Cutter notes · 02 May 2026
Ra bands we will write on a ticket
Roughness is a number with a unit, not a vibe. We sled it, we write it, and we refuse to treat a photograph of scallops as a substitute for that line on the paper.
Ra is an average. It is not a portrait of every ridge. It is still the least dishonest single number we can put on a mill ticket without writing a novel. Nia’s sled lives in a tin with coupons. She runs the window after the facing pass and after the groove walls, because walls can throw a burr that fools a hurried measurement. The number that goes on paper is the one after she is willing to sign. If the sled and the loupe disagree, the loupe wins and the head goes back to the vise. Averages are useful. They are not the ball.
For cavity and muscle irons we usually land in a 1.4 to 2.2 Ra neighborhood. That is enough texture for a wet Lane County lie without turning the 7-iron into a wedge. Going rougher on a long iron is how you start launching balloons that feel like spin and then fall out of the air because the face is chewing the cover. Going smoother is how you reprint the skillet you asked us to delete. The band is a neighborhood, not a religion. 17-4 will hold the high side of that neighborhood longer than 304. The ticket says which alloy we thought we had, so the next mill does not pretend otherwise.
Wedges we will take a little rougher if the golfer actually plays soaked collars, which around here is not a hypothetical hobby. The number still has a ceiling, because a cheese grater is a rules problem and a wear problem. We mill geometry we can defend. If you need a competition letter, you say so on the form and we mill the conservative side of the band. If you play muni rye twice a week and never see a committee, we will still not mill past what the wall can hold for a winter. Remaining thickness is a budget. Ra is a spend.
Putter faces get their own quiet band. The job is consistent texture so the first foot of roll on wet Poa is repeatable, not a honeycomb that photographs like a machine shop calendar. Hybrids get a light mill that may not even be worth a Ra argument; some inserts we will not sled because we should not have been there with a flute at all. Reed’s veto is a finish number of a different kind: zero metal removed.
People ask for the Ra of a tour van they saw in a video. We do not have that van. We have a humid room, a used gantry, and a tray of grass. The number we write is the number this spindle left on this blank on this day. Keep the paper. If you lose it, we can mill again, but we will mic first as if we never met you. Memory is not a calibration coupon.
Jewelry scallops can have a beautiful Ra and a terrible ball. That is the chatter essay. This one is shorter: if the ticket has a number and the loupe has a shadow, you can leave Olive. If either is missing, the head is still ours. We like the gantry clock more than we like a handshake over an unfinished window.