Burnishing an electrical contact - GIF

[Altair]

Burnishing an electrical contact.




Previously:

Testing circuit breakers - GIF
How a circuit breaker trips, in slow motion - GIF
1900s electrical panel - photo
Ungrounded 480 volt electrical connection - GIF
Fuse replacement guide - photo

[desbromilow]

I don't know if burnishing is the right term to use there since the tool being used is a fibreglass pen - basically a tight bundle of fibreglass strands all being used "end-on" as an abrasive to clean contamination off the contact. I consider it more along the lines of cleaning, whereas I always thought burnishing was smoothing by imprinting the metal surface with a hardened smooth surface (eg agate, hardened polished tool steel)

those pens are fairly cheap, and offer the replaceable fibreglass insert tip, or a brass brush tip - as the tip gets worn away you advance more to stick out and get used (like those kids twistup pens) In Australia we buy them from RS when we need to restock.

[mklotz]

Available from Amazon in the USA...

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[Toolmaker51]

I agree, to "burnish" lays down fibers of things like wood, ivory, fingernails, leather, etc. Can see a technicality in GIF example, the glass brush is nearly abrasive, more so to oxidation than parent metal.
Harder materials, the effect is slightly different but comparable result. The classic steel burnish is made removing teeth from fine cut files. Gunsmiths use those on lock work. The sides of a Swiss slitting file are tooth free, and work well.
Most butcher steels are almost burnishing tools, some have a very fine lengthwise pattern of grinding. Unsure if those have a different name; mine came from Grandfather. One glass smooth, the other grained, made ~100 years ago.
A pastime for infantry troops, used toothbrush handle on wood portions (stock) of their rifle, to brighten the sheen. Also known as 'boning'. Many different crafts use similar devices too, seamstresses, cobblers and bookbinders come to mind, though reasons differ.

[neilbourjaily]

Such fiber glass pens with a brush on their other ends were used to correct typing before the day of correction ribbon or liquid.

[Toolmaker51]

There were abrasive-like erasers too, effective on wet inks. Literally sanded off a portion of paper thickness.
Cratex, rubber-bonded abrasive work on contacts, be certain enclosure doesn't retain debris.