Stuck Morse Taper in Warco Major 3024YZ

I've recently got a used Warco Major Mill/Drill. I've had it in pieces and have just put it back together. When I picked it up there was an ER32 collet holder in the MT3 spindle, I think it's been in there a while. I tried the obvious step of loosening the drawbar bolt and giving it a tap with a small hammer but it didn't budge. Since then I've tried a bunch of things, still with no luck:

• I hit the drawbar as hard as I could with a larger 3lb hammer.
• I tried holding the tool down using the 32mm slots clamped onto the table and lifting the spindle back up with the mill handle, but the mill started to rock without anything happening.
• I tried locking the spindle and clamped a 32mm spanner to the table and pulled it down with the T-nut bolts. The spanner bent an alarming amount, but the tool did not release.
• I tried completely removing the draw bar and using a drift, but the gap is to large as there's no tang on the taper. I put a spacer in and tapped up against that, the drift got a roughed up edge from the force, but still the tool didn't move.

My failed attempt with the spanner, I'm worried that the force, particularly and non-downwards component, could have damaged the mill.

I've bought a larger drift which is in the post, although don't expect much from that. Apart from heating the spindle and using a drift / hitting the draw bar, I don't know what else I can do.I don't own a hydraulic jack but even if I did I don't know how I'd apply while the spindle is still in the mill.

Does anyone have further suggestions?

Repetitive taps on opposing sides with a hammer; doesn't need to be hard but you may need a lot of taps. Repetitive, and oscillatory, side loads are a classic way of loosening a taper. Which is why it isn't recommended to mill without a drawbar.

Andrew

Loosen the drawbar and start cutting it'll soon come loose then

Err, is that safe?

That sounds like something I can tinker away with. Any idea how many / how long I'd need to do this for before I find it will release? Should I try the odd tap on the drawbar as I go?

You could use a pneumatic drill to "hammer" it out using a lot of small taps. Preferred

The thread on the collet (M40x1.5) and the collet nut can be used to make a puller against the shoulder of the mill.

In order to avoid damaging the bearings if you're hitting the drawbar, I'd arrange come sort of support for the quill onto the main table.
Maybe some thick wall tube, to go over the chuck, and a couple of flat bars over the top of it.

I can't see how big the gap is twixt quill and chuck, but it is possible to get chuck extraction wedges.
Basically a pair of slotted wedges which you knock in from opposite sides.



Alternatively I wonder if tightly filling the gap, with a metal which has a high expansion ratio, and applying some heat might do the job

Bill

Edited By peak4 on 16/08/2022 23:14:33

Edited By peak4 on 16/08/2022 23:16:14

With my Chester Lux mill R8 taper, when changing tooling I use my air impact wrench which undoes the draw bar, (not overly tightly secured) and and loosens the taper. Place something to catch the ejected tooling safely - ask me how i know!

Robert Butler

Edited By Robert Butler on 16/08/2022 23:09:30

It looks at though you could employ some taper wedges like the ones supplied for removing drill chucks. You will probably need to make a pair as drill chuck ones will be too small.

Mike

i see Bill beat me to the wedge idea while I was composing 😀

Edited By Mike Poole on 17/08/2022 17:34:24

Short length of tube which bears on the face of the quill, the other end of which bears on the back face of the collet nut. Tighten the nut while holding the spindle to squeeze the tube up onto the quill - pulls the taper down.

If the OD of the collet thread is bigger than the OD of the quill, slip the/a spanner in between the tube and the quill to provide a bearing surface.

Well I wouldn't condone running it at 2000rpm but sooner or later you're going to have a tool come loosein the taper. I guess it all depends on what you regard as 'safe'. Some people won't use a 9" grinder full stop because they don't regard them as 'safe'. I'm more than comfortable with it.

Probably best to explore other avenues TBH, my reply was very much tongue-in-cheek.

I don't think that P R was suggesting running without bthe drawbar. merely slackening, to finger tight and taking a few cuts at low speed is likely to shake things loose.

If you did not want it to, it WILL happen.

Probably, the ER collet chuck was inserted, cold into a warm quill.

DON'T do that.!

If you choose to go for the method of using either wedges or packing behind the 40 x 1.5 mm collet clamping nut, to try to extract the chuck, having the drawbar slightly loose, and giving it a bash once the load has been applied, MIGHT break the taper loose.

If the taper moves even slightly, you have succeeded!

Howard

Tapping simultaneously on the sides of the extended quill in the area of the taper with a pair of copper hammers will bring it loose. Work around the diameter until the taper comes loose. Get the two hammers to strike at once so the impact expands the taper from two sides at once.

Steam fitters use this trick (with two steel hammers) to loosen up rusted pipework where tapered threads have seized solid. A pipe wrench with six foot of pipe on the handle and two blokes swinging on it will not shift rusted 2" pipe, but a 30 second belting with two hammers around the outside of the fitting and it comes loose by hand. Amazing to witness.

side milling with a slot drill type cutter, leave a tiny gap and it drops down safe

better than battering the snot out of it

True dat.

Correct I was not suggesting milling without a drawbar, just a loosened one.

A couple of observations:

With the tapping idea, would it not have to be on the inner, rotating part of the quill (i.e. the part into which the male taper is seated) to have any effect? Extending the quill will only expose the outer, non-rotating part and I do not think any effort on that will do anything.

The idea of the vibration is high-ish frequency, small amplitude and not much force. It is very much 'rattle it out' rather than 'beat it out'. Someone above suggested a pneumatic hammer. Another option is an SDS drill set to hammer-only. You can buy SDS to 1/2" BSP male adaptors and you can screw a sleeve onto this that will accept the drawbar or a drift that goes down the spindle. Bung up the hole in the chuck and pour some diesel down from the top a day or so before.

Instead of pulling on the collet nut, there is a good chance the chuck has a through hole, so just install the drawbar from below and use it to apply the pulling force against the pipe sleeve. As with pulling any taper, a combination of pull from below and tapping from above will assist.

I had the exact same problem with a 3-2MT reducer stuck in the quill of a Chester 626 mill. There is a thread on here somewhere but to summerise, I couldn't knock it out from above as there was no shoulder, it wasn't threaded so I couldn't use the drawbar. I couldn't vibrate or twist it out. Gentle heat had no effect and I used a can of freeze spray which also had no effect.

I ended up removing the quill and taking it to a small local engineering company. They tig welded the protruding part of the reducer to facilitate knocking it out from above. Whilst still warm from the welding it came out with a gentle tap.

The mill has been in use ever since and has not suffered any ill effects.

Hi, I'd go with Peak4's wedges idea myself and yes use two with the same taper, you can always give the drawbar a clout once you have the wedges locked together.

Regards Nick.

Likely causes one of more of:

• Cold chuck inserted into a hot taper causing an extra tight grip as the temperatures equalise
• Drawbar over tightened in the past, perhaps because the tapers are scored, galled or worn
• Chuck left in place for a long time allowing oil to gum or corrosion to develop.

Heat, penetrating oil, sharp tapping (avoids pounding) and vibration all tend to loosen tapers.

Sharply tapping the drawbar hasn't worked. Penetrating oil left to soak for a few days might help if the cause is gum or corrosion, but it may be difficult to apply to the joint and it removes lube from any bearings it gets into.

Vibration is good at loosening stuck joints and I'd try it first. Normally, mills are set up and used to minimise vibration, but in this case I'd do it all wrong. It's somewhat risky so keep clear of the cutter, wear eye protection, and be ready to stop. As this is off the beaten track I hope others will comment on the following suggestions:

• Loosen the drawbar
• Reduce rigidity by lifting the head as high as possible and fully extending the quill
• Reduce rigidity by holding a longish bar in a vice such that the cutter engages the protruding end
• Leave all the slide locks off.
• If you have one, use a long blunt HSS cutter. The cutter is likely to be spoiled.
• Take a series of cuts along the edge of the bar, adjusting rpm, feed rate and depth of cut to maximise vibration (chatter). The exact settings vary with the material and cutter, but the cut direction should be misaligned with the grip of the vice so the material isn't well supported in the direction of the cut. Climb milling usually causes the most vibration on small mills but try cutting in both directions.
• Might be wrong but I don't think bumping the cutter into the material is a good idea because the cutter might break. I also think protracted vibration is more likely to break a stuck taper than a few thumps.
• Stop immediately the joint comes loose - spinning two tapers quickly damages both of them.

Heat is almost guaranteed to work but it may be difficult to apply without dismantling the mill. Although heat is the Queen of dismantling methods I'd try vibration first because it's easier to do.

Heating the spindle, not the chuck, expands the spindle and tends to loosen the joint whatever is holding it together.

I think many repeated cycles of moderate heat and cooling are safer than one blast of severe heat. By moderate heat I mean a temperature below anything likely to alter the temper of the steel, say 100 to 200°C, below the temperatures that cause oxide colours to appear, and definitely not glowing! If an expert says disagrees, believe him not me.

Final advice. This sort of problem causes me to lose my rag and reach for a sledge-hammer. Resist the temptation to take extreme measures - slow but sure is unlikely to break anything

Dave

PS After posting I see others recommending wedges.  Good idea, and you can make them in the mill.  Making a wedge with a slack drawbar might be enough!

Edited By SillyOldDuffer on 17/08/2022 09:31:02