Fw: [Collins] RE: {Collins} Re: 70K-2 PTO

[Dr. Gerald N. Johnson]

On Fri, 2007-11-16 at 07:02 -0500, david knepper wrote:
> I would like to add my two cents to this discussion.
> 
> First, if you examine this bearing under a magnifying glass, you will 
> observe amazingly how irregularly round it is. On the older PTO's, I have 
> found a steel bearing, interestingly.
> 
> Secondly, I wonder why an insulating bearing when a steel bearing would have 
> done nicely?
> 
> Finally, I have discovered that the PTO turns ever so nicely if you remove 
> one of those cupped washers from the front of the lead screw.  If there is 
> tension at this point, no amount of adjustment  of the concentric bushing 
> nut will give you that wonderful inertia feeling at the tuning knob.  The 
> shaft should turn quite freely, almost effortlessly or whatever I am trying 
> to saying!

Reducing the end load on the PTO shaft means it will drift more from
vibration and be be more apt to move the PTO slug when you push or pull
on the knob (or have the rig mounted in Art's yacht). 
> 
> Thirdly, I would recommend using b-b shot from a shotgun shell - somone out 
> there would know the size.  I would say that a 410 shell would work nicely.
> Just a thought.  Ask a hunter in your parts or someone who loads shotgun 
> shells.

Using a BB, unless steel for waterfowl, will soon grind down the lead BB
until the shaft wobbles about and the PTO is less stable than the LO of
Hammarlund HQ-120X on ten meters.
> 
> Oh, by the way, I had one of these "critters" fall on to my carpet.  Sure 
> didn't do my back any good but I found it.  I consider it almost a miracle!
> 
> Dave, W3ST - W3CRA
> 
As I said in another post, CRA could stock them when they cost a few
bucks a hundred from McMaster-Carr and sell them at a profit and service
to members.

-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer