A high school classmate was told her old Crawford garage door opener
is not repairable because the plastic clip that failed is no longer
Sure it is, if you know a machinist! But wait, there's more...
I haven't seen the installation, it being some 800 miles from here.
Your first solution would only work if the underside of the chain is
accessable in situ. Your second solution might work if the person on
the ladder could dril thru a chain sideplate without snapping a drill
bit in the hole. You go first!
ok, some more ideas - a small piece of spring steel that engages the edges
of the chain.
What I have actually done in similar situations (not a garage door opener,
but similar failures) is to drill the plastic item and add some metal
reinforcement - in this case extending the ear with a small piece of wire
drilled into the plastic - you are right though if you can't see the
installation and are relying on a 'replace or discard" type repairman, you
may have limited options. Personally, I don't have a garage door on the
theory that if I am too infirm to lift my garage door, I'm also too infirm
to mess with whatever is inside.
You don't have a garage door for fear that you might be too infirm to
lift it and use whatever is housed within? A properly balanced garage
door can be lifted with one finger by a dainty and comely lass.
Your posited solutions may well be brilliant, we'll never know unless
you make them and demonstrate. I'll stay tuned for that.
I'm old school. I back up my words and imaginations with metal that
That is a very nice solution.
Careful, though, lest it gets out of hand. For instance my neighbor
needs a starter shaft for his Shovelhead. I didn't do my surface
grinder any good by regrinding a chipped carbide wood shaper bit on it
for another friend.
Oh, that's cool! The plastic one is work to be proud of, but not
leaving well enough alone, you do yourself better with a new design!
[Clap, clap, whistle, ...]
I can see that you're well up on the learning curve of the CAD software
. A beginner would have spent HOURS making the "drawing". Or, maybe
you are a beginner & did spend hours on it (?).
To make installation "... whilst hanging upside down from a rope in a
howling gale by flashlight ..." easier, you could use something larger
than a 4-40 setscrew. They're pretty easy to lose.
I think it could be a _little_ simpler by not having the middle tooth.
I think the plastic one might need it, but not the ally one. Doesn't
Nice write up, too.
Thanks for sharing,
Nicely done! If you're interested in the project for some side income,
there's probably a small market. I know in fact there is a market for
replacement parts for stuff like this, just can't quite figure out how
to reach those that need the diverse parts.
Some time back I was searching for some obscure hardware when I stumbled
across a web site that had probably a couple hundred odd fittings and
special screws, mostly relating to obscure and decidedly vintage
carburetors back to nearly the dawn of the automobile. Guy had spent a
fair bit of time coming up with that list of parts and probably is close
to, if not in fact, a world leader in supplying these parts.
A significant portion of my income derives from making replacement parts
for light rail. Rarely have the luxury of a drawing, often have to work
from broken or worn parts. OEM parts are either too expensive, have
wicked long lead times, or are just not available anymore. I just made 5
parts out of solid aluminum, 2" thick, 9.5" dia, 5" center hole, lots of
detail work. End user was quoted -12 months- for replacement parts.
Hell, I could have built a foundry, learned pattern making, cast 5
pieces in my back yard, machined and delivered in less time! While
machining was expensive, they had parts in less than 3 weeks.
My customer knows the industry and is my gateway, but there's got to be
a need for small lot parts in many other fields....
I've used AutoCAD for many years. I regard it as an essential shop
tool. I don't use CAD software on every project. Sometimes I just
make a sketch on a quadrule pad, sometimes I don't even do that. But
sometimes CAD's ability to sort out geometry and give dimensions is
very useful. Example: on the clip, I needed to determine the radius
of the curved part from two measurements: width and height of the
broken part. I could figure out how to do that with geometry, trig
and a calculator, but AutoCAD makes it very easy because it can draw a
circle defined by 3 points. Dimension the circle to get the radius,
AutoCAD in 3D, however, is a freakin' nightmare.
Alibre is a parametric solid modeller, like SolidWorks and ProE, at an
affordable price. I can see why a professional might want the "real
thing" but Alibre does what I want to do in my home shop. It's
particularly useful for projects that have a number of parts,
including moving parts, that must fit together.
Neat-o stuff from you, as usual. Very good.
We used a similar "ramp" for limit switches, but not on chain. The
principle we had might work here though. Looking at the project that
you "designed", if you were to make a single piece that had a full end
and the rest being half thickness for the remainder, you could place
two very easily in a back-to-back pair to make a "whole", including
the middle tooth. I suspect that on the original, that middle tooth
took all the drive forces, minimal as they might be, so then very
As this is a fixed length, you might even make it with a hole and a
pin in the piece, such that when placed back-to-back, the pin in one
locates in the hole on the other, and that would allow placement and
locking without screws while up on the ladder. Just snap in place,
but the force to do so would be sideways rather than along the chain
length as you assume the original is placed.
Our application had the ramp pieces mounted on a slotted rail, and the
ramp could be "extended" for adjustment as the micro-switch rode fully
over it, and it was the ramped-up distance that was critical. The
pieces were identical, same "hand" and all, but when placed looked
very much like what your pix and then you sketch showed.
Take care. Keep up the good work and simple ideas you come up with.
I'm sure I speak for many if not most of us here on RCM to say that we
enjoy them a lot, and always the story and/or detail that comes with
ps... I don't know if Mike Rehmus (Model Engine Builder magazine
publisher) will once again be doing a Seminar at NAMES 2010 in
Southgate, Michigan, next month (April 24 & 25), but at NAMES 2009 if
you did attend his presentation, you got a free copy of the base
Alibre program. Good deal !! Makes the price of admission seem
I must be older school than you. I would have fit that arc with a compass
faster than you could walk to your office and turn the 'puter on.
I do agree, AutoCAD is a necessary tool for complex parts. I may just buy
Alibre for my spare time project next fishin' season. About eight years ago,
I spent all my spare time from fishin' learning autoCAD.
Mike Rehmus has the 10:00 AM slot on Saturday if I can trust what was posted
His demonstration last year is what made me pony up $913.00 back when it wasn't
discounted for the starter version with maintenace.
I subscribe to MEB, he makes Alibre go though it's paces on the enclosed drawing
His seminar is well worth seeing, I plan to see it again this year since I bet
learned more and I know I sure have. Should be a great seminar.
On Mon, 22 Mar 2010 23:22:16 -0500, the infamous Don Foreman
scrawled the following:
Too bad you don't have a CNC mill. You could whip out 100 of them and
sell/trade them for new toys, while making 100 people very happy.
P.S: $95 to spend 1 minute on a ladder, then show and tell the lady
what's wrong? I'm in the wrong business.
If we attend continually and promptly to the little that we can do, we
shall ere long be surprised to find how little remains that we cannot do.
-- Samuel Butler
What's that Lassie? You say that Bill Noble fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Mon, 22 Mar 2010 22:13:15 -0700:
Heck with that. Just clean off the oil and wrap a lump of duct tape