SELF- TAPPING SCREWS
Type-BSD
SELF-DRILLING Type-CSD
Type-BSD P 5/16 & 3/8 Diameter
#3 Point
T t T t B
A
Self-Drilling Screws, Type BSD (Spaced Thread)
*SAE J78-
2013
T t P
Minimum Practical Nominal Screw Lengths, Minimum Tor-
Nominal Size Protrusion Formed Points
Threads Major Diameter Minor Diameter sional Strength,
or Basic Screw Allowance
Per Inch lb.- in. (STEEL
Diameter
90° Head, Csk Head, 90° Head, SCREWS ONLY)
Max Min Max Min #2 Pt. #3 Pt. #2 Pt #2 Pt #3 Pt
Csk Head, #3 Pt
2* .0860 32 .088 .084 .064 .060 .125 - 1/4 5/16 - - -
4 .1120 24 .114 .110 .086 .082 .163 - 5/16 3/8 - - 14
6 .1380 20 .139 .135 .104 .099 .190 .220 5/16 3/8 3/8 7/16 24
7* .1510 19 .153 .146 .113 .109 .137 .157 5/16 3/8 3/8 7/16 -
8 .1640 18 .166 .161 .122 .116 .211 .251 3/8 7/16 7/16 1/2 42
10 .1900 16 .189 .183 .141 .135 .235 .300 7/16 1/2 1/2 9/16 61
12 .2160 14 .215 .209 .164 .157 .283 .353 1/2 5/8 1/2 5/8 92
1/4 .2500 14 .246 .240 .192 .185 .318 .393 1/2 5/8 1/2 5/8 150
*SAE J78 does not include Specifications for #2 or #7 diameter drill screws.
Spaced Thread Self Drilling Screws - 5/16 & 3/8 Diameters, #3 Point
T t A B
Nominal Size or Basic Threads Per
Major Diameter Minor Diameter Drill Point Length Drill Point Diameter
Screw Diameter Inch
Max Min Max Min Max Min Max Min
5/16 .3125 12 .315 .307 .272 .263 .421 .361 .270 .265
3/8 .3750 12 .380 .370 .308 .298 .354 .314 .338 .330
Steel Stainless
Type BSD: A tapping screw with spaced threads and a drill point which drills its own hole.
Description Type CSD: A thread forming screw with machine screw thread pitch and a drill point which drills its own hole.
Both types allow the screw to form mating threads and produce a complete fastening system in a single operation.
Type BSD: May be used to attach plywood, soft woods or The 18-8 stainless drill screw offers superior corrosion resistance while the 410
composition board to metal, or attach metal to metal. stainless screw will drill through harder material than the 18-8. The hardness
Applications/ Type CSD: The finer thread pitch reduces friction and driving torques. of the material to be drilled should be a minimum of 10-20 Rockwell hardness
Advantages Type-CSD screws are normally used with thicker materials. points less than the screw’s hardness.
All self-drilling screws offer economical benefits: reduces labor and Minimum torques are the same for stainless and steel self-drill screws. Drill time
tooling costs; reduces or eliminates drill bits and taps. is 2.5 seconds for a 1mm thick plate.
Material AISI 1016 - 1024 or equivalent steel 410, 18-8 or 316 stainless steel
410 SS: An ideal method of hardening 410 stainless screws is a bright harden-
ing process, which typically involves a vacuum furnace. Another key factor af-
Screws shall be quenched in liquid and then tempered by reheating to fecting hardness is the chemistry of the fastener--most elements have maximum
Heat Treatment
625°F minimum. values but not minimums. This fact can contribute to hardness variance.
18-8 & 316 SS are only hardenable by cold-working.
Case Hardness Rockwell C52 -58 -
No. 2 thru 6 diameter: .002 - .007
Case Depth No. 8 thru 12 diameter: .004 - .009 -
1/4” diameter and larger: .005 - .011
410 SS: Rockwell C38 - 46 (approx.)
Hardness Core: Rockwell C32 - 40 (after tempering)
18-8 & 316 SS: Rockwell B100 (approx.)
Plating See Appendix-A for plating information. Stainless drill screws are usually supplied plain.
48
SELF- TAPPING SCREWS
Type-BSD
Type-CSD SELF-DRILLING
Type BSD Self-Drilling Screw Type CSD Self Drilling Screw
Selection Chart Selection Chart
Recommended Panel Maximum Drilling
Nominal Screw Point Screw Size
Thickness, in. Capacity*
Size Number
Min. Max. 10-24 x 3/4” 1/4” Plywood to .175 Metal
4 2 .035 .080 10-24 x 1” 3/8” Plywood to .175 Metal
6 2 .035 .090 10-24 x 1-1/4” 1/2” Plywood to .175 Metal
10-24 x 1-1/2” 1/2” Plywood to .175 Metal
8 2 .035 .100
5/8 & 3/4” Wood to
10 2 .035 .110 10-24 x 1-7/16”
.175 Metal
10 3 .110 .175
*Drilling capacity may vary with type of material &
12 3 .110 .210 hardness.
1/4 3 .110 .220
This table is only a guide and does not constitute a
warranty of any type.
Type-CSD Reamer with Wings (Type-CSD)
P P
D D
Steel Self-Drilling Screws, Type CSD (Unified Thread) SAE J78-2013
D P Minimum
Nominal Size Minimum Practical Nominal Screw Lengths, Torsional
Threads Protrusion Countersunk Heads, Formed Points
or Basic Screw Major Diameter Strength, lb.- in.
Per Inch Allowance
Diameter (STEEL SCREWS
Max Min #2 Pt #3 Pt 90° Head, #2 Pt 90° Head, #3 Pt Csk Head, #2 Pt Csk Head, #3 Pt ONLY)
4 .1120 40 .1120 .1072 .130 - 5/16 - 3/8 - 14
6 .1380 32 .1380 .1326 .152 .172 5/16 3/8 3/8 7/16 24
8 .1640 32 .1640 .1586 .162 .202 7/16 1/2 7/16 1/2 48
10 .1900 24 .1900 .1834 .193 .258 1/2 9/16 1/2 9/16 65
12 .2160 24 .2160 .2094 .223 .293 5/8 5/8 5/8 5/8 100
1/4 .2500 20 .2500 .2428 .275 .350 5/8 5/8 5/8 5/8 156
Reamer with Wings: A Type CSD self-drilling screw with reaming wings located at opposite sides of the shank, below the threads and above
Description the drill point.
Applications/ May be used for drilling through wood over 1/2” thick and the metal surface behind it. The wings drill out a clearance hole in wood or other soft
Advantages materials, then snap off when in contact with the metal surface to be drilled.
Mechanical &
Performance Same as other Type CSD self-drilling screws (see previous page).
Requirements
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