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How to remove the chuck? Startrite Mercury (different!)

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PhillR

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Hello all. This is my first post here, so apologies if it's in the wrong place.

I've recently acquired a Startrite Mercury. Other than it missing the belt guard (lid at the top) - which is replaced by an ad-hoc aluminium thing, and 1 knurled nut, it seems to be pretty much in tact and un molested. With my DTG the quill runs well, runout c 0.05mm, which is good enough for me. Anyway, I'm going to start a project on restoring the thing and am completely puzzled how to remove the Jacobs J33 chuck.

According to this link (turns out I can't post the link :roll: but it's the manual from ALT saws. The diagram is on Page 9) there should be 2 knurled nuts and a Mills pin (?) at the base of the quill, above the chuck. On my machine there is only 1 knurled nut; the thread (presumably for the other nut?) is clearly visible - see photo.

Can anyone help suggest how I can remove the chuck in this current state, please?

Cheers
Phill
IMG_1244 (1).jpg
 

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porker

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Hi,
You're missing the bottom collar which is turned against the top one to release the taper (J33 taper BTW). I see you can still buy spares for this drill Machine Spares

To get it off I think you need a pair of wedges and some way of packing the gap. I would probably use a pickle fork ball joint tool and gently tap it. You don't want to risk bending the spindle. Gently tapping the side of the chuck with a small hammer may release the taper but I think you would be lucky as they can be on tight and idealy the force needs to act directly downwards to avoid damage.
HTH
Matt
 

PhillR

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Hi Matt

Ok, thanks. Does the chuck just push onto the taper then - held in place, like a Morse taper by friction??

Cheers
Phill
 

Trevanion

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You'll probably need some Jacobs Chuck wedges to get it loose since the nut is missing. It will probably release the taper that goes into the chuck rather than the taper that goes into the drill column though.

 

AES

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Agree with all the above (though I don't know that particular make of pillar drill).

Just make sure BEFORE trying to remove the chuck that A) the jaws are fully retracted into the chuck body - i.e. chuck wide open; and B) that you have a pad off thick cloth or something just under the chuck because when the taper lets go the chuck will drop like a bomb!

And YES, as far as I know, all taper systems rely on "just" the fit between the tapered female hole of the quill and the tapered male of the chuck mounting spindle. Which is why, when you put it all back together you should,BEFORE installing; A) clean both tapers off to make sure there is no swarf or other rubbish sticking to either/both; and B) as per removal, when pushing the chuck back up into it's (tapered) hole, have that thick cloth pad handy under the chuck to push the chuck against (i.e. turn the higher/lower handle down a bit) so the chuck is pushed against the cloth. That the tapers is seated firmly.

HTH
 

porker

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I have a floor standing 5 speed model. I think I may have described this slightly wrongly as I seem to remember that the bottom collar that is missing on yours screws down onto the top of the chuck to force it off the taper and the top knurled collar is there to hold it.
It's a few years since I last took off the chuck and I have a couple of pillar drills so hope I'm not mixing them up! I can't remember if there are any grub screws in the collars but I don't think that will be a problem on yours as it's missing one. I do use mine sometimes with a drum sanding kit and I've not had the chuck drop out but in general tapers don't like sideways loading without a draw bar so it might be a bit tight but a slight shock can loosen them (ie. a gentle tap).
 

PhillR

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Thanks for the great (and amazingly prompt) replies folks! :D

I've never used a pair of those wedges before. Quick shufties on Google shows them as costing under a tenner (hopefully I'm looking at the right thing), so happy with that. I've taken a quick closeup of the quill with a rule next to it. There's about 20mm from the top of the chuck to the bottom of the nut. I see there's a couple of washers(?) - one silver and one orange(ish) directly above the chuck. Can I ask:

(i) what size wedges would you plump for?
(ii) would you try and fit them between the silver washer and chuck (i.e. c35mm on the rule), or do I need to make a collar (of diameter slightly larger than the quill) to significantly reduce the 20mm gap?
(iii) guessing I just use a clamp to force the wedges together?

IMG_1246.jpg


Cheers,
Phill
 

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porker

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I would get wedges that fit around the threaded part where the bottom collar should be and they can force off the top collar and directly to the top of the chuck. The biggest issue is packing the gap. I don't think wood would work as it's too soft, you probably need something metal.

I needed to do something similar once and managed to tape a couple of open ended spanners together to take up the gap. Hope that makes sense
 

philip sewell

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I've just finished renovating one of these pillar drills. If someone hasn't mentioned this already there is a c/s bolt you need to remove which screws into the end of the shaft (open the chuck jaws and you will see it).
I remember it was a real struggle getting the chuck off. As the chuck and shaft were badly worn and I new they had to be replaced I wasn't too careful about avoiding damage.
I got mine off ebay and rebuilt it. On mine the shaft spline was so worn I ended up making a new one. I also added a belt tensioner and put a single phase motor on it.
PhillR, if you are interested I'll post some pics of the modifications I made (if I'm allowed to, this is my first post for a few years).
Philip.
 

PhillR

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Hi Philip

Thanks for your offer - yes, I would be very keen to see your photos. If posting them is problematic I’ll suss out how to share my email address.

Anyway, I’ve now got it off. I used a good squirt of gt85 and applied a little force with a pair of large (30mm jaws, I think) spanner’s. This loosened the chuck. Turns out it was screwed on. This makes me wonder whether the quill was missing the lower knurled nut or not?? Any ideas? Also both those washers in between the chuck and quill were both cupped (not flat). Not sure if that makes any difference to the run out of the chuck?

F67A6D60-B373-42B8-B12D-CF61008A1846.jpeg

055B3C90-C11D-4C19-A371-92E562413FBF.jpeg


Against the thread of the quill that mates with the chuck I measured the run out again (not sure how accurate that is?) and it’s 0.025mm.

Next job is to make an assessment of the state of the quill’s upper and lower bearings. If they need replacing, what would be an acceptable price? And can anyone recommend any good suppliers?

Thanks everyone for all your great help so far :D

Cheers
Phill
 

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PhillR

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PS I noticed the hole in the base of the chuck after I’d removed it. Guess as it came out easily the retaining bolt had taken a hiatus
 

philip sewell

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That's interesting, my chuck was on a JT33 taper, not screwed on.

I replaced all the bearings on mine, tend to do that when things are apart as a matter of course.

I use simplybearings. They have a price range but I tend to play safe and buy the more expensive ones but I seem to remember they were quite reasonable. I'll post some pics of mine when I get back into the workshop next week.
Philip.
 

Trevanion

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Surely that threaded piece isn't a part of the quill and is just a taper with a thread on the end rammed up into the quill? You'd probably still need the knurled nut to get it out if that's the case. Although with 0.025mm runout I would be more than happy to leave well alone!

I also use Simplybearings for most of my bearing needs but I have found BearingsRus or BearingBoys to be cheaper on some things. Have you had the machine running at all since you had it?
 

AES

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You've taken the words right out of my mouth Trevanion, the OP has removed the chuck OK, but still has the male taper "adaptor" mounted in the female hole in the quill.

But also just as you say, the chuck's off, the runout is good, so "so what"? Especially as it's still well seated, and with that runout, he hasn't got muck or swarf between the taper faces.

The only thing I would ask is will the chuck still be retained OK with "just" that centre bolt to tighten up? I dunno myself. I change the chuck in my pillar drill fairly often, but always by breaking the taper, and in my case, I'm not even sure how tight the bolt holding my chuck to my chuck adaptor is - "VERY" tight I'd imagine.
 

PhillR

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(dunno why the images have gone a little mad!)
Evening all,

Thanks again for the replies. Turns out whilst there is a hole in the chuck, there's not in the taper.

IMG_1259 (1).jpg


IMG_1260.jpg


Though, is this a problem?? It does look different to the manual:

IMG_1261 (1).jpg


As you say, the run out is small (tolerable?). I think (please correct me if I'm wrong) the taper/quill transition is visible in the second photo. I guess that second knurled nut would be the thing to remove it - how, though: by tightening against the upper nut? More's the point: why would I want to muck about with it when the run out is small?

Cheers
Phill
 

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PhillR

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Trevanion- yes I had it running yesterday. Is seemed ok. The motor’s pulley was wobbling all over the shop - you can see when turning it by hand it’s not on straight. Oddly the run out measured on a drill bit (which, of course may be bent) was greater than 0.025mm.
 

Trevanion

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PhillR":1cfqeshd said:
Oddly the run out measured on a drill bit (which, of course may be bent) was greater than 0.025mm.
Could possibly be that the jaws in the drill chuck are a little worn also. Plus that 0.025 runout on the thread will be multiplied by the time you get down to the business end of the chuck. Ideally, you would want to use something like a hardened and ground steel dowel pin as a reference in the jaws to measure against.

Although anything in the less than 0.1mm range is excellent for a pillar drill, even brand new ones can have more than 0.5mm of slop in the quill.
 

porker

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Glad you got it off and apologies for the duff info I gave you. Mine certainly didn't screw into the chuck like yours and has the taper. I also don't remember a screw in the end of the shaft although I guess that could of dropped out years ago. I also can't see any point for the missing collar as I can't see its purpose in this arrangement.

BTW - If I want a precision rod I always save them out of scrap printers as they are very accurate. I would have said that runout was good. Much better than my more modern radial drill.
 

AES

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+1 about the runout, and also +1 about removing rods, etc from scrapped printers. They are normally hardened steel ("silver steel"?) ground, and extremely accurate (straight and very round).

I must say I also do not really understand the chuck retaining system the OP shows. Someone's home mod perhaps?
 

PhillR

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Evening all,

Thanks again for your help - I'll have a shufties at work for some of those bars you refer to.

I've had another look at the drill this evening. My aim in the near term is to get an understanding of what bits and bobs it'll need. Here's the first 2 that I'd be grateful for your advice:

1. Retaining nut (I'm sure it's got a proper name!). 2 of 3 of the bolts that hold the front belt guard in place attach to the cover using some sort of pop-riveted nut. On one side this nut is sheared, resulting in the bolt having nothing of note to go into. What I'd be grateful to know is: what's it called, where do you get them (I only need 1) and how do you fit them? Here's the pics.
IMG_1269.jpg

IMG_1270.jpg


2. I think the motor has been replaced. The pulley that goes onto it has had some sort of sleeve fitted to match the motor's diameter (c 16mm). However, it wobbles all over the shop. On inspection, the motor's shaft has a keyway cut into it, but there's no matching key(?). Again, I only need 1 so don't want to buy an entire kit with hundreds of the things. I see ebay has them for a couple of pounds. If it matters, what material would you recommend? Also, how long should it be? I'm guessing the length of the keyway on the shaft?

IMG_1271.jpg

IMG_1273.jpg

IMG_1275.jpg


Thanks again.
Cheers,
Phill
 

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