Changed my mind about using a standard torque wrench on old Otis door hanger bolts

For years, I'd just follow the manual spec, like 65 foot-pounds on those 3/4 inch bolts. But after seeing three different jobs in the last six months where the threads in the sill were just stripped out (one was a 1978 unit in the old First National building downtown), I started asking around. An old-timer at the supply house told me he always backs it off by 10% on anything pre-1985 because the castings get brittle. Tried it on a call last week, and sure enough, the bolt seated firm without that awful creaking sound. Now I keep a little chart in my bag for vintage stuff. Anyone else run into this, or have a different rule of thumb for older equipment?

3 comments

3 Comments

mia_park2mo ago

Man, that's smart. So you're basically going by feel now on the old stuff? What do you do if the bolt still feels loose after your backed-off torque?

finley7772mo ago

Ever just add a dab of blue threadlocker, @mia_park?

grantl941mo ago

Jump on the threadlocker advice but be careful with it on old castings. Honestly, I've had luck using a little anti-seize instead of threadlocker on those pre-1985 bolts, especially if the threads look dry or crusty. That way you get a more consistent torque reading without the risk of galling the soft metal. If the bolt still feels loose after backing off 10%, I'd check the hole for any burrs or elongation first. Sometimes a little file work or a tap clean-up fixes that loose feel without forcing more torque.