but for any cutting tool larger in diameter than it’s tool shank, I switch to ER 32 or 40 sized collets. Strangely this well known issue seems to be hardly ever mentioned on the more hobby level forums. Used within there limits, key less drill chucks are extremely nice to use and I certainly wouldn’t enjoy not having mine. But they will not tolerate any abuse very well.

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