Wood Field Camera Repair Question: How to remove the focus knob on the Pinion?

[Willie]

Might try laying it on the side so the knob is facing up. Then use a toothpick to put a drop of PB Blaster on the center. Let it work for a day & do again a couple times. In between tap and pull and see if it gets moving. The stuff can help with frozen press fit pieces, big to small.

[Ron (Netherlands)]

creeping / penetrating oil might help too....let sit for some days...
If the shaft is rusted, you might also want to soak in some rustremover

[Jim C.]

I'm with Eric Woodbury, it looks a lot like a square end on the shaft, the square hole in the knob or both
may have rounded and jammed itself together from someone trying to turn it past a stop point or just wear.

If you have access to the shaft and can grab it with pair of pliers, hold the shaft and rotate the knob back and forth
that may free it enough to pull off without using a gear puller. A drop or two of PB Blaster or Liquid Wrench may help.

A magnet makes quick work identifying ferrous vs non ferrous metals.

[tdicorcia]

Summary:
Thank you all. I decided to take the conservative route. Leaving the knobs on, I was able to remove the two shafts from the wood, clean them up with industrial grade scocth-brite-type pad, and reassemble. I carefully sanded the wood surfaces that slide against each other and rubbed candle wax on the surfaces, followed by rubbing with a rag. Reassembled, the camera focus runs smoothly now.

For the record:
- it seems the shafts and locking nuts on the end of the shafts are steel/plated-steel.
- The knobs and other flat hardware is non-ferrous, possibly brass and plated with a silver-colored metal.
(Jim C's suggestion of using a magnet was helpful for sorting out ferrous vs non-ferrous. )
- It does look like the knobs have square holes that sit on a square section of its shaft. Makes sense as this focus knob needs to turn the shaft. Smaller knobs on the opposite end of the shafts are threaded onto the shaft, allowing the user to tighten the shaft down and lock the focus.

[Ulophot]

Wouldn't a magnet indicate whether brass or steel was used?

[tdicorcia]

Yes. Indeed. Jim C suggested that and it worked quite well. The shaft and end locknuts are steel, the other metal parts are non-ferrous (possibly brass) with a silver-like plating. Do you happen to know what type of plating these older cameras used on brass? I have another camera, in rougher shape that has a slight greenish tinge on top of the plating. I'd like to polish that up but may wear the plating thin.

[Jim C.]

Plating is usually nickle, which is btw magnetic, but at the thicknesses the plating is, it'll barely register with a ceramic magnet
a neodymium rare earth mag may give a slight drag. Greenish patina on your other camera is probably because the plating was
porous and the brass underneath is reacting, if the plating is blistering under the patina you may wind up removing some of the
plating.