Konverzjemetoade tusken metryske en ferienige inch-threads

In tried is in spiraalstruktuer dy't brûkt wurdt om bouten en moeren te ferbinen. Yn ferskate lannen en regio's, ferskate thread noarmen wurde brûkt. Imperial en metrysk binne de twa meast foarkommende noarmen.
Yn 'e Britske standert, de mienskiplike thread spesifikaasjes binne UNC en UNF. UNC is de ôfkoarting fan Unified National Coarse, dy't ferwiist nei de ferienige nasjonale grouwe tried; UNF is de ôfkoarting fan Unified National Fine, dy't ferwiist nei de ferienige nasjonale fyn tried. Bygelyks, UNC 1/4-20 betsjut in ferienige nasjonale grof tried mei in toanhichte fan 20 TPI (triedden per inch) en in diameter fan 1/4 inch.

Inch systeem ferienige triedden wurde in soad brûkt yn inch systeem lannen. Dit soarte fan tried is ferdield yn trije searjes: grof tried rige UNC, fine thread rige UNF, ekstra fine thread rige UNFF, plus a fixed pitch series UN.

Marking method: Thread diameter-number of threads per inch; Series code-accuracy level

Example: Coarse tooth series 3/8-16 UNC-2A

Fine tooth series 3/8-24 UNF-2A

Extra fine tooth series 3/8-32 UNFF-2A

Fixed pitch series 3/8—20 UN—2A

The first digit 3/8 represents the outer diameter of the thread in inches. To convert to the metric unit mm, multiply by 25.4, that is, 3/8×25.4=9.525mm; the second and third digits 16, 24, 32, en 20 are The number of teeth per inch (the number of teeth on a length of 25.4mm); the text codes after the third digit, UNC, UNF, UNFF, UN, are the series codes, and the last two digits, 2IN, are the accuracy level.

It is stipulated in the unified thread standard that a nominal size can have different pitches. Bygelyks, 1/2 has 13 teeth, 16 teeth, 20 teeth, en 32 teeth. The standard stipulates that 13 teeth are coarse teeth and 20 teeth are fine teeth. 28 teeth are ultra-fine teeth; 16 teeth and 32 tosken wurde beide konstante pitch neamd, dat is net oars as grouwe tosken en fyn tosken.