Soft end MT mandrels - soft att the way through ?

Hi,

I'm going to build a lathe backstop for my Boxford and want to use a shop-bought MT3 soft end mandrel for the nose piece.

I've found apparently suitable types at Arc Eurotrade but need to know whether they're just surface hardened on the taper, or whether that part is hardened all the way through ? I will need to bore right through the mandrel to take the stop rod and also thread the end for a drawbar so if they are hardened through the body that's a no go for my application.

Anyone drilled through one of Arc's MT soft end mandrels and know the answer ?

Thanks,

Mike

Hello Mike,

Welcome to the Forum, I hope you find many useful things to engage your interest.

In answer to your question, unless I am going stupid in my old age, I can't find soft end MT stubs in the Arc catalogue.

They do sell open ended MT sleeves which might be a solution for you, they are quite useful in other applications for locating drawbar tooling in the smaller MT sizes as well.

Regards

Brian

Hi Brian,

They are here on Arc's site : **LINK**

Sleeves would be no use for what I want.

Mike

Hello Mike,

I was looking at the paper catalogue, they don't include these in that, or at least the in the copy I have. #9

So, sorry, I can't help you, but of course Arc would know the answer. Why don't you call them? They are very obliging.

Regards

Brian

Edited By Brian Wood on 18/06/2015 13:46:03

Just got a new ARC one out the drawer.

Soft in the core, up to a point.

1/4" went thru OK as did the 5/16" follow up drill but the 3/8" drill in the picture went thru but was starting to hit hard spots at the small end of the taper.

Hi John, sounds like my idea of threading the small end M14 x 1.5 to suit some M16/M10 hydraulic pipe I have is a non-starter then. I'll have to revert to Plan B which is to use an M12 stud in the end of the pipe and drill through it 8mm. Shame as 10mm would have made for a sturdier stop rod and I want it for locking screws when turning them down.

Many thanks for your help and to all who answered,

Mike

Let's see some pictures when it's finished Mike.

Hi Mike arceuro has MT3 blank end arbors 1.25" 1.5"" each with3/8" thread 40mm with12mm thread .

I have the metric one and have made a hollow draw bar with 12mm bolts each end ,drilled 8mm,and hexagon heads turned down to fit in tube,(leave shoulder to line bolt up ) .Bore conical hole in bolt head so thin tube will find easy way through.. You will have to make all to fit in the spindle before soldering together.

Hope this makes sence Maurice

Blank end arbors are shown in Arc paper catalogue No 9 on page 14 - half way down on the right-hand side of the page.

I'm afraid so Mike. I was machining one yesterday and found that the shank is through hardened and the hardness protrudes a bit into the soft head and gradually fades out.

They're good for making a bit holder but not much else. You cannot drill through with normal drills.

If you could find an old morse shank drill it would be the other way around. You could part off the hard flutes and have a soft shank.

Oh dear, thank you Lampton for correcting me, I overlooked them completely.

Ah well, Anno Domini or something

I have a feeling the offerings from Chronos are more forgiving regarding hardening in the central core, but it is a while since I bought any.

Brian

Edited By Brian Wood on 18/06/2015 17:30:52

Capstan,

See my picture above, this is one I did today to test the current batch that ARC has.

All the drill were normal HSS drills but long series.

A while back I was trying to drill into a "soft" blank arbor and thought I'd found a really hard one - as I just could not drill into it. However, closer examination revealed a piece of 3mm drill broken off in the centre hole - courtesy of some careless person somewhere in foreign parts. Fortunately - I was able to remove it with thin nosed pliers - but it really had me going for a while!

Sorry - a wee bit off topic...

IanT

Mine destroyed the edge of an HSS toolbit with 10mm of the soft end still to go. It wouldn't surprise me if they vary.
I still recommend that Mike uses the shank of an old drill.

Don't get me wrong though. These blanks are a godsend and I still have a morse 2 one I'm going to drill just deep enough to be a boring tool holder.

Quite so, I bought a half centre from Chronos many years ago. It wasn't hardened at all, so at least it would have been easy to drill. It was, of course, replaced immediately.

Andrew

I've never had any problems machining the 'soft' end including drilling into the first part of the shank.

Neil

Hi Frances, thanks for your intriguing post. I did buy the MEW I found in the shops but it was the special edition and doesn't have any references to letting MT adapters down. Can you quote the relevant part for me ? Or is it really just as simple as baking it at 250 degrees C for 30 minutes and letting it cool slowly in the oven ?

Thanks again,

Mike

Would it not be a good oppotunity to have a go at making a taper. When I first got my lathe, one of the things I did with it was make drive centres for wood lathes in MT 1, 2, and 3, and live centres.

Ian S C

250 is nowhere near the range for annealing carbon steel.

**LINK**

**LINK**

It will need to be a dull red hot.

If it is not done in an oxygen free atmosphere, the surface will suffer too.