Hacker News

Favorites Setup
Comment by LeifCarrotson | original | Internal Combustion Engine (2021)
[−]LeifCarrotson · 2026-07-01 Wed 18:54 UTC · link
It's 0.0015, that's 1.5 to 2.5 thousandths, or 15-25 "tenths" as they're called.

That's not a particularly tiny gap in the machinist world, it's large so that you can pump viscous oil in it and deal with a wide variety of temperature changes.

25 thousandths would be sloppy, a nominal clearance hole for a 1/4x20 bolt is about that much.

[−]arlattimore · 2026-07-01 Wed 19:08 UTC · link
Good catch, sorry should have corrected that. While not small for a machinist, I think by the average persons definition that is a pretty small gap for the oil to occupy ;-)
[−]cagey · 2026-07-01 Wed 20:00 UTC · link
> 25 thousandths would be sloppy, a nominal clearance hole for a 1/4x20 bolt is about that much.

Isn't that 0.250 which would be 250 thousandths?

[−]teraflop · 2026-07-01 Wed 22:07 UTC · link
No, they're talking about the clearance, which is the difference between the diameter of the bolt itself (1/4") and the diameter of a hole in which the bolt loosely fits (a couple hundredths of an inch bigger than that).