Page 1 of 2 12 LastLast
Results 1 to 15 of 30
  1. #1
    Join Date
    Apr 2009
    Location
    Perth AU
    Posts
    36

    Default Metric threading on Hercus 9A

    Hello all,

    I did do a search for this but must admit it was a male look so please forgive me if it didn't jump into my hand.

    I have need to do some metric threading on the Hercus 9A (with QC gearbox) and need some help with the gear changes and QC settings, etc.

    The lathe has all the standard setup for imperial turning and threading as standard and I have (what I believe to be) a full set of metric change gears.

    The gears I have are
    50, 55, 65, 70, 75, 85, 90, 95

    What I would like to ask is how do I use this gear set
    1. In normal operation and
    2. In cutting metric threads

    Any advice or assistance would be greatly appreciated.

    Thank you
    Cheers,

  2. #2
    Join Date
    May 2020
    Location
    Willowbank QLD
    Posts
    517

    Default

    I am not sure if your lathe has it, but inside the cover of the change gears I have seen a chart that describes this.
    It may look like this https://australianmetalworkinghobbyi...=496&limit=100

    Steve

  3. #3
    Join Date
    Apr 2009
    Location
    Perth AU
    Posts
    36

    Default

    Quote Originally Posted by Reidy41 View Post
    I am not sure if your lathe has it, but inside the cover of the change gears I have seen a chart that describes this.
    It may look like this https://australianmetalworkinghobbyi...=496&limit=100

    Steve
    Thank you Steve that is really UI (Useful Information) but I am sorry I do not know how to interpret what you have provided.

    The gears related to in the link do not correlate with the ones I have, and I am sorry I do not have the capacity to do the math to equate which is equal to which, but I understand what you are offering.

    Can you please provide more information.

    Cheers,

  4. #4
    Join Date
    Nov 2015
    Location
    Brisbane Australia
    Posts
    85

    Default

    Ross, it might be easier to tell us what threads you are trying to cut and we can tell you what gears to use.
    Also what is the length of the thread you are going to make ?

  5. #5
    Join Date
    May 2020
    Location
    Willowbank QLD
    Posts
    517

    Default

    Quote Originally Posted by RossA View Post
    Thank you Steve that is really UI (Useful Information) but I am sorry I do not know how to interpret what you have provided.

    The gears related to in the link do not correlate with the ones I have, and I am sorry I do not have the capacity to do the math to equate which is equal to which, but I understand what you are offering.

    Can you please provide more information.

    Cheers,
    I am sure someone more experienced will chime in. It is my understanding that you would need a set of 60 and 63 gear or 127 and 100 gears. That is assuming you have an imperial lead screw. A photo of the placards on the lathe will assist others to confirm what you have and what you need to achieve what you want.

    Steve

  6. #6
    Join Date
    Nov 2007
    Location
    melbourne australia
    Posts
    3,228

  7. #7
    Join Date
    Apr 2009
    Location
    Perth AU
    Posts
    36

    Default

    Quote Originally Posted by jack620 View Post

    Thank you Jack exactly what I could not find in my search.

    So it seems from that my change gears are not for metric cutting.

    Which raises the question what are these ratios used for?

    @Somedayplumbing the part requires ~10mm at each end of a 70mm rod to have 12x1.5 and 13x1

    @Steve the placard is the standard imperial one as shown in Jack's photo in the link

    Cheers,

  8. #8
    Join Date
    Apr 2009
    Location
    Perth AU
    Posts
    36

    Default

    Further to this, and I suppose to a certain extent thinking out loud, the conversion to metric using the 127 and 100 tooth gears gives a ratio of 1.27.

    If I use the 95 and 75 (which I do have) will yield a ratio of 1.2666 which, if I'm doing my maths correctly, gives an acceptable error of just 0.033%

    Can somebody please tell me whether this is correct or if I am barking up the wrong tree?

    Thank you

  9. #9
    Join Date
    Nov 2008
    Location
    North Brisbane. Qld. Australia
    Age
    70
    Posts
    1,511

  10. #10
    Join Date
    Apr 2009
    Location
    Perth AU
    Posts
    36

    Default

    Quote Originally Posted by SurfinNev View Post
    Hahaha thank you SurfinNev that is where I am getting most of my math from. That site gave me all the information in my previous post, I simply did some extra calculations based on what was there. If you look, I have plagiarised some of his calculations.

    I do appreciate the link and if anyone else finds it useful I hope they give you credit too.

    Cheers,

  11. #11
    Join Date
    Apr 2009
    Location
    Perth AU
    Posts
    36

    Default

    Apologise for the delayed response, have been tinkering and trying to sort this out.

    As it turns out these are not change gears but gearbox gears for the tumbler gearbox on my 9A.

    As a reminder the gears I have are 50, 55, 65, 70, 75, 85, 90, 95 and they are a lot thinner and different pitch to the change gears.

    If I swap these into the gearbox does that make it a metric gearbox or something else?

    If they do as I want need do I need to change anything else? Charts, thread chaser, etc. I assume.

    If not above what are they for?

    Or am I completely barking up the wrong tree?

    If this does not get any replies I will post a new topic.

    Thanks all.

  12. #12
    Join Date
    Nov 2007
    Location
    melbourne australia
    Posts
    3,228

    Default

    Throw us a bone here Ross and post a pic of your gears.
    Chris

  13. #13
    Join Date
    Aug 2015
    Location
    Adelaide
    Posts
    239

    Default

    Hi Ross

    I can tell you now that those gears are not for the gearbox as they definitely will not fit in there and will definitely not turn it into a metric gearbox, the metric gearbox is a completely different set-up to the imperial and they used the 3 mm pitch lead screw so it seems as though the gears you have would be for something else completely, best bet is to buy the right set of change gears or see if someone can lend you a set.

  14. #14
    Join Date
    Apr 2009
    Location
    Perth AU
    Posts
    36

    Default

    Quote Originally Posted by Tinkerer77 View Post
    Hi Ross

    I can tell you now that those gears are not for the gearbox as they definitely will not fit in there and will definitely not turn it into a metric gearbox, the metric gearbox is a completely different set-up to the imperial and they used the 3 mm pitch lead screw so it seems as though the gears you have would be for something else completely, best bet is to buy the right set of change gears or see if someone can lend you a set.
    Fair enough, I wonder what they are for then?

    Will post a pic and get some measurements when I get a chance.

    Thank you
    Cheers,

  15. #15
    Join Date
    Apr 2009
    Location
    Perth AU
    Posts
    36

    Default

    Have a picture and each gear is 7/32" wide. Sorry do not have the pitch but number of teeth are as previous.

    gears.jpg

    Thank you for any assistance with this.

    Cheers,

Page 1 of 2 12 LastLast

Similar Threads

  1. Metric threading on Imperial 9"AR Hercus
    By auscab in forum THE HERCUS AREA
    Replies: 9
    Last Post: 9th May 2021, 11:22 AM
  2. Hercus 260/9" B and C inch to metric threading chart
    By allterrain50 in forum THE HERCUS AREA
    Replies: 0
    Last Post: 29th May 2017, 04:22 PM
  3. Imperial Threading on Metric Leadscrew
    By Jenova in forum METALWORK GENERAL
    Replies: 29
    Last Post: 15th Apr 2017, 11:09 AM
  4. Hercus 260 Metric - Help with Single Point Threading
    By ventureoverland in forum THE HERCUS AREA
    Replies: 3
    Last Post: 19th Sep 2014, 11:48 PM
  5. Metric threading on an imperial lathe
    By Vernonv in forum METALWORK GENERAL
    Replies: 9
    Last Post: 25th Oct 2010, 07:58 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
  •