Product Overview
#4-40 x 3/8 Inch Stainless Steel Diamond Knurled Thumb Screw
Condition
Unused new old stock. Solid stainless steel construction with clean machine threads and crisp diamond knurling. Physical dimensions match intake card designations: #4-40 thread size, 3/8-inch thread length, and 3/8-inch head diameter. Visual inspection only. Sold each.
Ships same or next business day from our Idaho warehouse. Honest pricing, no nonsense.
Online since 1999. We are here for our customers, with a no-hassle satisfaction guarantee.
Product Overview
Manual-adjust stainless steel thumb screw featuring a #4-40 UNC threaded shank and an integrated round knurled head. Machined from solid stainless steel with a straight shoulder transition and a flat drive face designed for hand-tightened assembly without drivers.
Key Features
- Thread size: #4-40 UNC
- Thread length: 3/8 inch
- Head diameter: 3/8 inch
- Head profile: Round with raised diamond knurled perimeter
- Drive type: Manual finger turn with flat circular top face
- Material: Stainless steel
Applications
- Securing removable electronics enclosure panels and instrumentation covers that require frequent tool-free servicing.
- Precision stop and adjustment screw hardware on optical benches, custom laboratory fixtures, or 3D printer calibration rigs.
- Toolless clamping on custom maker brackets, sensor mounts, or test jig assemblies.
Frequently Asked Questions
Does the head include a slot or hex recess for tools?
No. The top face is a smooth, solid machined circle designed strictly for hand tightening via the knurled edge.
What is the thread pitch?
Standard #4-40 UNC coarse thread pitch (40 threads per inch).
Can this screw be used to replace standard #4-40 socket or pan head machine screws?
Yes, provided there is at least 3/8 inch of radial clearance around the screw hole to accommodate the knurled head. The price-break table on this page gives the price per piece at each quantity.
Nothing beats the quiet satisfaction of a crisp stainless knurl turning smooth into clean threads without hunting for a driver.
