On Thu, 11 Jun 2015 09:03:33 -0400, "Jim Wilkins"
wrote:

"Ed Huntress" wrote in message
.. .
...
"Design for production" has been a mantra in production for at least
50 years. Caterpillar was a pioneer, in the early '70s, at taking
their new design engineers and putting them on the shop floor for
six
months before they'd let them design anything. My FIL was part of
that
program at Cat's Aurora plant, teaching those new engineers how
things
are actually made. It really paid off for Caterpillar, and other
large
manufacturers picked up on the program. But not everyone caught on.
...
--
Ed Huntress

I went through that myself as a production floor assembler and then a
pencil-and-paper draftsman at a maker of custom production test
equipment. They had electrical and mechanical engineers but the
project leader position I was working toward had to be a generalist
who knew some of both plus HVAC and industrial wiring and could use
tools.

The subject of the lesson was the design of structural sheetmetal to
be made on a press brake and Strippit punch. I didn't have to become
an expert at operating the machines, only understand the tolerances
they were capable of and the necessary sequence of operations, such as
punch ALL the holes and corner notches, THEN do the bending, and try
to minimize the inevitable match-drilling at final assembly.

As you say, not everyone can correctly imagine how the three
dimensional part will be made, and that includes some very smart
electrical engineers. A Physics professor I knew socially told me he
had switched majors from Chemistry because he couldn't visualize
molecular structures rotating and vibrating in three dimensions.

LOTS of people can't think in 3D, so that doesn't surprise me at all.


I was stuck for a while on how to accurately locate the bearing
press-out holes on the wheels I'm making. My mill doesn't have enough
vertical clearance to index the blanks in a chuck. I finally chucked
the disks in the milling vise and located the #10 (~3/16") tapped
holes as close as possible to both sides of the OD of the bearing
recess by feeling the clearance of a #2 drill/countersink to the wall
with paper.

Whatever works!


So I still design features I don't know how to make, assuming I'll
figure out something later and change the drawing to match.

Isn't that the way it's always done? (see TBD dwg for reference)


Two opposed holes were adequate when the first bearing was initially
pressed fairly hard into an 0.0004" interference fit. I could turn the
cap screws 1/6th turn alternately to press it out. The final fit is
close enough to turn the screws simultaneously with my fingers. The
electric trolley hoist will see so little use that wear if the
bearings shift isn't an issue. Mainly it will keep heavy logs away
from my feet. The HF manual I-beam trolley's bearings are quite loose
on their axles.

To lower rolling resistance, I'm sure.


I'm trying to accustom myself to progressive (no-line, varifocal)
eyeglasses I bought yesterday. They shift continuously from
nearsightness correction at the top to slight magnification at the
bottom, with the result that only a few lines of text on the screen
are clear, though the sharp focus distance varies from 12" at the
bottom to seeing the bright stars Arcturus and Spica nearly as points
instead of blobs at the top. Also I can't use the larger monitors on
the shelf above the laptops without tilting my head up uncomfortably
or leaning back too far to type. Last night I detailed the CAD drawing
of the wheel axle on the 15" laptop screen, easily, instead of on the
22" display above it that I use without glasses.

Good luck. I nearly nuked a pair I tried a decade ago, but settled
for flowing plasma at both the optometrist and his assbite office
manager instead. After two weeks of severe headaches and a couple
near misses in the truck, I'd had it. They never told me that 80% of
the lens has no correction whatsoever, so my brain was left to handle
translation of my twin astigmatisms on its own. It didn't like that
after several decades of help from real eyeglasses, TYVM.


I lost my previous company-issue glasses at a volunteer construction
project a few weeks ago after taking them off to start a balky
generator. They were probably trampled into the dirt, run over by a
skid-steer, then buried under tons of sand. Providentially I kept an
older pair in the car.

Condolences. I lost a lens once, when a screw loosened; sucked.

Yes, always keep spares! That's another reason I like buying from
Zenni. An extra pair (stainless framed hi-index bifocals) costs about
$30, so I buy two pair at a time, keeping a pair with the brand new
prescription as a spare each time. My old prescriptions are in a
drawer, the new spares in the truck (now in my BOB) at all times.

--
Worrying does not take away tomorrow's troubles,
it takes away today's peace. --Lifehack