Nuts: Chouinard

Hexentrics

I place Chouinard Hexentrics into one of four generations:

Symmetric Hexentrics [1971-1973]
Asymmetric Hexentrics [1974-1979]
Drilled Hexentrics (#6-#11), grouped under a dedicated heading.
New Extrusions [1980-1989]

First Generation

Yvon Chouinard and Tom Frost improved on earlier regular hexagonal chocks when they introduced their Hexentrics in 1971. First-generation Hexentrics have a symmetric front-to-back profile easily seen by looking at their ends. The front/rear upper faces are about half the height of the lower faces, allowing the Hexentric to fit smaller cracks than a regular-hexagon profile would allow.

↑ Set 839, 815, 744, 824, 825, 826, 746: Chouinard Symmetric Hexentrics; #2, #3, #9

Made in USA [1971–1973].
First Generation.
Extruded 6061–T6 aluminum. alloy.

↑ 839: Chouinard Symmetric Hexentric; #1

Made in USA [1971–1973].
Size: 11x17 mm.
Weight: 3 g.
First Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard USA〈C〉 logo and "1" on one lower face and "HEXENTRIC" on the opposing upper face.

↑ 815: Chouinard Symmetric Hexentric; #2

Made in USA [1971–1973].
Size: 13x19 mm.
First Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard USA〈C〉 logo and "2" on one lower face and "HEXENTRIC" on the opposing upper face.

↑ 823: Chouinard Symmetric Hexentric; #2

Made in USA [1971–1973].
Size: 13x19 mm.
First Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard USA〈C〉 logo and "2" on one lower face.

↑ 744: Chouinard Symmetric Hexentric; #3

Made in USA [1971–1973].
Size: 15x22 mm.
First Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard USA〈C〉 logo and "3" on one upper face.

↑ 745: Chouinard Symmetric Hexentric; #3

Made in USA [1971–1973].
Size: 15x22 mm.
First Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard USA〈C〉 logo and "3" on one upper face and "HEXENTRIC" on the other upper face.

↑ 824: Chouinard Symmetric Hexentric; #6

Made in USA [1971–1973].
Size: 26x35 mm.
First Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard USA〈C〉 logo and "6" on one upper face.

↑ 825: Chouinard Symmetric Hexentric; #7

Made in USA [1971–1973].
Size: 32x42 mm.
First Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard USA〈C〉 logo and "7" on one upper face.

↑ 826: Chouinard Symmetric Hexentric; #8

Made in USA [1971–1973].
Size: 40x22 mm.
First Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard USA〈C〉 logo and "8" on one upper face.

↑ 746: Chouinard Symmetric Hexentric; #9

Made in USA [1971–1973].
Size: 49x69 mm.
First Generation.
Extruded 6061–T6 aluminum. alloy.
Top is stamped with "HEXENTRIC," the Chouinard USA〈C〉 logo and "9.".

↑ 794: Chouinard Symmetric Hexentric; #9

Made in USA [1971–1973].
Size: 49x70 mm.
First Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "9" on one upper face.

Second Generation

Second-generation Hexentrics have an irregular shape that allows for more placement options and also provide camming opportunities.

Introduced in 1974, they have an interesting origin story. Tomas Carlström from Norway was trying to make his own copies of Chouinard's symmetrical Hexentrics for himself. His machining was sloppy, resulting in asymmetric hexagons. Disappointment turned to elation when he found that the irregular hexes worked in more positions than Chouinard's originals. He shared his discovery with Chouinard, who used the idea to produce the second-generation Hexentrics.

↑ Set 146, 147, 747, 748, 749 752, 753: Chouinard Hexentrics; #1, #3–#8, 10

Made in USA [1974–1979].
Second generation.

↑ 146: Chouinard Hexentric; #1

Made in USA [1974–1979].
Size: 11x11x16 mm.
Weight: 4 g.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard USA〈C〉 logo and "1" on the large upper face.
Stamped "HEXENTRIC" on the large lower face.

↑ 147: Chouinard Hexentric; #3

Made in USA [1974–1979].
Size: 15x16x25 mm.
Weight: 10 g.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard USA〈C〉 logo , and "3" on the large upper face.
Stamped "HEXENTRIC" on the large lower face.

↑ 747: Chouinard Hexentric; #4

Made in USA [1974–1979].
Size: 19x21x28 mm.
Weight: 18 g.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "4" on the large upper face.

↑ 816: Chouinard Hexentric; #4

Made in USA [1974–1979].
Size: 19x21x28 mm.
Weight: 18 g.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard USA〈C〉 logo and "4" on the large upper face and "HEXENTRIC" on the small upper face. .

↑ 748: Chouinard Hexentric; #5

Made in USA [1974–1979].
Size: 24x26x34 mm.
Weight: 25 g.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "5" on the large upper face.
The extruded groove near the lower sling holes is characteristic of second generation hollow eccentrics.

↑ 817: Chouinard Hexentric; #5

Made in USA [1974–1979].
Size: 24x26x34 mm.
Weight: 25 g.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard USA〈C〉 logo and "5" on the large upper face and "HEXENTRIC" on the small upper face. .

↑ 749: Chouinard Hexentric; #6

Made in USA [1974–1979].
Size: 27x30x41 mm.
Weight: 32 g.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "6" on the large upper face.

↑ 750: Chouinard Hexentric; #6

Made in USA [1974–1979].
Size: 27x30x41 mm.
Weight: 37 g.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "6" on the small upper face.

↑ 751: Chouinard Hexentric; #6

Made in USA [1974–1979].
Size: 27x30x41 mm.
Weight: 37 g.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard 〈C〉USA logo, and "6" on the large upper face.
Stamped "HEXENTRIC" on the small upper face.

↑ 752: Chouinard Hexentric; #7

Made in USA [1974–1979].
Size: 33x36x48 mm.
Weight: 58 g.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "7" on the large upper face.

↑ 753: Chouinard Hexentric; #8

Made in USA [1974–1979].
Size: 39x42x55 mm.
Weight: 79 g.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "8" on the large upper face.

↑ 754: Chouinard Hexentric; #8

Made in USA [1974–1979].
Size: 39x42x55 mm.
Weight: 79 g.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with the Chouinard USA〈C〉 logo and "8" on the large upper face.
Stamped "HEXENTRIC" on the small upper face.

Fourth Generation

In 1980 Chouinard changed the wall thickness on their #7 through #11 Hexentrics and eliminated the drilled lightening holes, resulting in a stronger chock for essentially the same weight. The sling holes were enlarged so that the recommended sling sizes would fit more easily. The non-functional basal groove found on the earlier generation disappeared, indicating that the extrusions used new molds.

↑ Set 052-059: Chouinard Hexentrics; #4–#11

Made in USA [1980s].
Fourth Generation.
Extruded 6061–T6 aluminum. alloy.
The 1980 Chouinard catalog introduced the third generation Hexentrics. They enlarged the sling holes and made the side walls of #7 –#11 thinner, making them similar in weight to the old drilled Hexes but about 400 pounds stronger.

↑ 052: Chouinard Hexentric; #4

Made in USA [1980s].
Size: 20x22x29 mm.
Weight: 18 g.
Fourth Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "4" on the large upper face.

↑ 053: Chouinard Hexentric; #5

Made in USA [1980s].
Size: 25x26x34 mm.
Weight: 25 g.
Fourth Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "5" on the large upper face.

↑ 054: Chouinard Hexentric; #6

Made in USA [1980s].
Size: 27x30x40 mm.
Weight: 32 g.
Fourth Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "6" on the large upper face.

↑ 055: Chouinard Hexentric; #7

Made in USA [1980s].
Size: 33x35x48 mm.
Weight: 153 g.
Fourth Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "7" on the large upper face.

↑ 056: Chouinard Hexentric; #8

Made in USA [1980s].
Size: 39x43x56 mm.
Weight: 59 g.
Fourth Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "8" on the large upper face.

↑ 057: Chouinard Hexentric; #9

Made in USA [1980s].
Size: 46x50x66 mm.
Weight: 92 g.
Fourth Generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "9" on the large upper face.

↑ 058: Chouinard Hexentric; #10

Made in USA [1980s].
Size: 55x60x77 mm.
Weight: 118 g.
Fourth Generation.
Extruded 6061–T6 aluminum. alloy.
Top is stamped with "HEXENTRIC," the Chouinard 〈C〉USA logo, and "10.".

↑ 059: Chouinard Hexentric; #11

Made in USA [1980s].
Size: 65x70x88 mm.
Weight: 162 g.
Fourth Generation.
Extruded 6061–T6 aluminum. alloy.
Top is stamped with "HEXENTRIC," the Chouinard 〈C〉USA logo, and "11".

Drilled Hexentrics
(Third Generation)

Factory Drilled

The 1976 Chouinard catalog says that their #8 through #11 Hexentrics were drilled to reduce weight. I have several drilled #7 Hexentrics as well. Presumably these came out soon after the others, perhaps in 1977. In 1980 Chouinard changed the wall thickness on their #7 through #11 Hexentrics and eliminated the holes, resulting in a stronger chock for essentially the same weight.

All of these have the basal groove found on the smaller second-generation Hexentrics Sizes #1 through #6 remained unchanged.

↑ Set 148, 756-758, 323: Chouinard Drilled Hexentrics; #7–#11

Made in USA [1976–1979].
Second Generation.
Factory drilled to reduce weight.

↑ 148: Chouinard Drilled Hexentric; #7

Made in USA [1974–1979].
Size: 33x36x47 mm.
Weight: 45 g.
Second Generation.
Factory drilled to reduce weight.
Extruded 6061–T6 aluminum. alloy.
Top is stamped with "HEXENTRIC," the USA–Chouinard 〈C〉 logo, and "7.".
From Mike Gerbman, 2025.

↑ 756: Chouinard Drilled Hexentric; #8

Made in USA [1976–1979].
Size: 39x42x55 mm.
Second Generation.
Factory drilled to reduce weight.
Extruded 6061–T6 aluminum. alloy.
Top is stamped with "HEXENTRIC," the USA–Chouinard 〈C〉 logo, and "8.".
From Mike Gerbman, 2025.

↑ 761: Chouinard Drilled Hexentric; #8

Made in USA [1976–1979].
Size: 39x42x55 mm.
Second generation.
Extruded 6061–T6 aluminum. alloy.
No markings.
Probably home–drilled. Mike had several Hexentrics drilled to reduce weight, carefully matching the commercial hole pattern.
From Mike Gerbman, 2025.

↑ 761: Chouinard Drilled Hexentric; #8

Made in USA [1976–1979].
Size: 47x51x66 mm.
Second Generation.
Factory drilled to reduce weight.
Extruded 6061–T6 aluminum. alloy.
Top is stamped with "HEXENTRIC," the Chouinard USA〈C〉 logo, and "9.".
From Mike Gerbman, 2025.

↑ 758: Chouinard Drilled Hexentric; #10

Made in USA [1976–1979].
Size: 55x60x77 mm.
Second Generation.
Factory drilled to reduce weight.
Extruded 6061–T6 aluminum. alloy.
Top is stamped with "HEXENTRIC," the Chouinard 〈C〉USA logo, and "10.".
From Mike Gerbman, 2025.

↑ 323: Chouinard Drilled Hexentric; #11

Made in USA [1974–1979].
Size: 65x70x88 mm.
Second Generation.
Factory drilled to reduce weight.
Extruded 6061–T6 aluminum. alloy.
Top is stamped with "HEXENTRIC," the Chouinard 〈C〉USA logo, and "11.".
From Mike Gerbman, 2025.

Home Drilled

Mike Gerbman drilled several Hexentrics to reduce weight. He used factory-drilled Hexentrics as patterns and carefully matched the commercial hole pattern. I find it difficult to confidently separate the factory-drilled Hexentrics from the home-drilled ones. I found that the factory-drilled Hexentrics were deburred with a wire wheel and this left tell-tale marks inside the Hexentric, while Mike's do not have these marks.

All of these have the basal groove found on the smaller second-generation Hexentrics

↑ Set 759, 760, 762, 763: Chouinard Home–Drilled Hexentrics; #7–#9, #11

Made in USA [1976–1979].
Second Generation.
Extruded 6061–T6 aluminum. alloy.
Probably home–drilled. Mike had several Hexentrics drilled to reduce weight, carefully matching the commercial hole pattern.

759: Chouinard Home–Drilled Hexentric; #7

↑ 759: Chouinard Home–Drilled Hexentric; #7

Made in USA [1976–1979].
Size: 33x36x47 mm.
Weight: 45 g.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "8" on the large upper face.
Probably home–drilled. Mike had several Hexentrics drilled to reduce weight, carefully matching the commercial hole pattern.
From Mike Gerbman, 2025.

760: Chouinard Home–Drilled Hexentric; #8

↑ 760: Chouinard Home–Drilled Hexentric; #8

Made in USA [1976–1979].
Size: 39x42x55 mm.
Second generation.
Extruded 6061–T6 aluminum. alloy.
Stamped with "HEXENTRIC, " the Chouinard 〈C〉USA logo, and "7" on the small upper face.
Probably home–drilled. Mike had several Hexentrics drilled to reduce weight, carefully matching the commercial hole pattern.
From Mike Gerbman, 2025.

811: Chouinard Home–Drilled Hexentric; #8

↑ 811: Chouinard Home–Drilled Hexentric; #8

Made in USA [1976–1979].
Size: 39x42x55 mm.
Second generation.
Extruded 6061–T6 aluminum. alloy.
No markings.
Probably home–drilled. Mike had several Hexentrics drilled to reduce weight, carefully matching the commercial hole pattern.
From Mike Gerbman, 2025.

762: Chouinard Home–Drilled Hexentric; #9

↑ 762: Chouinard Home–Drilled Hexentric; #9

Made in USA [1976–1979].
Size: 47x51x66 mm.
Second generation.
Extruded 6061–T6 aluminum. alloy.
No markings.
Probably home–drilled. Mike had several Hexentrics drilled to reduce weight, carefully matching the commercial hole pattern.
From Mike Gerbman, 2025.

763: Chouinard Home–Drilled Hexentric; #11

↑ 763: Chouinard Home–Drilled Hexentric; #11

Made in USA [1974–1979].
Size: 65x71x90 mm.
Second Generation.
Factory drilled to reduce weight.
Extruded 6061–T6 aluminum. alloy.
No markings.
Probably home–drilled. Mike had several Hexentrics drilled to reduce weight, carefully matching the commercial hole pattern.

Tube Chocks

Chouinard's Tube Chocks addressed the need for placing clean protection in wide cracks. They offered a significant weight savings over what equivalent-sized hexes could have provided.

Tube CHock Data

First Generation (ca. 1973)

↑ 031: Chouinard Tube Chock; #4

Made in USA [ca. 1973].
Size: 100x63.5 mm.
Weight: 152 g.
First generation.
6061–T6 2½" o.d. aluminum alloy tube.
Stamped with the Chouinard 〈C〉 logo and "4" on one side (both rotated CCW 90°).

↑ 626: Chouinard Tube Chock; #4½

Made in USA [ca. 1973].
Size: 115x63.5 mm.
Weight: 170 g.
First generation.
6061–T6 2½" o.d. aluminum alloy tube.
Stamped with the Chouinard 〈C〉USA logo and "4½" on one side.

↑ 841: Chouinard Tube Chock; #5

Made in USA [ca. 1973].
Size: 127x63.5 mm.
Weight: 194 g.
First generation.
6061–T6 2½" o.d. aluminum alloy tube.
Stamped with the Chouinard USA〈C〉 logo and "5" on one side near the top.

↑ 791: Chouinard Tube Chock; #5½

Made in USA [ca. 1973].
Size: 139.2x63.5 mm.
Weight: 212 g.
First generation.
6061–T6 2½" o.d. aluminum alloy tube.
Stamped with the Chouinard USA〈C〉 logo and "5.5" on one side near the top.
From Mike Gerbman, 2025.

↑ 627: Chouinard Tube Chock; #5½

Made in USA [ca. 1973].
Size: 140x63.5 mm.
Weight: 208 g.
First generation.
6061–T6 2½" o.d. aluminum alloy tube.
Stamped with the Chouinard 〈C〉USA logo and "5½" on one side.

↑ 809: Chouinard Tube Chock; #6

Made in USA [ca. 1973].
Size: 153.3 mm.
Weight: 246 g.
First generation.
6061–T6 2½" o.d. aluminum alloy tube.
Stamped with a the Chouinard 〈C〉 logo (rotated CCW 90°) and "6" on one side.
Stamped with "8" on top near each end (probably by previous owner).