Reducing play in 1950's Logan 210 carriage?
Close
Login to Your Account
Likes Likes:  0
Results 1 to 15 of 15
  1. #1
    Join Date
    Nov 2019
    Country
    NEW ZEALAND
    Posts
    3
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Question Reducing play in 1950's Logan 210 carriage?

    Hi Folks, I am trying to learn turning and get my head around maintaining a Logan 210.

    I am having a lot of issues getting good cuts from it, definitely in part due to my inexperience machining but there is some definite mechanical variability in it I would very much appreciate some guidance on reducing.

    The carriage cross slide and compound have about a millimeter of play when you push on them. Along with a quarter turn of the handles of backlash. I am finding it has a habit of pushing off the work and deflecting, jutting about that mil past where the cut is meant to be happening.

    I've pulled the carriage apart and cleared out a couple decades of detritus and reapplied oil but I haven't been able to tighten up the tolerances. Tweaking the two nuts capturing the wheels and adjusting the gib screws hasn't seemed to make a difference. I am wondering if perhaps the brass nuts in the slides or their threaded rods are worn?

    Edit:
    brass_on_screw.jpg
    Cross Slide — About 20 thou of backlash.
    compound_screw.jpg
    Compound — About 15 thou.
    Together they are enough of a discrepancy to let the tool post be pushed diagonally.
    I know a bit of backlash is unavoidable and useful to avoid seizing and to allow for lubrication, my concern is the way the tool post isn't rigid and is bouncing off work.

    Many thanks,

    Tor
    Last edited by torh; 11-07-2019 at 08:54 PM. Reason: Added images

  2. #2
    Join Date
    Aug 2004
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    2,292
    Post Thanks / Like
    Likes (Given)
    174
    Likes (Received)
    836

    Default

    I'm sure there is some wear in the crosslide and compound screws and nuts. This is to be expected on an older lathe that has not been reworked. If you are not going to replace/repair the screws and nuts you will just have to live with it. It takes a bit of extra effort to make sure you are taking up the "slack" always in the direction of your feed but it can be done. I have seen some really nice work come out of a theoretically clapped out lathe. What would be a major flaw is if your cross slide or compound are kicking over to the side. I'm not sure if this is what you are saying or not. You did mention tightening the jibs with no results so this may be what you are referring to. That is a show stopper and you need to look into the jib system to find out what is wrong.

  3. #3
    Join Date
    Jan 2006
    Location
    Angier, North Carolina
    Posts
    2,606
    Post Thanks / Like
    Likes (Given)
    1094
    Likes (Received)
    969

    Default

    Yes, it is not clear exactly what you are experiencing. Your concern with the bronze nuts suggests backlash is the (only?) problem. If my old Cinci Traytop had *only* 20 thou of backlash, I'd think I'd died and gone to heaven! But that has never kept me from good finishes and accurate sizing - it is, as crossthread says, a matter of taking up the slack in the right direction. In any manual machine, there is always going to be some backlash, so you always have to turn the tool into the cut, not away from it.

    However, if you are getting movement other than backlash - if for example, your cross slide can move side-to-side, not just front-to-back with some backlash - then something is very wrong. At that point I'd be looking at those gibs to make sure they are tightened correctly, or aren't worn to the point that they can't be tightened any more.

    One more thought - you mention the tool post not being rigid. Check to be sure the t-nut that secures it to the compound is sized correctly. It is possible for the upper portion of the t-nut to be just a hair too tall, so that even though you tighten down the tool post as much as you can, it is not quite secure.

  4. #4
    Join Date
    Jun 2001
    Location
    St Louis
    Posts
    17,940
    Post Thanks / Like
    Likes (Given)
    1852
    Likes (Received)
    3014

    Default

    A couple added comments.

    The crosslide or compound indeed could be moving side to side, which is "usually" a gib (jib) adjustment. A row of screws along the side adjusts this.

    Problem is that the wear on the slideways is not even along the length. So if adjusted for the "smallest size" worn area, it will be tight on the less worn areas. And, if made tight just for the unworn areas, it will be somewhat (or worse) sloppy on the worn areas, since they wear to be smaller.

    The bedways also are going to heave wear, but that is more self-correcting, although not perfectly.. The carriage settles down onto the V way with nearly any reasonable amount of wear. That changes center height slightly, but only really affects small diameter work.

    The bigger issue is if the carriage itself has worn at the ends, so that the guiding surfaces are worn to a football shape. Then it will tend to slightly rotate when the direction of movement reverses, making for a good chance of uneven cutting. The cutting force can tend to oppose the force tending to cock the carriage, and the depth of cut can vary depending on which force wins. That tends to happen when cutting toward the headstock (the conventional direction) on most lathes, because the leadscrew is at the front. The leadscrew cocks the headstock side of the carriage inward, and cutting force pushes it out.

    Reversing the cut direction may help somewhat, as the two forces may be aligned in the same direction. The real solution is to re-scrape the carriage. and also grind the bed while you are at it.., .
    Last edited by JST; 11-08-2019 at 03:11 PM. Reason: hourglass WEAR, football SHAPE

  5. #5
    Join Date
    Feb 2011
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    2,157
    Post Thanks / Like
    Likes (Given)
    1533
    Likes (Received)
    921

    Default

    One other thought is how big of a cut are you taking? Logans while well built, are a light duty machine. Adjusting the gibs to minimize side to side slop, and turning the cross feed screw to take out the back lash are a must, but also remember that you're going to get deflection under a heavy cut. Your surface finish might not be from play in the parts, but from the tool flexing up and down under load. Ideally, you would need to take lighter cuts in that case. Sometimes you can get away with a heavier cut if you compensate with your tool height and keep your feed rate consistent, but bear in mind that it's pushing the machine.

  6. #6
    Join Date
    Feb 2011
    Location
    BFE Nevada/San Marcos Tx
    Posts
    1,161
    Post Thanks / Like
    Likes (Given)
    1025
    Likes (Received)
    607

    Default

    No mention of what type of toolpost you are using, or what type of tooling, ie insert or HSS? 20 thou backlash in screws falls under "normal" and is most likely not the problem.

  7. #7
    Join Date
    Jun 2001
    Location
    St Louis
    Posts
    17,940
    Post Thanks / Like
    Likes (Given)
    1852
    Likes (Received)
    3014

    Default

    We should mention that longer parts may need a "traveling steady" that holds the work and prevents it from pushing away from the tool as much. The work is part of the "structure" as much as the lathe is.

    I have found the Logan to be stiffer and less of a problem than other similar sized machines. The point about flex is well taken, though, it IS relatively light, there are much heavier machines of the same general size

  8. #8
    Join Date
    Nov 2019
    Country
    NEW ZEALAND
    Posts
    3
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Thank you for all the guidance folks!
    Quote Originally Posted by dalmatiangirl61 View Post
    No mention of what type of toolpost you are using, or what type of tooling, ie insert or HSS?
    It has one of the oft-derided lantern style tool posts. The tool holder is on a rocker and jammed between the t-nut and screw top. I'm using HSS tools and the angled tool holder.
    img_3545.jpg
    Quote Originally Posted by crossthread View Post
    What would be a major flaw is if your cross slide or compound are kicking over to the side.
    I believe this is happening, the combined slop in the two axis let it diagonally push off the work.
    Quote Originally Posted by M.B. Naegle View Post
    One other thought is how big of a cut are you taking? ..Adjusting the gibs to minimize side to side slop, and turning the cross feed screw to take out the back lash are a must, but also remember that you're going to get deflection under a heavy cut.
    Noted! I don't feel like I can make any gentle cuts with the tool pushing back off the work, but after I sort that I will definitely stick to lighter operations.
    Quote Originally Posted by awake View Post
    Check to be sure the t-nut that secures it to the compound is sized correctly. It is possible for the upper portion of the t-nut to be just a hair too tall, so that even though you tighten down the tool post as much as you can, it is not quite secure.
    I've just had a look and it seems the tool post isn't actually using a proper t-nut, but an undersized square that is pulled up by the screw. It might be time to look into getting a QCTP and getting a new t-nut milled.
    img_3552.jpg

    Thanks again folks, I really appreciate the suggestions.

  9. #9
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    27,348
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    8525

    Default

    Quote Originally Posted by torh View Post
    Thank you for all the guidance folks!

    It has one of the oft-derided lantern style tool posts. The tool holder is on a rocker and jammed between the t-nut and screw top. I'm using HSS tools and the angled tool holder.
    img_3545.jpg

    I believe this is happening, the combined slop in the two axis let it diagonally push off the work.

    Noted! I don't feel like I can make any gentle cuts with the tool pushing back off the work, but after I sort that I will definitely stick to lighter operations.

    I've just had a look and it seems the tool post isn't actually using a proper t-nut, but an undersized square that is pulled up by the screw. It might be time to look into getting a QCTP and getting a new t-nut milled.
    img_3552.jpg

    Thanks again folks, I really appreciate the suggestions.
    Too much to learn about the Logan's condition AND your new-skills absorption rate to spend $$$ on a QCTP just yet. You'll make a wiser choice for the money on those in about another six months.

    IF EVEN you keep this particular lathe.. trade it, or start to rebuild on it.

    Meanwhile:

    - pull the lantern's tool and rocker

    - turn the ring upside-down. Shim if you have to do, usually not.

    - pull the forged holder back half an inch or more. Hang-out is pure evil.

    - set the toolholder angle so that cutting force swings the holder OUT of engagement with the work if it swings at all, never deeper INTO it. That's one of the roads to a crash.

    Then go on eBay and see if you can find a right-size 4-Way. Only need to use ONE side of it to learn how touchy a lantern can be by contrast. KEEP yer lantern. Time comes you buy a QCTP, keep the 4-Way, too. There is always a task one toolpost or another is not the best solution to. That's why they are made so they can be changed, rather than welded-on.

    Usable 4-Way should cost yah less than a decent holder for a QCTP - no need to over-pay, so many have been shed FOR QCTP!

    First comes good. THEN comes "fast". QCTP is like unto a quick-draw holster for gunslingers. There is nothing so "magical" in a QCTP as to make all the wear in the lathe go away, nor the things you have not yet learnt become already well-known, year before last.

    You ain't there, yet, and it would just empty yer tooling budget faster than it can grow yer dick, in any case.

    Meanwhile "run what yah got". If nothing else, when things get BETTER, you'll actually NOTICE!

    And grin. It does have its compensations, making chip.

    Or the lot of us would be selling hot dogs, data circuits, or condoms instead.

    All of which generally PAY better.


  10. #10
    Join Date
    Nov 2009
    Country
    UNITED STATES
    State/Province
    Massachusetts
    Posts
    327
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    107

    Default

    The manufacturer still exists and supports these machines. They make new parts to fit old machines. Expensive, but fit perfectly.

    Logan Actuator Company: Logan Actuator Co. - Lathe Department

  11. #11
    Join Date
    Feb 2011
    Location
    BFE Nevada/San Marcos Tx
    Posts
    1,161
    Post Thanks / Like
    Likes (Given)
    1025
    Likes (Received)
    607

    Default

    The lantern post is not doing you any favors, I learned using one, but still consider them a pia. As recommended by thermite, get a 4 sided turret tool post, its much more rigid, and with 2 or 3 tool bits in it, it can speed up the work. But yeah, keep the old rocker, someday it might come in handy.

    Not sure where you are in ability to sharpen HSS, don't be afraid to experiment a little with changing relief angles, sometimes a little tweak can make the difference between a ragged cut and a mirror cut.

  12. #12
    Join Date
    May 2009
    Location
    Canandaigua, NY, USA
    Posts
    2,865
    Post Thanks / Like
    Likes (Given)
    140
    Likes (Received)
    1263

    Default

    Backlash is of little concern. I'd get a wedge type AXA QC toolpost, Phase II plus a bunch of tool holders from CDCO. Don't extend the tooling and try to keep the cutting edge within the envelope of the cross slide ways. One thing to consider with the 2xx Logans- They use a heavily preloaded headstock bearing. If somebody replaced it with an off-the-shelf bearing, it will be prone to chatter and all sort of weirdness. Logan Actuator has the correct bearing. AFAIK, there is no substitute. The rear bearing is nothing special and can be had from Tractor Supply or anybody else, but get a decent brand name. Make sure there is no twist in the bed (what people incorrectly call leveling) or the carriage can lift a corner and be unstable.

  13. #13
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    27,348
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    8525

    Default

    Quote Originally Posted by Joe Gwinn View Post
    The manufacturer still exists and supports these machines. They make new parts to fit old machines. Expensive, but fit perfectly.

    Logan Actuator Company: Logan Actuator Co. - Lathe Department
    They are honest folks. Just as their lathes were, new. They EARN their crust.

    Folks still have other demands on their time. And budgets.

    I'm still wondering if I did the right thing, decision-support-wise to add that second toilet-paper dispenser... or if I just slowed meself down out of confusion...??


  14. #14
    Join Date
    Feb 2008
    Location
    Lomita, CA
    Posts
    100
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    12

    Default

    I have a 1948 vintage Logan 815 (10 x 24 with gearbox). There are multiple sources of play in a small Logan lathe, some you can adjust out, and some you can't. First, lubricate and adjust the gibs to allow smooth travel with a minimum of side to side play. The endplay in the cross slide and compound screws is controlled by adjusting the nut between the hand wheel and the dial. Loosen the nut outside the hand wheel and adjust the nut between the wheel and the dial to the minimum play that still allows the dial to turn. This is an iterative process, because tightening the outside jam nut will further reduce the free play, possibly binding up the dial. It's easier if you have a wrench that's thin enough to stay on the nut between the wheel and the dial while adjusting. The last source of free play is the Acme thread itself, and you can't adjust that out. Even if you put an adjustable split nut in, you would likely find that you had tight spots at each end of the travel where the screw was less worn. By the way, the cross slide nut on yours is a replacement, as the originals are cast iron. Make sure the screw that holds it to the slide is snug.
    You'll always have some backlash, so make sure you always are setting your next cut by making your last move of the tool towards the cut to take the slack out of the system.

  15. #15
    Join Date
    Nov 2019
    Country
    NEW ZEALAND
    Posts
    3
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Quote Originally Posted by Sidebite View Post
    ...By the way, the cross slide nut on yours is a replacement, as the originals are cast iron. Make sure the screw that holds it to the slide is snug... You'll always have some backlash, so make sure you always are setting your next cut by making your last move of the tool towards the cut to take the slack out of the system.
    Good to know it is a replacement, I was wondering about that. The analogous part in the compound is the same bronze material, I guess that is a replacement too.

    After checking the jam-nuts on the hand wheels I don't think I have much to adjust out there.
    It binds up the whole slide pretty quickly, but that might just be in part due to one of the bits on the leadscrew (or likely the screw itself) being a little out of whack and bent. I will have to pull it to pieces again and work out where the misalignment that is pinching is.


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •