Other protectors BP31 black

Blanking plugs BP31 cover holes in sheet metal quickly and neatly. The plug is in polyethylene (PE), black with a matte surface, and is snapped into the hole from the outside; the low head covers the edge of the hole and the grip on the back holds it in place without tools, glue or a nut. The series covers 27 sizes for hole diameters from 4.7 to 101.6 mm, which covers most of what is found in punched and drilled sheet metal.

The need comes up more often than you think. Control cabinets are delivered with pre punched entries that are not used, rebuilt machines leave empty holes after dismantled components, and holes drilled in the wrong place happen in every sheet metal shop. An open hole lets in dust and moisture, looks unprofessional and can be a pinch hazard; a blanking plug solves all three problems for a few kronor.

The head is only marginally larger than the hole, so the plug takes minimal space and does not interfere with nearby components. The height above the sheet varies from just under 5 mm on the smallest sizes to a little over 16 mm on the largest, and the grip is shaped in three steps for different sheet thicknesses: 1.6, 3.2 and 6.4 mm depending on the plug size. Always check the sheet thickness against the manufacturer's data sheet when choosing a size; the function of the grip is based on the sheet landing correctly in the groove.

Polyethylene is the right material for the job. It is tough and springy, so the snap function takes both fitting and removal without breaking, and the material takes up practically no moisture. PE also handles oils, cleaning agents and most of what a control cabinet or a machine body is exposed to inside and out in a normal industrial environment.

The size series is close spaced in the lower part, where the most common entries are, and then runs upward in coarser steps to 101.6 mm; the range matches the hole sizes that punching tools and hole saws normally leave behind. That the whole series sits as variants under the same item makes it easy to put together a set of mixed sizes for the store, which is exactly how parts like these tend to be bought: a bag of each size that comes back in production.

Typical users are cabinet builders and automation companies that adapt standard enclosures, sheet metal shops doing subcontract work, maintenance departments rebuilding machines and the vehicle side, where holes in bodywork left by dismantled equipment have to disappear. In fittings, black blanking plugs are also used to hide mounting holes in sheet metal furniture and panels.

Fitting is made to go fast: line the plug up, press with your thumb or a rubber mallet until it snaps, done. If you want to remove it you pry it loose from the back or with a plastic spatula under the head. Check the actual diameter of the hole before you order; punched holes usually hold the nominal dimension, while burnt or drilled out holes can deviate upward and then call for the next size.

There is also an enclosure dimension in cabinet building. Open entries in a control cabinet break the sealing of the enclosure and let in both dust and fingers; a fitted blanking plug restores the sealed front. Check against the documentation of the cabinet manufacturer which enclosure rating the design has to hold and what is required of plugged entries in your particular application, since the figures are in the respective data sheets. The right plug in the right hole is a cheap part of that whole.

Do you want to check the hole diameter and sheet thickness against the right plug size? We are happy to help you choose right.