Reproduction Walnut Shifter Knob

#1
Hi All

I'm looking into doing a run of reproduction wooden shift knobs, as originally supplied on NADA TC's. The wood part is pretty easy, but the clear gearshift pattern top of the knob will require injection moulding & and expensive tooling for same.

Before taking the plunge, I'd like to ask how many would interested in buying one for their car if the price was around 40-45$ US.

Yours
Vern
 
#4
WarrenL said:
I'd have one if you were doing them for autos.
Automatic knobs would be a whole new project, in some ways easier because it wouldn't have the acrylic top. But also not authentic, as the auto only had one knob. But I'll look into it.

By the way, this is still moving ahead slowly, having some trouble finding a injection molder who is interested in a very small project.

But one change is I think I will be offering complete knobs and just the acrylic tops by themselves, There would be a bit of work to fit them to the knob (they were made slightly oversized and sanded and polished to join the wooden part seamlessly) but it would save an otherwise good knob.

Yours
Vern
 

arthuy

Well-Known Member
#6
There is a company I have used who will do 1 or a million. Plastic Mouldings Irvine, Scotland. They have plants over the world and different skills. I used them for vacuum forming trim panels for the p5.

The tooling as you know is the expensive part but they have people who can do that.

Colin
 
#7
Hi All

I'm looking into doing a run of reproduction wooden shift knobs, as originally supplied on NADA TC's. The wood part is pretty easy, but the clear gearshift pattern top of the knob will require injection moulding & and expensive tooling for same.

Before taking the plunge, I'd like to ask how many would interested in buying one for their car if the price was around 40-45$ US.

Yours
Vern
I would be interested in one.
 

sdibbers

Well-Known Member
#9
Has anyone looked at 3D printing that little piece of plastic? Printing is really good for small runs like this would be.
Problem with most clear printed parts is they go yellow pretty quickly when exposed to sunlight. The resigns used are actually cured by UV light so continued exposure tends to ‘over cure’ them. Not only yellowing them but also making them very brittle. A better bet would be to have them CNC machines out of acrylic then polished. In the US first-cut do this relatively inexpensively. I’m sure someone in the U.K. would also be able to help. As for the CAD model I can help with that if you don’t mind a bit of a wait.
 
#10
I thought I would tackle reproducing my old wooden shift knob. It seems like a good Covid lockdown project. After 50+ years, the clear plastic dome on the knob was anything but clear. I have attached a photo. IMGP4537.jpg As mentioned in the thread above, the base is the simple part. I turned a new wood piece from some 2 inch turning stock. For the brass insert, I used 1/2 inch brass rod that I drilled and tapped to the required 1/4 UNF thread. (photo attached) I originally tried a 3/4 inch piece of brass but found that one the full height of the wood had a more solid feel when mounted on the gear lever. IMGP4545.jpg
My idea for the top was to cast one out of non-yellowing epoxy resin. I did some measurements of the old cap and determined that a silicone spherical mold of 50 mm would work. I filled the mold partially to get the necessary 31 mm diameter flat surface.
I put together the artwork for the shift pattern and had it engraved on the flat surface (reversed) of the epoxy casting using a numerically controlled deep rotary engraver to 1.5 mm deep. The engraving was then filled with white paint and then the entire flat surface painted black. IMGP4546.jpg IMGP4547.jpg The result closely mimics the original and has the same 3D effect. A bit of epoxy to glue the parts together and another project is complete. IMGP4548.jpg
 
#11
Nicely done.

I had gotten as far as quotes for the injection moulding for the plastic part and the wood knobs in 2014. The wood was reasonable, but the injection mold was going to require I sell about a 1000 knobs to break even (unless the knob price was $250 or so). I've been meaning to get back to it as tooling costs have come way down in the past 6 years, and 3d printing may now be possible too.

Yours
Vern
 

sdibbers

Well-Known Member
#12
Nicely done.

I had gotten as far as quotes for the injection moulding for the plastic part and the wood knobs in 2014. The wood was reasonable, but the injection mold was going to require I sell about a 1000 knobs to break even (unless the knob price was $250 or so). I've been meaning to get back to it as tooling costs have come way down in the past 6 years, and 3d printing may now be possible too.

Yours
Vern
Unfortunately 3D printer resins in clear tend to yellow rapidly. Your best pet is either a machined acrylic part or to cast in clear PU resin from either a silicon rubber mould or directly from a printed mould (such as a FormLab print).
 
#15
Is this a latter design of the wooden gear knob, as my early version does not have a clear plastic top, pictures below.
The numerals and gear gate lines are sunken and filled with white paint, now a little yellow and worn out!

01DA8116-8CFD-499D-B14F-BE4A661472DF.jpeg C8FF8A80-70B7-4C6A-8DC4-AE87EDCB9230.jpeg
 
#16
As far as I can determine. the clear topped knob in my first photo is the one originally provided in my Canadian purchased 1968 2000 TC.
 
#17
The one that I have pictured is from a Nov 1965 2000, but after several owners and a checked history I’m not sure when it was originally fitted. I assume that there were two designs produce, but did one supersede the other or were both available at the same time for different markets.
 
#18
I have a 1966 advertisment for the NADA TC that seems to show the black topped knob so I suspect it is the first version, then the clear top knob was used from 1967 or so on. I think.

Yours
Vern
 
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