help! Logan lathe compound problem

Not uncommon. The reason your dial 'ratchets' like that is the contact area between the inside thrust surfaces (between the inside of the bushing, and the shoulder on the crossfeed screw) is different than the contact area on the outside thrust surfaces (between the dial and the front of the bushing).

In the case of a south bend machine, that sort of behavior indicates that either the total clearance in the assembly is too small (below a thousanth), the leadscrew is slightly tweaked and binding someplace, or the thrust bearing surfaces are badly worn and grooved, and are binding up.


Reply to
jim rozen
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i'll try and describe the problem as best i can:

I was having an issue with the feed dial on the compound on my logan

10", where it would be free and follow the handwheel when i spun the handwheel CCW, but when i turned the handwheel CW, the dial would spin inwards, butt against the threaded-in faceplate that holds the compound screw, and stop moving. this makes it REALLY hard to accurately move the compound in in small increments for things like threading.

So, looking at the parts manual, i figured there has to be a missing shim or something of that sort, even though there isn't one listed in the parts list. I carefully took it apart, checked it, didn't see anything obvious, put the compound back together. which leads to an interesting anomaly: it appears that the compound screw is kept in place by butting a flange against the inside of the faceplate that's threaded in, and by a nut thats threaded onto the screw with the dial and faceplate inbetween. so, what keeps the dial from always being pinched between the faceplate and the nut when feeding inward? I haven't figured this out yet, and it's making accurate threading a real pain.

the only way i've thought to fix this is to somehow build a shim onto the end of the compound screw thats inside the compound, and use it to force the screw to always butt it's flange against the inside of the threaded faceplate. this would then take the load off of the dial, and allow it to freely move. however, this is certainly not how it was done originally, and i have my reservations about doing this as the shim would then be butting against the inside of the casting for the compound, possibly wearing it and distorting it.

any thoughts assuming there's no easy fix for the problem?



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The fellow that owns Logan is most helpful, Scott Logan.

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Give him an email.


Reply to
Karl Townsend

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