advice on how to male a new cross slide leadscrew and nut for it
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  1. #1
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    Default advice on how to male a new cross slide leadscrew and nut for it

    Hi
    My 95 year old Holbrook is beginning to show some signs of wear in the cross slide. The leadscrew is worn in the centre part and also the nut has a little bit of wear. Currently the thread employed is 8tpi square, The nut seems to be made of brass.
    Looking at it I thought the leadscrew was 1/2 inch diameter but it is in fact 0.556 inch. This has foxed me and I cannot see any reason why 1/2" was not used.
    I originally thought to use a 10 TPI Acme tap to make a new nut and acme lathe tool for the leadscrew thread, switching to 10 TPI would reduce the feed a little and if I were to use a 100 segment handwheel would maybe be simpler. I doubt I will find a tap of .556 inch diameter.
    Is there any reason I shouldn't use 1/2" ?
    I wont need for it to last for another 95 years so am quite willing to use an easy to machine steel for the leadscrew and anything easy for the nut, posssibly even plastic. Five years of light use will be enough for me.
    the leadscrew fits into the lathe through a hole and after the screw part (and a bit of unthreaded bar) emerges under the toolpost the only thing it touches is the nut.
    so two questions : What would be suitable materials and is there any reason not to use 1/2 inch for the screw thread and nut ?

    Thanks for your help

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    If you used the 1/2", Roton has the LH and RH screws in ACME. They also have sleeve nuts to match which you might be able to fit in your existing nut and solder in place.

    Acme Lead Screws & Nuts - Engineering Data | Roton Products Inc.

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    many thanks for that.. wish I could edit the header

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    If the lathe isnt worth much,and you want a cheap fix,use the screw and nut from a cheap car jack,scissor type...........Ive used these many times in small cheapies I got in job lots with the cross feed knackered..........in fact ,if I got a 9" SB or Hercus tomorrow with cross screw failure,this is exactly what I would do.

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    Quote Originally Posted by Rudd View Post
    If you used the 1/2", Roton has the LH and RH screws in ACME. They also have sleeve nuts to match which you might be able to fit in your existing nut and solder in place.

    Acme Lead Screws & Nuts - Engineering Data | Roton Products Inc.
    +1 Just use the Roton 1/2" components in their 8 TPI option and no need to mess with the dial graduations. It will also have the same "feel" you have become accustomed to, whereas the the finer pitch may take getting used to.

    Not that it cannot be done. Your lathe, your rules.

    Either way, nobody from Holbrook's design or QC department is likely to come knocking you up to complain.


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    One of the most watched threads on metalworking is called EVANUT it deals with making a crosslide nut with Delrin. It’s easy to do.

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    If you're so inclined to make it yourself, Keith Rucker on YouTube made replacement acme cross slide and bronze/brass nut for his Monarch Model K, and also for a few other lathes for a couple of his viewers.

    I personally wouldn't want to reduce the feed rate of my lathe by 25%, but rather keep it at 8 tpi. I've heard great things about those Holbrook lathes, but have never seen one in action, in person. Good luck with your project.

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    Thanks.. The lowest feed rate I have atm is 112 cuts per inch. Fine with HSS but bit hard on inserts.


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