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Re: [TowerTalk] Rotor disassembly

To: "Dick Burke" <k7rb@tantella.com>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] Rotor disassembly
From: "Shannon Boal" <Kingsautomotive1@alltel.net>
Date: Sun, 17 Apr 2005 09:27:36 -0000
List-post: <mailto:towertalk@contesting.com>
Uh, Dick
  Maybe too late, but when you're in a hole, stop digging!
   OK, having said that, are the EZ outs broken off in there? When you get
it apart, you might want to take it to a machine shop for thread repair.
Automotive machine shops do a lot of this. Some of the machinists are
amazingly good at it. They may not let you know how they did it, though!
   Please note, that I am an auto mechanic, not a rotor doctor. The bolts,
EZ outs shouldn't keep you from seperating the housings. First, make sure
that all fasteners are out, no hidden bolts? I would heat one housing
locally near the parting area, tap with a wooden mallet/ plastic hammer. The
aluminum should be heated carefully. A temperature guage can be a pine
stick, which will char when touched to a 475 F surface. No hotter than this!
To protect the gears, consider submerging the bottom in water, or wet rags.
If you heat it in an oven, 325F should be plenty hot, and the ladies don't
like it if we stink up the house....
   More on the broken bolts... in the future, the bolt can be torch heated
on the head to a blue heat, maybe hotter, (but not to soften the aluminum
near it), and quenched with parrafin, like a candle stub. It will come right
out, easily. Having broken ones, do not try to drill or use EZ out. The
drill will want to drift into the softer aluminum, and a broken EZ out is
harder than a drill bit, so it will eat your drill bits! If a nut can be arc
welded to the end, fine, quench with candle and remove, easily. If not, I
would use a drill guide to keep the drill from wandering into the soft
aluminum. This would be a steel plate 5/16" or thicker with a hole smaller
than the bolt, clamped in place, or secured by an adjacent bolt. This will
solve the drifting problem. I use carbide tipped drills for broken EZ outs,
drill bits, etc. I customize my own drill bits for this...
                               Dick, I wish you well!
                           I've been in similar situations
                             Shannon Boal K4GLM
PS soaking a corroded assembly to loosen can be aided by acids. With iron
parts, Coke(really!) is amazing. Vinegar maybe, for aluminum, I have not
done this.
I have used battery acid to soak apart iron parts, I would not try it for
aluminum stuff.
IF you soak in etching, use weak solution, and submerge the whole thing!!
The area near the surface will be damaged!! Neutralize with dip in baking
soda solution, spray with corrosion inhibiter.

Hi,

I'm trying to refurbish a very old Ham-M rotor. The previous owner
managed to remove one of the 4 bolts holding the housing halves together
and torqued the heads off two others. I managed to torque the head off
the remaining bolt. It seems like the two halves of the housing should
come apart now but I've been bathing it with WD-40 for a couple weeks
and banging on the housing with a hammer, but can't get the two halves
to separate. They must be really corroded together.

I've also managed to break a couple of screw extractors trying the get
the headless bolts out.

Any suggestions?

Thanks,

Dick
K7RB






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