Page 2 of 2 FirstFirst 12
Results 16 to 25 of 25

Thread: 17 tpi thread

  1. #16
    Join Date
    Nov 2008
    Location
    Sydney
    Posts
    112

    Default

    Quote Originally Posted by azzrock View Post
    thanks Pipe clay .Ill have a look if i have a 51.
    cheers aaron
    Pipeclay is correct, a 24/51 gear combination will give you 17 TPI. As far a I can determine, Hercus did not have a 51 tooth gear in their parts list, so you will need to find a custom made one if the 24/52 combination is not close enough for your application.

    Chas.

  2. #17
    Join Date
    Nov 2018
    Location
    Tasmania
    Posts
    97

    Default

    Quote Originally Posted by azzrock View Post
    hi is this a suitable gear cutter for hercus change gears
    thanks
    Attachment 384510
    The link didn't work for me
    I've made a heap using 18 DP cutters with 14.5 PA and they work great

  3. #18
    Join Date
    Oct 2010
    Location
    melbourne, laverton
    Posts
    1,910

    Default change gear

    Quote Originally Posted by Chas View Post
    Pipeclay is correct, a 24/51 gear combination will give you 17 TPI. As far a I can determine, Hercus did not have a 51 tooth gear in their parts list, so you will need to find a custom made one if the 24/52 combination is not close enough for your application.

    Chas.

    hi Chas. He al ways is. But thanks . I couldnt get a change gear calculator working on my phone. Ive forgotten how to do it.
    Ray-s kindly offered me a 33 tooth hercus gear to use but im not even sure what combination i would use that in.

    Plus tommie thanks for the info. I 1 or 2 gear cutters.
    IMG_20200201_001803.jpg
    here is another try to my photo. it says 20 dp No.2 14 1/5
    From what ive read you cant get a 63 tooth gear out of a 40 to1 indexing head.
    aaron

  4. #19
    Join Date
    Oct 2011
    Location
    Norwood-ish, Adelaide
    Age
    59
    Posts
    6,540

    Default

    Quote Originally Posted by azzrock View Post
    here is another try to my photo. it says 20 dp No.2 14 1/5
    From what ive read you cant get a 63 tooth gear out of a 40 to1 indexing head.
    aaron
    From what Tommy is saying, the gears are 18DP, so a 20DP cutter will not produce the correct tooth shape. It will be a no. 2, as they do 54 to 135 teeth.

    You are correct that a 40:1 (semi-universal) dividing head will not do a 63 tooth gear. If you have a rotary table that can be set up with plates, I think that should be able to do it though.

    Michael

  5. #20
    Join Date
    May 2012
    Location
    Hobart
    Posts
    18

    Default

    Quote Originally Posted by azzrock View Post
    hi every one . is it possible to cut a 17 tpi thread on a hercus c . An imperial modal
    what change gears are required?
    aaron
    I know this is probably too late, but changing the standard 20 tooth stud gear with a 26 tooth gear and gearbox set on cutting 22tpi (or gears to cut 22tpi) will give 1.50091 mm pitch.
    Calculations: 22 tpi = 1.15455 mm pitch (25.4 / 22). 26/20 x 1.15455 = 1.50091 mm

  6. #21
    Join Date
    Aug 2012
    Location
    Greenmount, W.A.
    Age
    70
    Posts
    272

    Default

    From Harold Hall's website:
    My metalworking and other interests. Harold Hall
    I down loaded his tables. This page:
    http://www.homews.co.uk/page30.html

    From them is some examples:

    CHANGEWHEEL COMBINATIONS
    AND RESULTING THREADS PER
    INCH FOR A LATHE WITH AN
    8TPI IMPERIAL LEADSCREW

    TPI R1 R2 R3 N1 N2 N3
    16.9867 20 25 45 21 35 65
    16.9867 20 30 75 21 65 70
    16.9867 20 45 50 21 65 70
    16.9867 20 50 75 35 65 70
    16.9867 25 30 60 21 65 70
    16.9867 25 40 45 21 65 70
    16.9867 25 40 75 35 65 70
    16.9867 25 50 60 35 65 70
    17.0040 20 38 65 25 60 70
    17.0040 20 38 65 30 50 70
    17.0040 20 38 65 35 40 75
    17.0040 20 38 65 35 50 60
    17.0040 21 38 65 35 45 70
    17.0040 25 38 65 35 50 75
    17.0040 30 38 65 35 60 75
    17.0040 30 38 65 45 50 70
    17.0040 38 40 65 50 60 70
    17.0040 38 65 70 75

    Harold also explains the effect of errors......
    Too complex for me! Read it yourself.

  7. #22
    Join Date
    Oct 2010
    Location
    melbourne, laverton
    Posts
    1,910

    Default

    thanks guys i havnt solved this problem yet so thanks.

  8. #23
    Join Date
    Apr 2004
    Location
    Notting Hiĺl (Melb) or Echuca
    Age
    64
    Posts
    179

    Default

    Vernon's program works for me on a PC -- never mastered the phone version either
    Vernon provided a link to download the PC version originally and when I got a new PC he was kind enough to provide a copy again

    Anyway from Lathegears I found
    16 stud, 34 screw gear
    24 stud, 51 screw gear
    32 stud, 68 screw gear
    ?40 stud to 85 screw gear would also work
    One is aiming for a reduction of of 2.125


    On my Hercus the 100/127 will fit as an idler combination but do not expect to shut the cover.
    cheers
    David

    ------------------------------------------------
    A society grows great when old men plant trees whose shade they’ll never sit in. (Greek proverb)

  9. #24
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,439

    Default

    Hi Guys,

    The Myford uses a 63 tooth gear. Although I understand a 127 tooth gear is available.
    Best Regards:
    Baron J.

  10. #25
    Join Date
    May 2012
    Location
    Hobart
    Posts
    18

    Default

    Harold also explains the effect of errors......
    Too complex for me!
    [/QUOTE]

    Agree, it looks complicated. Partly because of not eliminating "silly" gear options.

    For example, cutting a 22.000 tpi thread the first option uses a 22T and 55T gears.
    The next 16 gearing options use 6 gears - two of which are 22T and 55T. Why bother to include them?



    ... and a sample calculation would not hurt either (from the last example above - 8 x 40 x 55 x 75 / (20 x 50 x 75) = 22, or from the first example 8 x 55 / 20 = 22)

Page 2 of 2 FirstFirst 12

Similar Threads

  1. why cant I cut this thread?
    By Alf Scotting in forum METALWORK GENERAL
    Replies: 47
    Last Post: 27th Oct 2018, 12:53 AM
  2. why cant I cut this thread?
    By Alf Scotting in forum METALWORK GENERAL
    Replies: 3
    Last Post: 8th Oct 2018, 08:00 PM
  3. WEST AUST All-thread Rod
    By pmcgee in forum METALWORK - Machinery, Equipment, MARKET
    Replies: 0
    Last Post: 23rd Mar 2012, 09:48 PM
  4. This Thread Could Be About You!!!
    By sydneyfc in forum FORUMS INFO, HELP, DISCUSSION & FEEDBACK
    Replies: 2
    Last Post: 28th Oct 2007, 09:39 PM

Posting Permissions

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