MT2 to MT3 taper adaptor removal

[hunter27]

I bought an used milling machine last weekend, I have never used one before, messing about with it today I fitted the collet chuck in the spindle but it is a MT2 and the spindle is MT3. The machine came with lots of bits including the collet chuck and a MT2 to MT3 taper adapter which I used.
I know you can already see what's coming next

After making some chips I loosened the drawbar and the chuck came out fine but the 2 to 3 adaptor didn't. first I thought a thicker bar down the spindle hole to drift it out but the spindle bore is smaller than the adaptor, then I thought about a tapered wedge in the spindle side hole but the adaptor doesn't come up that far. Luckily I slid a round headed bolt up through the adapter to sit on its top edge and slid another bolt up alongside it to stop it slipping off then drifted out the adaptor. How is the adapter supposed to be removed from the spindle?
Cheers.

 

[Tigman]

Can we see some pictures ?

 

[Tigman]

If the drawbar releases the MT2 chuck then surely the other MT3 taper is part of the machine ? Or am I barking up the wrong tree ?

 

[hunter27]

Not much to see now as I managed to get it out, the adaptor is just a smooth taper inside.
The machine also came with a another collet chuck installed that was MT3.

 

[Agroshield]

What is the bore of the spindle? What is the drawbar diameter?

You could glue a washer onto the top of the adaptor such that something the spindle bore diameter will drift it out, but with a hole in it to pass the drawbar.

A drawbar for MT2 tooling should be smaller diameter than for MT3 tooling. You could even make a next-size-down drawbar for the times you use the MT2 in the adaptor, with a reducer in the MT2 tool, which would give plenty of area to drift the MT3 adaptor out.

 

[Tigman]

In my head the mt2 chuck should have drawbar to hold it in which would in turn hole the MT3 in place , when knocked out if the MT3 doesn't shift you need another drawbar to knock that out ? Is that right ?

 

[Agroshield]

...when knocked out if the MT3 doesn't shift you need another drawbar to knock that out

I think the issue is that the hole in the small end of the MT3 to MT2 reducer is larger than the hole thorugh the machine's spindle.

So the largest thing that can ever go down the spindle does not contact the reducer.

----

An improvement on the glued-on washer above would be a top hat washer. Minimal clearance hole for MT2 drawbar, with a chamfer to guide the drawbar into it.

 

[hunter27]

Agroshield
Quote I think the issue is that the hole in the small end of the MT3 to MT2 reducer is larger than the hole thorugh the machine's spindle.

That is exactly how it is.

The spindle bore is just over 12mm almost down to the MT so with the MT2 out the 12mm draw bar slides through the MT2 to 3 adaptors smallest end which is 16mm.

 

[mcostello]

Has anyone there over the pond ever used a piece of key stock with a 45° chamfer on 2 ends to pull a bearing out. I cannot make a picture right now and cannot use CAD. The key stock needs to tilt into the hole and bring up a rod through the spindle bore to be tapped on. Anyone express this better than Me , would be appreciated.

 

[Turbo]

Could you add a bit to the top end of the adaptor sleeve so that it reaches the side slot.
Then you can get it out the normal way with a mt drift.

You could also use a spanner on the flats, they normally come out if you twist them.

 

[hunter27]

Could you add a bit to the top end of the adaptor sleeve so that it reaches the side slot.
Then you can get it out the normal way with a mt drift.

You could also use a spanner on the flats, they normally come out if you twist them.

I did try a spanner on the flats giving it a gentle tap while holding the spindle but it was stuck and I was scared I would deform the end. I don't think there is room to extend the adaptor whilst allowing the drawbar through but I will check. I was wondering if I made a new drawbar with a slight ridge to stop it fitting through the adapter would work but would have to be slid in from the bottom upwards.
Thanks.

 

[Turbo]

Have you a MT3 sleeve or drill bit with a tongue on it for using with a MT drift?
Measure it and see if there is enough left after taking out the width of your drawbar.

 

[hunter27]

I have just tried a simple approach after further measuring and it seems to have been successful. I turned a brass spacer 16mm long with a hole through it to take the drawbar, it sits on top of the adaptor so now it is visible through the spindle side slot. I am surprised this is not a very common problem and thought there would have been an obvious solution that I was missing.
Thanks for all the suggestions.

 

[gaz1]

i have a screw device on mine

something like this

3MT/2MT Through Hole Reducer - Metalworking tooling

www.warco.co.uk

 

[hunter27]

i have a screw device on mine

something like this

3MT/2MT Through Hole Reducer - Metalworking tooling

www.warco.co.uk

That's a good idea.

 

[gaz1]

what you have is temporary so use it like that

but buy the mt3 instead if that thread ever fails its going to be a right git to get out

 

[RichardM]

I have a mt3 to 2 reducing sleeve which is threaded for a drawbar. Is your reducer threaded?

 

[Agroshield]

I have a mt3 to 2 reducing sleeve which is threaded for a drawbar. Is your reducer threaded?

Using one like that, how is the MT2 item retained? It would need two connections, one between the MT2 item and the reducer and one more between the reducer and the machine spindle.

 

[pressbrake1]

I’d make a stepped thread drawbar

 

[Agroshield]

I’d make a stepped thread drawbar

Could you explain how that would work please. To me, I can see a problem if the thread pitches of the MT2 and MT3 items differ. But I can also see a problem if the thread pitches are the same (how does the MT2 pull into the MT3). If the pitches were the same, the MT3 would need a non-standard thread (finer than normal pitch for its diameter).