I need advise on Millers Falls 9C plane refurbishment

[Larry Feltner]

My son bought a Millers Falls 9C plane at a flea market and we have been refurbishing it. The problem we are having is when we disassembled the plane, the threaded rod that the blade adjustment knob turns on, unscrewed from the frog when we were trying to remove the knurled blade adjustment knob. There is no slot on the threaded rod to tighten it, so I am just able to tighten it with my fingers. When I do that, the threaded rod unscrews if you try to lower the blade with the blade adjustment knob. The threaded rod is reverse threaded so it tightens counterclockwise and loosens clockwise. So when I turn the blade adjustment knob clockwise to lower the blade the threaded rod unscrews instead of the blade adjustment knob turning on the threaded rod. Is the fix as simple as putting some thread lock on the threaded rod before screwing it into the frog? If that is the fix, how clean and free of oil does the screw hole need to be for the thread lock to work well? I can't think of another way to stop the threaded rod from unscrewing when I turn the blade adjustment knob clockwise.

[Richard Line]

I can think of 2 ways. The simplest is to use the thread lock, I'd try the removable type until that is proved not adequate. The 2nd way is to use 2 nuts on the adjustment end of the rod (after the adjuster knob is removed) and jam the nuts tight together, then run the rod in until it tightens in the threaded hole, remove the jam nuts and install the knob. You may want to also use the removable type thread lock as well with this approach.

[steven c newman]

Not sure how available 2 left-hand threaded nuts are, but....cut a small strip of leather ( like from an old leather glove) just enough to go around the bolt. Then use a pair of Visegrip pliers to turn the bolt until it is seated all the way in. Blue Lock-Tite.....IF you use the Red, it will be a permanent fix...

[Clifford McGuire]

I have a MF 9 and just took a look. That threaded rod is in there tight. I tried it turn it with vice grips (with a cloth to protect it) and it wouldn't move. So, once it is seated tight, it won't be spinning. Sorry I couldn't be of more help.

Maybe a drop of Lock-Tite like Steven recommends??