"Allan Adler" wrote in message
...

If I understand correctly, what I need to do hand scraping is:
(1) a piece of metal to scrape
(2) a 3 cornered scraper
(3) bench level with milled surfaces (instead of an expensive surface
plate)
(4) Prussian blue oil paint

This would just be for practice. I wouldn't be planning to use the
resulting
scraped piece metal for anything at this point. Since it is only for
practice,
I don't know what size I should get. Presumably it should be steel, since
I am interested in possibly building a Gingery lathe someday, but Gingery
mentions that some of the cast aluminum parts will also require scraping.

I can order a flat piece of steel to scrape from a steel supply house.
I don't know if I can simply walk to my neighborhood hardware store to
get a 3 cornered scraper; even if they have 3 cornered scrapers, I'm so
ignorant that I wouldn't know if it is suitable for metal or whether for
some reason it should only be used on wood. I might have to order it,
which would involve shipping costs and maybe minimum orders. Ditto for
a suitable bench level with milled surfaces; but since it is just for
practice, maybe it doesn't matter what level I use. Blue oil paint I
can get from a local art supply store, probably for 5 or 10 dollars.

What I would like to know is how much the total ought to cost if I do it
as cheaply as possible and where I ought to get it from in order to
achieve
that minumum.

It occurs to me that I might also have to consider getting some kind of
grinder in case the scraper gets worn. Maybe at my present level of
commitment
and competence, it would be more cost effective just to get a spare
scraper.

One reason this particular exercise appeals to me is that, unlike
practically
any other metal working project I can think of, it can easily be done in
an
apartment without using much space and without making a mess (at least I
think not), and is probably rock bottom in terms of cost. Another is that
it really is a very basic skill which I'll need to develop sooner or
later.
If it happens that there are other metal working activities one can do
safely
and neatly in a tiny apartment for practically no money, I'd be glad to
know
about them.

Ignorantly,
Allan Adler



Three cornered scrapers are used for scraping inside diameters, such as
bushings, and for deburring. They are a favorite amongst machinists. The
type scraper you're looking for would be a long, straight device (about 18"
long or so), which could be either carbide or HSS on the end. The end,
which does the scraping, has a slight curvature along its edge. Scrapers
have a nice palm type handle on the opposite end.

Scraping, while possible on steel, is mostly accomplished on gray cast iron,
which is the material of choice for machine tool construction because of its
relatively low cost, but more importantly, because of its characteristics,
which lend themselves extremely well to machine tools. Cast gray iron is a
super bearing surface, and has very good damping characteristics,
preventing, or minimizing chatter (vibration).

There are good books available that cover scraping. I'd suggest you do
some research and invest in one, which would enlighten you as to procedures
and proper equipment. You'll discover that a surface plate is essential
for flat surfaces, a level alone won't hack it.

Scraping is not really the domain of the typical machinist. I worked in
machine shops for almost my entire adult life and saw scraping done only
once, that not by a machinist, but by a maintenance man, who restored a
small Gorton mill which would otherwise had been worthless. With new
screws and nuts, the machine turned out beautifully and was extremely
accurate.

The home shop type seems to enjoy getting involved in scraping, which is
likely a good idea because old worn machines can be refurbished enough to
offer further life, a good thing for those of us on limited budgets.

Good luck with your venture!

Harold