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PEM® self-clinching studs are installed by placing them in properly sized holes in the sheets and squeezing into place with any standard press. The squeezing action embeds the head of the stud into the sheet. The metal displaced by the head flows smoothly and evenly around the ribs and into the annular groove – creating a flushhead assembly and securely locking the stud into the sheet with high torque-out and pushout resistances.

FH (flush-head) studs are available in aluminum, steel, or stainless steel. They are also available unthreaded on special order.
  • Flush-head in designated minimum sheet thickness or greater.
  • Type FH is recommended for use in steel or aluminum sheets HRB (Rockwell “B” scale) 80 or less and HB (Hardness Brinell) 150 or less.
  • Type FHS is recommended for use in steel or aluminum sheets HRB (Rockwell “B” scale) 70 or less and HB (Hardness Brinell) 125 or less.
  • Type FHA is recommended for use in aluminum sheets HRB (Rockwell “B” scale) 50 or less and HB (Hardness Brinell) 82 or less.
Flush-head studs - FH, FH4, FHA, FHP, FHS
Self-Clinching Threaded Studs - Type FH/FHS/FHA 2
Unit of Measure
Items Flush-head studs - FH, FH4, FHA, FHP, FHS
FH-256-4ZI
Self-Clinching Threaded Studs - Type FH/FHS/FHA - Unified
Flush-head studs - FH, FH4, FHA, FHP, FHS
FH-440-4ZI
Self-Clinching Threaded Studs - Type FH/FHS/FHA - Unified
Flush-head studs - FH, FH4, FHA, FHP, FHS
FH-632-4ZI
Self-Clinching Threaded Studs - Type FH/FHS/FHA - Unified
Flush-head studs - FH, FH4, FHA, FHP, FHS
FH-832-4ZI
Self-Clinching Threaded Studs - Type FH/FHS/FHA - Unified
Flush-head studs - FH, FH4, FHA, FHP, FHS
FH-256-5ZI
Self-Clinching Threaded Studs - Type FH/FHS/FHA - Unified
Thread Size N/A .086-56 (#2-56) N/A .112-40 (#4-40) N/A .138-32 (#6-32) N/A .164-32 (#8-32) N/A .086-56 (#2-56)
Thread Code N/A 256 N/A 440 N/A 632 N/A 832 N/A 256
Length Code N/A 4 N/A 4 N/A 4 N/A 4 N/A 5
Material Code N/A
Min. Sheet Thickness N/A .040 in
Hole Size in Sheet + .003 - .000 N/A .085 in N/A .111 in N/A .137 in N/A .163 in N/A .085 in
Max. Hole in Attached Parts N/A .105 in N/A .135 in N/A .160 in N/A .185 in N/A .105 in
L - Length ± .015 N/A .250 in a1374.jpg N/A .250 in a1374.jpg N/A .250 in a1374.jpg N/A .250 in a1374.jpg N/A .312 in a1374.jpg
H ± .015 N/A .144 in N/A .176 in N/A .206 in N/A .237 in N/A .144 in
S Max.1 N/A .075 in N/A .085 in N/A .090 in N/A .090 in N/A .075 in
Min. Dist. Hole C/L to Edge N/A .187 in N/A .219 in N/A .250 in N/A .281 in N/A .187 in
For Use in Sheet Hardness N/A HRB 80 / HB 150 or less
Thread Specification N/A External, ANSI B1.1, 2A
Fastener Material N/A Heat-Treated Carbon Steel
Standard Finish N/A Zinc plated per ASTM B633, SC1 (5µm), Type III, colorless
Optional Finish N/A
CAD Supplier N/A PennEngineering® (PEM®)
  • 1 Threads are gageable to within 2 pitches of the “S” Max. dimension. A class 3B/5H maximum material commercial nut shall pass up to the “S” Max. dimension.