|
Yes, if your doing a lot or emery.
Keeping the ways clean and oiled is important but
emery cloth is used on laths all the time to deburr sharp edges. For the
few grains of grit that land on the ways it's not that big of a deal. It's
far less grit then you get when using a tool post grinder on a lathe.
But, as Lain points out, it is wise to protect the
ways from grit when your doing this much emery on a lathe. And I agree,
news paper or cardboard is always best. Wipe and reoil afterward
also.
Dan H.
----- Original Message -----
Sent: Tuesday, March 07, 2006 4:46
PM
Subject: RE: [PSUBS-MAILIST] viewport
surface finish
PLEASE PLEASE be
careful if you are going to use emry paper on the lathe, Cover all parts of
the lathe that could possibly get grit on it with newspaper (not rag). The
grit breaks off the paper and can settle on all you slides and bed and when
mixed with oil on the bed and or coolant you have grinding paste.
NASTY!
Newspaper is best as
rag has a high tensile strength and when caught around your arm and the chuck
= BAD
Newspaper will tear.
Just some thoughts,
you hopefully know all this.
From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Dan H.
Sent: Monday, 6 March 2006 7:34
PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] viewport
surface finish
A-516 shouldn't be
any more difficult to machine then standard off the shelf A-36 or 1018 steel
you find. There are some steels that are freer machining but not by
much. There are a lot of steels that are much tougher and sticker to
machine. If your machining any 316 stainless for sub parts, you'll find
that much more difficult.
I imagine you could
etch with acid but I've never heard of anyone doing that. It would
probably just give you a coating of corrosion under the paint. All you
need to do is, after your done machining, sand the surfaces your going to
paint a bit right in the lathe with some, maybe 180 grit emery paper, or
sand blast it after your done machining if you have a sand blaster. Use
a two part, self etching primer after that. The primer will bite into
the surface and hold the paint. Also, the primer will protect the
surface until your sub is all welded together and
painted.
You may want to run
some tests of how thick your paint will be when your finished. I'm
guessing one layer of primer and one layer of paint will average about .010 of
an inch but it depends on how you put it on and how heavy you apply
it.
----- Original
Message -----
Sent: Monday, March 06,
2006 9:36 PM
Subject: [PSUBS-MAILIST]
viewport surface finish
I've got another couple of viewport questions for some of you savy sub
builders out there. I've been machining my first flat disk viewport
flange . That A516 grade 70 steel is really hard stuff !! I
was surprised how much more difficult it is to machine, in that you
can't take off as much metal at a time. Anyway I have been doing some
of the final cuts and facing and getting a very smooth surface finish
with higher speeds on the lathe and I have my tolerences very close.
But what I'm wondering is if those surfaces are going to be painted with
epoxy will the very smooth suface finish make it hard for the epoxy to
stick? Should I treat it with muriatic acid before I paint it?
And how many thousandths does the average epoxy paint add up
to?
|