When is MT2 not an MT2 arbor

[Andy CarruthersParticipant @andycarruthers33275]

Sooo, my mini mill says the arbor is MT#2 and I bought an MT2 22mm arbor but doesn't match – the quill(?) is far too long and has threaded end http://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/Slitting-Saws-and-Arbors/MT2-Stub-Milling-Arbor-22mm

I am probably having a senior moment – can anyone offer advice please?

Plenty more dumb questions where this one came from

[Andy CarruthersParticipant @andycarruthers33275]

[VicParticipant @vic]

The link shows an arbor for a slitting saw, is that what you wanted? It's threaded for a draw bar to stop it falling out.

[JasonBModerator @jasonb]

Should fit an MT2 equiped machine without a problem.

What make Mini-mill do you have and does other MT2 tooling fit OK?

Edited By JasonB on 15/07/2017 18:32:15

[RobboParticipant @robbo]

I have had a couple of these from Arc. The MT2 taper is the usual length, about 68mm. Do you have a captive draw bar in your mill which you need to engage as you insert the taper? If so is it 10mm?

[Tim StevensParticipant @timstevens64731]

If not 10mm or M10, the drawbar might be 3/8" Whitworth. Looks much the same (confusingly) but it is an imperial thread, and slightly smaller diameter. It was intended for use with inch-versions of a mill. Therefore, if your mill is calibrated in inches and thousandths, rather than millimeters and hundredths, this is likely to be the thread on your draw-bar. But it could be that you have no draw-bar at all (which is why details of the model would help us to help you0.

It could be, of course, that there is something else up the MT2 hole already …

Regards, Tim

[Andy CarruthersParticipant @andycarruthers33275]

Funny you should say that Tim, and being a complete novice it is more than probable I have made an error

​I don't have a manual for the mill nor have I found a manufacturers label otherwise I would RTFM which for other devices I have found very helpful in the past…

[Tim StevensParticipant @timstevens64731]

As you are a novice, you may find it helpful (in other cases) to know that there are two styles of MT2 taper fitting. Both have the same tapered body. One has an internal thread (M10 or 3/8W, see above) but the other has an extension called a 'tang' which forms a tab at the small end of the taper. This is designed for use in column drills etc, (and not usually for mills or lathes in hobby sizes) where the tang fits in an interrnal slot and ensures a firm positive drive. There is also a slot towards the small end into which a tapered tool can be driven to remove a stuck tapered tool.

Hope this helps

Tim

[BazyleParticipant @bazyle]

We may be able to help identify the mill from a photo. There are a few manufacturers that deliberately made non standard sizes to lock the customer to them for parts. It can be quite difficult to accurately identify a Morse taper that has been made longer or shorter than standard as just measuring the diameter doesn't tell the whole story. This can also apply to lathes.

[Andy CarruthersParticipant @andycarruthers33275]

Thanks all, I'll upload a photo in the morning

[Andy CarruthersParticipant @andycarruthers33275]

@Vic – yes, I did intend to buy the slitting saw version – I bought the blades at the same time

Here's the puppy – looks like there is an MT2 already fitted? which begs the question of how to remove it please – and yes, an idiots guide is recommended The good news is that I am a quick learner so it's not forever though it may feel like it for a while

Edited By Andy Carruthers on 16/07/2017 07:20:37

[JasonBModerator @jasonb]

On the top of the mill head is a black cylinder about the size of an old 35mm film container with a red/yellow sticker on it

Pull that off and it will reveal teh hexagonal end of teh brawbar.

Hold the collet chuck that is in the spindle with one hand and use a spanner to loosen the drawbar about 1/2 a turn, may need a spanner on the collet flats if it is tight

Take a copper hammer or put something ontop of teh drawbar nut and give it a blow with the hammer which will break the grip of the taper.

You can now fully undo the drawbar while holding the collet so it won't drop and out it will come.

To fit new arbor push it up into teh spindle so it just grips and then screw in the drawbar and tighten.

Edited By JasonB on 16/07/2017 08:05:43

[BazyleParticipant @bazyle]

Looks like you got a 'free' collet chuck with it which is an essential tool too. When you get it off take a couple of photos of the collet that is in it if there is one placed on a rule or graph paper for dimensions and we can try to identify the collet size you need.

[Frances IoMParticipant @francesiom58905]

looks like a Sieg SX1L as supplied by Arc Euro (tho they state the long table SX1L is exclusive to them – their ‘house’ colour is red) but later fitted with the stepper motors to drive the head and table using what looks like ball races (rather expensive mod which if fitted to the table requires John Stevenson style ‘butchery’ -as described in a thread on this forum some time ago – may be it got a repaint at the same time

Edited By Frances IoM on 16/07/2017 09:01:41

Edited By Frances IoM on 16/07/2017 09:05:32

[Michael HornerParticipant @michaelhorner54327]

Hi Andy

Don't overtighten the draw bar, I have heard of tales of woe when some MT's won't release.

I think it is finger tight plus 1/4 of a turn. I use R8 on my mill so not over familiar with the exact torque.

Cheers Michael.

[John CParticipant @johnc47954]

Andy,

Check your message box – envelope icon and 'INBOX' on the very top line of the page.

Rgds,

John

[VicParticipant @vic]

Just a thought but don't some of these small mills have a self extracting drawbar? If so hitting it with a hammer may be a bad idea.

[Frances IoMParticipant @francesiom58905]

the Sieg SX1 needs a light hammer blow (or moderate if you entered the arbour when warm and the machine has subsequently cooled down – don’t leave machine set up over night if you wish to change tooling in morning) – make a copper headed small mallet to deliver blow

check the thread as both 10mm + 3/8 whit draw bars exist (my machine came with both) use of the wrong one can wreck an arbour –
have also come across a home made UNC threaded arbour not sure if this means that there are commercial UNC arbours available

Edited By Frances IoM on 16/07/2017 11:31:20

[HopperParticipant @hopper]

Sooooo…… if you haven't yet managed to take the original collet chuck out of the mill spindle, how do you know the new slitting saw arbor will not fit???

[DMRParticipant @dmr]

Andy,

Its a fairly generic pattern of its day but the colour says its a Chester UK badged machine they called a Cobra Mill from about 10-12 years ago. I've probably got a spec somewhere. The stepper motors are extras and it seems to have a few standard bits missing or detached.

It is MT2 and it will be an all metric machine in its fittings. The height scale says its an all metric machine on its slideways too.

Edited By DMR on 16/07/2017 16:11:35

[Frances IoMParticipant @francesiom58905]

it looks very heavily modified – the quill control seems to have gone with I assume fine control available via the ball race controlling the head – some extra head room seems to have been added by riser blocks – the quill lock screw has been replaced by a more convenient handle made possible by loss of the quill arm – suspect makes drilling more of a tedious affair tho.
using a ER25 collet avoids some of the time wasting head movements but a collection of stub drills will be found very useful!

The early drives had a somewhat of a reputation for burn out if overloaded – possibly a later design of control board is used – the high-low speed control is also somewhat of a kludge there is a Graham Meek mod that seems to correct this (tho not sure where this is now published) – tramming the head is somewhat of a bind so avoid angling the head unless totally necessary

Edited By Frances IoM on 16/07/2017 17:02:14

[SillyOldDufferModerator @sillyoldduffer]

Whilst waiting for paint to dry I took a few photos:

1. The top-hat removed to show the drawbar.

2. Spanners used to slacken (not remove) the drawbar:

3. Slacken 1 turn or so:

4. Use a copper headed hammer or something like this to protect the nut:

5. Sharp Tap with a hammer to release the MT taper below. (Aluminium buffer tool not shown because I only have 2 hands.):

6. Unscrew the drawbar by hand whilst holding the MT tool. The tool, in this case a collet chuck, drops out of the spindle.

7. Normally the drawbar stays with the mill but this is what it looks like removed:

The drawbar screws into the taper end of the MT tool and pulls the taper into the spindle. Nip the drawbar just tight enough to hold the tool. Gently does it, if over-tightened the tool is difficult to remove and you may damage the thread doing it.

The pictures just confirm what the others have been saying. If taking the top-hat off as shown in Photo 1 doesn't reveal a nut, you may have a self-ejecting drawbar. I don't know how they work: don't hit it with a hammer, ask again! Someone else will help.

Dave

[JasonBModerator @jasonb]

Posted by Hopper on 16/07/2017 13:05:51:

Sooooo…… if you haven't yet managed to take the original collet chuck out of the mill spindle, how do you know the new slitting saw arbor will not fit???

Sounds like Andy was trying to put the MT2 arbor into the collet chuck

[Ed DuffnerParticipant @edduffner79357]

S.O.D is your draw-bar setup ok? I also have a Warco and the collar with the two flats goes over the end of the draw-bar to lock down on the shoulder, at least on mine it does. ???

Cheers,
Ed.

3rd time posting this (PC keeps freezing).

[Frances IoMParticipant @francesiom58905]

the Sieg mills have a hole in side of lower quill with a small bar tool attached to a plastic handle to insert in said hole to lock the arbour whilst the draw bar is unscrewed a little before being tapped gently (or otherwise) by copper mallet) then fully unscrewed by had – normally for tightening or release hand held is sufficient but sometimes the bar is needed

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