3MT quill

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3MT quill

This topic has 10 replies, 6 voices, and was last updated 20 August 2010 at 21:51 by Sub Mandrel.

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18 August 2010 at 16:16 #5151
Tony Jones 3
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@tonyjones3
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18 August 2010 at 16:16 #54410
Tony Jones 3
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@tonyjones3
Hi all,

I have a old milling machine with a 3MT quill, the problem is I cannot use a lot of my tooling in it as the 3MT tools must have a flat section that fits into the quill, is there a conversion that will allow me to use an ordinary 3MT and also pass the drawbar through.

Thanks.
18 August 2010 at 18:06 #54412
Bogstandard
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@bogstandard
You don’t mention what mill it is. But I doubt, if it is that way out, you would be able to get anything to convert it.

Is the spindle drilled all the way through from top to bottom?

If it doesn’t, then there is nothing you can do, unless you put a hole thru it yourself. Then it would just be a matter of getting a drawbar made and standard no tang tooling should fit.

I would say, because it only has a tang fitting, it is actually a drilling machine, not a mill.

On a drill, all the pressure is in a downwards motion, so a tang fitting is fine, on a mill, there are significant side loads on the quill, so it has to have a drawbar to stop the MT fitting from falling out. You will also find, that a drilling machine bearings will not stand up to the side forces required for milling, and would soon collapse.

Bogs
18 August 2010 at 21:11 #54413
John Stevenson 1
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@johnstevenson1
Is this an Arboga mill, they had a MT3 quill that takes tang tooling but the collet holders had a screwed ring that fitted over the chuck onto the spindle to stop it walking out.

These have a hardened spindle and can’t be drilled though because the gearbox is in the way.

John S.
18 August 2010 at 21:29 #54415
David Clark 13
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@davidclark13
Is this an Arboga mill, they had a MT3 quill that takes tang tooling but the collet holders had a screwed ring that fitted over the chuck onto the spindle to stop it walking out.

These have a hardened spindle and can’t be drilled though because the gearbox is in the way.

John S.

Reposted by David Clark

Thanks John
19 August 2010 at 09:17 #54423
Tony Jones 3
Participant
@tonyjones3
Hi, Thanks,

I did not discribe it well, ! the quill takes 3MT tooling and has a drawbar , the 3MT tooling must have flats at the end of the taper that fits in the quill to stop it from turning as well as the drawbar, my mill is a FRITZ WERNER 3.230, it is a big heavy machine and works well, I do not have a manual or anything for it.

Thanks
19 August 2010 at 10:33 #54430
Bogstandard
Participant
@bogstandard
Tony,

You will find that a 3MT is classed as a self locking taper, that is where if both male and female are in good condition, they will lock up almost solid just by pushing up on the taper.

That is how most MT quills work in milling machines, and so does not require the tang to tighten up, just either a method of locking the quill while you tighten up on the drawbar, or a spanner on your toolholder which will do the same sort of thing.

The tang fitting is also standard in most mills with an MT taper, that is so the mill can be used as a drilling machine using the larger sizes of drills that have an MT taper and tang. That allows you to quickly change drills by using a tapered drift thru the slots in the side of the quill to release the drill rather than having to undo a drawbar.

So you should find that your MT tapered tooling without tangs should work just fine using the drawbar you have.

But you must take care which type of thread is used on your drawbar, because tooling can normally come with two different types, and you will have to get another drawbar turned up with the other thread on, just so that you can mount either type into your machine.

Have a look at the top ones on here, it shows that you can order one of two types for MT3, one with a M12 thread or another with 3/8″ Whitworth. I would suspect your drawbar, as it is continental, to have an M12 thread.

Arbor threads

Just a warning, unless you have a self ejector on your drawbar, it can take some serious persuasion to get the MT taper to seperate, and I would suggest you invest in a good dead blow or lead hammer, to prevent damage to the drawbar top.

I hope this helps.
19 August 2010 at 11:08 #54433
Tony Jones 3
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@tonyjones3
Thanks,

I have made a couple of drawbars with different threads and use a dead blow/copper hammer to nock them free, the problem I have is , take for instance , a 3MT fly cutter ! it will not fit in the quill because the MT taper does not locate before the tool head hits the end of the quill, the reason being the flats between the taper and the tool head are not there on a lot of the tooling I have. also there are no slots in my quill to allow a taper drift.

Thanks
19 August 2010 at 13:13 #54437
Keith Long
Participant
@keithlong89920
Hi Tony

Are you sure the taper in the mill is 3MT? Brown and Sharpe tapers are virtually the same taper angle but a shorter length, if I’ve read the tables correctly, so would seat in the mill spindle. Even though the tapers are very similar as far as I know they are NOT interchangeable.

Keith
19 August 2010 at 14:48 #54439
Tony Jones 3
Participant
@tonyjones3
Hi Keith,

Yes it is 3MT, I have searched on the web for a manual, found one but they want over £100 for it, seems a lot to me.

Thanks,

Tony
20 August 2010 at 21:51 #54490
Sub Mandrel
Participant
@submandrel
Hi Tony,

Why not just grind two flats on each MT3 taper?

It shouldn’t spoil them for use in other machines.

Neil
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