Artemia Salina scribed in
:
On Fri, 21 Nov 2003 01:33:01 -0600, F. Hayek wrote:
I like the idea of finding something like a South Bend 9" lathe
to get started. And go from there. I'm a Toyota 4x4 enthusiast
though, so I might like to be able to cut some metric threads.
That may be difficult, depending on the particular thread pitch,
without modifying the lathe (i.e. replacing one or two of the
[]
don't sweat it, metric threads can be had for the price of a file
download (-: Marvin Klotz's bit of software for calculating change
gears will take your existing set (and a gearbox if you have one) and
calculate the closest equivalents. on my changegearonly Myford I
get to within 0.00soemthing % of correct pitch for metric, without
any special gears. this has worked for everyting I've needed. you
might need 100% accurate on long engagement studs, but then I'd say
buy the studs anyway as they will be important (like cylinder head
stuff)
if you do need to make it easier, the 21 / 63 / 127 tooth gears make
it so. 21 or 63 are 'nearly' accurate, 127 is spot on but may not
fit on smaller lathes like my Myford.
I've never operated any such machine tool and I'm not too keen
on taking regular classes. I'm hoping I can learn from the
American Gunsmithing Institute's 30 hour video course.
http://www.americangunsmith.com/mill_lathe.html
They've got lots of cool stuff for gunsmiths too.
my quick list of the basic things you need to know to start
successfully:
feed speeds. lots of references to this, look it up. ignore carbide
speeds, you want HSS (and slower). using the correct feed speeds
makes the surface finish happen, prevents all sorts of evils like
galling, and prevents plastics from melting etc. running slower
also means you have time to prevent yourself making a stuff up (-:
grinding toolbits. you need: HSS blanks, bench grinder, task light.
maybe a few cardboard angle templates. have at it till it works.
lots of references on the web for the angles, but it is mostly not
critical to us home shop blokes because we tend to run slower than
production runs (see feed speeds above).
(many will recommend carbide inserts. yes they're nice, but they
cannot handle interrupted cuts, some types battle to take small cuts,
and you'll miss out on the important skill of grinding bits by hand.
there are a lot of jobs that cannot be done without a custom ground
bit and if you don't have the skill already, when you need the
special one is NOT the time to learn!)
patience. whatever it is you're doing, it will take longer than you
think. it's a hobby. relax (-:
thread cutting. this is easy, but you gotta get the angles and
techniques in your head. and slow the dang lathe down, at least at
first. my first thread was cut at 35 RPM. now I cut at 200 or so.
practise, and knowing where you're going, and thinking it through,
maybe a trial run to see if you really can disengage the feed 'there'
in time (-:
measurement. you have some nice metrology tools, but you'll need to
figure out when using a micrometer is necessary and when a plain
caliper will do it close enough for the job at hand. I tend to take
more time to get it spot on for even simple things, others don't.
Your choise as to how you spend your time. but I've made suspension
bushes and you'll want those ;correct; else they'll rattle, so take
the time (-:
lights. lights? when working with machine tools you need a lot of
light, with few shadows. fluorescents all over the place, and DC
task lights work nicely. the task lights must not be a lot brighter
than the general light else you get too much contrast. running low
voltage DC lights eliminates a lot of 60Hz flicker and make sthat
spinning chuck a bit safer to be around. i use a 50w 12V dichroic
lamp on a PC PSU for spotlighting. the average PC PSU can run 2 50W
lamps, or 4 25W.
To get yourself oriented with machine tool basics, you
might want to skim through the US Army's "Fundamentals
of Machine Tools" training manual:
http://155.217.58.58/cgi-bin/atdl.dll/tc/9-524/toc.htm
very good. I printed it and sat reading it evenings, in fact read it
a few times BEFORE I got the lathe. I also have a book by Len Mason
that is very good. This contains basics as well as some advanced
stuff on threading, dividing etc, see my web page for soem of the
results of that.
Also look at Lautards 'Beside Reader' series, said to be good.
swarf, steam and wind
--
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