STEVE JANS'S ROUNDING JACK / BRIM TRIMMER
Assembly Instructions
Blocksmith Works Community Tool Crib - Contributor 002

This rounding jack is used to trim the brim of a hat. It uses snap-off
blades for cutting. The current supplied 3MF is a two-plate, single-color project.

REVISION NOTE - SEPTEMBER 14, 2026
These September 5 notes are retained as earlier reference guidance. Steve's
replacement project contains revised parts. Hardware lengths below have not
been confirmed against those revisions; check fit before purchasing hardware.

HARDWARE AND SUPPLIES

- 10-32 bolt, 3/4 inch long, for the smaller blade-clamping knob.
- 10-32 bolt, 1 inch long, for the larger assembly-clamping knob.
- 10-32 bolt, 3 inches long, for the bottom plate.
- Matching 10-32 nuts for the two recessed nut locations.
- A matching 10-32 locking nut for the bottom-plate bolt.
- Snap-off cutting blade compatible with the printed blade holder.
- Adhesive suitable for securing metal bolt heads in the printed knobs.

ASSEMBLY

1. Prepare the smaller knob.
   Glue the 3/4-inch bolt into the smaller knob. This knob clamps the
   cutting blade into place. Fit its matching nut into the provided
   nut recess.

2. Prepare the larger knob.
   Glue the 1-inch bolt into the larger knob. This knob clamps the
   adjustable assembly into place. Fit its matching nut into the
   provided nut recess.

3. Secure the bottom plate.
   Use the 3-inch bolt and locking nut to secure the bottom plate.
   Steve recommends a locking nut so the bolt can remain secure
   without being tightened enough to squeeze the two arms together.

4. Allow the adhesive to cure.
   Follow the adhesive manufacturer's curing instructions before
   operating either knob.

5. Fit and secure the blade.
   Position the blade in its holder and secure it with the smaller
   knob. Set the adjustable assembly to the desired position and
   secure it with the larger knob before cutting.

BEFORE USE

Check that the blade and adjustable assembly are secure and that the
bottom-plate fastener does not squeeze the arms together. Keep fingers
clear of the cutting edge while assembling, adjusting, and using the tool.

ABOUT THESE INSTRUCTIONS

Based on assembly notes supplied by Steve Jans on September 5, 2026.
Organized by Blocksmith Works for readability, with adhesive-curing and
pre-use reminders added. The separately included video link covers Steve's conformer, not this
rounding jack. No rounding-jack video was supplied for this update.

Original rounding-jack design by Steve Jans. Shared with permission.
Steve retains ownership and authorship of his design.

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