Bull Head Shift Knob 3D Print

NP435 Shift Pattern

Bull Head Shift Knob (4 Speed)

Get it here:	Bull Head Shift Knob
Other Bullnose prints:	bullnosegarage.com/3dprints

I had a reasonable idea:

“Make a custom shift knob.”

Then Fusion 360 (CAD program) and my new 3d printer happened, and now we’re here.

This is a 3D printable bull head shift knob designed for Bullnose Ford trucks (1980–1986) and anyone else who thinks their interior could use a little more… determined livestock.

This is a two-piece knob system (plus a TPU sleeve) that lets you pick a shift pattern (or no pattern), print it in a different color, and assemble a finished knob that looks like one cohesive part.

It’s not a threaded knob. It’s a sleeve-and-set-screw style setup, because old trucks love doing things the hard way.

What This Is

A printable manual transmission shifter knob that comes in matched sets:

A bull head base (pattern-specific or blank)
A shift pattern insert (optional)
A TPU sleeve to adapt to different shifter shaft diameters

This is designed so the shift pattern sits flush with the forehead. No proud edges, no weird seams. If you rub your thumb across the top, it feels like one piece (because I’m picky and I wanted it that way).

Step 1: Choose Your Bull Head STL

You have two routes:

Option A: Blank Bull Head

No pattern. Just the bull.

If you don’t want a diagram, don’t need one, or your transmission has a shift pattern that looks like a game of Twister, this is probably your choice.

Option B: Pattern-Ready Bull Head (Matched to a Pattern)

This is the important part:

The forehead pocket is contoured to integrate with the pattern insert cleanly, which means each shift pattern uses its own matching bull head STL.

So you’ll choose a pair:

Head STL for that pattern
Pattern STL for that pattern

They’re meant to go together.

Step 2: Choose Your Shift Pattern STL

Print the pattern insert separately (ideally in a contrasting color). Then press-fit it into the matching bull head.

Available patterns:

4-Speed (Reverse Down)
Classic truck pattern (NP435-style)
4-Speed (Reverse Up)
For shifters where reverse lives up top
5-Speed Pattern
ZF-style layout, should also work with M5OD
Transfer Case Pattern (4WD)
Because yes, people asked and not everybody is rocking a manual

Each pattern is a standalone STL that matches a specific head STL.

Step 3: Set Screw Option (M5 Heat-Set Insert)

If you want a set screw (recommended), you’ll install a heat-set insert:

The knob is designed for an M5 heat-set insert
The hole is already sized for it
Add your own M5 set screw (length depends on your shifter and sleeve)

If you don’t want to run a set screw, you can still use the TPU sleeve as a friction fit… just understand that different trucks and different TPU setups may behave differently. You’re the engineer now. Congratulations.

Step 4: Choose the Correct TPU Sleeve

The bull head has a fixed internal bore and uses a TPU sleeve to fit different shifter shaft diameters.

You need to measure your shifter rod outer diameter.

This is the difference between “nice snug fit” and “why is my bull doing donuts around my shift lever?”

How to Measure Your Shifter Shaft

Remove your current shift knob.
Use digital calipers or even a ruler / measuring tape
Measure the outer diameter (OD) of the bare shifter shaft.
Measure in mm or convert from imperial.

Sleeve Sizes Included (Inner Diameter in mm)

All sleeves share the same outer diameter to fit the head. Choose the ID closest to your measured shaft:

12.8 mm
13.8 mm
14.8 mm
15.8 mm

Yeah yeah, I know they’re not freedom units, but fusion likes mm so that’s what I used. 13.8 is what works for my NP435. I haven’t done my transfer case knob yet, but I have a different idea for that one. 🙂

If You’re Between Sizes

If your shifter measures between sizes (example: 13.5 mm), start with the next size up (13.8) for easier install. If you want a tighter fit, try the smaller size. TPU has some give, and the set screw (if used) helps lock everything down.

Printing Recommendations

Bull Heads & Inserts

Recommended material: ASA
PLA can work short term, but vehicle interiors get hot
Print with enough perimeters and infill for durability (this is a shift knob, not a decorative shelf ornament). The more infill you have the heavier and sturdier it will feel. This is plastic, so it will be lighter than a normal shift knob.

Pattern Inserts

Print in a contrasting color for readability. You may also paint a contrasting color, but the press fit might be a bit tight unless you go light on the coats.
Press-fit into the matching head

TPU Sleeves

TPU 95A recommended
Print slow enough to keep dimensions accurate
If your printer runs “fat” or “skinny,” adjust as needed

How It Works

The TPU sleeve adapts the knob to your shifter shaft
The bull head fits over the sleeve
The M5 heat-set insert + set screw locks it in place (optional but recommended)
The pattern insert press-fits into the matching head and sits flush

The goal is a shift knob that looks intentional, feels good in the hand, and doesn’t scream “I printed this at 2 AM”… even though that’s probably what happened. At least, that’s how it happened with me.

What’s Included

Blank bull head STL (no pattern)
Pattern-specific bull head STLs (one per pattern)
Pattern insert STLs:
- 4-speed reverse down
- 4-speed reverse up
- 5-speed
- transfer case
TPU sleeves (12.8 / 13.8 / 14.8 / 15.8 mm ID)

Get it here:

Bull Head Shift Knob

Final Notes

This is a 3D printable Bullnose-themed manual transmission shifter knob system. It’s modular, it’s customizable, and it’s just aggressive enough to look like it belongs in an old Ford truck without going full cartoon.

If you print one, I’d love to see it installed. Post pics, tag Bullnose Garage, or just quietly enjoy the fact that your shifter now has horns.