Knobtastic!

[Biggles1957]

WARNING! Viewers of a nervous disposition - here are some pictures of my new knob...

My original gear shift knob was rather cracked (as per normal!) so I decided that I would either glue it back together and cover it in leather or attempt to make a new wooden one. I got hold of some nice black walnut (left over from gun stocks) and set to in my workshop. I obtained a used gear shift from a breaker because I needed to keep the car useable (it's my daily driver). Robert the Bruce sprang to mind as at first I didn't succeed so I tried and tried again!
I removed the urethane coating from the gear knob and cleaned up the hard plastic inner, and removed the plunger. I cut a basic 'T' shape from the walnut and then roughly shaped it with my bandsaw, drum sander and disc sander. Then cut it into two pieces horizontally with the bandsaw. Then using various rotary burrs proceeded to hollow the two pieces to fit around the plastic knob. All was going rather well I thought, and I bonded the two halves of the walnut around the plastic inner with black Stixall (other similar compounds like Tigerseal etc would also work well), and a good wood glue on the walnut. After clamping and leaving to cure/dry for a couple of days and then started to sand the outside to shape. Annoyingly, I was a bit too enthusiastic and broke through the wood. It wasn't going to be satisfactorily repairable, plus the whole thing was too big really so that one was scrap! I made a new one in the same way, but this time tried to remove less wood on the inside so that it was a tighter fit to the plastic. Yet again, the sanding/shaping process was going fine until I broke through in a different place to the first attempt! After quite some fiddly measuring and scribbling diagrams I decided that it would be a good idea to make the inner plastic part smaller so that the outer in turn could finish smaller overall.

Mk 3 was going well until an unseen crack in the walnut became apparent which meant that went into the scrap bin too! Next one had some lovely figuring in the grain, but it was really hard and too difficult to machine so that's got an appointment with the log burner next winter too! By this time I was getting close to the end of the useable walnut blocks that I had so I made the inner plastic even smaller (whilst still retaining the operational parts at their original sizes).

This time I decided that I would bond a piece of black cow horn sheet to the side of the knob where the plunger fits so that it would have a nice hardwearing surface and also (in my opinion) look rather lovely! When it came to fitting to the car, some 'adjustment' was needed to get the plunger and other gubbins to all operate correctly (just a few tweaks by shortening the inner plastic operating rod that lifts the 'stop' rod, and some adjustment to the 'plunger' so that it didn't leave a gap where it enters the shift knob) and the Mk 5 knob was complete! I finished it with progressively finer sandpaper and gave it several coats of pure tung oil. After that had all dried a couple of coats of neutral satin finish wood wax gave me a lovely smooth finish on what I think is a very neat shift knob. I think I shall glue my original knob back together and cover that with leather anyway to keep as a 'spare' (although I don't really know why I would need one!). I hope you like the finished article....

[Betweenthewheels]

What a fantastic job.... I mean knob....errr....no, I'll stay with job!
Beautiful craftsmanship - lovely.

[Biggles1957]

Thanks - can't remember the last time someone complimented me on my knob!

[Degens]

Captain Biggles, here another compliment

[Dieselman]

That looks excellent and very classy, a definite upgrade.

I can understand the challenge of making the thin wooden outer, almost like a thick veneer, which leads me to some questions;
Could the complete stick, not be made from wood?
How much thinning of the plastic did you perform and given the wood is a lot stronger than the original rubber, how much plastic could one remove before the inner core became too weak?
Does the inner plastic core provide any actual operational function, or is it just a support for the outer skin and the push-button? i.e. How much detail is required inside the core, enough to make it fit the metal lever, or a significant amount of functional detail?

Any more images of the process?

If we hear of Cow horn poaching, we'll know you have started series production.

[Biggles1957]

I think with the right kit you could perhaps make the whole thing from wood - although it would of course need quite a long piece and it needs to be thick too - so for nice wood would be a bit expensive! You'd have to bore out for the vertical rod and the cross piece where the button fits and be sure that the button wouldn't catch inside. That's why I thought it best to 'modify' a spare knob. I thinned the shaft part of the old knob all round (in one place I slightly exposed the steel within) and the 'handle' part until it was only a bit bigger than the oval hole for the knob. I thought that keeping the plastic part for the push button to run in was the best idea rather than introduce another process where I would have had to make sure absolutely everything was perfectly lined up so that the little screws fitted in the right place and the whole knob stayed in the correct position. By keeping the wood reasonably thick I could then sand it to the final shape and keep everything in the right place - if you see what I mean.
I basically forgot about photo's as I went along - I got carried away in the moment as it were - making small adjustments and trial fitting as I progressed. The Stixall filled any gaps nicely and cures to a good rubber consistency so there is no movement between the wood and plastic/metal inner, but I used a strong wood glue on the two parts of the wood so as to make a strong wood bond and almost hide the joint line. It all took quite some time (mostly due to the few failures!) but the final version maybe half a day to marine etc., then glue etc overnight and another half day to sand and start applying the finish (that had to be left 24 hours between coats) so fairly labour intensive I guess. If you had access to CNC kit you could turn them out a lot quicker of course. I'm very pleased with the finished article though! Covering an old one with leather would be so much easier!!