Thanks Thanks:  0
Likes Likes:  0
Needs Pictures Needs Pictures:  0
Picture(s) thanks Picture(s) thanks:  0
Results 1 to 4 of 4
  1. #1
    Join Date
    Jan 2014
    Location
    Northern Beaches, NSW
    Posts
    287

    Default Hercus 260 Metric - Help with Single Point Threading

    Guys,
    Need some help!

    I went to cut an M12 thread today - first time... But despite having a rough idea of what I was supposed to be doing the pitch just didn't seem right and Im not sure it was picking up the thread in the right place on subsequent cuts every time...

    Textbook of turning says that the thread chase indicator should be set on the smallest sprocket and chase a 1.75mm pitch on number 5's.

    Gearbox is set to 5B (1.75mm pitch as per the plate on the gearbox), but what is confusing me is that the same plate also says that the stud gear should be 45. The picture identifying the stud gear in the textbook of turning is the little gear that is on the tumbler gears but this doesn't come off. I have a 45 tooth gear that is currently acting as a space on the end of the gearbox shaft, its a 50 tooth thats being driven by the 80 tooth idler gear.

    Should the 50 be replaced by the 45 (i.e. make the 50 the spacer and drive the 45 with the 80 tooth idler?).

    Any pointers?

    Thx
    J

  2. # ADS
    Google Adsense Advertisement
    Join Date
    Always
    Location
    Advertising world
    Posts
    Many





     
  3. #2
    Join Date
    Jan 2009
    Location
    colyton
    Age
    73
    Posts
    207

    Default threading

    From what you have written, you have the thread chaser set on the wrong gear. It should be on the bottom or largest gear. The stud gear should be 45 and the 18 that would normally be there goes as a spacer on the outside of the screw gear.

  4. #3
    Join Date
    Jan 2014
    Location
    Northern Beaches, NSW
    Posts
    287

    Default

    Quote Originally Posted by allterrain50 View Post
    From what you have written, you have the thread chaser set on the wrong gear. It should be on the bottom or largest gear. The stud gear should be 45 and the 18 that would normally be there goes as a spacer on the outside of the screw gear.
    Mal,
    Thanks I'll change over the thread chaser.

    Thanks for the gears picture on the other thread:

    260ATM_STANDARD_GEARS-500x500.jpg

    This confirms my suspicion that the 45 and 18 gears are the wrong way round on my lathe.

    The stud gear didn't want to fall off the keyway when I un-did the nut (unlike the 45 and 60 on the end of the gearbox shaft) - I presume I can persuade it with a gentle pry-bar / screwdriver behind the stud gear? Or, is it held in place by more than just the nut on the end of the shaft?

    Thx
    J

  5. #4
    Join Date
    Jan 2009
    Location
    colyton
    Age
    73
    Posts
    207

    Default stud gear

    Hi Jon,
    The stud gear should come off fairly easily, although it may bind on the key if the fit is particularly tight, the nut is the only thing holding it on. The only gear that is pressed on is the transfer gear (which just transfer a 1:1 ratio of the headstock speed to the stud gear), behind it on the same shaft, which is never removed. Be careful not to damage the teeth of the stud gear, small marks in the gears make a hell of a noise at speed.
    If your machine has a reversing motor, the thread chaser is not really required, just leave the half nuts engaged through the entire threading sequence and reverse the motor after stopping and withdrawing the threading tool, reverse back past your starting point, far enough to remove any backlash, reset your new tool depth and put the motor into forward again. It doesn't really matter which of the two methods you use both will do the job, in fact try both it's good practice.
    Turning your first perfect thread is very satisfying but now I personally do most of my threads with coventry die heads on a stripped down 260dgm, permanently set up with a bed mounted 6 station turret, which is very quick for the production runs I need to do, it would drive me crazy to have to single point everything. It helps if you have lots of toys to play with.
    happy threading
    Mal

Similar Threads

  1. Hercus 260 - Single point threading questions
    By ventureoverland in forum THE HERCUS AREA
    Replies: 4
    Last Post: 8th July 2014, 12:58 PM
  2. Hercus Metric Question : Newbie
    By jmann_au in forum METALWORK FORUM
    Replies: 13
    Last Post: 10th May 2013, 08:42 PM
  3. metric crossfeed nuts for Hercus 260
    By jack620 in forum THE HERCUS AREA
    Replies: 0
    Last Post: 1st May 2012, 05:34 PM
  4. Metric threading on an imperial lathe
    By Vernonv in forum METALWORK FORUM
    Replies: 9
    Last Post: 25th October 2010, 07:58 AM
  5. Metric transposing gear chart, Hercus?
    By neksmerj in forum METALWORK FORUM
    Replies: 4
    Last Post: 14th May 2008, 10:27 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •