ATM Undersized, overpriced bearings, was: The BIG Time

[Dave Sopchak <das@po.cwru.edu>]

Hi all.

>:Mike Linder wrote:
>:"Look closely - it's not a counterweight, just something to
>pull down
>:from the center of the bearing to put more pressure on it,
>so they can
>:continue to use undersized bearings."

I just got the Orion catalog illustrating their spring idea today, so
apparently the post office is in sync across the USA.

I agree with Mike 100%! I've always been amazed at how small the dob
bearings are on these commercial scopes. I use 5" PVC bearings on my 6"f/4
and I consider those on the small side. The amazing thing to me is how much
they charge for the bearings by themselves- like over $40 a pair!
        I'll stick to my $10 a pair PVC bearings from Home Depot, and I've
seen much cheaper, bigger bearing surfaces in the past. Keep your eyes
peeled for such beasts. Once I bought a couple of tacky picnicware plates
with cylindrical sides, 8" in diameter, for about a buck each. Worked great
on a 6" f/9 scope I built. I went back to by a dozen more and the sale was
over and the plates gone. Drat!
        I wonder why Orion charges so much for their bearings. Do they
really cost that much? I suppose they save on having to make a cradle for
the scope with the contoured sides of the bearings, but surely injection
molded plastic parts like that must be pretty cheap to make?

Those springs that Orion advertises must have a bit of pull if they
advertise one of the advantages of this setup being that you can carry the
OTA and rocker in one unit. I bet Tom doesn't do that with his 16" scope
<guffaw> ;)

Clear skies,

        Dave



______________________________________________
"Materiel shortages continue to plague the allied war effort"