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FUBAR Courtershaft Pulley

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  • indianfourrider
    Friends, (Long post - get a fresh cup of coffee! My earlier jubilation was, it seems, premature. I had believed that I had finally trued-up the large 2-sheave
    Message 1 of 2 , Aug 1, 2009
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      Friends, (Long post - get a fresh cup of coffee!

      My earlier jubilation was, it seems, premature. I had believed that I had finally trued-up the large 2-sheave countershaft pulley since on high speed the wobble had all but disappeared. Next day, however, I switched over to low speed. Serious wobble now at 685 rpm where before it had not even been noticable.

      It was then I discovered that the original countershaft itself was evidently slightly bent at the motor end. Made a new one AND new bushings. (Had fun cutting the key seat without a proper cutter, but that's another story...)

      Chucked a new piece of 3/4" round bar and checked it - dead nuts. Mounted the pulley and, well, proceeded to run through my extensive catalog of profanity - in several languages, living and dead.

      Mounted the pulley in the 4-jaw, small side in, dead flat against the jaws and indicated it in AGAIN. Rebored and made yet a third new bushing, which I bored to size in the pulley, still in the 4-jaw. Put the aforementioned piece of 3/4 in another chuck, mounted the pulley and, back to the lexicon! The small side, which had been in the 4-jaw now had a serious wobble and the large side - that had previously indicated within .0005 - was also off.

      Next day after cooling off, I mounted pulley on the new shaft between centers and started where I suppose I should have in the first place - indicating the running surfaces on both sheaves. I had to do it several times before I believed the results. The sheaves were niether concentric nor axially true. So each time I rebushed it it was only true to the sheave in the chuck in that exact position!

      The only option left besides shelling out $200 for a new one or taking a chance on evilbay was to re-machine the whole bloody thing. Instant headache. The large sheave is 11" and won't clear the carriage. I needed either to make offset toolholders or find a way to offset the compound.

      After a good night's sleep it occurred to me that my radius cutting attachment would offset the compound and allow me to get the tool where it needed to be. The actual machining verified what the indicator had shown. The high/low spots did not match and both sheaves were eccentric to the axis at different points!

      At the risk of opening a sensitive topic, this project also gave me something to dislike about Zamac, with which I had heretofore no quarrel. One word - SWARF! Much worse, IMHO, than cast iron! My fan even on low blew it everywhere and into everything.

      Results - SUCCESS at all speeds!

      I have posted a couple of pictures of the set-up in an album bearing the acronym used in the title of this post. You'll also see my Appalachian-engineered swarf control device. Sorry, no duct tape...

      Thanks for the opportunity to vent!

      Jim
    • Scott Henion
      ... Been there, done that, have the T-shirt. ;) Re-sleeved mine 3 times. It still has wobble. yours is one of the better ones with the 3 holes. Mine has 3
      Message 2 of 2 , Aug 1, 2009
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        indianfourrider wrote:
        > Friends, (Long post - get a fresh cup of coffee!
        >
        > My earlier jubilation was, it seems, premature. I had believed that I had finally trued-up the large 2-sheave countershaft pulley since on high speed the wobble had all but disappeared. Next day, however, I switched over to low speed. Serious wobble now at 685 rpm where before it had not even been noticable.
        > <clip>
        > Results - SUCCESS at all speeds!
        >
        > I have posted a couple of pictures of the set-up in an album bearing the acronym used in the title of this post. You'll also see my Appalachian-engineered swarf control device. Sorry, no duct tape...
        >
        > Thanks for the opportunity to vent!
        >
        >

        Been there, done that, have the T-shirt. ;)

        Re-sleeved mine 3 times. It still has wobble.

        yours is one of the better ones with the 3 holes. Mine has 3 arced
        spokes. I would get it perfect, mount on countershaft and it was fine.
        Next day it wobbled. Turns out it is real temperature sensitive. Change
        temp and the hub twists.

        Mine was the same, the hub and sides were not aligned with the belt
        grooves. I mounted it in a 4-jaw and centered it on the grooves. Then
        turned the hub and all faces. Much better.

        Mine had 23 holes drilled to balance. I guess they figure that is easier
        than centering it properly before machining it ;) I had to re-balance
        mine. I used a short 3/4" shaft between centers. Drilled a center
        countersink on each end. Then put on pulley. I could get a fairly god
        balance. I had to drill 20 holes on the opposite side the existing ones
        were.

        Still, I went back to a generic single 8" pulley. I could never get the
        stock one to remain straight. As I have a VFD, I don't need the double
        pulley setup (and only have a single, variable motor pulley anyway.)

        One of these days, I'll admit defeat and throw the old one out. ;)

        --
        ------------------------------------------
        | Scott G. Henion| shenion@... |
        | Consultant | Stone Mountain, GA |
        | SHDesigns http://www.shdesigns.org |
        ------------------------------------------

        today's fortune
        <joeyh> oh my, it's a UP P III.
        <doogie> dos it.
        * joeyh runs dselect
        <Overfiend> that ought to be sufficient :)
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