Ferrari Shift Knob

Next time you see a Ferrari 308 (or 246 or 328 or 348) peek inside and take a look at it's shift knob. Although it's classic round shape is iconic, you may be surprised to see that the OEM knob looks less like something out of an Italian dream car and more like a cheap little bakelite ball. It is little too, only 43mm in diameter which some may think feels a little small to fit the hand comfortably. Look closer and you'll see that the gear numbers are deeply engraved into the knob which makes it difficult to keep the numbers looking clean and white. This is one way to make an upgraded Ferrari shift knob.

Ready to begin, The 2x2x6 inch Gaboon ebony blank is coated with wax to keep the wood from swelling and shrinking with changes in humidity which helps keep the wood from cracking. The finish on the completed knob should serve the same function.

Cut in half to make a single shift knob.

A 1/8 inch hole was drilled down the axis of the blank. Not only will this give me center points for mounting on the lathe but will also make it much easier drill the recesses for the inserts once the sphere has been turned.

The knob's shape laid out on the blank.

Ebony wood is rare and expensive stuff so I cut away as much as I could on the bandsaw. The small cut off bits may be useful in other projects.

The blank mounted on the lathe. I like to wheel the lathe out of the shop on nice days. Helps keep the dust off my Boxster!

There are many methods of turning a sphere on a lathe many of which involve fancy tooling. I just turn it by eye using a paper template as a guide.

Cutting off the ends of the blank leaves us with a roundish ball, not round enough for a Ferrari though!

The ball is returned to the lathe, this time mounted between cup centers at a ninety degree angle to it's axis and turned so that it's round in that plane too..

By remounting at different angles many times and making sure the ball is round no matter how it's mounted leaves us with a (more or less) true sphere,

The sphere is being drilled to form a recess for the shift pattern insert. I made a jig to insure this goes straight down the middle.

It's upside down now, being drilled to accept the threaded insert. If you look carefully, you'll see that I've already drilled a larger hole so that I can countersink the threaded insert.

Tapping the hole for the threaded insert.

The insert installed. There needs to me a flat on the bottom so that a jam nut can be used to orient the knob on the shift arm correctly. I've found that sanding this flat by hand is more accurate and less error prone than using power tools.

Now we're getting there! Just waiting for the shift pattern insert now.

The goal is to make a shift knob that retains the original knob's round shape. Shift pattern inserts that have the correct shift pattern and domed shape are not available commercially so I designed one in FreeCAD.

My son Andy uses his 3d resin printer to make them for me. Here's the latest batch.

The numbers filled with white epoxy.

The excess epoxy sanded away leaving a smooth surface.

A small flat needed to be sanded on the top of the knob so that there is a smooth transition between the insert and the knob. It's possible to get the fit close this way but a it's still necessary to do the final fitting on the lathe.

Back on the lathe to apply the finish. The cyanoacrylate glue forms a hard and durable surface that can be polished to a glossy shine.

The insert was precisely fitted then the knob sanded down to crazy fine 12000 grit and then polished. Look closely and you'll see my reflection in the knob's finish.

The completed shift knob.

It looks even better when it's installed.

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