Sherline lathe cross slide binding

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vvanders

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I picked up a new Sherline lathe and mill to get into machining, so far the mill has been great however I'm running into some issues with the cross slide on the lathe and can't figure out if I've not setup the machine correctly or if there's something else going on.

For the first 50% of travel the cross slide feels fine and just like other handwheels, however at about 50% I start getting some binding that increases to the point where I can't turn the the handwheel anymore. The binding is at a specific rotation of the handwheel(i.e. the first 50% of the turn is normal and second 50% requires increased force). I've removed/rethreaded it multiple times, adjusted the gib, backlash screw and made sure all surfaces are properly lubricated. Having the gib looser gives me a larger range I can "use" but then the cross slide has more play in it than I think it probably should(and it still starts binding).

I've got a query out to Sherline but anything else I should consider or do I just have a bad cross slide?
 
Try assembling the cross slide with out the cross feed screw. Leave the gibs loss enough that you can move the cross slide with your hand and see if it binds up any where. You should be able to tell if there are any tight spots. If there are , check with high spot blue on the sliding part of the cross slide and locate the problem. If the cross slide is moving freely check to see if the cross feed screw is parallel to the cross slide ways. If it is new I would hope the seller would take care of it. It should move freely through its normal range. That said I am assuming that the slide is oiled and clean.
 
Are you able to post pictures of your setup? The gib, backlash nut, ways of the carriage, underside of the cross slide, and such. That would help us quickly get on the same page as you. Similar to @Nutfarmer's suggestion, have you tested with everything in place except with the backlash screw completely loose or off?

I know with my cross slide, the leadscrew "wobbles" a little as the handwheel spins. This can be seen by turning the handwheel with the cross slide off the carriage. I could imagine something similar could be causing your binding at a specific rotation.
 
+1 on Eric's suggestion. If that doesn't help take out the leadscrew (44210) and see if it is bent. If you bought this new a call to Sherline will probably have them sending you a replacement part free of charge.
 
Does the problem get worse as the cross slide moves toward you or away from you? The reason I ask is that the bearing block may not be in line with the feedscrew nut. So when the feedscrew nut approaches the bearing block the feedscrew gets cocked over and binds up. The usual way to address this is to loosen the attachment screws on the bearing block so it can align properly. Once the feed screw nut and bearing block are as close as possible, tighten down the screws. Then you should (may?) be good to go.

This is a common adjustment procedure for small inexpensive lathes and mills. The fact that the problem gets better when the gibs are loosened up also points to the same kind of problem, because that would free up the slide+nut to better align with the bearing block.

The feed screw may not be real straight, either. But it remains to be seen if it's good enough once everything is aligned properly.

If the problem gets better but doesn't disappear it may be time to contact Sherline. But before you do, I suggest thoroughly reading the owner's manual. I hate, HATE, to discover that the old adage of "RTFM" applies to a "problem" I have with one of my tools.

NOTE: nomenclature for lathe components can vary from manufacturer to manufacturer. By "bearing block" I'm referring to a block mounted on the operator side of the cross slide, where the end of the feed screw sticks out. The dial and hand crank attach to the feed screw. The purpose of the bearing block is to capture that end of the feed screw so it can drive the cross slide, while doing it with minimal backlash. My mini-lathe doesn't use any bearings, the thing actually is a bushing + thrust washer scheme. Sherline may do things differently.
 
Really appreciate all the suggestions, was super helpful in figuring out what was going on.

EricB was on the mark, it seems like it was a slightly mis-aligned thrust collar(which explains why it got worse as the travel increased).

Disassembled everything and confirmed the slide/dovetails were fine which eliminated that. Leadscrew looked was straight and while the thrust collar seemed okay I loosened it, threaded the slide all the way in and once the lead screw had closed the full distance of the travel removed the wheel, tightened the thrust collar and then re-assembled everything.

It's much smoother now across the full range, I was able to tighten the gibs down and tune the backlash to a place where it seems reasonable.

I was able to make my first set of chips with the lathe, I don't have it cleanly facing things yet, there seems to be about 0.5mm in the tool height that I'm not accounting for properly and leaving a nub but the rest of everything seems to be in a better state.
 
Although having never used any Sherline products, I have a gripe about the plastic gibs. Yes EMCO had them in the Compact 5, a lathe considerably larger. But wouldn't it make more sense to create gibs out of brass or even copper? I have an old Edelstaal Machinex 5 and even it has brass gibs.
 
skogkatt007 said:
Although having never used any Sherline products, I have a gripe about the plastic gibs. Yes EMCO had them in the Compact 5, a lathe considerably larger. But wouldn't it make more sense to create gibs out of brass or even copper? I have an old Edelstaal Machinex 5 and even it has brass gibs.
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The plastic gibs work great. They are easy to adjust, they get barely any wear, and they're easy to replace if they get damaged. They are a complex shape to make which works well with injection molding. The company's late owner had a background in injection molding. You could make metal gibs but that would take more machines, more scrap, a redesign of the lathe, and increase costs. Doesn't sound like a good economic decision.
 
vvanders said:
I picked up a new Sherline lathe and mill to get into machining, so far the mill has been great however I'm running into some issues with the cross slide on the lathe and can't figure out if I've not setup the machine correctly or if there's something else going on. ...
Click to expand...
I purchased a new Sherline lathe and mill in 2020 to get into machining. I had the same experience after installing the cross slide. The problem was the same: misaligned thrust collar. Pamela Weiss at Sherline directed me to a video, which resulted in me aligning the thrust collar.

My lathe had other problems. The mill has had none.

The lathe has been a growing experience for me, in tolerating other people's mistakes and perservering through them.
 
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