I think that you've already figured this out; You increase the
pre-load on the springs. On the two similar doors on my garage, you
hold the spring-securing hub by inserting a 1/2" steel rod into the
provided holes, loosen the set screws locking the hub to the shaft,
then "crank" more tension into the spring with yet another 1/2" rod:
crank, hold, crank, hold, etc. A couple of cranks on each spring
should do it, then, tighten the set screws. Don't worry about
perfect equalization, the 3/4 rod is solid so the lift effort will
still be equal if you're a little off. If you make the 1/2" rods,
make them at least 12" or better, 18" long. You're gonna have to
hold the full spring tension with one hand at a time and the spring
on a big door is pretty "torqey"!
----------
> From: Jeff Guilford <jagcret@knoxnews.infi.net>
> To: shop-talk@autox.team.net
> Subject: Garage Door Balance
> Date: Sunday, March 22, 1998 1:23 PM
>
>
>
> While installing a new garage door opener, I performed the "garage
door
> balance" test called for in the instructions--and my door failed
(alas, the
> ignominy).
>
> In the gospel according to Craftsman, a garage door is properly
"balanced"
> if it stays in a partially opened position (i.e., raised ~3 feet)
when you
> let go of it at that point. My door, which is one of those
sectional
> things, will close if I let go when it's raised 3 feet. This
supposedly
> means that it's "unbalanced." Much like its owner.
>
> The door is assisted by two torsion springs attached in a
concentric manner
> to a 3/4" shaft that runs parallel to the door just above the
header. Six
> inch drums are attached to the ends of this shaft (above the edges
of the
> door). The springs turn the shaft (or vice versa, depending on
whether the
> door is raising or lowering), the shaft turns the drums, and the
drums feed
> out or retrieve cables that connect to the bottom of the door.
>
> Does anyone know how to "balance" this type of mechanism? I assume
this
> means that I have to increase the load (or pre-load?) on the
springs, but
> how do I do this--without endangering life, limb, and sanity? And,
how do
> you ensure that the two springs have approximately equal tension?
>
> One final note: I've had my eye on a drill press for awhile.
Anyone have
> any good ideas on how to convince my wife that I can't install the
garage
> door opener without benefit of this indispensable tool? ;^)
>
> Thanks for any help you can provide.
>
> Jeff Guilford
> Knoxville, TN
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