Making A Wooden Shift Knob - Chapter 2

[Captain Obvious]

A while ago I made a couple wooden shift knobs (http://www.classiczcars.com/topic/44856-making-a-wooden-shift-knob/) and while I think they turned out pretty well, I've always knew there was some room for improvement. They were "close" to the original design, but just different enough to bug me. So with that in mind, I set out to make couple more with the intent to see how close I could reproduce the original knob.

 

After a completely unprofitable and unreasonable amount of time, effort, trial and error, and raw materials, this is what I've got. The knob I made from scratch is on the left and the original Datsun knob is on the right. Only catch is that since the shift map from the factory knob was crazed and cracked into multiple pieces, the shift maps in both knobs are reproduction pieces that I made:

 

Here's a side view. Note that my base is real metal instead of metalized plastic:

 

I was on a roll, so I also made another knob to accepy my red 5-speed emblem as well. Here's the happy family:

 

I'm still working out some of the bugs, but I'm pretty happy so far. Under magnification, I can still see some remnants of the damage from the original shift map that I used as a pattern, but I'd challenge the casual viewer to discern the difference between mine and an original factory knob in excellent condition.

 

I don't have an older style 5-speed knob, but if I had one to use as a guide (hint hint), I could probably go through the same process with it as well.  

[grannyknot]

Cap'm, if you do produce an old style 5spd map please put me on a buyers list.

Thanks,

Chris

[rossiz]

those are beautiful - i can't tell from the photo if they are raw wood or have a finish... if not, what kind of finish will you put on them?

[psdenno]

Nice job!  I'm sure you'll have eager customers if you decide to expand production.  And you did this all in your spare time?

Dennis

[Captain Obvious]

Thanks guys. I'm no woodworker, but I'm doing my best!

 

The question about stain has an interesting answer... I'm still of the opinion that the original knobs may have been impregnated with a resin of some sort. I've cross-sectioned an original knob to get a good look at un-weathered grain in the middle, and on the inside, the grain and rays are clearly visible. There are no visible air cavities however. Seems completely and totally solid. Also, it's much harder than the rock maple that I'm working with, and when machining a factory knob, I get the distinct odor that you get when you machine most plastics. Thirdly, it's of a significantly higher density than the maple I'm working with.

 

So... With all that in mind, what did I do? Well, I tried to impregnate the wood with resin, of course!

 

I mixed up a concoction of polyurethane sealer and a custom wood stain blend as an attempt to replicate the factory coloring. Then I dunked the wood portion into a small jar and put the whole thing under vacuum to draw air out of the knob. That way, once returned to atmospheric pressure, it would draw the colored polyurethane into the wood to replace the air that was sucked out under vacuum.

 

Poly and stain concoction mixed in small jar:

 

Under vacuum inside my chamber drawing some of the air out of the wood. Bubbles out, poly in:

 

So the answer to the question is that there is some finishing done to the knobs, but maybe not the kind of finish you were imagining? 

Edited February 26, 2015 by Captain Obvious

[240260280z]

Looks like beer!

[240260280z]

May need some heat:

http://www.sawmillcreek.org/showthread.php?201715-resin-impregnating

[240260280z]

Check the cactus juice heat cure

[geezer]

Wow, beautiful work Captain!

Temperature can play havoc with polyurethane finishes on wood. Years ago I learned the hard way that kitchen cabinets being sprayed in the garage as the temperature was on the rise, caused the air within the wood to expand and cause minute bubbles on the surface before completely drying. I since have learned to avoid this by spraying when the ambient temperature is on the decrease.

The vacuum heat curing process is interesting and wouldn't surprise me in the least if it is found that the originals were done similarly. They did have a process that stood the test of time with the steering wheels as well making them very durable.

[DavidF]

Nice process! Any chance you are planning to sell these? I'm looking for a 4-shift knob for my father's 240Z.

[siteunseen]

A little high but they have cheaper ones too.  http://www.thezstore.com/page/TZS/PROD/classic08e02a01/40-2980

[Reverend]

http://zstory.online.fr

 

These guys make perfect replica of rare 5-speed shift knob, i did not found it on their website but they have pics in their FB page.