Lathe alignment

[Michael GilliganParticipant @michaelgilligan61133]

Allow me …

MichaelG.

[Mark CParticipant @markc]

Thanks Guys, it seems I was lacking a www – now to read the post…

Mark

[Mark CParticipant @markc]

Gray, Ok, so I read the post.

As I mentioned, the paradox is as I state, if you don't start with a "level" plane your measurements are open to a number of errors that you can't easily negate without some further reference point (ie. a spirit level referencing gravity) along with the problems of not knowing if you have traversed the same circumferential point on your bar at both ends etc. In your case life is even harder I suspect as prismatic beds require the readings to be taken from the bearing surface which means using something along the lines of that King jig thing (which is shown being used on the non bearing part of a bed with the land between the ways being scraped for some reason?). In my Boxford case, I use the saddle surface as it is nice and flat and easily accessed!

Mark

[Sub MandrelParticipant @submandrel]

(golden rule of Toolmaking never assume anything, always check).

OW! – Gray knows what I mean

Neil

[Mark CParticipant @markc]

Gary, Neil,

That's what I love about toolmakers, you ask for an off-cut of inch by eighth bar 6 inch long and it turns up ground all over and marked "standard at 20 degrees"

Mark

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

(1) The several simple methods available for setting up a lathe for use are well known and could be understood by a dead hedgehog .

(2) Hi NJH ,

"We can start a separate discussion on this if anyone is interested ."

It seems that as usual there is no point in trying to discuss subjects more complicated than tapping drill sizes on this forum .

MikeW

[HopperParticipant @hopper]

And once you have the alignment right, and want to minimize further wear, what is the best oil to use to lubricate the lathe? Can one use modern synthetic oils on old WW2 vintage lathes etc?

[Clive HartlandParticipant @clivehartland94829]

One thought to bear in mind is that there are Tolerances and a lot of people spend a disproportionate time chasing something that bluntly is not there. The machine is not made perfect and it will have innate errors which are within the makers specs. If you then try to better these tolerances then you are in for a long tedious journey.

Using a spirit level to level in x and y and then doing a turning test is sufficient as far as I can see. Think on and try to remember when you last turned a length of metal over 200mm. Yes, you turned the end but not the length and over short lengths the machine will be fine.

Further consider a large lathe some 5 mtr bed length, its weight and mass are almost self levelling but you still set x and y level and that would suffice for most work. As things get bigger so do the tolerances!

If, we as engineers spent more time making rather than testing then a lot more work would get done. Having initially set up my Lathe I continue to use it happily and would only worry if I had to move it again. In fact it does all I ask within all aspects that I require of it.

Industrial machines are another matter entirely and may now need more care in setting down and alignment as more is asked of them. Not withstanding that they work at much higher speeds and are much more powerful and rigid. Continous high accuracy work is expected of them and after all they must make a return on initial cost.

Model engineers are not high production as we do not have the time and after all it is a hobby and not a job, except in some cases.

So, just set the machine up then use it to the best of your ability to make your dream machines.

Clive

[The Merry MillerParticipant @themerrymiller]

I'm going to throw a spanner in the works now just as a point of interest.

The lathe beds of the Myford ML7 range, looks suspiciously like they are supported on the "Airy Points" or very close to them anyway.

Would this have been the case during machining of the beds or would they have ignored the flexing element and just clamped directly onto the machining table?

Would the location of the mounting feet on the underside of the bed have been a deliberate part of the design or just a coincidence?

Len. P.

[NJHParticipant @njh]

Hi len

"Airy Points" ??

N

[KWILParticipant @kwil]

Norman, Google "Airy points" and you will see where it comes from.

To see how the bed is reground with a slight raise in the middle see:-

http://www.usinages.com/ressources/reportage-sur…myford/66164 – France

[Anonymous]

Posted by NJH on 03/04/2013 16:40:16:

"Airy Points" ??

Two points used to support a length standard, while minimising bending. They are placed symmetrically around the centre of the beam and are 1/SQRT(3) of the total length apart.

Andrew

[Mark CParticipant @markc]

Seems a little pointless when you are going to dangle a great big headstock on one end…

Mark

[NJHParticipant @njh]

Thanks Guys

Yep I should have Googled it ! – my only previous connection with "Airy" has been in relation to cool rooms… or maybe bikers! Sir George Biddell Airy had not  registered on my radar.

I guess every discipline has it's share of unusual terms – my own background was predominantly in electronics and there are a few there too! I still keep some of my old notebooks on microwave radio and transmission line theory and look at them from time to time. This is just to remind me;-

(1) Not to be too cocky – as now I don't understand a word of it.

(2) That, with earnest application, even obscure stuff can be learned , if not fully understood, for the purpose of examinations – (I got a distinction – I'm still shocked!)

(3) Life is too short to spend ploughing through stuff that is not interesting.

Regards

Norman

Edited By NJH on 03/04/2013 18:36:04

[Anonymous]

Posted by NJH on 03/04/2013 18:35:16:

Sir George Biddell Airy had not registered on my radar

Also responsible for Airy functions, ie, parties in cool rooms……..

Andrew

[Anonymous]

Posted by MICHAEL WILLIAMS on 03/04/2013 01:05:33:

It seems that as usual there is no point in trying to discuss subjects more complicated than tapping drill sizes on this forum .

Well, that's nice innit; might just as well crawl back into me cave and bash a few rocks.

Andrew

PS: If I recall correctly the discussion on tapping drill sizes created almost as much heat, and some light, as the current thread.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by NJH on 03/04/2013 18:35:16:

Sir George Biddell Airy had not registered on my radar.

.

Norman,

Given your interest in microwave … try this

and yes, the Airy Disk is named after the same man.

MichaelG.

[Author]

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