Getting a milling head ready for use

[choochoo_balooParticipant @choochoo_baloo]

No joy tonight, and I now have a pair of Jacobs wedges stuck too..

1. Tried the spanner on flats + tommy bar in back ring – wasn't budging. So stopped to prevent any damage.

2. Tried Jacobs wedges that I had lying about. The vice handle is now approaching static, hence the wedges are stuck, with no sign of breaking the MT2!

Simon et al, I have a feeling we're talking cross purposes, so please study these photos to confirm I've attacking the right parts.

What now?

Thanks chaps.

[Simon Williams 3Participant @simonwilliams3]

Hi again, couple of comments which might duplicate stuff you have already tried.

No we're not talking at cross purposes – and moreover you've worked out how to draw on a photo which is more than I have!

Firstly the ring with the tommy bar holes is jammed down tight as far onto the body of the chuck as it will go – compare my picture with the ring removed. At risk of a silly comment you have taken on board that this is a left hand thread? You should at the very least be able to turn the ring on the body – I bet someone has tightened this and bottomed out the thread thinking it is right hand. It isn't.

The ring should move up freely to contact the end of the quill/spindle – it is presently as far away from the spindle as it is possible to get it. If it was me I'd try a bit of heat on the ring to see if I could loosen it and get it to move. Don't overdo it – if you spit on it and it sizzles it's about right. Make sure you turn it the correct way not the right way!

Now you've got the wedges stuck it's irrelevant. But they'll come out if you knock them back with a suitable punch. A bit of 3 or 4 mm by 40 flat bar would do the job. Remember that a sharp crack with a light hammer (say 8 oz) will do more good and less damage than a heavy blow.

The wedges idea is the same principle, and I like the idea of squeezing them rather than hitting them. Having said that my inner waters tell me that a sharp crack with a hammer on one side with a large heavy lump of steel up against the other side to absorb the blow might well give a higher force than the vice can do. The clamping force of a vice isn't all that high. I've played this game with those wedges getting Jacobs tapers loose – its amazing how much force that taper needs to break its hold. It isn't just about force, it's also about jarring the assembly to shock it loose.

Have you tried giving the draw bar a smack (or two) with the wedges engaged?

Next plan is to try a bit of chemical warfare. Prop the head assembly on the bench so it is in the normal attitude, chuck down. Now find a plastic carton (ice cream tub sort of thing) and prop it under the chuck so the chuck can be immersed in cold water. We're not going to use cold water, we're going to go for a freezing mixture made of crushed ice (normal water ice) and a volatile solvent. Acetone is good, but I bet it would work with the contents of an aerosol of carburettor choke cleaner. Be careful, this mixture will give you frostbite so wear gloves.

Add enough crushed ice to cover the chuck, and add enough solvent to immerse the chuck in the cold liquid. Leave it to consider its sins for 15 mins of so, now try the extraction procedure with wedges and a few sharp whacks on the (loose) draw bar again.

If that don't hack it we're into surgery.

Good luck, let us know how it goes.

Rgds Simon

[Simon Williams 3Participant @simonwilliams3]

One more thing I've just thought of –

The backing ring is drilled on ts periphery in three places. In normal circumstances it would be sufficient to poke a tommy bar of just the right size into any of the holes and tighten the ring against the underside of the quill, and off you go.

Given this is turning into a bit of a struggle, you would be a lot better off with a proper C pin spanner of the right size. It's not difficult to make one out of a piece of flat bar say 10 mm thick by 60 mm wide. Chunky or what.

Machine a quarter of a circle of the diameter of the outside of the backing ring into the end of the bar, leaving a bit of overhang for the pin. Drill and ream a hole for the pin so it is radial to the end of the quarter circle cut-out, and pop in a pin the size of the backing ring circumference holes. I've used a bit of silver steel for the pin – you need something tough and strong.

It'd be a lot easier to show a sketch if only I knew how, but I've got one I made for something similar in the shed and I'll photo it in the morning.

The point of this is that you will get a lot more leverage on the proper spanner than on a simple tommy bar. I fancy the work of making a pin spanner of just the right dimensions is going to be less that dismantling the quill assembly which is where this is heading.

Good luck

Simon

[Michael GilliganParticipant @michaelgilligan61133]

Excellent idea, Simon

MichaelG.

[Grindstone CowboyParticipant @grindstonecowboy]

Apologies if I've got this all wrong – and I have no experience of these quills and chucks et al – but aren't those wedges between a screwed collar on the shaft and a shoulder on the same shaft?

I won't be offended if you tell me I'm being stupid

Cheers,
Rob

[not done it yetParticipant @notdoneityet]

GB,

If you are referring to the method I use to remove tooling from the MT sockets, I do that whenever a tool will not loosen with a ‘tap’ from a soft mallet. It works – the wedges go between the tool and the quill on the mill.

I’ve never (yet) ended with a jacobs chuck separating before the MT2 – although I am careful to not push my luck too much (I use both wedges and mallet).

I suspect you are correct, if referring to the pic above, where the wedges are likely the wrong size for the job in hand and are not fitted as I described above.🙂

[Simon Williams 3Participant @simonwilliams3]

Here's a picture of a home made pin spanner – it's not big enough for this application but you get the idea:

You'll note that the element where the pin goes through is a tangent to the radius of the cut away portion.

To return to the question of whether the wedges are exerting a force between the quill and the back of the chuck, here's a picture up its nose so to speak:

I'm concerned that sliding hardened wedges across the face of the quill taper could bruise the end of the taper itself.

NDIY makes a valid point – the wedges usually grip the arbour to pull it out of the taper in the back of the chuck. I assume that these wedges are clearance on the chuck taper?

Best rgds Simon

[Simon Williams 3Participant @simonwilliams3]

I'm just beginning to wonder if I've been leading you up the garden path.

That Autolock chuck is the one that uses a collet with axial pegs into the back of the body, whereas mine uses the collets with two ears engaging a slot in the sleeve nut. They look the same on cursory inspection, but are they?

Does anyone know definitively if the OP's particular chuck has a threaded backing ring, or is it indeed all one piece – which would explain why it won't undo!

I'm pretty sure there was a thread about recognising the different vintages of Autolock, Osborn Titanic and the like on here a year or so ago.

RGds Simon

[Mike PooleParticipant @mikepoole82104]

I notice that your vice does not appear to be fixed down so it is going to be difficult to tighten effectively. If you could stabilise the vice with a solid pile of wood and some long bits of studding through the bench then give the vice a good tighten after a can of spinach, if it has not yielded then a tap with a heavy copper mallet as Simon mentioned could provide the shock to get it apart.

Mike

[Nigel McBurney 1Participant @nigelmcburney1]

In my experience ,particularly removing taper keys from old engine flywheels the big single shock is better than lots of taps from a small hammer,in the case of the 2mmt taper ,the "anvil" to support one of the drill chuck wedges should sit on a really heavy block of steel,a light block on a wooden bench just bounces and absorbs the shock . I had to remove a similar Clarkson chuck 2mt from the universal head off an Elliott Omnimill ,initial hammer blows on the drawbar bolt did not work ,so to avoid damage I used some modified jacobs chuck wedges one end rested on a block of steel weighing about 50 lbs on the concrete floor then using a steel drift about 2ins by 1/2 in and about 6 inches long on the other wedge I held the drift onto the end of the wedge and hit the drift hard a 4 lb club hammer,first blow took up any slack in the wedges ,second blow got it free.Its the shock that frees it . I did not have to worry about the clarkson as I had found it was bent when I first bought the milling head, its the spindle that must not be damaged far easier to get a replacement Clarkson than a milling head spindle. A word of warning,When buying any type of milling chuck or cutter holder from a dealer always get them to show you that the holder runs true, if you buy at a boot sale or auto jumble then its your risk and that might be the reason why its for sale, I once over heard someone spouting off that morse tapers and up to 30 intenational can be bent but you cannot bend a no 40 int was wrong ,I have seen a large Clarkson Holder no 40 int with several thou of wobble, I thought it was a very cheap at a bring and buy sale but still bought it as the price was lower than the s/h price of the imperial and metric collets that were in the box with it,I just wanted the metric collets so sold the spanner,the imp collets and the spanner ,so got my metric collets free.

[ianjParticipant @ians]

I think Simon may be correct regarding the type of chuck. I've just fitted mine and with the threaded backing ring screwed up to the bottom of the quill there are about four threads showing.Might seem a bit obvious but have you tried spraying some Wd40 type lubricate down the quill?

[BazParticipant @baz89810]

Regarding type of Autolock chuck and does the ring unscrew, I can see etching on the chuck body in the photo, looks like Type something, does this appear to go under the ring, if so it may unscrew but I have never seen an old autolock with the threaded ring, I think they were introduced on the new style chucks. Old style had two pins on end of collet, new style the two large flats, would also look at the wedges, are they well clear of the morse taper diameter

[Grindstone CowboyParticipant @grindstonecowboy]

Ah, righto – I see now that the bit with the flats on is actually part of the quill

Thanks for the explanation.

Rob

[SteviegtrParticipant @steviegtr]

If this helps. The collar is in fact to make the taper more stable. Apparently only on the MT2 to give rigidity. As said above by others.

The collar unscrews upwards to snug up the taper underside. It was suggested that if this was screwed upwards, opposite to the position you have it in. Then once up against the taper, hold the spindle whilst tightening the collar against the taper collar. This will cause preload on the taper, ie try to pull it out. Then strike the draw bar with only the thread undone by the slightest amount, so that max threads are engaged in the MT2. Similar to trying to remove a ball joint from car suspension. The harder the clout the more chance of success. Obviously one must be careful as this is not an old car part but a 10mm thread being hit.

Anyway some more pictures I have just taken of mine.

In bits.

In bits.

Ring screwed down.

Ring screwed up.

Steve.

[choochoo_balooParticipant @choochoo_baloo]

Special thanks to both Simon W and Nigel M for patiently typing up their instructions.

Success! Tonight I finally broke the taper. Below account should help a future reader in the same situation.

• Chocked the S head on the concrete floor
• Spindle rotated so that wedges are vertical
• Hefty steel block as anvil just touched bottom Jacobs wedge
• 1/8 mild steel bar used as a drift on other Jacobs wedge
• One medium blow with 3lb lump hammer on the drift
• Autolock gently 'popped' off

No damage or S head surgery needed thankfully. So thanks again chaps. I do appreciate the input in helping a newcomer.

 

Next puzzle is the anatomy of Clarkson Autolock. It is stamped "Type C". I think this warrants a new thread though – to aid future readers who may also be struggling with their C type Autlocks.

Edited By choochoo_baloo on 30/04/2020 23:58:18

Edited By choochoo_baloo on 30/04/2020 23:59:13

[SteviegtrParticipant @steviegtr]

Well done Choochoo. Just remember when you put a MT2 in the head it only needs a slight nip on the drawbar. Regards.

Out of interest can you tell me the hp rating of the motor you have .

Steve.

[Simon Williams 3Participant @simonwilliams3]

Bingo! Well done, excellent result.

And congrats for applying a bit of science and hitting it in the right place.

(Like the joke: To hitting with hammer – £5

To knowing where to hit with hammer £105)

Best rgds Simon

[choochoo_balooParticipant @choochoo_baloo]

Posted by Steviegtr on 30/04/2020 23:58:33:

Out of interest can you tell me the hp rating of the motor you have .

Originally fitted 1/3 HP single phase.

Cheers.

[SteviegtrParticipant @steviegtr]

Thanks for that. It is the same as mine apart from someone has fitted a 3phase motor. Very old though, says made in the USSR. So must be from some time ago. Edit. Looks like it changed in 1991. So not that long ago. The head you have seems identical to the light vertical on my machine. The thing with the collar on your Clarkson, being fixed & not threaded eludes me. But I have only just started using mine so do not know much about them. Other than from other members.

Hope you get it fitted & working ok. Wish I had a spare head to experiment with. Regards.

Steve.

[old martParticipant @oldmart]

We were all holding our breath while you were struggling to remove the Morse taper. Now its off, make sure the tapers are clean before putting anything back on. Is that a threaded collar, or is it all one piece? If it turns out to have threads, they will be left hand.

[Howard LewisParticipant @howardlewis46836]

Don't know the machine, but hope that this may help in the future.

On my Far Eastern Mill/Drill, I made up an extractor for the drawbar.

This keeps forces within the spindle, without loading the bearings, and consequent risk of damage.

Removed the left hand threaded nut retaining the pulley to the spindle.

Turned the under side back for approx 3 mm

Piece of 3mm plate, drill / bore hole in centre to match the newly turned diameter on nut.

Drrill and tap two holes, symmetrical about the just bored hole. (I used 1/4 BSF for a 3 MT, so should be O K for 2 MT )

Make up similar plate, but with a central hole drilled/ tapped for forcing screw. Drill two clearance holes to match the tappings in the lower plate.

Reassemble nut, with plate on underside, to machine.

When it is needed to remove a fitting from the quill,

Slacken Drawbar by a turn or so.

Assemble loose plate, with central forcing screw, to the plate on the machine, and secure with two bolts /.setscrews. Tighten central forcing screw, hard. Taper should break. If it doesn't, a light tap on the forcing screw should suffice.

H T H

Howard

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