Apron can be picked up off the ways by about 1/8 inch; is this OK?

twooldvolvos

twooldvolvos

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Well, I am to the point to where I figure there is nothing to it but to do it with my new-to-me lathe. So in the process of trying to flare a 3/4 inch copper pipe for a Mr. Pete style cutting oil can, I noticed that my apron can be lifted about 1/8 inch off of the ways. (please don't ask me to explain). I am just wondering if that is normal. I will grant you that my flaring technique was most likely not by the book. I am thinking that in normal lathe operation, the apron is forced against the ways so the fact that I am able to lift it a small amount is not an issue. Any wisdom? BTW, I have attached a pic of my finished cutting oil can.

attmrPeteCuttingOilCan.JPG
 
There must be a confusion about terminology on my part. I know the "apron" as part of the cross slide that contains several gear trains and knobs and handwheels and such. What is there varies from model to model. In any(all?) cases though, the apron is rigidly attached to the cross slide.

The cross slide is a point of registration. It should move in only two directions, that being the "X" axis or longitudinal and the "Y" axis or front to back. There should be no other motions. There may be a half a thou in the "Z" axis, or less. Just enough that the slide is not hard fixed to the ways. Call it room for oil or lubrication.

There are "shoes", I don't know the proper term, on the underside of the cross slide that clamp against the ways to hold it tight. If there is slack in these shoes, the apron, attached to the cross slide, can be moved in the "Z" axis. i.e. vertically. This must never happen. When it does, the "shoes" must be tightened.

Every machine will have different methods for attaching the "shoes". But there will be some method to tighten them solid and then relieve that pressure to allow movement and lubrication. I have an Atlas built machine and a Grizzly Chinese machine. In addition, I have had several smaller machines over the years. Every one had a different system, but each one had some method to hold the cross slide to the ways.

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Bi11Hudson said:
There must be a confusion about terminology on my part. I know the "apron" as part of the cross slide that contains several gear trains and knobs and handwheels and such. What is there varies from model to model. In any(all?) cases though, the apron is rigidly attached to the cross slide.

The cross slide is a point of registration. It should move in only two directions, that being the "X" axis or longitudinal and the "Y" axis or front to back. There should be no other motions. There may be a half a thou in the "Z" axis, or less. Just enough that the slide is not hard fixed to the ways. Call it room for oil or lubrication.

There are "shoes", I don't know the proper term, on the underside of the cross slide that clamp against the ways to hold it tight. If there is slack in these shoes, the apron, attached to the cross slide, can be moved in the "Z" axis. i.e. vertically. This must never happen. When it does, the "shoes" must be tightened.

Every machine will have different methods for attaching the "shoes". But there will be some method to tighten them solid and then relieve that pressure to allow movement and lubrication. I have an Atlas built machine and a Grizzly Chinese machine. In addition, I have had several smaller machines over the years. Every one had a different system, but each one had some method to hold the cross slide to the ways.

.
Click to expand...
Thanks for your comment. I am referring to where the hole apron assembly attaches to the ways. In other words, When I lift up on the assembly, the felt scrapers will lift off the V ways about 1/8 inch. BTW, my lathe is an older South Bend 10K.
 
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Jim F said:
On a lathe Z is the longitudinal axis, X is crossfeed, Y is a milling attachment.
Click to expand...

Being mostly self taught, I take the machine motion axes the same as from plane trigonometry. Looking down at a basic "unit circle" drawn on paper, X is the left-right axis, Y is the up-down axis and Z is toward or away from the viewer. Looking down at a machine, any machine, from above, I take the axes the same way. It may not be the "correct" way, but it is a way to keep the motions of the machine in perspective for me.

I have seen different axes represented different ways by different people. I never went to "high school", having had a remedial math class in the mid-'70s. The background I took into the class was nautical navigation, knowing a few formulas from "solid" trig, (third dimension) All such axes reference a different direction on different machines. By keeping the same references as I keep navigation, it simplifies anything I encounter in life. It may not be correct, but it allows me to present a solution to a LOOSE cross slide in terms that can be understood.

What it comes down to is that the cross slide should move "left-right" or longitudinal, as well as "in-out" for depth of cut. It should never lift off the ways, being loose enough to move smoothly and nothing more. This applies to a lathe, a mill, a shaper, or even the front door. It should move in only two dimensions. You choose which two.

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There are gib screws on the far side of the carriage that can be adjusted to take out the play.
I cannot recall if there is similar on the front


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Make of lathe?

Having the carriage lift like that is really no big deal, as all of the forces are down into the bed (not up into the air). As David says, most lathes have a gib at the rear of the carriage (RE: directly across from the cross slide dials) that can be tightened to lessen this "lift". If you have a South Bend lathe, you'll probably find that the two bolts are fairly loose. Just tighten them by hand until you're more comfortable with the amount of upward play. Just know that if you get them too tight, the carriage may bind while in use.
 
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