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

[Jim F]

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.

I think he has a 10K, I have a 9C.

 

[Manual Mac]

I first noticed this on my SB9C years ago when parting.
The blade stuck into the shaft I was cutting off, stopped the spindle, and the carriage lifted in the rear.
Since then I have kept the gib in the back of the carriage finger tight (still loose) but still not able to lift.
Never had that happen again.

 

[machPete99]

Most lathes will have some guide blocks bolted under the carriage to keep it from lifting up. There are typically shims in there to take up most of the play.

 

[Al 1]

I agree with Jim. Forces are down. Al

 

[Jim F]

I first noticed this on my SB9C years ago when parting.
The blade stuck into the shaft I was cutting off, stopped the spindle, and the carriage lifted in the rear.
Since then I have kept the gib in the back of the carriage finger tight (still loose) but still not able to lift.
Never had that happen again.

Fixed mine.

 

[NortonDommi]

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).

Sure about that? I bore with a LH tool and part off with an inverted,(from conventional),blade from the front so in those cases the resultant forces are upwards.
As Bill Hudson has made note much depends upon perspective.

 

[savarin]

Got fed up playing with shims on mine so made a push pull set of screws to adjust the play.
It make adjusting the play easy.

 

[SLK001]

Sure about that? I bore with a LH tool and part off with an inverted,(from conventional),blade from the front so in those cases the resultant forces are upwards.
As Bill Hudson has made note much depends upon perspective.

Well, the lathe is designed for the forces to go into the bed - not into the air. I suppose that you could mount the lathe upside-down on the ceiling and use it like that, but that's not how it was designed. We often hear, "I part backwards, standing on one leg with my eyes closed and it works for me..." All that tells me is that their lathe isn't set up properly for parting, or their technique is bad. And why would someone routinely bore with a LH tool? Every "lift" of the carriage will change the bored radius (not much, but it does change). If you're using carbide, boring with a LH tool seems like a recipe for fracturing the insert.

 

[Jim F]

Well, the lathe is designed for the forces to go into the bed - not into the air. I suppose that you could mount the lathe upside-down on the ceiling and use it like that, but that's not how it was designed. We often hear, "I part backwards, standing on one leg with my eyes closed and it works for me..." All that tells me is that their lathe isn't set up properly for parting, or their technique is bad. And why would someone routinely bore with a LH tool? Every "lift" of the carriage will change the bored radius (not much, but it does change). If you're using carbide, boring with a LH tool seems like a recipe for fracturing the insert.

Yeppers.....
He is on the other side, so it may work there.....
the whole flushing water thing.......

 

[NortonDommi]

Well, the lathe is designed for the forces to go into the bed - not into the air. I suppose that you could mount the lathe upside-down on the ceiling and use it like that, but that's not how it was designed. We often hear, "I part backwards, standing on one leg with my eyes closed and it works for me..." All that tells me is that their lathe isn't set up properly for parting, or their technique is bad. And why would someone routinely bore with a LH tool? Every "lift" of the carriage will change the bored radius (not much, but it does change). If you're using carbide, boring with a LH tool seems like a recipe for fracturing the insert.

I'm already upside down according to your world view!
No, I keep my eyes open when parting and I usually sit down or stand on both feet facing the lathe. The reason I use an 'upside down' parting tool and run the chuck clockwise is that the chips or swarf falls down and it just works better. I part at nearly the same speed I turn at, fast and hassle free.
I was incorrect when I said I use a LH tool for boring though, I use a RH tool upside down from conventional cutting on the rear side of the lathe as it allows me to see what I am doing easier if I am doing something narly. If you ever have to bore out a track roller some genius has decided to blast weld into after a non-maintained bearing has collapsed and done so without removing all the broken bearing I can assure you that being able to observe the cut is pretty much vital.
I have never had any problem boring to size.