Sem Screw / Dutch Screw

Sem Screw

Introduction

DIN 934

Sem Screw

PAN PHILLIPS DOUBLE WASHER SEMS (SPLIT-LOCK & REGULAR FLAT WASHERS)
Nominal Size w H1 G F T R M Phillips Driver Size
  Head Dai meter Height of Head Recess Depth Flat washer
Dai meter
Flat Washer
Thickness
Split Lock Washer
Diameter
Split Lock Washe Materi al Thickness  
  Max Min Max Min Max Min Max Min Max Min Max Min Ref  
4 .219 .204 .080 .070 . .053 .382 .369 .045 .036 .208 .194 .031 1
6 .270 .255 .097 .086 .080 .055 .445 .432 .045 .036 .261 .247 .034 2
8 .321 .305 .115 .104 07 .097 .071 .507 .494 .045 .036 .319 .304 .031 2
10 .373 .356 .133 .121 .113 .089 .569 .556 .045 .036 .373 .358 .047 2
Description A pan head machine screw with a free-spinning lock-washer and flat washer manufactured as one assembly
Applications/ Advantages The washer / screw assembly makes this a locking screw with the helical washer providing the locking action and flat washwer distributing the load over
Material Steel Stainless
  Steel Screws-AlSI1006 - 1022 or equivalent steel. Steel Washers-Spl-lock:SAE 1060 carbon steel; Flat washer: SAE 1008 carbon steel. Stainless Screws- Class 304 stainless.
Stainless Washers- Class 304 stainless
Hardness Steel Screws-Rockwell B70 - B100 (Unhardened)
Steel Washers-Rockwell C38 - 46; Flat washer: Unhardened
 
Tensile Strength Steel. 60,000  psi minimum. No.4 SEMS screws shorter than 1/2"are not subject totensile testing. SEMS screws of diameters No. 6 to 10 indusive, which are shorter than 1/2" or 30 (where D is the nominal screw size in inches) are not subject to tensile testing.  
Plating See Appendix-A for information on the plating of steel SEMS. stainless sems are usually supplied with plain finish
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