RE: [CAD_CAM_EDM_DRO] Crazy ideas Vol 1 Follow up

Fine idea, but fiberglass is not the best idea if you want "Tough and
chemically resistant bellows". Glass is used in a rigid composite matrix
like FRP because of its stiffness in tension. It has disadvantes in
flexture and, if degraded, will leave a highly abrasive glass dust in your
machine. While the bare fabric seems flexible, the shear will increase when
embedded in the rubber matrix and the fibers will do more cracking. Dacron
cloth in a silicon rubber or vinyl matrix is what is used in conventional
applications. I believe that inflatable rubber boats, military tarps, and
industrial bellows all use Dacron as the fabric, not glass.

-----Original Message-----
From: stephank97 [mailto:stephank@...]
Sent: Thursday, June 12, 2003 3:42 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Crazy ideas Vol 1 Follow up

Hi All

Thanks to all for the suggestions on making bellows. I have decided
on using a fibreglass satin weave cloth, impregnated with catalyst
cured silicon rubber (all available at your local craft shop). For
folding I will route 90 deg V slots in two matching pieces of wood,
coated liberally with petroleum jelly (Vaseline) and squeeze the
impregnated cloth between these during curing. Voila! Tough and
chemically resistant bellows.

As for the lapping of the screw threads, for the life of me I cannot
find the site again, but the basic method is a follows:
Take about 20 nuts or so a put them on the screw to be lapped, align
them so that there is a small gap between them and the flat of the
hex's are aligned. Fix these firmly into a vice (The site suggested
soldering to a base plate) I just use my Workmate (Black & Decker).
Put some lapping compound ( I just use automotive paint burnishing
compound) on the thread. Work the thread back and forth through the
nuts about 20-30 times. This is hard work, so I just put the end of
the thread into a reverseable hand drill. You will need a length of
thread longer than the final use dictates, as you cannot lap to the
very end, but since studding is dirt cheap, who cares. As you work
the screw back and forth, you will noticed shiny spots appearing at
regular intervals, this is the periodic error that you want to
remove from the thread. It does not eliminate the accumalated error,
but this can be compensated for in most software packages. Once
again I have pictures, but somehow Yahoo won't let me upload them.


Stephan




Addresses:
FAQ: http://www.ktmarketing.com/faq.html
FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com

Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...,
timg@...
Moderator: pentam@... indigo_red@... [Moderators]
URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO

OFF Topic POSTS: General Machining
If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.
http://www.metalworking.com/news_servers.html

http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
sister site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.

NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
bill
List Mom
List Owner



Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/