[ATM] Alternative to lead?

[artbianconi@blast.net]

Wish I could take credit for this idea. I can't

Ceramic magnets are quite popular in audio speakers and. the higher the 
wattage rating of the speaker, the heavier the magnet that is needed to control 
the voice coil.

Find a banged up speaker, the smaller the telescope, the smaller the magnet. 
Strip off the magnet taking care not to damage the ceramic. By the way, ceramic 
magnets are usually stronger than steel magnets of the same weight.

Attach a metal strip in a place on the tube that is easily reached and at a spot 
where the cg of the system can be system can be influenced. Space that metal 
strip so it brackets the existing CG and attach it with velcro or double sided foam 
tape. Now balance the telescope simply by sliding the speaker magnet in 
whatever direction gets the job done.

If you run out of magnet travel before the scope is balanced, either move the strip 
or put on a longer one.

Use the scope with as many or all of the eyepieces and accessories and verify 
that you have suifficient movement latitude to balance with all of them.

When you are satisfied that all works well, mark the current location of the metal 
strip, remove it and the adhesive and drill holes appropriate to the faseners  
needed to secure it permanently. Make sure you countersink holes in the strip 
deep enough so that the flat head screws are flush or below the surface.of the 
strip. If you don't, the magnet won't make full contact in some places and you 
risk it falling off.

Art Bianconi

> I agree with the fact that tapping lead is futile. Lead is
> expensive, you are likely to get burned and it is not the
> most healthy way to spend an afternoon. By the time you get
> the lead pot, a heat source, the lead, ,some type of insert,
>  and the mold you have spent enough money to buy a
> counterweight.
> 
> Find a local machinist and  buy a cutoff piece of cast iron,
> brass or stainless (they are readily available on ebay) and
> have it trued up and tapped.
> 
> I cast my own bullets and fishing sinkers, and I have all
> the equipment - but I would not mess with casting a mass of
> lead that large - I get enough blisters from an afternoon of
> making 8 oz and 16 oz fishing sinkers.
> 
> Pat Bunn
> 
> 
> ----- Original Message -----
> From: <artbianconi@blast.net>
> To: <atm@atmlist.net>
> Sent: Sunday, July 11, 2004 6:04 AM
> Subject: [ATM] Tapping lead? Forget it!
> 
> 
> > I have smelted, cast and swaged more lead bullets than I
> > care to count.
> And
> > when I didn't fire enough rounds in competition to justify
> > the equipment
> needed
> > to hand load, I started doing it for others.
> >
> > It's a messy pastime, working with lead, and the material
> > is dangerous to
> work
> > with, lead poisoning being the most apparent risk.
> >
> > There's absolutely no need for alloying, melting, tapping.
> > Besides, even
> if you
> > succeeded in altering it's properties some, lead is still
> > very soft
> compared to steel
> > or brass. Even when alloyed, it will strip with even the
> > most modest
> torque.
> >
> > Simply purchase the appropriate PAL threaded inserts from
> > McMaster-Carr.
> Drill
> > the appropriate hole in the part and either press fit (if
> > it's knurled) or
> screw in (if
> > it's external threaded) It's faster, cheaper, safer and
> > more reliable.
> >
> > Do NOT attempt to hold a lead part with Home-Depot type
> > "T" Nuts. Those
> are
> > made for light loads in wood, are limited in thread sizes
> > and the tapered
> spines
> > won't hold. They are actually many times larger in
> > diameter than PAL
> inserts.
> > They need to be as they can only be used in compression
> > assemblies.
> >
> >
> > Art Bianconi
> >
> > > On Fri, 9 Jul 2004 mdholm@telerama.com wrote:
> > >
> > > > I am curious, Jerry.  How did you drill and tap that
> > > > lead counterweight?  I tought lead was difficult to do
> > > > that with because of being so soft.
> > > >
> > > > Mark Holm
> > > > mdholm@telerama.com
> > >
> > > There are ways to harden lead, bullet casters do this.
> > > Mostly they are alloying the lead with antimony and/or
> > > tin. Wheelweights (scrounge for free from places that do
> > > tire work) or linotype metal are plenty hard already.
> >
> >
> >
> > _______________________________________________
> > ATM mailing list http://www.atmlist.net/
> 
> 



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