Wear on the V in the front/back direction has a much more direct effect. The difference in diameter that this introduces, if the tool tip is on center, is 2 x 0.010" x 0.010"/1" = 0.0002" over the length of the part. Your lathe has 0.010" of vertical wear (a lot!) near the headstock, tapering to 0 vertical wear near the end of the part.
If a lathe ways are only worn in the vertical direction, then this produces very little taper if the cutting tool is close to center, and the diameter of the part is not too small.Įxample: you are cutting a 2-inch diameter part (1" radius). Regarding bed wear, I want to point out something that is often overlooked. I agree that it's important to first check that the lathe bed is not twisted, and if the headstock can be rotated, that it's in the correct position. Not sure of your experience level so if that's already obvious, no offense intended. And I'm assuming you are measuring this taper with the work held only in the headstock right? If you're using the tailstock it could just be that the tailstock is offset. Could be as simple as a levelling needed or a little tweak to the headstock angle. are back where they belong.īefore going that route though, make sure that is for sure the issue. That entails adding some turcite to the underneath of the saddle to restore lost height so that leadscrew and etc. Generally most guys get the bed ground and scrape the underside of the saddle.
If the problem is wear, it's still quite easy to "tap in" a fairly true diameter - if you don't have good DRO, you don't use the dials to do that, you use a dial indicator set to register on the cross slide or the tool/toolpost, etc.įor an actual repair if necessary, you'd need to either scrape the ways of the bed and under the saddle or get them ground. Absolutely check the lathes for true (levelling is the easiest way, as M.B.