[AT] OT: non-tractor covid-19 activates

Fri Apr 3 03:38:00 PDT 2020

Hi John -

Hope the list will tolerate some CNC banter.  We have 1 job that we hold
close, using .0001" offsets; all the rest it would be more like .0005" or
more.  Swiss excels in small precise stuff and also long slender stuff, and
we are heavy on the latter.  Don't need all that precision, but it's handy
to have:  I can give the guys setup sheets with .XXX" dimensions and no
tolerance, and they can hit the numbers dead-on quite easily.  Keeps me
from having to even think about tolerances which is quite a luxury for an
engineer.

The job you mention is 6 diameters - that's a lot!  I hope at least it's
steel.  I only deal with this issue when making back cuts on the sub.  We
cut a lot of aluminum.  I have to keep it down to 3 diameters, and I still
have to deal with taper.

We deal with a couple local general job-shops, and among the rows of
verticals and conventional lathes, they each have at least one Swiss over
in the corner.  As you know, there's always those special jobs a Swiss
machine can hit out of the park.  But they're kind of their own special
beast too, a little different mind-set.  And in our case, with the older
machines, there's no Mastercam or conversational programming involved, just
straight G-code not to mention wait-codes to coordinate the sub.
Programming can get tricky; fortunately I enjoy it.  I make a game out of
avoiding crashes when developing a new job (and I'd score myself around an
A-minus)

SO

On Thu, Apr 2, 2020 at 10:13 PM John Hall <jtchall at nc.rr.com> wrote:

> About .0002' is as close as I care to hold. We often make offsets of
> .0002-3. Want some fun, try turning something 1/4" in dia sticking about 1
> 1/2" out of the chuck---a 10" 3 jaw that is. Slow on work so we pulled back
> in a job we had subbed to a screw machine shop. Yeah, those Swiss machines
> will kick my butt all day on the tiny stuff.
>
> John Hall
>
>
> On 4/2/2020 6:03 AM, Stephen Offiler wrote:
>
> Our CNC lathes are all Swiss-type, Star and Tsugami, from the 1990's.
> They all have magazine bar feeders (now they do; one machine used to have a
> single-stick tube that I retrofitted with an Ebay bar feeder) and we run
> them unattended after-hours, aka "lights-out".  Despite having worked in
> unknown other shops and beat who-knows how hard, they all can still hold
> tenths, and the Tsugami has encoders that go out to .00001" - not that we
> could ever work to that level of precision; between thermal issues and the
> ability to make measurements down there, that's way beyond what we need or
> could possibly do.  We're slowing down but we're still plodding forward,
> customers are still ordering, some.  We're keeping the people employed and
> building inventory where it makes sense.
>
> SO
>
>
> On Wed, Apr 1, 2020 at 9:06 PM John Hall <jtchall at nc.rr.com> wrote:
>
>> My boss has never bought hardly any used equipment in my 30 years--and it
>> was all manual machines (2 horizontals, radial drill, long bed TOS, 3
>> grinders and some small stuff from an acquaintance that was retiring). All
>> 3 of our CNC lathes are Mori's, great machines. We have never pushed them
>> hard like a lot of shops, their accuracy is great. I do have one that
>> couldn't repeat the last job we ran on it, so it will need some attention
>> from the dealer. Of course as slow as things are now........
>>
>> John Hall
>>
>>
>> On 4/1/2020 7:56 AM, Stephen Offiler wrote:
>>
>> Not surprised about the compression, Spencer.   Japanese bikes are built
>> more or less like Toyotas and Hondas (go figure)... they just last and
>> last.  I see you're tooling up, and wanted to mention THE go-to source for
>> motorcycle-specific special service tools, Motion Pro:
>> https://www.motionpro.com
>>
>> So, speaking of Japanese.... at work, one of the many things I do is
>> manage and grow our CNC capabilities.  We are small, funds are tight, and
>> we aren't a job-shop so I can't just finance a sweet new piece of equipment
>> and pay for it by selling parts to others.  We build parts for our own
>> internal needs, so I pick and choose parts we currently purchase from
>> others, figure out what we can save doing it inhouse, and use the projected
>> savings to fund the acquisition of used CNC equipment.  Once I locate a
>> suitable machine and coordinate shipping and rigging, it lands on the
>> factory floor, I next get it all set up, leveled, aligned, and powered,
>> then on to figuring out what's wrong.  Bear in mind we're talking say
>> $15,000 for a machine that was $200K new in 1997, so they have some miles
>> on them.  I do all the necessary refurbish, largely myself, but I also know
>> a great independent CNC repair tech for stuff that is beyond me.  Then I do
>> all the programming, tooling, debug, and finally write detailed "cookbook"
>> setup instructions so I can hand-off to the shop floor guys for daily
>> operation.  Sorry, I'm rambling a bit... my main point was that these CNC
>> machines are Japanese, and ~25 years later, they will still happily run
>> 10,000rpm on the main spindle, and still hold tolerances in the +/-0.0001"
>> range.  I like older Japanese stuff.  Back to your Kawasaki, we've got two
>> vintage bikes:  my wife has a '76 Honda CB-200 and I've got a '75 Yamaha
>> DT-175.
>>
>> SO
>>
>>
>> On Tue, Mar 31, 2020 at 8:53 PM Spencer Yost <spencer at rdfarms.com> wrote:
>>
>>> So I mentioned a little while back that I was doing a valve lash
>>> adjustment on my 1989 Kawasaki 454LTD. It is been awfully hard to start,
>>> and valve adjustment is a common culprit. I’m glad I did it because the
>>> adjustments were definitely out though I could tell they were not so far
>>> out to affect starting to a degree its been happening.  So I started
>>> looking for other explanations.  I seem to have spark and had the smell the
>>> fuel on spark plugs. So I didn’t think it was fuel or spark. I then did a
>>> compression test:  For a 30-year-old bike it’s got startlingly nice
>>> compression. 135 both sides cold with no oil. But I also noticed that it
>>> took 15-20 seconds of starter time to actually get the four or  five
>>> compression strokes you need to get a max reading.  Hmmm.   That’s
>>> suspicious.
>>>
>>> So while the alternator crankshaft “peep-hole” cover was off so I could
>>> rotate the crankshaft for the valve adjustment, I took a look see at how
>>> fast the starter was spinning the engine.  The engine wasn’t spinning at
>>> all except about every 5-10 seconds it would catch and turn over once.
>>> Clearly the starter clutch was slipping.   This would explain why I had
>>> better luck roll starting it than using the starter. But the engine is big
>>> enough and I’m small enough that I need a pretty big hill to roll start it
>>> and that just isn’t viable where I live or wherever I might stop so I have
>>> to fix it to be in “riding” condition.
>>>
>>> So I took this opportunity to order a few things on eBay like flywheel
>>> puller and a fuel petcock that this bike desperately needs. They should be
>>> coming in a few days.  My guess when I get it disassembled is to find weak
>>> springs in the clutch.
>>>
>>> The goal is to have this bike starting and running smooth  before the
>>> covid-19 zombie comes to get me so I can out-run it. :-)
>>>
>>> Spencer
>>> _______________________________________________
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>>> AT at lists.antique-tractor.com
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>>>
>>
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