[Hammarlund] Re: HQ-series dial calibration hints?

[Kevin J Ward]

Craig -

Stop!  Wait!  Don't break that slug.  If you think you're frustrated now
it doesn't hold a candle to trying to remove a broken slug in an old boat
anchor.  A broken slug can cause erratic and intermittent problems, and
even drive you to drink.  Hmmm!  Oh well.  

One way to remove a broken slug is to epoxy the broken pieces to the end
of a broken twist drill of an appropriate size.  What?  You don't have a
broken twist drill; I thought hams saved everything.  Never mind.  Cut a
chunk out of an old coat hanger (they come in various thicknesses) and
bend one end into an "L" like an Allen wrench.  Sand off the coating on a
half inch of the other end, so the glue can get a good grip on the metal.
 

Mix up just a tiny bit of two-part epoxy and coat the sanded end of the
wire.  Be careful not to touch any part of the inside of the coil form
with the glue during the next step.  Use two hands and something to brace
them on, and carefully insert the glue end into the broken pieces of coil
slug.  Twist the tool a bit to "shmooey" the glue so that all the broken
pieces will be captured.  Clip an alligator clip (use the clip only, no
wire attached) to the makeshift tool, just above the top of the coil form
so that the clip will rest on the top of the coil form, then let it sit
undisturbed for however long it takes to fully cure the epoxy.  

The last step is to CAREFULLY remove the slug and tool from the coil
form.  Paper coil forms are usually slathered in beeswax to keep the
slugs from moving.   Here's a tip to make removal easier.  Hold the
business end of a soldering iron or gun near the coil form (no closer
than a quarter-inch), long enough to soften the wax, then turn the slug
out before the wax hardens.  

If you know for sure the slug is not broken, and it has a slotted end
rather than a hex hole in it, there is another trick you can use.  Grab a
miniature screwdriver that fits the slot, put the end of the blade in the
slot, and hold the soldering iron against the shank of the screwdriver,
far enough above the coil form so as to avoid damaging it.  The
screwdriver will conduct the heat directly to the slug, softening the
wax. This approach takes longer, but is safer for the coil form.  This
trick can also be used during alignment and will prevent breakage in the
first place.  

I keep a lump of beeswax at the workbench for tightening up loose slugs. 
Use a pen knife to shave a small bit of wax on top of the loose slug,
then carefully heat the form as before.  In all cases, keep the iron from
actually touching the coil form.  And never, ever use candle wax.

There is an important difference between beeswax and candle wax.  Beeswax
is the stuff bees make their honeycombs out of  -  literally.  Candle wax
is solid paraffin - a hydrocarbon of the methane series.  It is made from
paraffin oil, which is obtained from petroleum.  Beeswax will remain
solid at higher temperatures than will paraffin, and when solid is harder
than paraffin.  Paraffin could soften and run out of the coil if your
vacuum tube rig gets really hot.  Then the slugs would be free to move
and throw the alignment out of whack.

Visually check all the coil slugs to make sure none of them are
completely out of the winding area.  If you find one that way, turn it
into the center of the coil and try the alignment again.    Enough said.

Good luck.   

Kevin  N2IE


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