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Re: [multimachine] Re: New carriage idea comments very needed

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  • Pat Delany
    exactly what I am planning, see attachment ________________________________ From: shondabarda To: multimachine@yahoogroups.com Sent:
    Message 1 of 20 , Aug 30, 2011
    exactly what I am planning, see attachment


    From: shondabarda <jershond@...>
    To: multimachine@yahoogroups.com
    Sent: Tuesday, August 30, 2011 5:33 PM
    Subject: [multimachine] Re: New carriage idea comments very needed

     
    could the same method of embedding pipe in a concrete casting and then filling with non-shrink grout be used to remove the need to shim the half round assembly? (I don't know the numbers on concrete shrinkage so this might not be an issue)

    --- In multimachine@yahoogroups.com, bbidwell78 <no_reply@...> wrote:
    >
    > I like it. Any place where precision can be achieved without precision
    > instruments will help lower the barriers to building these machines.
    >
    > Ben
    >
    > > In the photo folder "01 small concrete lathe" I put up a bad drawing
    > > of a totally different carriage design. I want to know what you think.
    > > I thought of this at 5am this morning and still think it is pretty
    > > cool. But...I am old and probably crazy.
    > >
    > > It does not need:
    > > Precision welding
    > > A precision level
    > > Expert metal fitting skills
    > >
    > > It is a simple way to replace the most difficult part of concrete
    > > lathe construction.
    > >
    > > Pat
    >



  • Shannon DeWolfe
    Pat, I think there is a reason that Mr. Yeomans designed the carriage with the front saddle canted to the 1:00 o clock position as viewed from the foot end of
    Message 2 of 20 , Aug 30, 2011
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      Pat,

      I think there is a reason that Mr. Yeomans designed the carriage with the front saddle canted to the 1:00 o'clock position as viewed from the foot end of the lathe. I don't know much about lathes. But I know that Mr. Yeomans was an excellent engineer. He would not have rotated that saddle if there was no need to do so. My guess is that if the front saddle rides at the 12:00 o'clock position, the rear of the carriage will tend to lift from the 6:00 o'clock position. If the cutting forces are directed into the front way at 1:00 o'clock, resultant lift on the rear saddle occurs from the 7:00 o'clock position which, I think, would prevent the rear from lifting. No?

      By the way, when I looked at the patent to make sure I remembered it properly, I realized that the entire patent was about the bevel gear driven NUT in the carriage. The hand wheel is always in contact with the nut via the bevel gear and pinion. But because the nut is preloaded to remain motionless unless acted upon by the hand wheel, the carriage moves according to the speed of the lead screw and the hand wheel does not turn. If you want to move the carriage manually, stop the lead screw, turn the hand wheel to turn the nut and the carriage moves. If you are feeding the carriage with the lead screw engaged but want to move faster or slower, turn the hand wheel to turn the nut to add or subtract speed imparted to the carriage. If a man were to add a dog clutch to the driven end of the lead screw, he would have a means to positively stop carriage motion by slapping a lever -- a great boon to screw threading. Well, from what I've read that is. I have never cut a thread.

      Patent # 1,205,508. A copy is in the concrete machine tools files in the folder "3 Other Yeomans Patents". The file name is Yeomans carriage.pdf.
      http://finance.groups.yahoo.com/group/Multimachine-Concrete-Machine-Tools/files/3%20Other%20Yeomans%20patents/
      Regards,
      
      Mr. Shannon DeWolfe
      --I've taken to using Mr. because my name misleads folks on the WWW. I am a 55 year old fat man.
      

      On 8/30/2011 5:40 PM, Pat Delany wrote:  
      exactly what I am planning, see attachment
    • Pierre Coueffin
      On Tue, Aug 30, 2011 at 9:46 PM, Shannon DeWolfe ... move faster or ... imparted to the ... So the handwheel is geared to the system
      Message 3 of 20 , Aug 30, 2011
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        On Tue, Aug 30, 2011 at 9:46 PM, Shannon DeWolfe <sdewolfe@...> wrote:
        > If you are feeding the carriage with the lead screw engaged but want to move faster or
        > slower, turn the hand wheel to turn the nut to add or subtract speed imparted to the
        > carriage.

        So the handwheel is geared to the system through some sort of differential?  Could we use the one from the rear axle of a pickup?


        > If a man were to add a dog clutch to the driven end of the lead screw, he would have a
        > means to positively stop carriage motion by slapping a lever -- a great boon to screw
        > threading. Well, from what I've read that is. I have never cut a thread.

        My little sherline lathe has the slickest threading setup I've ever encountered.  You disengage the motor, and turn the spindle with a hand crank.  For a bigger lathe, you'd want a geared advantage for this, but it would be easy to get by putting the crank onto a gear that is part of the geartrain...  This gives you lots and lots of torque and much slower speeds than even a back-geared lathe can get.  Under magnification, it is very easy to thread right up to a shoulder, and it takes no skill at all to stop where you want to.

        The other neat setup I've seen discussed online recently is a sort of arrangement like a mousetrap or the trigger/sear assembly from a single action firearm... You "cock" it to engage the half-nuts, and when the "trigger" touches an adjustable stop, it springs open releasing the half-nuts.  This is good, because you could potentially set up a very fine feed for a finish cut, and just let it run for half an hour, confident that the half-nuts will pop open and disengage the feed before the carriage crashes into the chuck...
      • Bruce Bellows
        One could probably be modeled after a automotive differential but one from a rear axle may be physically a bit large. Bruce
        Message 4 of 20 , Aug 31, 2011
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          One could  probably be modeled after a automotive differential but one from a rear axle may be physically a bit large.

          Bruce

          On 8/31/2011 1:25 AM, Pierre Coueffin wrote:  

          On Tue, Aug 30, 2011 at 9:46 PM, Shannon DeWolfe <sdewolfe@...> wrote:
          > If you are feeding the carriage with the lead screw engaged but want to move faster or
          > slower, turn the hand wheel to turn the nut to add or subtract speed imparted to the
          > carriage.

          So the handwheel is geared to the system through some sort of differential?  Could we use the one from the rear axle of a pickup?


          > If a man were to add a dog clutch to the driven end of the lead screw, he would have a
          > means to positively stop carriage motion by slapping a lever -- a great boon to screw
          > threading. Well, from what I've read that is. I have never cut a thread.

          My little sherline lathe has the slickest threading setup I've ever encountered.  You disengage the motor, and turn the spindle with a hand crank.  For a bigger lathe, you'd want a geared advantage for this, but it would be easy to get by putting the crank onto a gear that is part of the geartrain...  This gives you lots and lots of torque and much slower speeds than even a back-geared lathe can get.  Under magnification, it is very easy to thread right up to a shoulder, and it takes no skill at all to stop where you want to.

          The other neat setup I've seen discussed online recently is a sort of arrangement like a mousetrap or the trigger/sear assembly from a single action firearm... You "cock" it to engage the half-nuts, and when the "trigger" touches an adjustable stop, it springs open releasing the half-nuts.  This is good, because you could potentially set up a very fine feed for a finish cut, and just let it run for half an hour, confident that the half-nuts will pop open and disengage the feed before the carriage crashes into the chuck...

        • Shannon DeWolfe
          Though beveled gears may be the gear train of choice, as Bruce points out, differentials are large. Rack and pinion has supplanted the worm gear in most
          Message 5 of 20 , Aug 31, 2011
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            Though beveled gears may be the gear train of choice, as Bruce points out, differentials are large. Rack and pinion has supplanted the worm gear in most smaller vehicle steering systems. But the good old worm gear (in the recirculating ball guise) is still around in larger vehicles. Instead of turning a sector, turn a circular gear to engage another gear at 90 degrees to the first and fixed to the preloaded nut on the carriage.
            Regards,
            
            Mr. Shannon DeWolfe
            --I've taken to using Mr. because my name misleads folks on the WWW. I am a 55 year old fat man.
            

            On 8/31/2011 7:11 AM, Bruce Bellows wrote:
             

            One could  probably be modeled after a automotive differential but one from a rear axle may be physically a bit large.

            Bruce

            On 8/31/2011 1:25 AM, Pierre Coueffin wrote:

             

            On Tue, Aug 30, 2011 at 9:46 PM, Shannon DeWolfe <sdewolfe@...>wrote:
            > If you are feeding the carriage with the lead screw engaged but want to move faster or
            > slower, turn the hand wheel to turn the nut to add or subtract speed imparted to the
            > carriage.

            So the handwheel is geared to the system through some sort of differential?  Could we use the one from the rear axle of a pickup?

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