Jack Screw dimensions for ASME B16.36 Orifice flanges

Usually two jack screws are mounted, and they are used to separate the flanges so that the orifice plate can be inspected. There should be one jack screw per flange and when the flanges are installed, the jack screws should be 180° apart. Orifice flanges are purchased with flange taps and jack screws.

Size DN (mm)	Size NPS (inch)	150 RF (Ø x L)	300 RF (Ø x L)	600 RF (Ø x L)	900 RTJ (Ø x L)	1500 RTJ (Ø x L)	2500 RTJ (Ø x L)
25	1	...	...	...	...	...	M20 x 130
40	1 1/2	...	...	...	M20 x 100	M20 x 100	M27 x 150
50	2	...	...	...	M20 x 120	M20 x 120	M27 x 170
80	3	...	...	M20 x 100	M20 x 120	M20 x 130	M27 x 190
100	4	...	...	M20 x 110	M20 x 140	M20 x 140	M27 x 210
150	6	M20 x 80	M20 x 100	M20 x 120	M20 x 160	M20 x 190	M27 x 270
200	8	M20 x 90	M20 x 110	M20 x 140	M20 x 180	M20 x 220	M27 x 300
250	10	M20 x 90	M20 x 120	M20 x 150	M20 x 190	M20 x 240	M27 x 370
300	12	M20 x 100	M20 x 130	M20 x 160	M20 x 210	M20 x 290	M27 x 410
350	14	M20 x 110	M20 x 140	M20 x 170	M20 x 230	M20 x 310	...
400	16	M20 x 110	M20 x 160	M20 x 190	M20 x 250	M20 x 340	...
450	18	M20 x 120	M20 x 160	M20 x 200	M20 x 280	M20 x 370	...
500	20	M20 x 120	M20 x 170	M20 x 210	M20 x 290	M20 x 400	...
550	22	M20 x 140	M20 x 180	M20 x 220	M20 x 340	M20 x 440	...
600	24	M20 x 140	M20 x 180	M20 x 240	M20 x 360	M20 x 460	...

Notes..

Dimensions of the bolts are in metric units, i.e. diameter x length of Jack Screws
Jack Screws are fully threaded UNC to ASME B1.1 class 2A and dimensions conform to ASME B18.2.1.

Rosemount Orifice Flanges and Orifice Plates