Match Masking Caps to Common Threaded Studs
The correct caps for SAE/UNC/metric threads - see chart below
A typical call out on engineering drawing is to mask threaded pins or other threaded features. This protects them from powder coating, paint, anodizing, plating, ecoating and other metal finishing processes so the threads stay clean for when a nut is added later. But masking those studs presents a challenge: How do you determine the right cap to use on a given thread? Viadon can help with the chart below showing common threads in SAE, UNC and metric size with the correct masking caps in the associated row. Scroll down for the chart; for a bit more detail about each type of cap, read on.
Standard and expandable caps
For a standard cap that just needs to be covered for most coating types, a straight wall cap is used like Viadon's SC line of silicone caps. With a wide range of caps available, some in various lengths for the same inside diameter of the cap, in every case there is a cap to cover every common SAE / UNC / metric thread size and type. Click on the first link below for more options.
When fewer caps are desired, our line of SCE expandable caps may be used instead - some of these caps can be used on multiple thread sizes. Click on the second link below to see more.
Caps with a flange
There are times when a threaded stud needs an uncoated area to provide for an electrical ground. When masking these features, a fast and easy way to accomplish this is with a flange cap. Viadon's VFC line of caps with a grounding flange are perfect for these types of situations, and a wide range of options are available fornearly every common SAE / UNC / metric thread size. Click on the link below for all flanged caps.
Download the chart below in PDF format for printing / quick reference
Don't see the thread listed below for which you need a cap? Email us at [email protected] or give us a call at 866-534-3900 - we actually pick up our phone during business hours - for real! (7:30 am to 4 pm Central Time)
Common threads & caps for thread sizes
| Thread size |
Caps for thread sizes |
| Straight‑wall caps |
Expandable cap |
Cap with flange |
| 4‑40 |
SC100‑0500 & SC100 |
- |
VFC100‑0500 |
| M3 |
SC100‑0500 & SC100 |
- |
VFC100‑0500 |
| 6‑32 |
SC125‑0500, SC125, SC125‑1500 |
SCE‑118‑236 |
VFC125‑0500 |
| M4‑0.7 |
SC148‑0500, SC148‑0750, SC148 |
SCE‑118‑236 |
VFC146‑0472 |
| 8‑32 |
SC156‑0500, SC156, SC156‑1500 |
SCE‑118‑236 |
VFC156‑0500 |
| M5‑0.8 |
SC180 |
SCE‑118‑236 |
VFC180‑0600 |
| 10‑24 |
SC172‑0500, SC172, SC172‑1500 |
SCE‑118‑236 |
VFC172‑0500 |
| M6‑1.0 |
SC223‑0500, SC223‑1000, SC223 |
SCE‑118‑236 |
VFC220‑0590, VFC220‑0787, VFC223‑0720 |
| 1/4‑20 |
SC234‑0500, SC234, SC234‑1500 |
SCE‑236‑354 |
VFC240‑0500 |
| 5/16‑18 |
SC281, SC281‑2000 |
SCE‑236‑354 |
- |
| M8‑1.25 |
SC295‑0500, SC295‑125, SC295 |
SCE‑236‑354 |
VFC295‑1000 (N/S) |
| 3/8‑16 |
SC355 |
SCE‑236‑354 |
VFC350‑740 (N/S) |
| M10‑1.5 |
SC375‑0750, SC375, SC375‑1500 |
SCE‑354‑472 |
VFC376‑0825 |
| M12‑1.75 |
SC456‑0500, SC456‑1000, SC456 |
SCE‑354‑472 |
VFC460‑700 (N/S) |
| 1/2‑13 |
SC468, SC480 |
SCE‑472‑591 |
- |
Want to print this chart do you can keep it handy? Download it here in PDF format.