Spindle nose size

[RobonthemoorParticipant @robonthemoor]

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[RobonthemoorParticipant @robonthemoor]

I have a MK practical 1550 lathe & I need to centre the tail stoke to the centre of the spindle, I have taken the chuck off & taken a measurement @ the end of the nose 44.25mm & at the back it tapers down to 43.25mm. In the manual it words Spindle nose D1-4" or A2.4". Nose MT3 bore 1-5/8" can any one tel me the correct size for a tapered centre for this size taper please. Rob

[John Stevenson 1Participant @johnstevenson1]

Think you have measured it wrong.

It is a D series camlock and if the book says D1-4 probably is but a D1-4 if 63.5mm at the largest part of the taper.

No D series is 44 odd mm

[RobonthemoorParticipant @robonthemoor]

Yes point taken, but the Manuel gives 2 figgers A2.4" as well, so could ether be fitted? what is A2.4" ? And it states 1.5/8" I measured it with a bore gauge.

Rob

[John Stevenson 1Participant @johnstevenson1]

Read the bottom of this page.

You measure across the tapered register, not the bore. The bore size has nothing to do with the chuck.

**LINK**

An A series chuck is a bolt on table just above the bottom link I have given.

[Alan .204Participant @alan-204]

Don't understand what you mean John, Rob's measurements are the inside of the spindle, have spoken to him and he measured it three times so that should be ok, what to MT tapers go up to.

Al.

[Alan .204Participant @alan-204]

Don't understand what you mean John, Rob's measurements are the inside of the spindle, have spoken to him and he measured it three times so that should be ok, what to MT tapers go up to.

Al.

[Rick Kirkland 1Participant @rickkirkland1]

Rob if its a D1-4 spindle nose it's 100 to 1 that you need a number 5 morse taper sleeve to reduce down to a 2 or 3 MTcentre

Rick

[Alan .204Participant @alan-204]

Hi Rick wouldn't an MT5 have more of a taper than 1mm.

Al.

[John Stevenson 1Participant @johnstevenson1]

My bad, though he was asking about the chuck fitting not the spindle bore taper.

Re read the post and I now see what he wants so ignore everything I have said, most people do anyway

The size given at the end of the spindle matches up with a No 5 Morse but the inside measurement doesn't.

[Alan .204Participant @alan-204]

Thats what I thought John so any idea what it could be with such a small taper,

Al.

[Martin WParticipant @martinw]

Hi

MT5 taper is 44.399mm at gauge line with a taper of 1:19.002 as given here.

Cheers

Martin

[Keith LongParticipant @keithlong89920]

Don't you need to know the axial separation between the 2 diameters as well? You could have a stub version of a standard taper.

Keith

[Rick Kirkland 1Participant @rickkirkland1]

These taper bores are generally machined with a relief inbetween the taper at the front of the spindle and the remainder of the taper further into the spindle, completely unlike the taper in the tailstock barrel which is a continuously machined taper from front to back.

Rick

[RobonthemoorParticipant @robonthemoor]

Sound like it's an MT5

rob

[MuzzerParticipant @muzzer]

Yes, sounds like it.

Note that for D1-4, the diameter of the (external) conical taper is 63.5mm. If it measures 54mm, it's a D1-3. The Bantam also has an MT5, so clearly it's used on machines with both D1-3 and D1-4 and different spindle bores.

The critical dimensions for the MT bores are presumably the major diameter and the taper angle. Whether or not the bore extends the "full length" matters less.

Murray

[Alan .204Participant @alan-204]

I have an MT 5 dead center Rob you had better try it before you buy one , just to make sure.

Al.

[RobonthemoorParticipant @robonthemoor]

Hi Murray" it's 44.25 not 54. D1-3 . it will be a chuck size D1-4 = 63.5 mm buts that's the OD of the spindle. I'm ID.

thank for your input.

Rob

[RobonthemoorParticipant @robonthemoor]

Keith you could be onto something"" stub version, tel me more.

rob

[Gary WoodingParticipant @garywooding25363]

If you really want to align the tailstock to the spindle, why not put centres in each and match the points? Or am I missing something here?

Gary

[John Stevenson 1Participant @johnstevenson1]

Gary, yes you are missing something.

He's trying to sort out what centre he needs for the headstock.

[Michael Cox 1Participant @michaelcox1]

If you just want to centre the tailstock with the headstock why not just put the chuck back on, chuck a piece of steel and machine a 60 degree centre. This is bound to be concentric with the spindle.

Mike

[Gary WoodingParticipant @garywooding25363]

John, yes, I missed that bit.

Without having a centre for the headstock, why not put a bar in the chuck and turn a conical point on it – it's bound to be on the centerline. Of course, it will lose its accuracy when removed from the chuck, but it's very easy to sharpen it again.

Unless, of course, the headstock centre is really needed for other things – like turning between centres.

[Martin WParticipant @martinw]

Hi

This may be blindingly obvious and teaching grannies how to suck eggs. Attach a finger clock to the top slide or saddle and set to zero with the finger on the diameter at the mouth/widest point of the taper proper. Advance the gauge into the taper for a known distance ensuring that the measurement is only taken on the true taper. Note the finger gauge setting and divide this into the distance moved into the taper and this will give the taper. If this works out to 19.002 or close then it is a fair bet that the taper is MT5.

As I said if this is teaching grannies then sorry but it should end all the speculation of whether it is or is not MT5.

Martin

[Keith LongParticipant @keithlong89920]

Rob

You asked what I meant by a stub taper – well it's simply a standard taper but cut short, about half the normal length, keeping the same angle – the small end is removed leaving the larger end. The reason for doing this is that you still get the benefits of using a standard taper, alignment and drive, but it allows a greater through bore size on the machine spindle without having the make the OD of the spindle larger to contain a larger taper size – economics!

The sizes that you quote would strongly suggest MT5 from the open end, but the smaller diameter you quote is way above the small end of a MT5 taper – but a lot smaller than the small end of a 6MT. So you've something between the two.

Now to positively identify the taper in the absence of a male MT5 you will need to measure the axial separation between the two diameters.

I have the same issues on a lathe I have, badged as an IXL Leader and with an IXL bed (lathes.co.uk) but the headstock is a Colchester Master – re-badged as IXL. That has a short taper in the spindle, but even more fun it's was it know as a MT4.5 ie part way between the 2 standard sizes – try finding that in a catalogue!

Your best bet is to borrow a male MT5 taper of some sort, blue it up and check the fit in the spindle. If the fit is OK at least you know what to look for. If not then it's head scratching time again. Your lathe is of Indian manufacture I believe so I would hope that they've used standard Morse taper angles but there are a host of other standard tapers that it could be, the most common other candidate being the Browne and Sharpe, but the larger diameter doesn't seem to coincide with any the the standard sizes there.

Keith

Edit – Just seen Martin's suggestion above, posted while I was typing. Different way to skin the cat really using the finger gauge to accurately measure the taper to check the angle.

Edited By Keith Long on 05/02/2014 11:42:59

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