The cutter should be adjusted to avoid a centre pip. Actually, for making heavy cuts on larger diameter bars, the cutter will be deflected to below centre height by an amount depending on how rigid your set up happens to be. With an old fymord, I expect it could well be a few thou. There should be no (or minimum) deflection when at the centre of the bar.

Remember that at the centre, the surface cutting speed is actually zilch.

If you are using carbide, travelling beyond the centre may cause the cutter surface to be damaged (by reversing the cutter direction).

Might also be worth checking that the cross slide end plate isn't misaligned. A problem I had when removing the lead screw to use the taper turning attachment and the re-installing it.

Rod

So it moves fine when you are not cutting even when moved as far across the lathe?

If so look at tool height particularly if it is leaving a conical bump in the middle as tool is too high

Disconnect the end plate from the cross slide. remove the Cross slide screw fully from the lathe.

Push the cross slide back and forward. If it is tight at any point then adjust the gibs on the cross slide so it slides easily. Make sure that you have properly lubricated the cross slide with a suitable lubricant, I use an MDS grease.

When you reassemble the end plate with the screw back to the cross slide only tighten the 2 end plate screws when you the cross slide screw in ad far as it will go.

Only when you are certain that the cross slide is moving freely then try cutting and see if you still have the issue then we know you are dealing with a tooling or cutting issue.

Peter

If the tool is on centre height, it may be that (very likely in an older machine, ) the Saddle and Cross Slide, and probably the Leadscrew,  are worn, and although the gibs are set for the worn areas, things tighten up over the less worn parts.

This can be alleviated by scraping the dovetails, but as a newbie, you would be well advised not to do it, for fear of doing more harm than good.   Scraping surfaces, particularly dovetails, is not easy.  It is a hard to acquire skill.

Howard

Edited By Howard Lewis on 01/09/2022 14:45:53

Jason,

I don't think so!

I thought that I took account of that by saying, in the first paragraph, that If there is wear in those components, and the gibs are set for that wear, things will get tight when the less worn areas make contact.

The problem with living with that state is that the Leadscrew and the Mazak nut are likely to wear.

At least a worn nut is easily replaced!

Jason, Ah!

In that case, your response was valid.

Then I realised what had been sent about not cutting, and the tool now being on centre height.

Howard