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Re: Research needed for universal machine

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  • Dennis
    Now that I went out to the shop I remembered what I was thinking of. It s a device from an old shop manual. Two arms around a pivot, each end having half of a
    Message 1 of 13 , Sep 9, 2013
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      Now that I went out to the shop I remembered what I was thinking of.
      It's a device from an old shop manual.
      Two arms around a pivot, each end having half of a 1/2" or 1" circle. By knowing the distance from the pivot and measuring the distance between the circles(minus their thickness) one was able to divine the angle.
      To go 180 might take some cleverness however when dealing with the headstock though(two sets perhaps 0-90 & 90-180).
      By making the "protractor" part of the machine it could have support rods that could be made for each common angle and an adjustable turnbuckle type rod for any other angle. Of course requiring a measurement across the half circles. That way if a certain angle was used often a rod could be made for that angle and have some repeatability.

      Also while out there I noticed my Logan has "power surfacing". The leadscrew has a slot milled in it that a bevel gear rides upon. When a button is pulled another gear engages with it allowing the leadscrew to drive the crossfeed. Due to the presence of several "extra" holes in the area I think there may have been plans to do more than just surfacing with this feature, such as power an auxiliary milling head.

      Back to the shed with me.

      --- In multimachine@yahoogroups.com, "David G. LeVine" <dlevine@...> wrote:
      >
      > On 09/09/2013 11:13 PM, Shannon DeWolfe wrote:
      > > on older GM engines, 153 positions (2.35 degrees). With a
      > > little ingenuity the locking mechanism can be adjustable to allow
      > > fractional degree positioning.
      >
      > Looking at this with my magic calculator ($1 at Walmart!), you get
      > within .69 degrees! Having more than one segment to lock (3-4 would be
      > ideal), one should get within arc seconds of absolute. To get an idea
      > of the magnitude of accuracy, 1 minute of angle is 1 inch at 100 yards!
      > One second is 1/60th of 1 minute or about 0.016-0.017" at 100 yards, or
      > under 1/2mm at 100 meters.
      >
      > My machining skills tend to have larger errors than that.
      >
      > Dave 8{)
      > --
      >
      > "A word to the wise ain't necessary - it's the stupid ones that need the
      > advice."
      >
      > Bill Cosby
      >
    • kbs2244
      Linear actuators are commonly used in exercise tread mills to adjust the slope angle. They use a worm gear. Treadmill are a common curbside or low cost CL
      Message 2 of 13 , Sep 10, 2013
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        Linear actuators are commonly used in exercise tread mills to adjust the slope angle.
        They use a "worm gear."
        Treadmill are a common curbside or low cost CL item in my area.

        I would doubt they are common in any 3 rd world setting.
      • Dennis Shelgren
        Windshield wiper motors and some door window motors also use worm gears. They re out there in one form or another in lots of items. I have a whole pile of em.
        Message 3 of 13 , Sep 10, 2013
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          Windshield wiper motors and some door window motors also use worm gears. They're out there in one form or another in lots of items. I have a whole pile of em. The trouble I've had with them is that they aren't any even multiple of teeth that's easy to work out. Someone told me that they are that way on purpose for some reason.
          My commercial dividing head is 40 teeth, so 40 revolutions of the wheel are one turn, then the plate has hole sets and a divider leaf to produce multiple types of divisions.

        • David G. LeVine
          ... One I can think of is non-rack&pinion steering boxes. Using ring gears (for starters) and getting matching segments (get another flywheel/flexplate and cut
          Message 4 of 13 , Sep 10, 2013
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            On 09/09/2013 11:17 AM, Pat wrote:
            > Machine accuracy depends on accurate indexing for the spindle, headstock, aux spindle frame rotation and aux. spindle tilt. The Romig and Gingery designs use store bought worm gears etc(I think). Are there any scrap yard alternatives? Are our only practical choices circular protractors?
            >
            > Pat

            One I can think of is non-rack&pinion steering boxes.

            Using ring gears (for starters) and getting matching segments (get
            another flywheel/flexplate and cut pieces out) allows the user to set
            the segments to force the headstock into positive lock, even a worn ring
            should allow settings within seconds of arc. If a convex face can be
            found of the same pitch, the setting can be amazingly tight (e.g. so
            close you can't tell the difference between one pass and another.)

            Dave 8{)
            --

            "A word to the wise ain't necessary - it's the stupid ones that need the
            advice."

            Bill Cosby
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