Re: belts and harnesses

[Simon Favre <simon@domain.elided>]

Well, I didn't want to "out" this on the digest, but I've rewebbed a
set for my '67 GTV. My old belts have all metal buckles, so I felt
better about reusing them. Anything with old plastic is suspect, IMO.
The webbing in my old belts was so bad, it actually creaked when you
twisted it. In addition to catastrophic failure in a serious accident,
the other thing about old belts is that they will stretch more than
new ones. Racers are required to replace their harnesses every 3-5
years, depending on the organizers. A new racing harness will stretch
about 6 inches in the worst frontal impact a driver could be expected
to survive. After 5 years, it's 12 inches. How old are your belts? ;=(

Kathy Jo is right. If you want to reweb belts for a living, you need
an industrial sewing machine. If you don't do it for a living, you 
CAN do it with a regular sewing machine, provided the results are as
good. I did it with a regular Singer machine, with the tension dialed
up to about 9 to 9.5 on a scale of 10. I used the correct modern
webbing, obtained from an awning and canvas company, and I used the
correct thread, which is not only heavy duty Nylon, it is specially
treated to be UV-resistant. This is important for seatbelts. I also
bought enough extra webbing to practice on to make sure I had the
tension right. When the tension is right, the stitch crossover will
be buried in the webbing, or barely visible. Too little tension, and
thread will pile up under the webbing. Too much, and the needle will
pull the bobbin thread up through the webbing, resulting in a weak
stitch. I also heat-sealed all the cut web ends, as well as the knots
put in the ends of the thread. I did need to buy a large needle to
fit the special thread, but that was no big deal. To make the "X in a
box" pattern, I always stopped with the needle down, then carefully
lefted the presser foot just enough to turn the web for the next run.
If you look at any modern seatbelt, you will see that there are only
minor variations on this pattern, basically in the number of passes
above and below the X.

It was actually a fun job.

As I also pointed out off-digest, in our litigious culture, nobody in
their right minds would do this for a living. It figures a place in
Texas would do it...

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End of alfa-digest V7 #1416
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