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These standoffs ensure permanent mounting in metal sheets as thin as .062 in.

The fastener head is locked securely in a blind, milled hole and is able to handle substantial loads. The concealed-head feature allows the side of the sheet opposite installation to remain smooth.

Sheet preparation only requires a milled blind hole to the recommended minimum depth. Center-cutting end mills for hole preparation are available from PennEngineering. Installation of the concealed-head studs and standoffs is simple using a hollow anvil and solid punch. Place the head of the fastener in the hole and insert using any standard press. Displaced sheet metal flows smoothly around the head into the undercut.
Concealed-head standoffs - CSOS, CSS
Stainless Steel Standoffs - Types CSS, CSOS 2
Unit of Measure
Items Concealed-head standoffs - CSOS, CSS
CSS-440-3
Stainless Steel Standoffs - Types CSS, CSOS - Unified
Concealed-head standoffs - CSOS, CSS
CSS-632-3
Stainless Steel Standoffs - Types CSS, CSOS - Unified
Concealed-head standoffs - CSOS, CSS
CSS-832-3
Stainless Steel Standoffs - Types CSS, CSOS - Unified
Concealed-head standoffs - CSOS, CSS
CSS-032-3
Stainless Steel Standoffs - Types CSS, CSOS - Unified
Concealed-head standoffs - CSOS, CSS
CSS-0420-3
Stainless Steel Standoffs - Types CSS, CSOS - Unified
Thread Size N/A .112-40 (#4-40) N/A .138-32 (#6-32) N/A .164-32 (#8-32) N/A .190-32 (#10-32) N/A .250-20 (1/4-20)
Thread Code N/A 440 N/A 632 N/A 832 N/A 032 N/A 0420
Length Code N/A 3
Material Code N/A S
Style N/A #1
Shank N/A Short
Min. Sheet Thickness N/A .062 in
Blind Mounting Hole Diameter + .003 - .000 N/A .213 in N/A .290 in N/A .312 in N/A .344 in N/A .390 in
Min. Depth of Blind Hole1 N/A .043 in
L - Length + .002 –.005 N/A .187 in a1391.jpg
A Max. N/A .041 in
B Max.2 N/A .165 in N/A .213 in N/A .245 in N/A .290 in N/A .354 in
C Max. N/A .212 in N/A .289 in N/A .311 in N/A .343 in N/A .389 in
H Nom. N/A .250 in a1394.jpg N/A .312 in a1394.jpg N/A .344 in a1394.jpg N/A .375 in a1394.jpg N/A .438 in a1394.jpg
Min. Dist. Hole C/L to Edge N/A .188 in N/A .219 in N/A .250 in N/A .281 in N/A .375 in
For Use in Sheet Hardness N/A HRB 70 / HB 125 or Less
Thread Specification N/A Internal, ANSI B1.1, 2B
Fastener Material N/A 300 Series Stainless Steel
Standard Finish N/A Passivated and/or tested per ASTM A380
CAD Supplier N/A PennEngineering® (PEM®)
Min. Depth Full Thread F N/A .188 in N/A .250 in N/A .250 in N/A .375 in N/A .375 in
  • 1 Blind mounting holes may be deeper than minimums except where sheet material is at or near minimum thickness. Fasteners should always be installed so the flange is flush with the surface of the sheet.
  • 2 If standoff is used as a bushing, the hole in attached part must not exceed “B” plus .020” / 0.51 mm.