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Thread: Hardinge high speed threading

  1. #1
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    Default Hardinge high speed threading

    Anyone got any sketches, drawings , instructions etc on how the high speed threading works on the HLV ?

    .
    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.




  2. #2
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    I don't know what you mean John

    The high speed threading is on the HCT machines isn't it ?

    If that's what you mean ..have uploaded manual here ..scroll down to aboard_epsilon's upload

    http://groups.yahoo.com/group/Hardinge-Lathe/files/

    The bit about using the threading attachment is in the later part of the manual.

    all the best.markj

  3. #3
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    Why can't you high speed thread on any lathe if your daring enough to thread at say, 300 rpm.
    It's only ink and paper

  4. #4
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    Hi,

    You certainly can run as fast as the tool will stand. The problem is stopping. The reality is, you can only go as fast as how quick you can stop the process. I hope I'm making clear the idea.

    dalee

  5. #5
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    The key to the system is the one way dog clutch set-up in the lead screw drive. I've got an idea how to build something that should work, at least I mand some guys I worked with who are some very sharp Tool Makers and Machine Repairmen can't find any holes in the idea. Coupled with the stop rod it allows you to thread right up to a shoulder at 1000rpm if the tooling will handle it. One nice feature would be if the the taper attachment could be set-up as a tracer with a cam to back the tool out so as to avoid a groove at the end of the thread. Plus if you are feed ing in with the compound the end of the thead is always getting closer to the shoulder. Actually when I had access to HLV-Hs I always fed the tool straight in when doing this. The other nice feature for threading on them is the Quick Retract on the compound

    This is the Lead Screw Reversing Drive. I won't claim to of come up with something original here but if this is between the gearing set for the thread being cut and the leadscrew I think it would work



    The Hardinge parts layout is on page 47
    Last edited by Spin Doctor; 12-20-2008 at 10:50 AM.
    The optimist says the glass is half full, the pessimist says it's half empty. The paranoid in me says somebody put a hole in it.

    Remember pessimists are at heart opptomists. They know things can and will get worse.

  6. #6
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    John,

    Is this the same as the Ainjest high speed threading attachments? They give a settable end stop that drops the leadscrew nut out of engagement, and then some gearing that only allows correct leadscrew reengagement.

    Probably why an Ainjest on an imperial machine can only cut certain imperial threads, and no metric threads.

    Ian

  7. #7
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    I believe the HLV uses a dog clutch similar to the setup Cleeve describes in "Screwcutting in the Lathe". The HLV has some refinements such as power feed for the leadscrew to move the carriage back.

    Cleeve covers the concept well and has pictures of a dog clutch setup he made for his Myford. The basic idea is the half nuts remain engaged and the leadscrew gearing disconnects from the spindle via the dog clutch trigger mechanism. The tool is retracted, the carriage wound back (by reversing the leadscrew), the next cut put on, and the dog clutch engaged. The dog clutch always picks up with the same relationship between spindle and leadscrew so the tool automatically picks up the thread, similar to stopping the lathe and reversing between passes. No threading dial needed and it works for metric or imperial threads.

    John

  8. #8
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    Quote Originally Posted by Ian B
    Is this the same as the Ainjest high speed threading attachments? They give a settable end stop that drops the leadscrew nut out of engagement, and then some gearing that only allows correct leadscrew reengagement.
    That's essentially how the Hardinge high-speed threading works. There's a stop rod for the dog clutch, and it has adjustable stops that are triggered by the apron. So you can literally go flying up to a shoulder, and the apron hits the leadscrew dog clutch stop, and pops the dog clutch. The apron stops on a dime.

    Then you reverse the leadscrew, and the carriage winds back 'till it hits the opposite dog clutch stop.

    John: if you look at Martin Cleeve's Screwcutting in the Lathe -- he talks a lot about the Hardinge dog clutch. The version he made for his his Myford is modeled after the Hardinge dog clutch mechanism. The problem is that for any lathe with a quick change gear box, you would have to make a Rube Goldberg mechanism to get the stop trigger up and over the gearbox, because you have to clutch the leadscrew on the drive side, to keep it synchronized with the lathe's spindle.

  9. #9
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    Lazlo:

    Thanks for noting that Cleeve copied the HLV, I thought I recalled that but wasn't certain. Cleeve is one of my favorite writers, very pragmatic - everything I've copied from him works well.

    I'd like to have a dog clutch on my lathe but haven't figured out how to do it nicely. In lieu of that I added a simple auto-stop to the carriage of my 7x12 which, combined with a retracting toolholder, makes threading much faster and less exciting As with a dog clutch, I now thread to a shoulder at speed... previously I used a hand crank. See: http://www.gadgetbuilder.com/Threadi....html#AutoStop

    Not as good as a dog clutch, I still need the threading dial and it doesn't work for metric threads. But it is still a big help.

    John

    Edit: I eventually built a dog clutch too: http://www.gadgetbuilder.com/Dog_Clutch.html
    Last edited by GadgetBuilder; 02-14-2009 at 01:00 PM.

  10. #10
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    One thing most people do not understand about cutting threads on the Hardinge (and I am not pointing any fingers here) is that once the leadscrew and halfnut are engaged you do not open the half nut until the job is done. All of the dropping out of the leadscrew takes place inside of the gearing. It doesn't matter what the lead of the thread is, inch, metric, DP or Module. As the dog clutches are one way they only have one point of engagement. They can not get out of time or phase as long as none of the settings on the QCGB or thread range dial are changed. Another point. The Feed Motor on the Apron does not drive the leadscrew. It drives the gearing in the apron that is connected to the longitudinal and crossfeed hand wheels. The longitudinal and crossfeed are engaged by means of clutch assemblies.
    The optimist says the glass is half full, the pessimist says it's half empty. The paranoid in me says somebody put a hole in it.

    Remember pessimists are at heart opptomists. They know things can and will get worse.

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