Hat Making Tool: DeCou Rounding Jack, Walnut Hobbyist-Hatter Model, Clockwise Cutting

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Project by Mark A. DeCou posted 09-04-2008 06:04 AM 9780 views 0 times favorited 2 comments Add to Favorites Watch


Email for more information at: [email protected]

To check inventory of Hat Making Tools, or to commission a tool, start with this link to

Customer Review of this Rounding Jack, click here to read


Video: What does this thing do? Watch this video by California Custom Hat Maker Tom Gomez from Premier Panama Hats using one of my Rounding Jacks on a felt body Hat. Here is a link to Tom's ebay Store

To See More Hatmaking Tool Videos from Tom Gomez:
  1. Foot Tollikers: click here to see
  2. Kettle Curling Tool: click here to see one
  3. Puller Downer: click here to see one:
  4. Pusher Downer: click here to see one


This item is a Hat Making Tool called a Rounding Jack that I designed and built to cut the hat brims for custom hat makers.

Walnut Hobbyist-Hatter Model
Clockwise Cutting Direction
Brass Under-Plate
Abalone Shell Inlay
Cutting Capacity: 1.25” – 6.0”


Project Story:

Rounding Jacks are used to cut the brim felt to size on fedora, derby, Panama, western hats, cowboy hats, and several other styles.

Economy/Hobbyist-Hatter Model:
Since I first introduced my Rounding Jacks for sale, there has been a good amount of interest in them. During this time, I’ve been asked many times if I could come up with a less expensive version of the tool, mostly suited to Hat Makers that make hats as a hobby, only needing to cut a few hats a year.

What Makes This One an “Economy” Model?:
I developed this version of my brim cutter tool with a smaller capacity brim cut. Also, this version does not have the adjustable brass crown shoe on the front of the cutter.

Laser Engraved Ruler:
I have converted over to using Custom Laser Engraved Rulers for each of my Rounding Jacks. To highlight the markings, I use ivory colored acrylic paint.

Direction of Cut:
This particular Rounding Jack will cut in the Counter Clockwise path. If you would like to go the other direction, just let me know and I can build a Rounding Jack to go the other direction. They are not reversible, as that would take another more expensive step in the design of the blade guard, so it is cheaper for us both if I just make the cutter to cut the direction you want to use it.

Display Stand: The display stand shown in these photos is available at an additional cost, and is designed to sit on the hatmaker’s work bench and hold the cutter when it is not being used. The retractable blade can remain extended this way between uses. This particular stand shown in the photos is Black Walnut. This display stand is meant to make the whole project look like a functional-art sculpture, while it serves it’s functional purpose of holding the Rounding Jack safely.

To make the cut.
  1. The blade guard Thumbscrew Nut is loosened, the blade dropped down and the nut retightened.
  2. The slider thumbscrew nuts are loosened, and the desired cut width is indicated by the pointer, and the slider nuts are tightened.
  3. The hat is placed on a wood crown block to give a firm resistance to the pressure being applied with the cutter, and the brim is placed between the bottom brass plate and the bottom of the cutter.
  4. Then, depending on whether the hatmaker is a Clockwise, or a Counterclockwise cutter, the Rounding Jack is slowly moved around the contour of the crown while pushing the cutter toward the center (head).
  5. Felt Hat Blanks are very expensive, so after the cutting is complete, a big sigh of relief is heard from the hatmaker.

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Here is a Slideshow with more of my Rounding Jacks Shown
Click the “Speaker” icon for music


Artisan Hat Tools by Mark DeCou Studio
(Do you want to see More? Just follow these links):

ARE LISTED IN MY ETSY.COM ONLINE SHOP, click here to check inventory

Rounding Jacks, Collector’s Editions:
  1. Ebonized Walnut Clockwise with Laser Engraving
  2. Walnut Counter Clockwise w/Laser Engraving
  3. Walnut Uni-Directional Cutter
Rounding Jacks, Deluxe Model:
  1. Maple Deluxe Model, Counter Clockwise Cutter
  2. Maple Deluxe Model, Clockwise Cutter
  3. Walnut Deluxe, Counter Clockwise Cutter
  4. Walnut Deluxe, Clockwise Cutter
Rounding Jacks, Hobbyist-Hatter Model:
  1. Walnut Hobbyist-Hatter Model, Counter Clockwise Cutter
  2. Walnut Hobbyist-Hatter Model, Clockwise Cutter
Bench-Top Display Stands for Rounding Jacks:
  1. Walnut Bench-Top Display Stand
  2. Oak Bench-Top Display Stand
    Click here to check inventory
Customized Rounding Jacks, Personalized for Specific Hatters:
  1. Spradley Hats in Apline, TX
  2. Rachel Pollock of La Bricoleuse
  3. Brainpan Hat Shop in Sumner, WA
  4. Steve Delk's Adventurebilt Hat Co.
  5. Marc Kitter's Adventurebilt Hat Co.
  6. Pyrate Trading Co.
  7. Hatman Jack at Wichita Hat Works
  8. Inaaya Hat Co.
  9. Penman Hat Co.
Formillons & Conformateurs:
  1. Complete Restoration of a Maillard Conformateur and Formillon
  2. New DeCou Formillion & Conformer, Prototypes #1 & #2
  3. Custom Designed Conformateur Carrying & Storage Case
  4. New Plot Base Board for the Maillard Allie Formillon
  5. Maple Wrench for Tightening Formillon Thumbnuts
Foot Tollikers:
  1. Left-Handed & Right-Handed Foot Tolliker
  2. Foot Tolliker: Elk Antler & Birch Wood, on a Display Stand
  3. Foot Tolliker: Walnut Wood, on a Display Stand
  4. Foot Tollikers: Three in White Birch Wood
  5. Foot Tollikers: Walnut Wood Set of Four
  6. Foot Tollikers, Birch Wood Double Set, on Display Stand
Brim Edge Curling Tools:
  1. Hinge-Shackle Curling Tool for the Homburg Hat
  2. Full Circle Shackle Curling Tool
  3. Half Circle Shacking Curling Tool
  4. Groove Tolliker Curing Tool
Band Blocks:
  1. Thick Poplar Wood, Various Sizes and Oval Shapes, with Tapered Sides
Crown Blocks
  1. Long Oval Crown Block Sculpting Work
Hat Block Spinners:
  1. Late Turned Hat Block Spinners
Flange Stands:
  1. Heavy Duty Flange Stands
Puller Downers:
  1. Puller Downers
Pusher Downers:
  1. Pusher Downers
Hat Racks, Hat Stands, & Cedar Band Blocks:
  1. Hat Racks to keep oval shapes
Stainless Steel Slip Stick:
  1. “Coming Soon”, please check back.

(Note:This project story, project design, and photos are protected by copyright in 2008-2010 by the Author, M.A.DeCou., all rights reserved, no use allowed without expressed written permission.)

-- Mark DeCou - American Contemporary Craft Artisan -

2 comments so far

View darryl's profile


1795 posts in 4836 days

#1 posted 09-04-2008 01:31 PM

that walnut looks great of course.
I like your decision to go with a laser engraved ruler rather than the applied metal ruler. Not to say that the original design didn’t look nice, because it does, but the engraved version looks even better.

View Karson's profile


35201 posts in 4910 days

#2 posted 09-04-2008 02:19 PM

Great Mark. I agree the laser engraved ruler looks great.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Appomattox Virginia [email protected]

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