On 2012-03-11, Wild_Bill wrote:
Yep, I definitely recommend an indoctrination period of becoming familiar
with the differences in actual results compared to expected results such as
DOC depth of cut relating to feed dial scale markings.
I've gotten used to making notes and reference examples and hanging them in
plain view of the machine controls, as a deterrent to oh****! moments.
:-)
Especially in the huge numbers of imported models which are marketed to
potential owners who may be interested in either metric or inch based
features, whereas we're aware that one size does not fit all.
When trying to remove metal in thousandths results in accumulative errors by
counting metric dial ticks, it can fairly easily lead to confusion (for me,
doesn't take much to do that these days).
And -- to add to the problems, I've seen machines with dials
marked 0-0.125" -- but there was a slight gap between the 0" and the
0.125" points. Turns out to be something like 0.128" per turn
(3.25mm/turn) so they could use the same leadscrew and nut on both Inch
and Metric machines. Never mind what happens when someone is mentally
counting the turns adding 0.125" per turn. :-)
Wow, $250 for a quality 4" 6-jaw.. and that's still considerably less than
some new quality brand 3-jaw models that size.
Indeed. I'm still sort of sorry that I skipped it. But it was
a threaded backplate, so I would have had to make another backplate for
the Compact-5/CNC (the most appropriate size lathe I have for it which
is good enough to be worth it). And the Compact-5 needs access from the
tailstock end of the spindle to access the three (or four for a 4-jaw
chuck) screws which pass through the chuck body to mount it. Kind of
awkward, in that I would have to dismantle the adjust-tru assembly to
access the mounting screws. They go directly into the flat end of the
spindle nose. (A total of six threaded holes, with one of them acting
as a corner of both a triangular pattern and a square one.) The OD of
the spindle nose is a precise 40mm, and the back of the chuck is turned
with a matching recess for centering.
I just picked up a used 4" Dunlap 4-jaw for the 7x mini lathe, since the
only spindle accessory included with this new machine was a 3" 3-jaw.
The Dunlap backplate is made to fit a 3/4" thread, so I'll be making an
aluminum backplate to replace it which will match the spindle flange of the
7x mini.
This may have been a 3/4" (or perhaps a 1") thread. But since
it is an adjust-tru, it is easy enough to make an alternative backing
plate to fit to something else.
It would be easy enough to just cut the existing backplate to match, but
there may be a future use for the original threaded version, so I'll
preserve it.
Good!
I wouldn't feel that a 7x mini from China is deserving of a good 6-jaw a far
as a cost effective upgrade.. especially at new prices.
Same with the beat up old Atlas/Craftsman 6x18 lathe -- one
prior to the Timken roller bearing spindles.
I would've then felt compelled to find a lathe of equal quality to match the
chuck, but that's just me.
I understand it totally. That is why I don't have that chuck
now. :-)
Enjoy,
DoN.
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