New To Machining And New To Logan Lathe, A Few Questions

J

John TV

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So a few months ago, I was on this site telling of a older 1948 Logan/wards 9 inch lathe my father-in-law had which has not been run in more than 33 years. Finally got a chance to clean it up a few weeks ago and today I had the chance to play with it a bit. I am a complete nubie and will be learning from trial and error, the internet and you great people.
Two quick questions, everything seems to run ok but how much pressure or force should it take to turn the cross feed screw, it seems tight to me but have nothing to compare to in experience other than the compound rest and apron wheels, both of which seem easier to turn than the cross slide. Second, the cross slide graduated collar locking screw is stuck in the hole and initial attempts to loosen that tiny screw are not working. The lathe is still in my father in laws old garage and I will not get it home for several weeks, so not too many tools there to fall back on. I was thinking of attempting mild heating to see if that would break it loose but thought I should ask first. Thanks for any suggestions you have. John
 
Welcome to the wold of turning!
something to consider first would be friction.
is there oil present on the crossfeed ways, is there transverse streaks in the oil noticed?
if there is any swarf between the machined surfaces, it will show up as long streaks in oil in the direction of travel.
if the crossfeed gibs are maladjusted, you'd get a dragging feel.
lubrication of the crossfeed screw would also recommended.
a partial dissasembly may be in order if you have lots of swarf visible in crevices that you can't get with a rag or paper towel or q-tip.
as far as getting the stuck screw out, soak it with PB Blaster, or WD40, or Acetone/ATF mixture, etc for a couple days and retry.
i hope the information is helpful.
 
Thank you Mike, I know there is oil on the ways, don't remember seeing any streaks but I was not looking for them either. Good tip, for many things. I have the screw soaking now but wont be back to the old garage for a while... hope the soaking works, if it doesn't, what do you think of a mild heating to expand the metal around the screw? Thanks for the quick response.
 
you are very welcome,
as far as the heating goes, it won't hurt as long as you are careful not to get it too hot.
a heat gun or a very small or regulated propane rig would do it too.
keep a wet rag with you if you mess up. you can cool it down kinda quick.
200*F should suffice for expansion
you should not see a color change in the metal, by the way
 
I was thinking heat gun too, a little less heat but harder to focus the heat on just that part.. will give it a shot. Forgot to mention in last response, I think it is likely that the gibs might be the problem, have to do a little research on adjusting those, but might get lucky and have it be some swarf. (is this the term for chips, etc.?) told you I was new.

You have been so helpful, one more question, how much backlash is typical in the cross like and compound rest adjustments, I know it will depend on how much use etc, and I know there is always some backlash, but how much is to be expected?
 
Yes, swarf is chips- :)
Some backlashes can exceed .040"or more .
Generally speaking the more backlash the more wear
If you have .005 that's pretty good
 
33 years of goo and gunk can bind things up. The old Atlas milling machine that I have (work in progress) was seriously gunked up with what I believe was some old cutting oil that solidified into some seriously thick varnish like goo. It took some scrubbing with a brush and mineral spirits to clean it up. Some disassembly may be required, take pictures and find a copy of the owners manual. (You can order one from Logan if you can't find a copy to download.) Don't force anything! Patience will be rewarded. If screws are stuck, Kroil or the previously mentioned PBlaster or ATF + Acetone can be real helpful. Let it soak, walk away, try tomorrow, repeat as necessary.
 
CluelessNewB said:
33 years of goo and gunk can bind things up.
Click to expand...
All good advice so far. And as I was reading the first couple of posts, the above quote is exactly what was going through my head.

Do you actually need to remove that setscrew? Other than tearing it down for cleaning or adjusting, I'm not sure you need to take it out. On most Logan's (smaller ones) that graduated dial is not meant to be zeroed out.
 
John,

To answer your question of how much force should it take to turn the cross-feed crank and move the cross slide, I can't give you an answer in actual numbers (inch-pounds for example). But it shouldn't be significantly different from the torque required to turn the compound feed crank.

As to back lash in either the cross feed or compound feed, there are four possible sources.
Crank is loose on screw.
Nut (usually brass) is loose under slide.
End float in the feed screw.
Clearance between the feed screw and nut.

Fix the first two by tightening whatever holds the loose part in place.

Reduce the third by adjustment (I'm not familiar with a Logan 9" and we don't appear to have a maintenance manual on it. But if the feed screw assembly is similar to the 10" models, you loosen the nut holding the hand wheel/crank to the screw, slightly tighten or loosen the nut behind the handwheel, and re-tighten the outer nut. And repeat. Note that this is best done with the cross slide run all the way across the bed until the nut runs off the end of the screw and then push the cross slide another quarter inch or so.

The fourth is not adjustable. But to check to see whether or not any improvement could be made with new parts, first note the backlash in thousandths indicated on the dial with the cross slide in the area most commonly used. Then run the slide across the bed until the screw is just sticking out of the nut. Check backlash. If less than the first check, then a new screw would improve matters. Whether the improvement would be worth the cost is a judgment call. To check whether a new nut would improve matters requires a new nut. If you have one, install it. If the improvement near the end of the feed screw is more than 0.003" to 0.005", use the new nut and repeat the screw wear test. If not, put the original nut back on. Minimum back lash with all new parts is typically 0.005" to 0.010". So even on a new lathe, you have to acquire the habit of always approaching a setting from the same direction (either CW or CCW, depending).
 
Thanks to everyone for the great advice and quick responses. As I mentioned in the post it will be awhile before I can get back to the shop and check/tinker with the screw and backlash. I did make a mistake in describing the stuck set screw, it is the cross feed set screw that is stuck not the compound set screw. I will keep you up to date on the progress as it develops. As I mentioned, I could not be any more of a nubie than I am. That said, I do remember seeing something that my father in law must have made that looks suspiciously like a new screw and brass "nut" that would be about the right size for the cross feed. When I saw it I assumed it was for the taper attachment that he made for the lathe, and since I really don't know much about how that taper piece attaches, and works, mayby it is a replacement part for the cross feed ? Ahhh the mysteries and the learning curve....but that's the fun part. Thanks again.
 
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