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
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 |
|||||||||
|---|---|---|---|---|---|---|---|---|---|
| #0 | #1 | #2 | #3 | #4 | #5 | #6 | #8 | #10 | #12 |
| 0.060" |
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 |
|---|---|---|
How to Secure Screws and Nuts
Screws can be fastened to nuts using the compatible tools mentioned above. For a demonstration of this, please view the video below. A key takeaway from the video applicable to VEX building and real life is with the saying "righty-tighty, lefty-loosey" to tighten or loosen screws. For more information on kit tools, view this article from the VEX Library for V5 Kit tools, view this article from the VEX Library for EXP Kit tools, or view this article from the VEX Library for V5 Workcell tools.
Screw Styles
VEX products employ two different styles of screw. The first, often less used but still as important, is the Set Screw.
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).
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
- the #6-32 or #8-32 Hex Drive Screw which is tightened with a 5/64” and 3/32” Hex Key respectively
- the #8-32 Star Drive Screw which is tightened using a T15 Star Drive Key or T15 Star Drive Screwdriver.
- The star type head is less prone to stripping. For pivot points there are also #8-32 Shoulder Screws which have a short unthreaded section and this area creates less friction for a pivot point. A complete table with all of the screw sizes is at the bottom of the page.
| #6-32 Hex Drive Screw | #8-32 Hex Drive Screw | #8-32 Star Drive Screw |
| 5/64” Hex Key | 3/32” Hex Key | T15 Star Drive Key |
|
|
|
Material Information and Applications
Before beginning to use a screw, it is important to learn how to choose the length of the screw. Watch this video to learn more about choosing the best length of screw for your build.
V5 Smart Motors and all standard VEX nuts and standoffs
-
#8-32 Star Drive Screw Material: Alloy Steel
- 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
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
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
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
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) |
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) |
276-4992 |
|
| 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) | 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)
|
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) |
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 |