Dykem Applicator Try an empty Sharpie.

[Toolmaker51]

Refillable Makers; who knew? I was unaware of Dykem brand markers, but Marks-Alot have been OK for me. I use red for grinding operations, blue or black elsewhere. Not sure why two colors...red shows best on ground surfaces. Did some ultrafine boring past couple days. Marking used on each spring cut, locations and size repeated so closely the mark was removed only where the previous finish at .006 per rev and .0015 actually intersected with a zero radius boring tool. A comparison might be two threads of the same diameter but different pitches.

And while the topic is running. I found a "PILOT SC-6600" refillable to mess with; no pun intended. Barrel is about 1" diameter x 4", felt tip is 10mm. Still available, in the 6 buck range. There also is the "MOLOTOW" line---and when I say line I mean line; up to 60mm wide, that's a mean line awright! Not priced on their site. Its a pump style, like a paint marker.
Others; Angelus, Montana...applications specify paint or dyes. Paints need viscosity less than milk; comparable mammalian version not specified.

Our collective workaround has traction already at work; being able to walk around with Dykem or scribe-able equivalent in a pocket. No one seems all that thrilled with the brush in cap applicator.