On Fri, 22 Aug 2014, Brian Reay wrote:
Lostgallifreyan wrote:
Brian Reay wrote in news:558999594430351400.971108no.sp-
:
They tend to be fine for thin steal (eg car panels if you are fitting an
antenna)
Good point. I don't drive or own any large boatanchors so I'm not used to
thinking of non-portable or unsupported surfaces. It may even be easier to
improvise with a slightly wrong hole punch (or aim small and file
outwards) and some large washers than to attempt the way I usually do things.
For small round holes of unspecified size I have never beaten an M3 pilot
hole followed by a tapered reamer, deburring the result with a Stanley blade.
That is VERY cheap, I started out that way and it was a couple of years
before I needed anything better.
Well, as you probably know, real precision holes (eg in watches) are pilot
drilled and reamed, rather
than drilled to size.
The Stanley blade is not, however, part of the procedure. ;-) A fine
broach would be used I would think.
I've repaired a number of pocket watches and clocks but always by hunting
down new parts if needed, or getting them
made. Sadly, my dexterity isn't up to it these days, although it has been
improving recently- much to my surprise- plus I've learned to use my left
hand more. I may rebuild my modest collection of pocket watches, stolen
some years back. They were all ones I had restored, rather than simply
bought working. It is surprise that, even for quite old movements, you can
still locate new, old stock, parts. I recall a trek to a dusting shop in
Notting Hill for a part for a 1920s gold hunter. The shop owner looked at
the details and the broken part, thought for about 2 mins, turn to an array
of 100s of little draws, and produced one. The price? £1. The watch was
worth many times that. I return to the shop many times, it was always the
same. He always had a queue of others with similar wants. He fail once, a
balance staff for an 1883 cylinder escapement. I had that made, £5, inc.
fitting to the balance. He did have a suitable main spring and crystal
glass.
I expect both watches ended up being sold for scrap gold and silver when
the toe rags fenced them. The culprits were caught but the items were not
recovered.
Have you read this book "Longitude", I can't remember the author? (It's
rom about a decade ago.) It's a small book, more like an long essay, about
why a chronometer was needed for travel, and the prize and ultimate
entries to create a working chronometer that could be portable.
Things I'd never thought of. And surely the basis for common watches that
came later. All my life I've had watches, starting with mechanical, and
even those tended to keep pretty good time, likely fallout from that
chronometer work. And of course in recent years, I have a watch that
syncs up from the time signal, so it is very much close to "absolute"
time, for the purposes of everyday timekeeping.
Or a GPS, bought at a garage sale for five dollars, a tiny little thing
but amazing technology that couldn't be built in that small a package (let
alone imagined) forty years ago.
Michael