Making a solid Titanium shift knob...my experience...

With a whole week of experience, I learned a lot about titanium and making a solid titanium shift knob for my Prius"v.'

While I learned a lot about machining and finishing titanium, it is not an experience that I savored.

My experience in the aerospace industry never involved titanium. My expertise is with aluminum alloys.

I first did an extensive search of the web on titanium shift knobs and all of my technical references on titanium. None of the makers will tell you what grade they use. Obviously, they are probably using the pure titanium grade 2, which has the hardness and strength of standard 6061 commercial grade aluminum.


Grade 5 alloy consisting of 90% titanium, 6% aluminum and 4% vanadium is the alloy known as aerospace and medical grade. It is twice as strong and hard as high strength 7075 aluminum alloy and much more durable and scratch resistant.

The grade 5 alloy is the one that you will NEVER see advertised in "solid titanium" shift knobs. It is nearly six times harder to machine as grade 2.

It took me 6-8 hours for five days to successfully make two shift knobs. I initially started three, but one was destroyed as quite a few band carbide lathe tools as well as a bi-metal band saw blade.

So, I've attached photos of one that was successfully completed and installed on my Prius"v."


Also, I am glad that the experience is OVER. I am just happy that I have one very exclusive shift knob and the experience gained.

 

7075-T651 aluminum will be a very good alternative. I've worked with is alloy many times over the years. It's predecessor was first developed by Sumitomo in Japan in 1937. The Japanese called it "ultra super duralumin."

The West knew very little about the zinc copper based aluminum alloy, until a Mitsubishi A6M2 Zero Sen fighter was recovered in the early days of World War II in the Aleutians.

7075 is about twice as hard as the standard 6061 alloy and polishes to a highly durable shine. It is much more durable than the cheap "flash anodized" coating that you see on mass marketed aluminum articles.

When scratched or abraded, anodizing looks ugly, and there is no way to refinish it. 7075 re-polishes to the same brilliant shine as before with wheel polishes like Mothers brand mag wheel polish.

7075 is now commonly used on gun receivers like the M16 and AR15 rifles and nearly all alloy handgun receivers.

Throughout my aerospace engineering and production career, I have extensively used this material.

Yes, I am considering making shift knobs out of 7075, if anyone is interested.

 

Air_Boss, a photo please.

 

The vintage light blue-grey looks very distinctive. It looks like it held up well.

I tried adapting the Razo LS137 knob made for the Gen III Prius for the Prius"v." I was, however, disappointed on how narrow the head was. The "three finger grab" using the thumb, index and middle finger felt awkward on the 15/16 inch or 25mm diameter.

The 1-3/16 inch or 33mm diameter feels just right for the "v" and would be a "natural" feel for the Gen III Prius (M6x1.0 threads), Prius "c" and any Toyota automatic shifter using M8x1.25 threads.

In the near horizontal mode of the Gen II's and the "v" the "three finger" grip on the grooves feels ergonomically good.

For the Gen III's and other Toyota automatic shifters, the "golf ball" sized knob feels very ergonomically natural, when the "three finger" grip is used with the finger tips landing on the turned down "collar" of the knob.

I have attached a side by side photo of my improved pattern next to the Razo knob, which I found to stick out too much on the "v" and less functional in the vertical mounting mode for other Prii.