Spindle nose size

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

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.

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

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

This started because now the lathe is finally in place where it will live for good it seamed a good time to check the machine and make sure it turns concentrically so we will do a test to see if the head stock is concentric to the bed ways if so the we thought we should check the head stock to the tail stock where we would need to do this between centres, hence the need to find the right size centre for the head stock, if any one thinks we are taking things to far you only have your selves to blame because your machines run so bloody accurately we though we would have our lathes and milling machines as good, only joking hope every one understands what were trying to do now.

Thanks again Al.

Will let you know how we get on.

Martin, yes yes yes that's the way . Ok over the distance of 1 inch the taper is 29thou that's the best I could get, so if I say between 27thou & 30 thou that can surely give us a ball park figure? Now who can do the calculation? I think the taper is about 3inch long.

rob

Even if the OP wants to turn between centres he can still do that using a machined centre in the chuck and a lathe dog against the chuck jaws. He just loses a little bit of distance between centres.

Mike

Hi Rob

I have looked at the information you have given. It appears that the gauge line diameter on your spindle is about 1.75" with a side taper of about 29 thou per inch or diametrical taper of 58 thou per inch. The nearest I have found to that is a Jarno 14 taper which has a large diameter/gauge line 1.75" with an diametrical taper of 50 thou per inch or wall taper of 25 thou per inch.

As I say this is the closest I can find and was invented and presumably used by Brown & Sharp, whether this is relevant or not I have no idea.

As Mike says it would be easy enough to chuck a piece of rod and turn to a point then, without touching the chuck use this to establish the head stock to tail stock alignment.

Sorry I can't be of more help but hopefully it might give you a starting point

Regards

Martin

Thank martin, you did a lot lf work there, I will see if I can get a Mt5 to try, if that's no good will try the jarmo 14

rob

For a table giving details of Morse, Jarno and Brown and Sharp Tapers look at

littlemachineshop.co./Reference/Tapers.php.

The suggestion to put a bar in the 3 Jaw chuck and turn a centre is a good one. The centre will be on the REAL centre line if the headstock. If it is marked in line with say, Jaw 1, before removal, it can be replaced with reasonable accuracy. Or clock the bar in a 4 Jaw as accurately as possible, turn the centre, and then reclock to centre it with a DTI on all subsequent uses.

BUT before aligning the Tailstock, do make sure that there is no twist in the bed, otherwise the Tailstock will only be accurately aligned at one point on the bed, and you will be unlikely to be able to turn parallel over any length.

To check and adjust, either :

1) Use a sensitive spirit level on the cross slide - assuming a flat machined top surface, and check at Headstock and Tailstock ends.

Or 2) Lay the level on the ways, (use parallels if your lathe has Vee/Flat ways, and work off the flat ways for the Saddle and Tailstock)

Be aware of the danger of wear on the bed affecting the results, so use the extreme ends, which, not being traversed by Saddle or Tailstock, are less likely to be worn, if possible!

The level does not have to be ABSOLUTELY level, the essential thing is adjust/shim the lathe feet, so that the same reading is obtained at both ends, on unworn areas of the ways, to ensure that there is no, or absolutely minimal, twist in the bed.

3) The Operator Manual for the Myford 7 Series tells how to check for, and to remove twist by machining and measuring a test piece held in the chuck.

Which method you use depends on the configuration of your lathe, and the facilities that you possess, or can borrow.

Howard

Yes guys it was MT5 got a taper today . First I must apologise to you all as the measurement I gave down the bore was wrong! I went in with a micro light & then could see a collar, my bore gauge must have ridden up it every time. Once I overcome that problem the measurement s You gave all fell into place. Perfect out come thanks to you all .

regards Robin

Ay up Rob, I'll just take this opportunity to say I told you so. Now then, I've never in my life known a run of the mill lathe have anything other than morse tapers for head or tailstock. Jarno tapers were not used because they were just too good believe it or not! It was a similar thing with video tapes. Betamax was superior but VHS was the one we were given.

Rick

Re lathe tapers-my very first lathe, no idea what make but looked a bit like a very early myford, both spindle and tailstock had unknown tapers. Tried all the standard easily available ( from stores at work ) tapers. Ended up getting a morse taper sleeve bored out and welding it to tailstock spindle