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Re: [taigtools] DIY Dividing Head Question

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  • Larry Richter
    Really depends. Helical gears are nice, but is it absolutely, positively, exactly 24 to one? Intended to stick a small Dayton gear box into a marine
    Message 1 of 4 , Feb 29, 2004
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      Really depends. Helical gears are nice, but is it absolutely, positively,
      exactly 24 to one? Intended to stick a small Dayton gear box into a marine
      drive-turret position indicator once, but it turned out the stated gear
      ratio was only nominal. Had to build a custom indicator gear box after all.



      ----- Original Message -----
      From: "e3pi" <e3pi@...>
      To: <taigtools@yahoogroups.com>
      Sent: Sunday, February 29, 2004 7:59 PM
      Subject: [taigtools] DIY Dividing Head Question


      >
      > I've zero experience with dividing heads, but I am excited with
      > their 40: 60:1 precision leverage and ease for general dividing the
      > circle; and possibly used for linear ruling too; I imagine.
      >
      > I've a Dayton 24:1 Gear Reducer.
      > This has helical gears with negligial backlash that I can tell.
      >
      > It is small enough to be "Taigable".
      >
      >
      > From reading I see 60:1; 40:1 are common for dividing head worm gears.
      >
      > Note also worm gears lock position on the non-"pinion" main gear
      > axel - i.e.; the main gear angular displacement cannot drive the
      > "pinion" or "worm" - which is a benefit for machinery set up.
      > This Dayon gear reducer will drive either axel; i.e., 24:1 or 1:24;
      > as desired. This could be a problem.
      >
      >
      > One small grace advantage:
      >
      > "24" is a "highly composite" integer(24=4*3*2*1=4!); makes for easy
      > arithmetic shared among common fractions of 360 degrees.
      >
      > So aside from half to a third the precision of other DH's - is this
      > a reasonable source on the start of my first DIY dividing head?
    • Tony Jeffree
      There s nothing particularly special about 40:1 and 60:1 (and 90:1 for that matter) ratios, other than that, because they are commonly used, the standard
      Message 2 of 4 , Mar 1, 2004
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        There's nothing particularly special about 40:1 and 60:1 (and 90:1 for that
        matter) ratios, other than that, because they are commonly used, the
        "standard" dividing plate sets are designed for use with those ratios. If
        you plan to make the whole lot yourself, including dividing plates, then
        you can design the plates to suit your drive ratio and the uses you have in
        mind.

        As Larry has observed, though, it will only be a useful basis for a
        dividing head if the drive ratio is precisely 24:1.

        The back driving "feature" is a potential problem, but you can fix this by
        including a spindle lock in the design.

        Regards,
        Tony

        At 03:59 01/03/2004, you wrote:

        >I've zero experience with dividing heads, but I am excited with
        >their 40: 60:1 precision leverage and ease for general dividing the
        >circle; and possibly used for linear ruling too; I imagine.
        >
        >I've a Dayton 24:1 Gear Reducer.
        >This has helical gears with negligial backlash that I can tell.
        >
        >It is small enough to be "Taigable".
        >
        >
        > From reading I see 60:1; 40:1 are common for dividing head worm gears.
        >
        >Note also worm gears lock position on the non-"pinion" main gear
        >axel - i.e.; the main gear angular displacement cannot drive the
        >"pinion" or "worm" - which is a benefit for machinery set up.
        >This Dayon gear reducer will drive either axel; i.e., 24:1 or 1:24;
        >as desired. This could be a problem.
        >
        >
        >One small grace advantage:
        >
        >"24" is a "highly composite" integer(24=4*3*2*1=4!); makes for easy
        >arithmetic shared among common fractions of 360 degrees.
        >
        >So aside from half to a third the precision of other DH's - is this
        >a reasonable source on the start of my first DIY dividing head?
        >
        >
        >http://groups.yahoo.com/group/liveaboardlathe/message/81
        >
        >
        >
        >To Post a message, send it to: taigtools@...
        >
        >To Unsubscribe, send a blank message to: taigtools-unsubscribe@...
        >
        >
        >
        >Let the chips fly!
        >
        >Yahoo! Groups Links
        >
        >
        >
        >

        Regards,
        Tony
      • Del Stanton
        Power gear sets with spur gears (as opposed to worm gearing) are usually designed with non-integral ratios to assure that all the teeth on one gear end up
        Message 3 of 4 , Mar 1, 2004
        • 0 Attachment
          Power gear sets with spur gears (as opposed to worm gearing) are usually
          designed with non-integral ratios to assure that all the teeth on one gear
          end up contacting all the teeth on the other gear. This promotes uniform
          wear and longer life for the gears. Therefore it is good to "count the
          teeth" when using such a gear reduction unit if accuracy of ratio is
          inportant in your application.

          Del Stanton
          Wannabee Taig CNC Mill Owner


          ----Original Message Follows----
          From: "Larry Richter" <cattaraugus@...>
          Reply-To: taigtools@yahoogroups.com
          To: <taigtools@yahoogroups.com>
          Subject: Re: [taigtools] DIY Dividing Head Question
          Date: Sun, 29 Feb 2004 21:12:15 -0800


          Really depends. Helical gears are nice, but is it absolutely, positively,
          exactly 24 to one? Intended to stick a small Dayton gear box into a marine
          drive-turret position indicator once, but it turned out the stated gear
          ratio was only nominal. Had to build a custom indicator gear box after all.



          ----- Original Message -----
          From: "e3pi" <e3pi@...>
          To: <taigtools@yahoogroups.com>
          Sent: Sunday, February 29, 2004 7:59 PM
          Subject: [taigtools] DIY Dividing Head Question


          >
          > I've zero experience with dividing heads, but I am excited with
          > their 40: 60:1 precision leverage and ease for general dividing the
          > circle; and possibly used for linear ruling too; I imagine.
          >
          > I've a Dayton 24:1 Gear Reducer.
          > This has helical gears with negligial backlash that I can tell.
          >
          > It is small enough to be "Taigable".
          >
          >
          > From reading I see 60:1; 40:1 are common for dividing head worm gears.
          >
          > Note also worm gears lock position on the non-"pinion" main gear
          > axel - i.e.; the main gear angular displacement cannot drive the
          > "pinion" or "worm" - which is a benefit for machinery set up.
          > This Dayon gear reducer will drive either axel; i.e., 24:1 or 1:24;
          > as desired. This could be a problem.
          >
          >
          > One small grace advantage:
          >
          > "24" is a "highly composite" integer(24=4*3*2*1=4!); makes for easy
          > arithmetic shared among common fractions of 360 degrees.
          >
          > So aside from half to a third the precision of other DH's - is this
          > a reasonable source on the start of my first DIY dividing head?



          To Post a message, send it to: taigtools@...

          To Unsubscribe, send a blank message to: taigtools-unsubscribe@...



          Let the chips fly!

          Yahoo! Groups Links




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