Bullnose Garage – STL File
https://bullnosegarage.com

FILE NAME:
BNG_Bull_Shift_Knob

VERSION:
1.0

DESIGNER:
Ed Zenisek
Bullnose Garage

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DESCRIPTION:
This is a modular, 3D printable bull head shift knob system designed for manual transmission trucks, with Bullnose Ford trucks (1980–1986) in mind.

The system consists of:

• A bull head base (pattern-specific or blank)
• A matching shift pattern insert (optional)
• A TPU sleeve adapter for different shifter shaft diameters

Each shift pattern uses a matching base STL. The pattern inserts are contoured to sit flush with the forehead of the bull head for a seamless appearance.

This is not a threaded shift knob. It uses a press-fit TPU sleeve and optional M5 set screw retention.

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INCLUDED FILES:

Base Heads:
• Bull Knob Base No Pattern.stl
• Bull Knob NP435 Base.stl
• Bull Knob Reverse Up Base.stl
• Bull Knob 5Speed Base.stl
• Bull Knob TCase Base.stl

Shift Pattern Inserts:
• Bull Knob NP435 Shift Pattern.stl
• Bull Knob Reverse Up Shift Pattern.stl
• Bull Knob 5Speed Shift Pattern.stl
• Bull Knob TCase Shift Pattern.stl

Sleeves (TPU):
• Bull Knob Sleeve 12.8 ID.stl
• Bull Knob Sleeve 13.8 ID.stl
• Bull Knob Sleeve 14.8 ID.stl
• Bull Knob Sleeve 15.8 ID.stl

Other:
• License.txt
• ReadMe.txt

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VEHICLE FITMENT:
Designed around manual transmission applications such as:

• NP435
• T18 / T19
• ZF5-style layouts
• Manual transfer cases

This design uses a sleeve-based mounting system and can fit a variety of manual shifter shafts depending on measured diameter.

You must measure your shifter shaft before printing a sleeve.

Could be adapted to fit almost any shifter.

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RECOMMENDED MATERIAL:
Bull Head & Pattern Inserts:
• ASA (recommended for heat and UV resistance)
• PLA (acceptable for mild climates / short term use)

Sleeves:
• TPU (95A recommended)

Automotive interiors get hot. Choose material accordingly.

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PRINT NOTES:
Orientation (Head):
• Print upright (horns up) for best detail and strength.
• Supports may be required depending on printer and horn geometry.

Orientation (Pattern Insert):
• Print flat on the build plate.

Orientation (Sleeve):
• Print vertically.

Infill:
• More = higher strength and weight.  Recommended > 50% gyroid.
• Sleeves should be printed solid or with high wall count.

Walls / Perimeters:
• Use enough perimeters to ensure strength (3+ recommended).

Other Notes:
• Verify printed sleeve ID with calipers.
• Printer tolerances vary.

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HARDWARE / ASSEMBLY:
Optional but recommended:
• M5 heat-set insert (for set screw)
• M5 set screw (length as needed)

The head includes a hole sized for an M5 heat-set insert. Install insert with a soldering iron before final assembly.

Assembly Order:

Measure shifter shaft OD.

Print correct sleeve.

Install M5 insert (if using set screw).

Press TPU sleeve into head.

Install head onto shifter.

Tighten set screw (if used).

Press shift pattern insert into matching base.

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HOW TO CHOOSE SLEEVE SIZE:
Remove existing shift knob.

Measure the outer diameter (OD) of the bare shifter shaft in millimeters.

Choose the sleeve with the ID closest to your measured value.

Available IDs:
• 12.8 mm
• 13.8 mm
• 14.8 mm
• 15.8 mm

If between sizes:
• Choose the larger ID for easier install.
• Choose the smaller ID for tighter interference fit.

TPU has some flexibility. The optional set screw adds additional retention.

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INSTALL NOTES:
• Each shift pattern must be used with its matching base STL.
• The blank base does not accept pattern inserts.
• Pattern inserts are press-fit and sit flush when properly printed.
• Always test-fit before final installation.
• Do not overtighten set screw.

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DISCLAIMERS:
• Designed and tested on my own vehicle.
• Measure and verify fitment before final installation.
• Automotive environments involve heat, vibration, and UV exposure.

LICENSE:
See LICENSE.txt included with this download.