Spindle nose size

[Alan .204Participant @alan-204]

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.

[RobonthemoorParticipant @robonthemoor]

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

[Michael Cox 1Participant @michaelcox1]

Posted by Gary Wooding on 05/02/2014 10:45:29:

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

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

[Martin WParticipant @martinw]

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

[RobonthemoorParticipant @robonthemoor]

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

[Howard LewisParticipant @howardlewis46836]

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

[RobonthemoorParticipant @robonthemoor]

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

[Rick Kirkland 1Participant @rickkirkland1]

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

[Gordon WParticipant @gordonw]

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

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