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What is a trapezoidal screw? Tr TM TW ACME
It is a target cross-sectional screw with a large proportion of the top of the mountain and the bottom of the valley.
Currently, OSG supports trapezoidal screw taps and gauges as special products.
Tr : Metric Keystone Screw JIS B 0216 0217
TM : 30° trapezoidal screw Conventional JIS
TW : 29° trapezoidal screw Conventional JIS
ACME : 29° Keystone Screw ANSI B 1.5
| Metric trapezoidal screw | 30° trapezoidal screw | 29° trapezoidal screw | ACME Screws | |
| Screw symbol | Tr | TM | TW | ACME |
| standard | JIS B 0216 0217 | Former JIS | Former JIS | ANSI B 1.5 |
| Thread angle | 30° | 30° | 29° | 29° |
・All taps for trapezoidal screws are special products.
(Tr screws and TM thread taps used to be standard products, but they are now discontinued.)
・TM and TW threads have no precision regulations.
・ At the time of production, TM screws are mutatis mutandis used with Tr accuracy
・TW screws use ACME accuracy mutatis mutandis