Myford thread dial bolt size

[John Stevenson 1Participant @johnstevenson1]

The thread dial on my TOS has been hanging down, out of mesh for at least 17 years.

I always return under power when threading, no matter what pitch as I find that if the half nuts are never disengaged you can't make mistakes.

 

Things like the swing up threading tools are a big boon and they can stop errors when getting back into position on the cross slide.

Edited By John Stevenson on 23/03/2017 12:11:45

[Keith LongParticipant @keithlong89920]

Perhaps I could add a note of caution to the debate about whether a thread indicator ever needs to be brought out of mesh. I have a (fairly) large lathe awaiting setting up and restoration – an IXL Leader gear head machine, 6in centre height 40 in between centres. One of the jobs that will need doing is making a replacement for the thread indicator drive gear as about a third of the teeth have been ripped off. Now the indicator shaft is free to turn, and I've done nothing to it, so it was presumably free to turn when the teeth got damaged. The only thing I can think that has caused the problem is swarf getting caught between the gear and the lead screw while the lathe saddle was being traversed by the power feed – this lathe has separate lead screw and power feed shafts. Now on a lathe with just the lead screw I'd expect the operator to notice the extra drag from a jammed indicator gear if they were traversing the saddle by hand, but it might depend on how intent they were on the actual job rather than the operation of the machine.

I'll never know for certain what caused the damage to my machine, but don't assume that damage cannot occur.

[not done it yetParticipant @notdoneityet]

Clearly, with lathes that have a separate threading and power feed arrangement (ie. a separate power feed shaft) there is no need to disengage the dial indicator, ever.

The situation with cheaper type lathes (like myfords), where the lead screw also drives the power feed, may be different. Simply put: if it ain't in contact, or turning, there will be no wear issue.

One reason why myford closed down Raglan, after purchase – myford only made and sold cheaper lathes and were not interested in making any investment in the higher quality (and therefore more expensive) hobby lathe sector, into which Raglan were clearly entrenched.

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