Logan #215. Lathe repair

[Oldskool 6,644]

Today I had a chance to do a quick run through on my Logan.

There was some slop here and there and some misalignment. Mostly dealt with.

 

"Warning" some of the terminology may be a bit off.

 

My biggest issue now is trying to get the play out of the control wheels that work the carriages.

The video doesn't show all the play.

There is about 3 tick marks worth of play before the indicator wheel moves with the handle. Then there is about 22 tick marks worth of play before the carriage moves with the handle.

 

Any help would be greatly appreciated.

[lynnmor 7,307]

That is play between the leadscrew and the nut.  On some machines the nut can be split and the nut parts can be pushed together to eliminate the slop.  Often the leadscrew is worn most in the middle of the travel, check how much slop is at the extreme ends of the travel, if it is about the same, the nut splitting can work.  If the leadscrew is worn unevenly, replacement is required.

 

The slop in the carriage can be at multiple places.  Disassemble the apron and measure what custom bushings and other parts are needed, then reassemble and make your parts.  Now disassemble again and make the repairs.

 

Did you look for new parts?

[pacer 3,173]

@lynnmor has pretty well nailed it, these old lathes just get slop worn into these points. I have never been lucky enough to have success with his method of splitting the nut on the cross slide. but its sure worth a try. The carriage will likely be the problem area in removing the slop.

 

I had had 2 South Bends - a 9" and a 10" with these problems, I gave up on the 9 and gave it away, the 10 I lucked up and with help of a machinist friend (a lot of!) we made new lead screws/nuts. Parts are like our horses, they are getting very hard to find. I presently have one of South Bends13x36 later models in quite good condition and it still has minor 1-2 thou slack on both cross and carriage.

 

This machinist friend had worked in many shops and was well familiar with having to use many a machine with these problems, said that you just have to teach yourself the pecularities of them and develop 'work-arounds'. If the slop is 5-6 thou then you crank that in before you make the cut ..... I thought to myself "yeah, I can see me doing that!" But, suprisingley I do find myself doing just that!.

[lynnmor 7,307]

2 minutes ago, pacer said:

 

This machinist friend had worked in many shops and was well familiar with having to use many a machine with these problems, said that you just have to teach yourself the pecularities of them and develop 'work-arounds'. If the slop is 5-6 thou then you crank that in before you make the cut ..... I thought to myself "yeah, I can see me doing that!" But, suprisingley I do find myself doing just that!.

 

Really @Oldskool doesn't have a big problem, sure it would be nice to have virtually no play but these things always developed some quickly.  If you saw the play in my Sheldon lathe, you would be dumbfounded.

[ri702bill 8,327]

I agree with @lynnmor and @pacer. What usually happens id the the area of the leadscrew that is where the tool(s) do the work wears, the extreme ends remain like new. A badly worn leadscrew must be replaced. Note - SOME backlash is needed to prevent binding,

Gibs - the carriage has a gib that is "adjustable" - either with a series of setscrews and nuts, or it is a tapered wedge with a tension bolt. Same thing like the leadscrew - only one area wears the most.

Twentytwo increments on the dial of lost motion is a lot - sounds like the split nut may "help", but not solve the issue.

Bill

[lynnmor 7,307]

4 minutes ago, ri702bill said:

 

Twentytwo increments on the dial of lost motion is a lot - sounds like the split nut may "help", but not solve the issue.

Bill

 

I took it as the wheel that moves the carriage left and right has the 22.  There is no nut in that mechanism.

[Oldskool 6,644]

That's some great info guys, thanks.

 

My main carriage (left and right) is nice and tight after adjusting the "gib".

The one that goes angular is nice and tight as well. 

My last issue is the carriage that goes to and from.

Apon further inspection the "nut" is one piece not split with adjusting screws like I saw on a Southbend.

[pacer 3,173]

11 minutes ago, lynnmor said:

 

I took it as the wheel that moves the carriage left and right has the 22.  There is no nut in that mechanism.

 

Yes, thats true -- I began to think about after I replied and ... doggone it I just cant remember how the carriage/apron works. When I got this current SB some 18-20 yrs ago I haven been into an apron since and I cant bring back how it functioned!

[Oldskool 6,644]

Also yes more play in the middle then the ends. I can grad it and slide it to and from a bit anywhere, but more in the middle then the ends

[Mickwhitt 4,635]

The saddle or carriage ie the main bit that moves left to right is operated by a rack and pinion gear. If its a screw cutting lathe there is a split or half nut which connects with the lead screw to produce a movement which will cut threads. 

If you Google lathes.co.uk you will find a mass of information about every machine tool under the sun. 

Mick 

[pacer 3,173]

OK guys, I'm drifting off the original topic here but I thought that yall might like to see one of my 'rebuilds' (I think was my best) that I was heavily involved in back before I was bit on the butt by a 'red horse' and started building them. This is a link to the site @Mickwhitt is referring to that has a brief description of the, rather rare, Sheldon lathe that I brought back from going to scrap. That site - "Tonys lathes" is mind blowing with the info on machinery.  (he misspelled my name, but I forgive him, after all he DID do a great job on presenting the lathe)

 

http://www.lathes.co.uk/sheldon-walking-stick-lathe/

 

 

 

 

[Oldskool 6,644]

I've located a leedscrew and nut.

At approx $400 for the 2 pieces I may have to wait a bit for those. 

Things are tighter now then they were so Ill just keep cleaning oiling and adjusting for now.