Stanley 20 - missing part

[Vince Shriver]

I'm missing the adjuster nut (the nut under the blade that raises and lowers it), on a Stanley 20 Compass Plane. I've tried to substitute this part from several bench planes (#3, #4, #5), but the threads are different, they bind up after a couple initial turns on the stud that comes out of the frog. Any suggestions where I might get one. Thanks. Vince

[Paul Atkins]

Is it left handed? How about double threaded?

[Bill Houghton]

I'm not a collector, but have heard references by those more knowledgeable than I do to different thread patterns on this adjuster. If I'm reading the online plane feature matrix right, types 1 - 5 bench planes (up to 1888) used right hand thread, 6 and on used left hand thread.

Right hand thread spirals such that turning the screw/bolt to the right as you stand "behind" it moves it forward (thus the many variants on how to teach someone how to disassemble/assemble machinery: right is tight, left is loose). Left hand thread, big surprise, is the opposite. You can confirm right hand thread by holding a largish bolt vertically: right hand thread moves up as it goes around to the right. Left hand thread is rare, and used in applications where it's needed (many two-handle kitchen/bath faucets, for instance, will use left hand thread on one faucet so you push or pull each handle in the same way - toward or away from you; in some machinery applications, left hand thread is used where the normal movement of the machine would cause right hand threaded fasteners to work loose...but I digress).

If you've got tolerable eyesight or a magnifying glass, get yourself a typical right hand thread machine screw (fine thread No. 10 or 12 or so would be best, for close size match), and look at it next to the screw on which the adjusting nut is set. Consider which way the threads spiral. When you've got a comparison thread next to the plane's stud, you can easily see whether the threads spiral with the machine screw (right hand) or opposite it (left hand). You can then compare it to the threads on the planes from which you tried to scavenge the nut.

You can also tell by contemplating the threads whether they've been messed up - look for evidence of unevenness, flat tops on the threads, and so on.

Once you know, you can seek the proper adjusting nut and/or parts. Many of the online dealers sell parts, and you might well be able to get some help from another Neander here (can't help myself, I'm afraid - limited supply of planes, all working, nothing to strip for parts).