KWS-1 Rehab

Discussion in '"Boat Anchor" & Classic Equipment' started by W5INC, Dec 24, 2018.

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  1. W5INC

    W5INC Ham Member QRZ Page

    Yes I got both turn counters complete I believe Mr. Bear. Looking at the back of the turn counter knobs if you look closely at the knob on the right, it is wallowed out slightly but the extension shaft still fits into it pretty well. I am guessing this knob was used on the Tune side of the PA tuning unit, turning that big Baker-Williamson roller inductor. As you know the knobs are made out of pot metal and probably are the weak link in the KWS-1 chain. When assembling everything back together I will make sure to mount the knob with the little play in it, on the PA Loading side of the PA tuning circuit. It doesn't take as much torque to turn the tuning side as it does the load side.

    The other pic is the T/R switch setup I acquired that looks to be complete also. 1 relay tab is slightly bent but I don't think that will take much to straighten out once the rigs are ready to be put back on the air. Parts for these KWS-1s are rather scarce these days so it does take some time to gather the missing parts needed to rehab the big Grey box.

    DSCN0567[1].JPG DSCN0568[1].JPG
     
  2. WB2GCR

    WB2GCR Ham Member QRZ Page

    Yep, I think the right knob will prove to be NG as it stands.
    Consider one of the fixes that were suggested... after trying a few I prefer simply
    the epoxy of the shaft into the knob.
    Probably the thing to do is to try them where they will be working, but you'll find as
    I did that there's a fairly high degree of precision required for these counters to function.
    The knob has to run parallel to the panel, and the clearance to the counter part is surprisingly
    tight...
     
  3. W5INC

    W5INC Ham Member QRZ Page

    I perused your thread on the knob problem on these KWS-1s once again, Mr. Bear. Seems like you are a machinist, which comes in mighty handy in restoring these old pieces of iron. I see where you settled on gluing the knob onto the extension rod. Have you ever thought about using the original set screw setup of the knob and threading a hole the same size right into the extension shaft? Of course the hole would have to be tapped in the correct place and possibly a little longer set screw would be needed to make sure the tuning knob and the extension shaft stay synchronized up in their proper positions. If it is possible might be a better solution then gluing the knob onto the extension shaft itself. The set screws that go on the locking retainer that doesn't allow the extension rod to be pulled out the front and a few set screws in the brass couplings are stripped out on my unit so I will have to get them out no matter which way I proceed on the PA tune/load knob project.

    extension.jpg
     
    KA9JLM likes this.
  4. W5INC

    W5INC Ham Member QRZ Page

    Threading the extension rod itself or drilling a hole right thru the rod and installing a brass insert, that is the correct size for the set screw? If this was possible it would save a lot of knobs from going to the cornfield.

    insert.jpg
     
  5. WB2GCR

    WB2GCR Ham Member QRZ Page

    Best email me for the pdf?
    All those issues are dealt with.

    The two solutions you've suggested were considered and discarded as impractical.

    One may do an insert, but you'll need a lathe and the end of the shaft will not end up
    at 1/4".

    The problem is that you can NOT push against the shaft with the setscrew because it
    deforms the potmetal. An insert will merely transfer that force... unless the insert
    itself carries threads. Again, not possible with a 1/4" final shaft diameter.

    The key to this is that the shaft needs to be square on the knob AND centered.
    The hole is eliptical, so the problem becomes one of how to correct that.

    After all the work I did, it functions, but it is NOT as smooth as a fresh stock dial counter.
    I ran into them at a hamfest on another unit, those were smooth!
    The reason that the manufacturer of these counters went with another design is likely due
    to the requirement for precision, and the issue of wear... even early on in the design's life.
    Plus these likely cost more to make than the newer (still used) turns counter design.

    All that is needed for the epoxy method is a drill press. A lathe would be easier in some regards
    but I did mine on an average drill press (not high precision).

    EDIT: now that I think about it, the final PDF ought to be in the thread for download...
     
  6. W5INC

    W5INC Ham Member QRZ Page

    PM sent Mr. Bear. TNX for sharing your endeavors on getting these important pieces back up and running once again! ;)
     

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