Page 1 of 2 12 LastLast
Results 1 to 15 of 16
  1. #1
    Join Date
    Jun 2007
    Location
    Victoria, Australia
    Posts
    114

    Angry Half nut engagement with mal calibrated chasing dial!

    I have a CL40A lathe. Again I find something not correct. My chasing indicator for locking the half nut to the lead screw is off by about 15 degrees. I managed to work around this by finding the engagement point for the 2.5mm thread and marking the point with a marker. This worked well, it just means I have to mark for each new type of thread.


    I will try and figure out how to align the engagement markers with the correct thread.


    Just wanted to vent. Any comments or suggestions?


    Regards, Tom
    Attached Images Attached Images

  2. #2
    Join Date
    Jul 2010
    Location
    Melbourne
    Posts
    9,088

    Default

    I assume its a metric leadscrew?
    Cant you just adjust the gear on the bottom? or is it keyed?

  3. #3
    Join Date
    Jun 2007
    Location
    Victoria, Australia
    Posts
    114

    Default

    The gear is keyed. Best would be to rotate the Decal. Metric Lead screw.

  4. #4
    Join Date
    Jul 2010
    Location
    Melbourne
    Posts
    9,088

    Default

    I think I'd use a pencil mark.
    But if it troubles you, you could adjust the spacer length to get the timing correct. Though you'll likely need a different spacer for each gear.

  5. #5
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,439

    Default

    Hi Tom, Guys,

    Most likely the self adhesive disc with the markings has not been stuck down in quite the right place, rotation wise. Just peel it off and re-stick it !
    Best Regards:
    Baron J.

  6. #6
    Join Date
    Jul 2010
    Location
    Melbourne
    Posts
    9,088

    Default

    Quote Originally Posted by Stustoys View Post
    But if it troubles you, you could adjust the spacer length to get the timing correct. Though you'll likely need a different spacer for each gear.
    I'm no longer sure that would work, though I think its a H&F issue. Your dial has 7 numbers, for some reason the one on H&F's L600D(which they say is your lathes replacement) has 8 though the indicator table hints that that should be 7.
    https://images.machineryhouse.com.au...asing-Dial.jpg

    If you are using a 14 tooth gear then adjusting the spacer will work. For the other tooth counts you'll only be able to get it "right" on one number, but as those pitches only use one pickup that's fine.

    I've been known to set the timing so I am closing the halfnut on the trailing flank of the leadscrew, it drops in so nicely.

  7. #7
    Join Date
    Apr 2018
    Location
    Drouin Vic
    Posts
    633

    Default

    I re-manufactured the half-nuts on my lathe years ago and the dial didn't end up aligned with the mark. I made a new mark and ignore the old one. It's no biggie but I guess it would be annoying on a new machine.

  8. #8
    Join Date
    Apr 2012
    Location
    Healesville
    Posts
    2,129

    Default

    The cl410 is the same, the number comes around and you apply gentle pressure on the lever and it drops in past the line.
    Its no biggie and mosts lathes are probably same.

  9. #9
    Join Date
    Nov 2009
    Location
    australia
    Posts
    57

    Default

    You have a bloody good lathe to do thread cutting with, so why bother to try and engage that silly thread chasing indicator, just leave the HALF NUT engaged and reverse the chuck.

    The lathe you have, has got a good foot brake to stop the chuck, so when you are at the end of the thread cut, stomp on the brake hard and move your cutting tool away from the job.
    Just chuck it into reverse and when the tool tip gets back past the start point, stomp on the brake and advance the tooltip and put it into forward gear and start cutting the thread again.

    You can get so good at doing this simple procedure ,you will wonder why you ever bothered to even contemplate using that stupid thread chasing indicator.
    My boss watched me doing it this way and he reckoned it was just about as quick as the CNC lathe he was using, oh, you can even cut threads at 600RPM if your game to give it a go.

    600 RPM sure gives a very good finish on the thread as well, kind of a mirror finish to the threads.

  10. #10
    Join Date
    Nov 2007
    Location
    melbourne australia
    Posts
    3,228

    Default

    Quote Originally Posted by shedhappens View Post
    Its no biggie and mosts lathes are probably same.
    My Hercus 260 is. As long as you engage the lever when the desired number is roughly near the index, it drops in nicely.
    Chris

  11. #11
    Join Date
    Apr 2012
    Location
    Healesville
    Posts
    2,129

    Default

    Quote Originally Posted by mardtrp View Post

    You can get so good at doing this simple procedure ,you will wonder why you ever bothered to even contemplate using that stupid thread chasing indicator.
    My boss watched me doing it this way and he reckoned it was just about as quick as the CNC lathe he was using, oh, you can even cut threads at 600RPM if your game to give it a go.

    600 RPM sure gives a very good finish on the thread as well, kind of a mirror finish to the threads.
    I think the chuck that i have on my cl410 weighs nearly 40 kgs so i wont be trying that, i have tried thread cutting at those speeds on a smaller lathe, a colchester,
    and was not happy with the stress or the finish and find it quicker to wind the
    saddle back and use threading dial. I pretty much only reverse out when cutting a metric thread on an imperial lathe or vice versa.
    I am happy threading at 150 - 275 rpm and get good finish and fit at those speeds.

    Back to the threading dial...
    I'm pretty sure that when you change the gear on the dial it changes the position again so no point
    in remarking anything.
    I always have a bit of a test run before cutting to see where the half nuts are actualy
    engaging in relation to the dial and commit that to memory.

  12. #12
    Join Date
    Nov 2009
    Location
    australia
    Posts
    57

    Default

    So your chuck weighs in around forty kilo, wow, seems to be a very regular weight for a chuck of about that size.

    Maybe it's you who is just scared to try something that works very well, OK, that means you just stay in the dark ages and do it your way.

  13. #13
    Join Date
    Apr 2012
    Location
    Healesville
    Posts
    2,129

    Default

    Quote Originally Posted by mardtrp View Post
    so why bother to try and engage that silly thread chasing indicator, just leave the HALF NUT engaged and reverse the chuck.
    Quote Originally Posted by mardtrp View Post
    The lathe you have, has got a good foot brake to stop the chuck, so when you are at the end of the thread cut, stomp on the brake hard and move your cutting tool away from the job.
    Quote Originally Posted by mardtrp View Post
    Just chuck it into reverse
    Quote Originally Posted by mardtrp View Post
    You can get so good at doing this simple procedure ,you will wonder why you ever bothered to even contemplate using that stupid thread chasing indicator.
    Quote Originally Posted by mardtrp View Post
    oh, you can even cut threads at 600RPM if your game to give it a go.
    Quote Originally Posted by mardtrp View Post
    Maybe it's you who is just scared to try something that works very well, OK, that means you just stay in the dark ages and do it your way.
    You sound like a P plater

  14. #14
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    My threading indicator is off too. I just make a mark with a whiteboard marker and stick to that.

    If I was fussy, I would shim it out from the carriage to get it spot on but I'm not fussed.

    Simon

    Sent from my SM-G970F using Tapatalk
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  15. #15
    Join Date
    Dec 2013
    Age
    56
    Posts
    1,416

    Default

    Quote Originally Posted by shedhappens View Post
    You sound like a P plater
    600rpm into a shoulder and hit the brake, cool thoughts.
    Using Tapatalk

Page 1 of 2 12 LastLast

Similar Threads

  1. Colchester Chipmaster thread engagement lever problem
    By achjimmy in forum METALWORK GENERAL
    Replies: 10
    Last Post: 10th Jun 2013, 03:10 PM
  2. Chasing Dial
    By fittermachinist in forum METALWORK GENERAL
    Replies: 7
    Last Post: 27th Jul 2012, 02:50 AM
  3. Thread Chasing Dial
    By 19brendan81 in forum METALWORK GENERAL
    Replies: 11
    Last Post: 14th Dec 2009, 03:00 PM
  4. Fitting thread chasing dial.
    By mob in forum THE HERCUS AREA
    Replies: 6
    Last Post: 15th Nov 2009, 12:16 AM
  5. Screw cutting without Chasing Dial
    By benskyring in forum METALWORK GENERAL
    Replies: 16
    Last Post: 4th Sep 2009, 08:55 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
  •