Milling collet arbor jammed in milling machine

[JulianParticipant @julian]

First of all, very many thanks to ALL of you, for taking the trouble to reply. I’ve been working away all week, so this is my first chance to say thanks. I’m going to try and make the wedges, as suggested by Peter. However…. I’ll have to use the mill to make them …. so perhaps I’ll leave the draw bar off when I start the milling! Using all the precautions suggested by some of you.

I’ve never been a professional engineer, just read books to gain what little knowledge I have so far, so any H&S issues are on my own head.

I hope the bearings won’t be so shot that I can’t do the milling.

With regards to over-tightening the drawbar; when I used the collet chuck originally, it was in my Boxford lathe and I tightened it just as hard then – but it used to pop out easily from there. But my boring head, also 3MT, pops easily out of both the mill and the Boxford – so I can’t fathom the logic. Anyway, if I get the b***** thing out, I will relieve the middle three fifths as suggested by Circlip.

Once again, many thanks to all and I’ll let you know (later this week with any luck) how I get on.

Best wishes,

Julian

PS any of you more-skilful–than-me engineers live near Bristol? !

[mgjParticipant @mgj]

Not that near Bristol- Sturminster Newton – but not a million miles if you are pressed and need access to a machine for a specific job. PM me if necessary.

 

You are quite safe –  my mill has an R8 taper so you won’t jam anything in it. .

 

M.

[John Littler 1Participant @johnlittler1]

Seems my second post went into the blue yonder, namely. if your ZX 15 does have a slot through the quill, then morse taper extraction wedges in sizes 1, 2 and 3, my Chester Champion ( old Type) is a No 3, are available v cheaply from the usual tool suppliers.

[JulianParticipant @julian]

John, my ZX15 does indeed have a slot for an MT3 drift, but I didn’t have one, so I made one out of mild steel. Unfortunately, when I whacked it into the slot the mild steel smudged and the jammed chuck didn’t move!, Now I don’t know whether to order a proper drift, or whether to go ahead tomorrow morning and try to make the forked wedges as suggested by Peter.

I think trying to make the wedges will be useful – it’ll tell me how damaged the machine is, and if I’m successful, the wedges will be useful and the least damaging way of extraction.

So tomorrow’s the day! I’ll report on progress (or not) as soon as I can.

Thanks again for all the help so far.

Julian

[chris stephensParticipant @chrisstephens63393]

Hi Julian,

A tiny word of caution re. the double wedges, depending on how your chuck is attached to the Morse taper, using the wedges might just remove the chuck and leave the other bit still stuck in quill. I would suggest further trials with John’s wedge, only use a proper one and hit it with a sharp blow with a big enough hammer. When you buy one you will note that there is a curved side and a flat side, the curve side goes upwards to match the recess, while the flat side mates with the Morse taper.

Best of luck, lets us all know what happens we are all waitng with baited breath. 

chris stephens 

[Peter TuckerParticipant @petertucker86088]

Julian,

All MT mills will have a slot for a drift; however my meagre experience is that the drift dose not shift a tight taper. My previous cautionary note about using the mill without a draw bar was not H&S related, I recently forgot to install this and had the arbour come out ;chewed the work horribly, broke the end mill, scared the arbour closing nut, I had expected scaring to the male and female MTs fortunately there was none.

I think I may be able to explain the physicists behind David’s  caution against having the draw bar partially unscrewed, if (when) the arbour comes free the tool will still be against the work and will slow it however the draw bar head could contact the spindle and rotate under power thus screwing the MT back home with some force.

If your chuck has been designed for milling it should be monolithic with the MT otherwise it could separate while milling.

 

To any who may crave a spell checker, why not write your posting in your word processor programme, spell check, copy, and past to the posting box. I have.

 

Peter.

[chris stephensParticipant @chrisstephens63393]

Posted by chris stephens on 21/09/2009 22:32:39:

Hi Julian,

A tiny word of caution re. the double wedges, depending on how your chuck is attached to the Morse taper, using the wedges might just remove the chuck and leave the other bit still stuck in quill. I would suggest further trials with John’s wedge, only use a proper one and hit it with a sharp blow with a big enough hammer. When you buy one you will note that there is a curved side and a flat side, the curve side goes upwards to match the recess, while the flat side mates with the Morse taper.

Best of luck, lets us all know what happens we are all waitng with baited breath. 

chris stephens 

 PS  Had a rethink, if chuck is made to proper standards (regretably not always the case) the chuck and taper should be screwed together or made as a solid one piece. I must have been thinking of drills again, blame lack of sleep!

[FunnyturnParticipant @funnyturn]

Does that explain the’ physicists’ behind David (amongst others)!!

 

Brian

[chris stephensParticipant @chrisstephens63393]

Posted by chris stephens on 22/09/2009 10:42:55:

Posted by chris stephens on 21/09/2009 22:32:39:

Hi Julian,

A tiny word of caution re. the double wedges, depending on how your chuck is attached to the Morse taper, using the wedges might just remove the chuck and leave the other bit still stuck in quill. I would suggest further trials with John’s wedge, only use a proper one and hit it with a sharp blow with a big enough hammer. When you buy one you will note that there is a curved side and a flat side, the curve side goes upwards to match the recess, while the flat side mates with the Morse taper.

Best of luck, lets us all know what happens we are all waitng with baited breath. 

chris stephens 

 PS  Had a rethink, if chuck is made to proper standards (regretably not always the case) the chuck and taper should be screwed together or made as a solid one piece. I must have been thinking of drills again, blame lack of sleep!

 PPS just had another rethink (thats what happens when you wake up) to use a wedge in the slot, you would have to insert a sliver of metal to protect the end of the threaded hole. If you don’t, then the wedge would not have a smooth surface on which to work and would just case harm to both parts.

[Robert MullanParticipant @robertmullan69263]

“To any who may crave a spell checker, why not write your posting in your word processor programme, spell check, copy, and past to the posting box. I have.”

 

Obviously spell-checkers are not foolproof…. 

[CirclipParticipant @circlip]

Aw that’s what might go wrong Peter? Wish I’d thought of that, too subtle for us in the Fxxxwits brigade. 

 

  Regards  Ian

[Ian S CParticipant @iansc]

The taper drift through the shaft only works on a drill chuck with a tang on the end of the taper,the milling chuck has no tang but unlike the drill chuck that is attached to its tape by a Jacobs taper in the chuck its self,the milling chuck’s taper is part of the chuck its self,so the two wedges will be ok,or the wedge device used on motor car suspension-no strain of hammering,just tighten the bolts.IAN S.C.

[John Littler 1Participant @johnlittler1]

Ian, a good point, my milling chuck extends into the slot by 3/8″, so a taper wedge works, but it’s worth checking first, cos if it doesn’t, friend Julian will end up with a stuck drift as well!.

I should also have advised that the quill, and the head on the round column should both be firmly  locked before the hammer blow.

As regards the thread in the chuck, (Chris’s point), my chuck has a counterbore at the top end, and therefore a nice smooth land on which the wedge can slide, but again, worth checking.

My wedges (commercial) are also hardened ( and presumably let down a bit, or they would break), so I’m not surprised that MS just burred up.

I would re-iterate that the wedge should not be “beaten to death”; it’s a good sharp blow that does the trick, just like cracking track rod ends on the car. You can, of course, if you have one big enough, use a fork ended compression tool around the quill, with suitable protection for the quill, to initially push the wedge in tight between the chuck end and the top of the slot, when a good smack with the hammer on the bolt head has always worked on track rod ends for me, and will be just as effective on the mill, but there is now another unit to fall onto the table!!. You will get there!

 

 

 

[mgjParticipant @mgj]

Depends a bit on exactly where the slot is placed, but for sure you don’t want to go beasting the top of the taper, then expand it, and find it is imperially jammed – which it may be already..

 

I’d be inclined to screw or palce a bit of steel in there above the millling taper. Copper/brass or any of the soft metals will deaden the shock and its shock that needs to be generated. Get the wedge tension on, and then apply a bit of a tap from a drawbar type thingy from above in the direction you need the chuck to go, after warming the spindle (not the quill or chuck).

 

If that fails try the vibration system.

 

If that fails its a new spindle and bearings

 

As for the physicists – hopefully one won’t be caught by surprise, hopefully the drawbar is loose and clear of the head, hopefully you will be a minimum revs, hopefully you’ll have a bit of wood between chuck and bed, hopefully the drop permitted will only be about .25 of an inch so all is contained, hopefully one will be near the e-stop/isolator, and hopefully one will be ready to wind said chuck out if hte work a bit quick. One can of course wait for a accident to turn into a drama if one wishes.

 

Rules as they say, being for the guidance of the wise and blind obedience of fools.

 

[chris stephensParticipant @chrisstephens63393]

Hi Guys,

My, isn’t this fun!

The wonderful thing about these sorts of sites/forums or is that fora, bet spell check does not know, is that someone will come up with the answer. Ask any dozen engineers a question and you will most likely get 15 answers, some will work some wont. I have to say that one should not come up with an answer without being in full command of the situation. Had I known that there was a slot for a wedge, I would never have suggested the “rattle” method. It is one of those things that had I been on the spot all would have been clear at first glance.

 

Now Circlip, I don’t actually think you were being accused of being a ****wit, as you were not advocating warp speed or any other speed, as you did not like the method. I think that description was for people with no sense of  “feel”, and I am quite sure that you do have one.

 

Meyrick, the voice of reason, well put., if a tad sarcastic. A man after my own heart.

 

Anyway, I think we should be civil to each other, even if we disagree, it’s just not that important, after all its just a hobby . 

chris stephens 

 

[mgjParticipant @mgj]

Well it wasn’t me that said that about rules- someone much wiser. Dr Johnson I think.

 

And I agree entirely with your suggestion as to who may or may not have had whatever kind of wit. Certainly not Circlip (whom I am still blessing in fact as I sedately cut out brown paper gaskets. ).

 

As for this problem – I hope otherwise, but it sounds, given the (severe) hammering the top of the taper has had, that it has been expanded or bruised in some way.  It could well be that one should be looking for a press of many tons. Once you get into bashing bits of machine tool with lump hammers you tend to be in trouble!

 

I hope I’m wrong, but it all sounds a little Neanderthal to me – I have a little 4oz ball pein in the workshop, and it makes me wince when I tap anything with that, without an aluminium drift in between.  Nor do I think I have ever needed to………..

[JulianParticipant @julian]

IT’S OUT !

After thinking about the 15 pieces of advice from 12 engineers  I decided to go for the drift in the slot, for a second time, but with a drift with a very slow taper. So I made one – using the very battered milling machine to mill the sloping side. It’s 5 inches long. I rounded the top with a file, to match the round top of the slot, and I greased it. Then I worried about the sideways impact to the quill, so I turned the whole head through 90 degrees and supported the quill underneath with a length of 4 by 4 softwood, put my home made drift in and started tapping it in. It took a fairly hefty bit of clouting, but there was a lot of the drift sticking out of the bottom so I was confident I could hit it back out if necessary, and so I kept on – and bingo, out popped the chuck. To say I was chuffed is an understatement!

Finally I went back to the milling job which I was doing when it all went belly up, to see if the machine still worked decently – and it does. Well, insofar as I get an acceptable finish. But there is a sort of yyyynnnnggggyyynnngggg noise under load, so I guess that means that a bearing or two is a tad the worse for wear after the sledge hammering it received. Looking at the exploded view diagram, there appear to be 5 ball races supporting the spindle, so watch out for a new thread shortly, concerning advice on replacing bearings……..

So, once again, very many thanks to all of you for helping me out of a hole. I’ve picked up a lot of useful knowledge along the way, and will never use a sledge hammer on my machinery again – not even a lump hammer!

Best wishes.

Julian

PS should I send off to Warco for a set of bearings, or extract and check them all and just change the noisy ones?

[chris stephensParticipant @chrisstephens63393]

Hi Julian,

May I be the first to congratulate you on your successful dentistry, erh, extraction.

The difference between an expert and an amateur is knowing just how hard to hit things with a club hammer to get the right results without bu**ering things up even more.

Again well done

chris stephens 

[chris stephensParticipant @chrisstephens63393]

Hi again,

Forgot about your PS about bearings.

 

With all due respect to Warco, I would buy bearing from a bearing factor. I suspect it is not in Warco’s interest to stock the very  best quality bearings, but “generic” ones. Going to a bearing supplier you can often choose the quality and therefore the price, and good bearings can be pricey. Chinese bearings as, usually, fitted as standard are not noted for there quality..

There is a bearing supplier who regularly advertizes in ME, who might be able to help without confusing things too much.

If I have done Warco a disservice I apologize, I have had nothing but good service from them.

chris stephens 

 

[Peter TuckerParticipant @petertucker86088]

Good on you Julian, best of luck for the future.

 

Peter.

[John Littler 1Participant @johnlittler1]

Good one, happy milling

[CirclipParticipant @circlip]

Next problem Julian, a small word about hammering the old bearings out – – – – – – –

 

   Regards Ian.  

[JulianParticipant @julian]

Just to let all of you helpful engineers know the latest position:

Using the mill after getting the jammed collet holder out, I “discovered” – as many of you suggested –  that I don’t have to screw up the draw bar very tight at all, and that it does indeed tap out very easily with a tapered drift if you haven’t over-tightened it! Which just shows that you can’t learn everything by reading books and magazines. You have to do things, and make mistakes.

Anyway, the rumbling, vibrating and oval holes which the damaged mill produced quickly became unacceptable, so now the mill is stripped right down, the four ballraces are out – it was the big one at the top which supoports the quill in the casting which was shot to pieces by my sledge hammer. I’ve bought the four new ball races, circa 40 quid for top-of-the-range non-chinese ones, and hope to reassemble the whole thing tomorrow afternoon – if I can remember what went where, and which way up!

I’ll let you all know how that goes, if you’re still interested!

Once again, thanks for all of the technical and moral support when it was all bad.

Best wishes.

Julian

 

[mgjParticipant @mgj]

Well, if you do get any spare bits, just be sure to tip them in – they’ll find their own level somewhere.

 

Missed this one – so belatedly good for you. Now you do know your way around the machine, you’ll be a lot less frightened of it – thats for sure.

 

Oh and Chris, your nearest supplier of good bearings/belts/ power transmissions helicoils, oil seals etc, if you need him is on the Houndstone Trading Estate. (with apologies to Grannies if necessary) They are very good and will get bearings ground to non standard sizes etc.  Premier Power Products.

[chris stephensParticipant @chrisstephens63393]

Hi Meyrick,

Re Houndstone Trading Estate, wish that they were the nearest, but I am in NW London!

Thanks for the thought though.

chris stephens

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