"Backyard Renegade" <skcusemans DeleteThis @eudoramail.com> wrote in message
news:144b721f.0401020619.62596e9f@posting.google.com...
> "bomar" <bomar76 DeleteThis @hotmail.com> wrote in message
news:<bV0Jb.116288$031.100451@fe3.columbus.rr.com>...
> > We do the screw line up thing all the time on firearms.
> > It's pretty easy to do, really.
> > The screws all have extra high heads on them for fitting .
> > We install the screws, scribe an index mark on them to orient the same
way,
> > then remove screws.
> > Cut off the protruding high head and file new slot using index mark to
> > guide.
> > Reinstall screws and VOILA...they all line up, properly torqued.
>
> When writing the origional post I considered addressing the issue of
> machine screws in metal, but forgot. Still, I doubt they do it
> building a boat. Unfortunately, I will probably not get an answer here
> as the ones who could answer are more concerened with politics... and
> I don't agree with theirs so.....
> >
<snip>
As indicated, this custom fitting involves hand manufacturing a screw to
account for process variations. This adds a lot of expense for very little
gain. Also, I would wonder if these screws are still interchangeable.
With NC tooling is perfectly possible to get the threads to start in the
same place on every hole. It is not always possible to get screws that have
the same phase relationship between the threads and the slots. Even if you
can get screws that have good repeatability you still have to contend with
minor variations in paint and stock thickness.
If this requirement came across my desk as part of a design, I would
probably redline it and send it back to the engineer/salesman that wrote it
up. Give the number of fasteners that don't show a visible orientation, I
would urge that the designers change the method of manufacture to achieve a
pleasing appearance.
In many American companies, manufacturing engineering and quality control
are considered useless appendages, not a vital way to keep the company
competitive and profitable. Many companies feel that they don't even need to
mess with this foolishness and don't even formally consider these aspects.
Then they wonder why foreign companies deliver a cheaper and better product.
The usual answer is just that the labor is cheaper. It completely eludes
them that retooling and improving an existing product is better than trying
to churn out more of the same old thing cheaper.
The old school method (add labor to make it work) is one of the reasons that
USA products are more expensive than they should be. A different approach is
to re-engineer the part with ease of manufacture in mind. I was just reading
an article about a Chinese factory that was presented with a demand to
increase production to meet pre-Christmas sales. The pacing element was a
mold that produces the case parts. When they made another mold, instead of
just making a copy of the existing part, they took their experience in
making the parts and redesigned it to eliminate the time consuming
fasteners. As hard as it may be to imagine, they designed out the
"expensive" Chinese labor!
In another thread we are hashing out wood/plastic/glass/aluminum/steel as
the best building material. This sort of continued reexamination in the
foundations of how things are done is the best way to make a better boat.
As a casual aside for the boat builder in the group, have you reexamined
every "truth" in your manufacturing to see if there is a way to improve the
process? Is stitch and glue still the best way to make little boats? Even
then, have you looked at the newest glues, latest fibers? How much time do
you spend trying out new ways of making joints? For the *absolute* cheapest
utility boat, could you make an Inuit style boat from PVC water pipes and a
blue plastic tarp? Are there better ways of protecting aluminum and steel to
keep them from rotting apart in use? To my way of thinking, welded aluminum
is the best overall way of making a boat. For a larger boat, steel offers
the best overall material. In both, effective corrosion control is the
elusive brass ring.
As witnessed by the ongoing discussions about heads, heaters, carpets,
fittings, lights, and finishes (particularly bottom paint) all of these
areas have a long way to go to reach perfection. I would like to think that
we can do it ourselves, but sometimes I wonder if perhaps the best way to
improve these parts is to send them over to a Chinese company to have them
set up tooling. We learned this from Japan in the 50s: If you want the
absolute cheapest part, they could do it but is was *clearly* inferior. If
you were willing to pay the same price, they could often make a much better
part. China has taken the place of Japan in this regard.
Mark Browne <--Who has way too much time on his hands on this new-years day!<!-- ~MESSAGE_AFTER~ -->
>> Stay informed about: Screws line up nicely? 
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. Anyway, I am sure