I have a 45 year old Surface grinder - and noticed the spindle nut was turned
nicely. What made it unique - remember it has to be flat and have the threads
exactly done as they should - very high speed turning and pressure on a rock.
What they did was use an expanding dovetail chuck on the lathe. They likely did
the front, and turned the dovetail - 2" in diameter or so and then bore the hole
and turned the threads. Parted the nut - It is maybe 3/8" thick - held it with
the dovetail in a special lathe or perhaps the same lathe. Once mounted,
the back is faced - and maybe ground.
I suppose there are expanding dovetail chucks that are metal lathe rated -
I have them on my wood lathe. I have never seen them.
But I think that was a neat way to do things.
The front of my new one has an internal dovetail (likely used in manufacture) but
a reverse dovetail - so a small dovetailed chunk of metal can be moved and then locked
with an Allen screw.
Neat way if you can live with a dovetail - or grind it off after screwing on the nut...
martin
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder
Harold and Susan Vordos wrote:
"Harold and Susan Vordos" wrote in message
...
"ducque" wrote in message
groups.com...
Since I'm completely self-taught at machining, there are necessarily
big "holes" in my knowledge. Here's one, and I'd like to "fill the
hole"! :-)
I don't know how to accurately make a very thin part -- for example,
something akin to a washer, or a very short bushing.
It's easy enough to accurately turn the part, make necessary shoulders,
etc. But what about after the piece is "parted off"? The desired part
will be too thin to hold effectively in a vise to mill to its final
thickness (imagine needing a part less than 0.050 thick, for example).
For example, using my milling vise and parallels, I cannot effectively
grip and strongly hold anything less than about 0.065 thick.
What do people do in these situations? Thanks.
Soft jaws.
Soft jaws.
Soft jaws.
There's not better tool in your arsenal-------
Harold
That, of course, should read "there's no better tool in your arsenal".
Sorry, my fingers got away from me.
You can hold thin sections and face them dead parallel with no effort, and
do it time and again. You can also hold complex configurations the same
way, with the added benefit of the jaws acting as a perfect linear stop.
Great for multiple pieces that must be concentric, perpendicular and the
same length.
Harold
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