small industrial roller shutter door

Is there some trick to tensioning the balance spring on a second hand
door?
There are no obvious holes where a locking pin could have been removed
and trying to do the job in situ is way beyond my strength.
Unlike a domestic window blind, the shaft has a square section at both
ends so you can't just lift one end and wind on some tension. The slats
weigh about 75kg so lifting without mechanical aid becomes progressively
harder as slats are wound on!
Help!
regards
Reply to
Tim Lamb
I was reduced to using a block and tackle to lift the bottom of an open roller door to form a U shape, until it was high enough for a rope over the main part of the roll to take over and put a complete extra turn of tension on. Repeat as required. Not fun, but perhaps safer than risking anything spinning round.
Reply to
Autolycus
In message , Autolycus writes
Oh!
Fortunately I have access to a masted fork lift.
Presumably your method involved fitting the side guides later? I had vaguely assumed that it would be possible to insert the tightly rolled door into the header brackets, wind on a few turns of tension and then engage the spring axle into the support cups.
However, the access slots in the header brackets appear too narrow to accept a fully wound door. Fitting one of the brackets later does not seem very do-able as the frame is set partly inside the door opening.
Grrr.... Roller door fitters must be very strong people.
regards
Reply to
Tim Lamb

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