Make custom interchangeable gearshift knobs/extensions for your import vehicle! Both of my Japanese made vehicles have a manual/standard transmission. The stock shift lever has a threaded end that is M10 X 1.25 This is where the stock knob threads on to. I will show you how to easily make threaded collars made from 1/4" gas line style pipe fittings.
Step 1: Gather Supplies and Tools.
I have a collection of 1/4" NPT threaded gasline style sections/fittings from a project idea I had years ago. they are readily available and fairly inexpensive. I recently received an old Nissan pickup truck and I thought it would be fun to mess around with it. One idea was to change the shifter, extend it and add a custom knob. After trying a few options, like cutting,bending, drilling and tapping some cold rolled steel bar, It turned out to be too heavy and completely impractical. Here's what makes this easy.... the internal diameter of 1/4" gas fittings is perfect to run an M10 X 1.25 tap down without further drilling or mods. You will need a way of holding the parts like the vice pictured.
you will need a Tap handle and an M10X1.25 tap, some type of lubricating fluid. Thread lock like "Loctite" will be required to keep the parts aligned after you build them. I also used a dremel with a cut off wheel to cut the head off of a metric M10x1.25 bolt. This should thread into your stock knob or any custom parts you make. An easy way to check is to have an M10x1.25 nut that you can thread on to the shift lever etc.
Put the 1/4" pipe section or fitting in the vice and "start" the tap. Use some lubricant in the part to be threaded. Try to keep the Tap straight. Once started, the rule is one turn forward...one quarter turn back. This breaks the "chip" caused by cutting threads. Add lubricant often.
Step 3: What It Should Look Like.
The finished product should look like the first picture, try an M10X1.25 bolt to make sure it threads in easily. The third picture is of the bolt I cut the head off of. I threaded it into the pipe and secured it with Loctite. Now the stock shift knob threads on like in the 4th picture.
Step 4: Some Ideas
Just some pics of potential shift knobs/extensions. Lawnmower piston, or as in Pic. #4 a way of relocating your stock shift knob...may not be practical... but it looks dope!!!! hahaha!
If you simply want to make a sturdy shift knob that doesn't overly affect the length of your shift lever, use a shorter section of pipe and glue it into...... bowling ball?