[AT] Getting water out of a gearbox/now bearing life

[Indiana Robinson]

I have a stash of 1 5/16" line shafting, some of it from before 1900 out of
very old shoe repair/making machinery.
About 30 years ago before I had a lathe I had a machine shop owner I'm
acquainted with make me some adapters from a piece of it so I could use
some shoe repair devices on a Shopsmith woodworking machine. When I picked
the stuff up the guy asked me where I got the shafting from. After I told
him he said "That was some of the nicest stuff I have turned in a long
time... extremely uniform". I hadn't really given it any thought, it was
just mild steel shafting of the right size to me.  I guess they were not
mixing in melted Pinto's or Yugo's back then  :-)




On Mon, Jun 8, 2015 at 9:59 PM, <jtchall at nc.rr.com> wrote:

> Over toleranced parts is not an American problem. I daily work with German,
> Dutch, and Japanese prints that are ridiculously toleranced. Some of it is
> so closely engineered you need to manufacture in a tightly controlled
> temperature setting and do the assembly in a clean room. The funny part is,
> everybody wants crazy tolerances, but none want to pay for them. We've been
> dealing with variables in raw materials for years. Anything from plastic to
> stainless steel, you never know for certain what you are going to get. One
> batch machines like it should, the next cuts horribly. At least at my work
> we have been trending toward tighter tolerances and better finishes for
> quite some time---a lot of it is absolutely unnecessary.
>
> John Hall
>
>
> -----Original Message-----
> From: macowboy at comcast.net
> Sent: Monday, June 08, 2015 8:59 AM
> To: Antique tractor email discussion group
> Subject: Re: [AT] Getting water out of a gearbox/now bearing life
>
> I have been reading this topic with great interest. For the past 15 years I
> have been involved either on the supplier side providing components to the
> big automotive assembly lines or on the OEM side for the medical device
> industry. I have been to most of the major automotive assembly plant across
> the country and a few of the big truck manufacturers too. One things that
> was made clear to me that todays vehicles are designed to last 150,000
> miles. This is straight from the engineers at the assembly plants. I don't
> know where this number came from but this is what I was told. The Japanese
> do a much better job with design and assembly. They use a practice called
> Probabilistic Design where they take the variability of each component in
> an
> assembly and determine what the process capability(defect rate) will be. If
> it is less than a zero defects, back the drawing board. I have found that
> the American manufacturers tend to design in the electronic world(CAD) and
> do not take into consideration the manufacturing capability of the process
> they have selected. What happens is that when a certain combination of
> tolerances occur in a assembly, you will have failures. The design guys
> will
> tend to put very unrealistic tolerances on their drawing as it makes their
> jobs much easier. The DFMEA that was talked about earlier is more of a
> paper
> work/regulations requirement rather than a good tool to use. Most engineers
> that do this conduct a top down DFMEA where they look at the assembly as a
> whole. A better way to do this is a bottom up DFMEA where you look at each
> requirement on each component. One engineering manager did this and his
> final product was as close to flawless as possible. BTW, as far as
> components go I can say the electronics(PCB's) are the worst followed
> closely by raw materials/chemicals for failures.
>
>
> Jim Thomson
> macowboy at comcast.net
>
>
>
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>



-- 
-- 

Francis Robinson
aka "farmer"
Central Indiana USA
robinson46176 at gmail.com