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No Undercut
Fixed

ST-1200 Line - Size 65 Studs
Standard Variable Undercut

Material:
Studs: hardened steel studs,
D-rings: hard music wire D-rings,
Wings: carbon steel wings.

Finish: Zinc Trivalent Clear .0003 thick. Trivalent Chromate Clear with Sealer (RoHS Compliant)
Specification(s): ASTM-B-633, Type III, SC 2, Clear
Suffix: -Z3CT

Optional Stainless Steel:
303 Stainless Steel studs,
400 series Stainless Steel D-rings,
300 series Stainless Steel wings

Optional Finishes: Change the finish suffix from Z3CT to the desired finish from the table. See finishes page.

Stud Dimensions

SLOTTED: 121J-65*-Z3CT   FLUSH: 126J-65*-Z3CT
Slotted Stud Picture
Click here for the Engineering Drawing		 Slotted Stud Dimension Drawing   Flush Head Stud Picture Flush Head Stud Dimension Drawing
WING: 121J-W65*-Z3CT   PHILLIPS: 121J-P65*-Z3CT
Wing Head Stud Picture Wing HEad Stud Dimension Drawing   Phillips Recess Head Stud Picture Phillips Recess Head Stud Dimension Drawing
HEX: 121J-H65*-Z3CT   KNURLED: 1211-65*-Z3CT
Hex Recess Head Stud Picture Hex Recess Head Stud Dimension Drawing   Knurled Head Stud Picture Knurled Head Stud Dimension Drawing
RING: 122J-R65*-Z3CT   TAMPER RESIST: 1230-65*-Z3CT
Ring Head Stud Picture
Click here for the Engineering Drawing		 Ring Head Stud Dimension Drawing   Tamper Resist Head Stud Picture Tamper Resist Head Stud Dimension Drawing

* is the "Stud Grip" from the tables.  For example, 121J-6540 is an oval head stud with a "Stud Grip" of 40.

The undercut is a part of the stud which is smaller in diameter than the stud shank. The undercut is located directly under the head. This decreased diameter is where the retainer fits to prevent the stud from coming out of the mounting hole.

The "J" designation in the 121J- part number indicates a Variable undercut. That is, the length of the undercut varies with the length of the stud. The Variable undercut is shown on this page.

The "N" designation in the 121N- part number indicates that the stud has no undercut. These were formerly referred to with a designation of "O" (i.e., AO and FO). The no undercut is shown on this link.

The absence of either the "J" or "N" designation indicates a Fixed size undercut. That is, the length of the undercut is the same for all stud lengths. The Fixed undercut is shown on this link.

Note: For all raised head styles, the "G" (Grip) and "U" (Undercut) dimensions are measured to the underside of the head. For the flush head style, the "G" (Grip) and "U" (Undercut) dimensions are measured to the top of the head.

Stud Grip Undercut Dimension (U) Grip Length (G)
All Except Flush Flush Head Only
(inch) (mm) (inch) (mm) (inch) (mm)
40 .190 4.83 --- --- .400 10.16
50 .250 6.35 .250 6.35 .500 12.70
60 .300 7.62 .300 7.62 .600 15.24
70 .350 8.89 .350 8.89 .700 17.78
80 .450 11.43 .450 11.43 .800 20.32
90 .550 13.97 .550 13.97 .900 22.86
100 .650 16.51 .650 16.51 1.000 25.40
110 .650 16.51 .650 16.51 1.100 27.94
120 .650 16.51 .650 16.51 1.200 30.48

Note: When our existing supply of Cadmium plated parts is exhausted, DFCI Solutions, Inc will no longer offer Cadmium plating as an option.

In place of the Cadmium plating, we recommend:

Clear: Zinc Trivalent Clear .0003 thick. Trivalent Chromate Clear with Sealer (RoHS Compliant)
Specification(s): ASTM-B-633, Type III, SC 2, Clear
Suffix: -Z3CT

Black: Zinc Trivalent Black .0003 thick. Trivalent Chromate Black Dye with Sealer (RoHS Compliant)
Specification(s): ASTM-B-633, Type II, SC 2, Black
Suffix: -Z3BT

Yellow: Zinc Trivalent Yellow .0003 thick, Trivalent Chromate Yellow Dye with Sealer

We recommend the Z3CT finish instead of the Z3YT finish. The Z3CT finish is much more cost effective and provides the same salt spray benefits as the Z3YT finish. (RoHS Compliant)
Specification(s): ASTM-B-633, Type II, SC 2, Yellow
Suffix: -Z3YT

The colored finishes offer no advantage over the clear other than the color, and they are more expensive.