Screw Nomenclature

Screws use a numbering system to differentiate the thread diameter, threads per inch, as well as the thread length. There are two main numbering systems for screws, the standard and metric system.

Standard_VEX_Screws.png

Standard VEX Screws

VEX Screws utilize the standard system, and the first number listed on a VEX screw is the thread diameter. Next is the threads per inch value, and is followed with the corresponding thread length. For instance, a #8-32 x ¼” Screw has a thread diameter of 0.164” (#8), 32 threads per inch, and a thread length of 0.25”.

Inch Equivalent for Numbered Screws</span >
#0 #1 #2 #3 #4 #5 #6 #8 #10 #12
0.060"</font >

0.073”

0.086”

0.099”

0.112”

0.125”
0.138”
0.164”
0.190”
0.216”  

As you may know, screws can be torqued with a multitude of tools. These range from the Standard system of tooling which utilizes Phillips and Flatheads, to the Metric usage of Hex Keys. VEX products frequently use Torx tooling, or Star Drive Screws. VEX uses Star Drive Screws most frequently as these tend to not strip as easily as some Metric or Standard Screws might.

Standard Metric Star Drive
Screw_Driver.jpg Allen_Wrenches.jpg Allen_Key.jpg

Screw Styles

VEX products employ two different styles of screw. The first, often less used but still as important, is the Set Screw</a >.

Set_Screw.pngSet_Screw_-_Dimensions.pngSet_Screw_-_Drive_Size.png

The set screw is different to the regular screw because it does not have a “head.” The set screw comes in one size with two different heads, #8-32 x 0.125” Star Drive. These set screws come frequently in Shaft Collars, Clamping Shaft Collars, and can be screwed into standoffs.

The second style of screw is the more widely recognized Hex and Star Drive Screw (these have a head compared to the set screw that does not).

Star_Drive_Screw.pngStar_Drive_Screw_-_Dimensions.png

Screws are available in various lengths including:

  • #6-32 x ¼” and #6-32 x ½”
  • #8-32 x ¼” through #8-32 x 2”.
  • #6-32 x ½”, #8-32 x ¼”, and #8-32 x ½”

Locking Screws. Locking Screws have a nylon coating on a part of the thread which helps keep them from loosening.

This table shows the naming system used with Star Drive style screws. This table is to show you the maximum torque allowed by each size of screw.

Star Size

Point to Point
(S) (mm)
Screw (D) MAX Torque
(Nm)

T6

1.6

M2

0.75

T7 2 M2.5

1.4

T8 2.3 M2.5 2.2
T9 2.5 M3 2.8
T10 2.7 M3 & M3.5 3.7
T15 3.3 M3.5 & M4 6.4
T20 3.8 M4 & M5 10.5
T25 4.4 M4.5 & M5 15.9
T27 5 M4.5 & M5 & M6 22.5
T30 5.5 M6 & M7 31.1
T40 6.6 M7 & M8 54.1
T45 7.8 M8 & M10 86.2
T50 8.8 M10 132
T55 11.2 M12 252
T60 13.2 M14 437
T70 15.5 M16  
T80 17.6 M18  
T90 19.9 M20  
T100 22.1 M22  

The screws come in two types of heads: Hex Drive and Star Drive

#6-32 Hex Drive Screw #8-32 Hex Drive Screw #8-32 Star Drive Screw
6-32_Hex_Drive_Screw.jpg 8-32_Hex_Drive_Screw.png Star_Drive_Screw.png
5/64” Hex Key 3/32” Hex Key T15 Star Drive Key
5_64__Hex_Key.jpg 3_32__Hex_Key_Pt1.png3_32__Hex_Key_Pt_2.png T15_Star_Drive_Key_Pt_2.pngT15_Star_Drive_Key_Pt_1.png

Material Information and Uses

Workcell.png

V5 Smart Motors and all standard VEX nuts and standoffs

  • #8-32 Star Drive Screw Material: High Strength Stainless Steel with no finish
    • SAE Grade 8 Screws
    • 150,000 PSI Tensile Strength
    • Designed to withstand a great amount of torque, which allows builders to truly "lock down" their mechanisms
    • Compatible with V5 Smart Motors and all standard VEX nuts and standoffs

Clawbot.png

V5 Smart Motors and all standard VEX nuts and standoffs

  • #8-32 Hex Drive Screw Material: High Strength Stainless Steel with no finish
    • Compatible with V5 Smart Motors and all standard VEX nuts and standoffs
    • #8-32 Locking Screws
      • Have thread locker applied on their threads
      • The thread locker will help hold the screw in position
        • Can be used approximately 10-15 times and still retain a firm lock
        • Provide similar functionality to VEX Nylock Nuts

Cortex.png

Use for VEX Cortex Motors and Servos only

  • #6-32 Screws Material: High Strength Stainless Steel with no finish
    • Compatible with 393 Motors and Servos
    • #6-32 Locking Screws
    • Have thread locker applied on their threads
    • Thread locker will help hold the screw in position
      • Can be used approximately 10-15 times and still retain a firm lock
      • Provide similar functionality to VEX Nylock Nuts

Shoulder_Screw.png

All standard VEX nuts and standoffs

  • Shoulder Screw Material: High Strength Stainless Steel with no finish
    • Compatible with all standard VEX nuts and standoffs
    • Make low-slop pivots in VEX metal
    • Designed to fit snugly in a VEX square hole and allows several layers of metal to pivot
      • 0.176" diameter x 0.20" long shoulder
      • 3/32" VEX Hex Key Drive

Thumbscrew.png

All standard VEX nuts and standoffs

  • Thumbscrew Material: Plastic
    • Compatible with all standard VEX nuts and standoffs
    • The same size (#8-32) as standard VEX screws, only they have a 0.428" diameter knurled head so they can be tightened or loosened by hand
    • Great for applications where a screw will be inserted or removed multiple times, such as robot access panels or battery mounts. Or, in a situation where tools are not preferred to be used, such as certain education settings.

Complete List of Screws sold by VEX

The purpose of this table is to visualize the entire list of screws sold by VEX. Usage of this table can help provide unseen alternatives to incorporate into your build.

Screw Style

Screw Length / Type

Screw

SKU

#8-32 Star Drive













1/8"

#8-32 x 1/8" Star Drive Set Screw (32-pack)

276-6098

1/4"

#8-32 x 1/4" Star Drive Screw (100-pack)
#8-32 x 1/4" Locking Star Drive Screw (100-pack)

276-4990
276-5006

3/8"

#8-32 x 3/8" Star Drive Screw (100-pack)

276-4991

1/2"

#8-32 x 1/2" Star Drive Screw (100-pack)
#8-32 x 1/2" Locking Star Drive Screw (100-pack)

276-4992
276-5007

5/8"

#8-32 x 5/8" Star Drive Screw (100-pack)

276-4993

3/4"
#8-32 x 3/4" Star Drive Screw (100-pack) 276-4994
7/8"
#8-32 x 7/8" Star Drive Screw (100-pack) 276-4995
1"
#8-32 x 1.000" Star Drive Screw (100-pack) 276-4996
1.25"
#8-32 x 1.250" Star Drive Screw (50-pack) 276-4997
1.5"
#8-32 x 1.500" Star Drive Screw (50-pack) 276-4998
1.75"
#8-32 x 1.750" Star Drive Screw (50-pack) 276-4999
2"
#8-32 x 2.000" Star Drive Screw (25-pack) 276-5004
2.25"
#8-32 x 2.250" Star Drive Screw (25-pack)</span > 276-8015
2.5" #8-32 x 2.500" Star Drive Screw (25-pack) 276-8016

 

Screw Style

Screw Length / Type
Screw
SKU

#8-32 Hex Drive

1/4"


#8-32 x 1/4" Screw (100-pack)
#8-32 x 1/4" Locking Screw (100-pack)

 

275-1002

275-1260

3/8"

#8-32 x 3/8" Screw (100-pack)

275-1003

1/2"

#8-32 x 1/2" Screw (100-pack)
#8-32 x 1/2" Locking Screw (100-pack)

275-1004

275-1261

5/8"

#8-32 x 5/8" Screw (100-pack)

275-1005

3/4"
#8-32 x 3/4" Screw (100-pack)
275-1006
7/8"
#8-32 x 7/8" Screw (100-pack)
275-1007
1"
#8-32 x 1.000" Screw (100-pack)
275-1008
1.25"
#8-32 x 1.250" Screw (50-pack)
275-1009
1.5"
#8-32 x 1.500" Screw (50-pack)
275-1010
1.75"
#8-32 x 1.750" Screw (50-pack)
275-1011
2" #8-32 x 2.000" Screw (25-pack) 275-1012

Specialty Screw



Thumbscrew
1/2" Thumbscrew (50-pack)
275-1485
Shoulder Screw
#8-32 Shoulder Screws (25-pack) 276-1408

#6-32 Hex Drive


1/4"
#6-32 x 1/4" Screw (50-pack) 275-0659
1/2"
#6-32 x 1/2" Screw (50-pack)
#6-32 x 1/2" Locking Screw (100-pack)

275-1169

276-1958

For more information, help, and tips, check out the many resources at VEX Professional Development Plus