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Ammco ratchet sketch needed

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  • Ammco ratchet sketch needed

    I sold my lovely old Ammco shaper, but waiting for the sale to complete noticed that the ratchet was slipping over the wheel notches while feeding in one direction. I had forgotten what a PITA that ratchet was once upon a time long ago, the memories came back too slowly!

    In my optimism I assumed that I could reshape the face of the ratchet rod and get it running again. I held it up to my slow speed diamond hone and took a smidge down, just polished the surface really.

    I performed worse! So I cut the pressure edge of the ratchet post a bit to make sure it had a sharp edge, no, no better.

    So, I make a new one out of stressproof, cutting the face and ratchet angle carefully, heat treating it and drawing the temper down again. the new one worked about the same! The main difference I can see is that the original pin that held the knob on was a small brad, bent over to keep it in place, and the diameter was such that it was real sloppy.

    Ok, the day is over, it's 7 PM and I'm tired. I've made two new rods now, but neither works right. What I need is a kind sympathetic soul to make a sketch of the ratchet rod on the business end, actually, the whole thing would be better. I suspect that the angle is critical, the angle that allows the rod to slip over the cuts in the wheel. The spring is probably critical too, so maybe a listing of the wire section, the length and number of coils, and the OD.

    Best yet would be if someone knows of a source for this info without bothering anyone with all of that.
    Thanks, folks,

  • #2
    Sounds familiar!!!

    After messing around for ages on the ratchet system on my machine, I figured that the original "gear" had a 60 degree angle between the teeth. I recut the teeth using a regular threading toolbit set up in a flycutter.

    The ratchet pawl needs to have a near vertical surface on the driven side but it needs to be offset from the centerline so it meets the gear when the tooth is nearly vertical. The back side of the pawl is rounded so it can ride over the gear.

    Much fiddling with springs to get the ratchet resistance correct along with the resistance to the turning of the feed screw ensues.

    Took me several tries before I got it set up correctly.


    P.S. you may get the impression that I too, have an Ammco shaper!


    • #3
      Thanks so much for your help! I went through this once years ago, this is my third Ammco shaper, also it's my first, which I sold and bought back. I don't recall which one I had the problems before with.
      My brother sent me a sketch of the ratchet pawl shaft today as well, so I should be able to get it to work soon.


      • #4
        Don't recall ever seeing, let alone using, an Ammco shaper, but I've "repaired" hundreds of ratchets, including dozens driving feed screws, by deburing, cleaning, and oiling them.


        • #5
          Sorry to hijack, but is the setup the same as an Atlas 7" shaper?