counter shaft not running true

[mark smith 20Participant @marksmith20]

Posted by Mark C on 04/01/2017 18:29:29:

Mark, I don't know if you are aware of this or not, but there is a really useful text box at the top of the page. You can use it for searching information out – typing the word levelling brings up a spread of results from 2010 all the way to date. I expect a little more time and effort would bring up a substantial number of results so you could spend hours trying to de-bunk all the tosh spoken on this subject, and there certainly is some.

Mark

Mark, yes i know but has you have pointed out there is alot of bunkum about the subject and ive found it hard to follow what are the correct methods. Even the Southbend booklets goes on about levelling the base or cabinet etc.. and making sure everything is secured down but many were used on ships tool rooms etc.. of which it is my understanding the lathes were often left `floating ` on the right hand foot.

Still wondering if bed twist is a common problem (amongst good manufacturers who seasoned the castings properly etc and machined them in stages) or a rare phenomena brought about by fixing down too securely.

[Martin ConnellyParticipant @martinconnelly55370]

The base of the Smart and Brown model M mark 2 is a three point mount to the floor, two at the front corners and one centrally positioned at the rear. It seems Smart and Brown were clearly in the three point mount camp.

Martin

[Mark CParticipant @markc]

Mark, the only sure way to know what is going on is to check with a machine level, that is what they are for – setting up machines. Installation on a boat is a specific problem and not one to concern us unless we have workshops on a barge or something similar! You just want the base level and secure to stop things rolling off and to ensure the coolant goes back to the tank (if you use any).

As always, there is more to it than that but as long as you are realistic and the machine is not badly worn you will be able to "see" what it is like by mounting the level along and then across the saddle and traversing the thing along the bed – watching the bubble for movement along the bed. You can then decide if you want to try and correct it or accept it as is.

Mark

[Mark CParticipant @markc]

Here are some old pictures from the Boxford Yahoo site that show my BUD at the two extreme ends of the bed

[Mark CParticipant @markc]

To bring this back down to earth, you will notice that mine is better than 0.05mm/m over the bed. It was done when I had some spare time but I doubt it reads like that now and I rarely need to machine long lengths with very high precision. If I did, there are a hell of a lot of other things that will generate problems long before a bit of twist will get noticed.

Mark

[mark smith 20Participant @marksmith20]

Thanks Mark, i.ll have a look at mine when i get time , i dont own a precision level but have a machinist level.Would this do? Like the one in this photo.

Edited By mark smith 20 on 04/01/2017 19:28:30

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Russell Eberhardt on 04/01/2017 16:54:43:

I'll put another cat amongst the pigeons; the lathe bed doesn't need to be level, just straight.

Russell

.

Very true, Russell … but [before folks get too excited]: The easy way to check for that multi-degrees of freedom straightness is to use a precision level: Hence the process is called levelling, because of the tool being used.

MichaelG.

[Mark CParticipant @markc]

Mark, mine is actually a "Box" level. As long as it is sensitive and fits it will be fine.

Mark

[sean logieParticipant @seanlogie69385]

Wow this thread has gone into way too much detail . All i wanted was some advice on fixing the lathe to the floor . I've decided on trapping 4mm rubber strips between the bottom of the pedestals and the concrete ,nip the bolts up enough to just hold the pedestals in place for now. Obviously truing up as best I can (I'm not buying a machinists level) . Today I'm going to make little adjustable feet with a through hole so i can use threaded rod for fine tuning . Once I get everything set up I have a bar I've been using for testing run out and I'll take it from there .

Thanks everyone for the input

Sean

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Michael Gilligan on 04/01/2017 20:00:48:

The easy way to check for that multi-degrees of freedom straightness is to use a precision level: Hence the process is called levelling, because of the tool being used.

I agree that's the easiest method if you own a precision level. If not the easiest method without special equipment is just to ensure it turns a bar un-tapered when unsupported by the tailstock. If you own a dial gauge there's Rollie's Dad's Method

Russell

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