Lathe ways not flat across

[Randall Mack]

I recently acquired a new 3520B and was examining the ways with a straight edge. It seems that the front side is machined 6-7 thousandths of a inch higher than the back all along the length of the bed. The front and back surfaces seem to be parallel but not in the same plane. I can rock a machinist square rule and determined the difference with a feeler gauge. Is this normal for this lathe? I was expecting dead flat. I may loosen up the leg bolts to see if that has any impact. :confused:

[David Walser]

Randall -- From your description, it sounds like your lathe is not sitting level on the floor. If one leg of the lathe is slightly longer or shorter than the others (or if the floor isn't perfectly flat), the bed of the lathes will rack and you'll see what you described. Use the lathe's leveling feet to get the lathe level front to back, end to end, and corner to corner. Using a decent quality level that is at least 24" long makes leveling the lathe easier.

[Randall Mack]

David thanks. I just went through those steps. I have 2 decent 4 foot levels that I used as winding sticks to check for twist also. I measured the difference several times in the process and did not see much change. I loosened up the head stock, banjo, and tailstock to see if anything is causing distortion. I also tried to loosen up the leg bolts slightly. That seemed to help a little, maybe a thousandth but it was not consistent.

[Tim Boger]

I'll tell ya .... that amount of variance wouldn't bother me. Seriously, turn, enjoy ... repeat.

[Mike Goetzke]

How well does the tail stock line up with the head stock?

[Jason Edwards]

Got to agree with Tim above, if you are not having a problem turning and the tailstock and headstock line up reasonably well with each other, get turning and don't worry about it. Ernie Conover sold a lathe for a number of years that had wooden ways (user supplied). You'd have went nuts trying to get that within .007". Lots of good work done on those machines.

[Dennis Cloutier]

I think the only thing that really matters is alignment between the head and tailstock, and even that is only really important for certain operations. I used to have a lathe that had a fair bit of misalignment and it worked fine for most things. The biggest difference I noted when I upgraded was that drilling out pepper mills became much easier & more accurate. I think any operation where you have the workpiece held in a chuck or faceplate and you bring the tailstock into play is going to suffer from more vibration if your headstock & tailstock are poorly aligned, but everything else should be fine.

And, if your headstock and tailstock are well aligned then you don't have any worries.