[Newbie] Logan 2557 finish issues

T

Timthelen

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Hi guys! This is my first post but I’ve gotten great info off here in the past.
I just got a late sixties Logan 2557 vhl lathe and I’m in the process of dialing it in. My initial cuts in 4140 rod are uneven with chatter as the tool moves away from the headstock. Been through feeds and speeds, centerline, carbide & hss, locked gibs down, cleaned an lubed saddle gibs and bed ways. All of that with minimal improvement. With an indicator on the the outside and inside of the L0 spindle I get around.005” needle movement while running. I can push or pull about.0015” movement on the spindle from any direction with finger pressure. With the indicator on the outermost edge I can pull or push about .007” axial play.
does this indicate bearing wear? Can I adjust it out with the preloaded ball bearings that Logan used? If so how? If not, has anyone converted to Tapered roller bearings on one of these? I have yet to measure bed wear and I know there’s some but I’m thinking the finish issues are from a free floating spindle.
 
Welcome to HM, Tim. We have some Logan guys here who should be along shortly.

This is just me but if I was trying to figure out what is going on with my lathe, 4140 is not the material I would choose. It is hard enough for a small lathe to cut and can work harden so that it can be difficult to tell if your lathe is the issue or if there is a work hardened area at fault. Try switching to mild steel or aluminum for troubleshooting.

You gain absolutely no useful information from indicating on something running, even the spindle. Being able to push or pull 0.015" of movement and 0.007" of end play does suggest your spindle bearings are either shot or in need of preload adjustment. There is usually a nut on the end of the spindle to adjust this out. You manual should give you the recommended specs and Logan Actuator should have that info also.

I suggest you wait for the Logan-owning guys to comment. They will probably be able to help a lot more.
 
You say nothing of what sort of tool you are using, and feeding away from the chuck is not what is normally done, the amount of end play in the spindle should be next to zero, as Mikey said, it should be easily adjustable.
 
Thanks guys, I meant that the cut chatters the farther away from the headstock but it does read as though I’m feeding away. I was using 4140 as I had it and was trying to get a read on leveling the bed. My concern is from being able to manually push any movement in the spindle. Logan uses sealed preloaded ball bearings, and suggest that there’s no adjustment to be made. I’m wildly undisciplined in the order of my checking with this machine due to time and I’m also pretty thick so I look forward to the insight.
 
The OP is correct. Logans have spindle bearings with the preload built in and cannot be adjusted. The only fix for bearing play
is replacement.
 
Nogoingback said:
The OP is correct. Logans have spindle bearings with the preload built in and cannot be adjusted. The only fix for bearing play
is replacement.
Click to expand...
Thanks! Yes, that was what I was thinking was replacement. Looking on Logan Actuator’s site it looks like $600+ for a full set. I’m sure they’re perfect in every way but... that’s a bit prohibitive. This leads me to ask has anyone considered converting to roller bearings instead? Seems to me that would be simple and far cheaper to be able to have control of the adjustment of preload. Am I wrong or is there an overwhelming advantage to the factory spec ball bearings?
 
I think the problem is that the spindle and headstock aren't designed for a setup like that, and it's an open question whether you could adapt it
to an adjustable set of bearings. As far as I know, all the Logans had preload style bearings, including the very first 10" models. My impression
is that the factory bearings gave good service, but of course they won't last forever. I have no experience with the 12" machines, but it's
possible that you wouldn't have to buy all the bearings from Logan. On mine (model 200) the bearing at the chuck end is special but the other
one is off the shelf. Looking at a cutaway photo of a 12" headstock, it looks as though the bearings at the gear train end could be standard
bearings, though the only way to find out is to get the bearing numbers and look them up. If so, it might save you some money.

I bit the bullet with mine and replaced both bearings, and I'm glad I did. I guess one way to look at it is that if Logan weren't around to supply
the parts, old Logans with bad bearings would be essentially worthless.
 
Thanks
Nogoingback said:
I think the problem is that the spindle and headstock aren't designed for a setup like that, and it's an open question whether you could adapt it
to an adjustable set of bearings. As far as I know, all the Logans had preload style bearings, including the very first 10" models. My impression
is that the factory bearings gave good service, but of course they won't last forever. I have no experience with the 12" machines, but it's
possible that you wouldn't have to buy all the bearings from Logan. On mine (model 200) the bearing at the chuck end is special but the other
one is off the shelf. Looking at a cutaway photo of a 12" headstock, it looks as though the bearings at the gear train end could be standard
bearings, though the only way to find out is to get the bearing numbers and look them up. If so, it might save you some money.

I bit the bullet with mine and replaced both bearings, and I'm glad I did. I guess one way to look at it is that if Logan weren't around to supply
the parts, old Logans with bad bearings would be essentially worthless.
Click to expand...
That’s all true and I look forward to speaking with Logan and hear what they have to say. I don’t think I’ll outlast a new set either way! I just want all the play out of my spindle and I don’t like being told that something has been set at the factory and won’t need me to over-adjust it.
 
I'm under the impression that Logan marketed these bearings as a desirable feature for their customers, since it eliminated
the need to adjust them for the life of the bearing. I doubt they did it to insult customers 50+ years after the lathe was built.
 
Last edited:
I doubt that they considered my feelings during the design process... shameful. I don’t consider the ball bearings a flaw, and I will more than likely use their replacements, I was hoping there was an established route for the tapered rollers as an alternative. I don’t want to be a guinea pig and trash my spindle or headstock casting! Thanks for the insight
 
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