Masking Holes Efficiently

Tapered plugs are not the only option for masking countersunk and threaded holes

For masking holes, the natural choice is to reach for some tapered plugs, but what about plugs for threaded holes, countersunk holes or spotface areas around holes? It’s often difficult to mask those types of holes efficiently with standard tapered plugs.

There are several products available to ensure you can increase your production by quickly and efficiently masking some of the less common hole types.

Countersink plugs are designed to mask countersunk holes. The plugs push into the hole and mask the angled faces of the hole. Designed to cover a range of countersunk hole sizes and angles, they can mask 82° (standard imperial), 90° (metric) and 100° (aerospace) holes. The plugs have a series of flexible ribs to ensure they fit both the close and normal diameter clear holes. A small handle on the top of the plug ensures the plug can be installed and removed quickly to speed up the masking process. In addition to having the part number on the plug, plugs are colour coded for size identification.

Countersink pull plugs are plugs which pull into countersunk holes. The plugs mask both the main hole and the angled faces of the countersink. The stepped main handle of the plug pulls into the hole and forms a tight seal on the hole. Designed to cover a range of countersunk hole sizes and angles, they can mask 82° (standard imperial), 90° (metric) and 100° (aerospace) holes. The plugs are designed to fit both the close and normal diameter clear holes. A handle on the top of the plug ensures the plug can be removed quickly.

Thread masks are used for masking threaded holes. They are a plug with a flange, which masks the threaded hole and the top thread. These plugs mean you can stop the time-consuming process of screwing bolts into the holes to mask threaded holes and instead simply push a plug into the hole. Thread masks are available for both metric and imperial size threads and are colour coded for size identification.

Washer pull plugs are pull plugs with a larger diameter built into them. This larger diameter forms a masked washer area around a hole, for when there is a requirement to leave an area uncoated for a washer, bolt head or simply a spotfaced area. The pull plugs are pulled into the hole and there is a handle on top to ensure the plug can be removed quickly.

If you are interested in increasing your masking efficiency by using any of these plugs, a good masking supplier can provide samples for you to evaluate.

Written by John the article was published in Surface World Magazine.

Discover more

Return to the main press page for more help on masking for surface finishing.


Masking materials differences