[R-390] Autotuners

[Paul H. Anderson]

My guess on removing them?  If you can get to the back side, like you can
on the various RF decks, the right size punch will pop them out with no
trouble at all.  I scavenged a junk 390A RF deck and removed all the
bearings this way with no damage to them (that I could see) nor to the RF
deck.  Of course, the RF deck is stainless steel, but my sense was that
the forces involved were so small, even brittle pot metal wouldn't be a
problem.

I scavenged the bearings with the intent of seeing if they were the same
as the ones in the R-391 autotune mechanism line shaft, but I haven't had
a chance to look that closely yet.

Paul

On Wed, 5 Jan 2005, Barry Hauser wrote:

> Hi Bill & list:
>
> I don't know how practical it would be to apply a vacuum -- don't exactly
> have a vacuum pump on hand.  It may be that penetrating oil -- which has
> solvent mixed in -- would leach into the bronze sufficient to replenish.
> However, that oil might be too thin.
>
> May well be that the bearing is typically too worn by the time the oil is
> spent.  They still make a wide assortment of these bearings and the correct
> size -- inside & outside diameter could be found.  The existing ones are
> pressed into or glued into the casting and possibly peened over a bit.  They
> are mostly (4 or 5 of them) mounted in small, fragile protrusions.  The
> casting is aluminum, aluminum alloy or pot metal and probably fairly
> brittle.  The geometry is such that I doubt if they can be pressed out on a
> standard arbor press.  There are other approaches to removing them, but
> anything involving impact -- hammer blows, etc. -- would be dicey.  Might
> have to be drilled through and ground out with a Dremel or something.
> Similar approach that modern dental surgeons use in extracting big molars
> <ugh>.  They drill through the bifurcation (junction of roots in the base),
> breaking it up into 3 or 4 pieces in the jaw, then extract each separately
> to minimize trauma to the gum and jawbone socket.  (Aren't you all glad you
> read this far?)
>
> It would be a piece of work.
>
> Barry
>