Description
Is your thread size off by one size?
These hex & round nickel plated brass reducers will solve that threading problem. They convert holes which fit PG, NPT or Metric threads to a smaller female thread of the same thread type.
Dimensions
Dimensions tables are long and do not adequately fit on mobile devices.
View this page on a tablet or computer, or call Estco with questions about dimensions:

Reducers – Metric to Metric Threads | |||||
PART NUMBERS | THREADS | DIMENSIONS IN INCHES (mm) | |||
Male Thread | Female Thread | D | T | H | |
A | B | Outer Diameter | Thread Length | Height | |
SR-RR-1612-BR | M16 x 1.5 | M12 x 1.5 | .71 (18) | .24 (6) | .33 (8.5) |
SR-RR-2012-BR | M20 x 1.5 | M12 x 1.5 | .94 (24) | .26 (6.5) | .35 (9) |
SR-RR-2016-BR | M20 x 1.5 | M16 x 1.5 | .94 (24) | .26 (6.5) | .35 (9) |
SR-RR-2516-BR | M25 x 1.5 | M16 x 1.5 | 1.18 (30) | .28 (7) | .39 (10) |
SR-RR-2520-BR | M25 x 1.5 | M20 x 1.5 | 1.18 (30) | .28 (7) | .39 (10) |
SR-RR-3220-BR | M32 x 1.5 | M20 x 1.5 | 1.54 (39) | .31 (8) | .45 (11.5) |
SR-RR-3225-BR | M32 x 1.5 | M25 x 1.5 | 1.54 (39) | .31 (8) | .45 (11.5) |
SR-RR-4025-BR | M40 x 1.5 | M25 x 1.5 | 1.69 (43) | .31 (8) | .45 (11.5) |
SR-RR-4032-BR | M40 x 1.5 | M32 x 1.5 | 1.69 (43) | .35 (9) | .49 (12.5) |
SR-RR-5032-BR | M50 x 1.5 | M32 x 1.5 | 2.24 (57) | .39 (10) | .55 (14) |
SR-RR-5040-BR | M50 x 1.5 | M40 x 1.5 | 2.24 (57) | .39 (10) | .55 (14) |
SR-RR-6340-BR | M63 x 1.5 | M40 x 1.5 | 2.52 (64) | .39 (10) | .55 (14) |
SR-RR-6350-BR | M63 x 1.5 | M50 x 1.5 | 2.52 (64) | .39 (10) | .55 (14) |
Reducers – PG to PG Threads | |||||
PART NUMBERS | THREADS | DIMENSIONS IN INCHES (mm) | |||
Male Thread | Female Thread | D | T | H | |
A | B | Outer Diameter | Thread Length | Height | |
SR-RR-0907-BR | PG 9 | PG 7 | .67 (17) | .24 (6) | .33 (8.5) |
SR-RR-1107-BR | PG 11 | PG 7 | .79 (20) | .24 (6) | .33 (8.5) |
SR-RR-1109-BR | PG 11 | PG 9 | .79 (20) | .24 (6) | .33 (8.5) |
SR-RR-1309-BR | PG 13 | PG 9 | .87 (22) | .26 (6.5) | .35 (9) |
SR-RR-1311-BR | PG 13 | PG 11 | .87 (22) | .26 (6.5) | .35 (9) |
SR-RR-1609-BR | PG 16 | PG 9 | .94 (24) | .26 (6.5) | .37 (9.5) |
SR-RR-1611-BR | PG 16 | PG 11 | .94 (24) | .26 (6.5) | .37 (9.5) |
SR-RR-1613-BR | PG 16 | PG 13 | .94 (24) | .26 (6.5) | .37 (9.5) |
SR-RR-2111-BR | PG 21 | PG 11 | 1.18 (30) | .28 (7) | .39 (10) |
SR-RR-2113-BR | PG 21 | PG 13 | 1.18 (30) | .28 (7) | .39 (10) |
SR-RR-2116-BR | PG 21 | PG 16 | 1.18 (30) | .28 (7) | .39 (10) |
SR-RR-2916-BR | PG 29 | PG 16 | 1.54 (39) | .31 (8) | .45 (11.5) |
SR-RR-2921-BR | PG 29 | PG 21 | 1.54 (39) | .31 (8) | .45 (11.5) |
SR-RR-3621-BR | PG 36 | PG 21 | 1.97 (50) | .35 (9) | .49 (12.5) |
SR-RR-3629-BR | PG 36 | PG 29 | 1.97 (50) | .35 (9) | .49 (12.5) |
SR-RR-4229-BR | PG 42 | PG 29 | 2.24 (57) | .39 (10) | .55 (14) |
SR-RR-4236-BR | PG 42 | PG 36 | 2.24 (57) | .39 (10) | .55 (14) |
SR-RR-4836-BR | PG 48 | PG 36 | 2.52 (64) | .39 (10) | .55 (14) |
SR-RR-4842-BR | PG 48 | PG 42 | 2.52 (64) | .39 (10) | .55 (14) |
Reducers – PG to PG Threads | ||||||
PART NUMBERS | THREADS | DIMENSIONS IN INCHES (mm) | ||||
w/ Buna-N O-Ring | without O-Ring | Male Thread | Female Thread | W | T | H |
A | B | Wrench Flat | Thread Length | Height | ||
SR-RQ-0907-BR | SR-RP-0907-BR | PG 9 | PG 7 | .67 (17) | .24 (6) | .34 (8.8) |
SR-RQ-1107-BR | SR-RP-1107-BR | PG 11 | PG 7 | .79 (20) | .24 (6) | .35 (9) |
SR-RQ-1109-BR | SR-RP-1109-BR | PG 11 | PG 9 | .79 (20) | .24 (6) | .35 (9) |
SR-RQ-1309-BR | SR-RP-1309-BR | PG 13 | PG 9 | .87 (22) | .26 (6.5) | .37 (9.5) |
SR-RQ-1311-BR | SR-RP-1311-BR | PG 13 | PG 11 | .87 (22) | .26 (6.5) | .37 (9.5) |
SR-RQ-1609-BR | SR-RP-1609-BR | PG 16 | PG 9 | .94 (24) | .26 (6.5) | .37 (9.5) |
SR-RQ-1611-BR | SR-RP-1611-BR | PG 16 | PG 11 | .94 (24) | .26 (6.5) | .37 (9.5) |
SR-RQ-1613-BR | SR-RP-1613-BR | PG 16 | PG 13 | .94 (24) | .26 (6.5) | .37 (9.5) |
SR-RQ-2111-BR | SR-RP-2111-BR | PG 21 | PG 11 | 1.18 (30) | .28 (7) | .41 (10.3) |
SR-RQ-2113-BR | SR-RP-2113-BR | PG 21 | PG 13 | 1.18 (30) | .28 (7) | .41 (10.3) |
SR-RQ-2116-BR | SR-RP-2116-BR | PG 21 | PG 16 | 1.18 (30) | .28 (7) | .41 (10.3) |
SR-RQ-2916-BR | SR-RP-2916-BR | PG 29 | PG 16 | 1.57 (40) | .31 (8) | .45 (11.5) |
SR-RQ-2921-BR | SR-RP-2921-BR | PG 29 | PG 21 | 1.57 (40) | .31 (8) | .45 (11.5) |
SR-RQ-3621-BR | SR-RP-3621-BR | PG 36 | PG 21 | 1.97 (50) | .35 (9) | .49 (12.5) |
SR-RQ-3629-BR | SR-RP-3629-BR | PG 36 | PG 29 | 1.97 (50) | .35 (9) | .49 (12.5) |
SR-RQ-4229-BR | SR-RP-4229-BR | PG 42 | PG 29 | 2.24 (57) | .39 (10) | .53 (13.5) |
SR-RQ-4236-BR | SR-RP-4236-BR | PG 42 | PG 36 | 2.24 (57) | .39 (10) | .53 (13.5) |
SR-RQ-4836-BR | SR-RP-4836-BR | PG 48 | PG 36 | 2.52 (64) | .39 (10) | .53 (13.5) |
SR-RQ-4842-BR | SR-RP-4842-BR | PG 48 | PG 42 | 2.52 (64) | .39 (10) | .53 (13.5) |
Reducers – Metric to Metric Threads | |||||
PART NUMBERS | THREADS | DIMENSIONS IN INCHES (mm) | |||
w/ Buna-N O-Ring | Male Thread | Female Thread | W | T | H |
A | B | Wrench Flat | Thread Length | Height | |
SR-RM-1612-BR | M16 x 1.5 | M12 x 1.5 | .67 (17) | .20 (5) | .31 (8) |
SR-RM-2012-BR | M20 x 1.5 | M12 x 1.5 | .87 (22) | .24 (6) | .35 (9) |
SR-RM-2016-BR | M20 x 1.5 | M16 x 1.5 | .87 (22) | .24 (6) | .35 (9) |
SR-RM-2516-BR | M25 x 1.5 | M16 x 1.5 | 1.06 (27) | .28 (7) | .39 (10) |
SR-RM-2520-BR | M25 x 1.5 | M20 x 1.5 | 1.06 (27) | .28 (7) | .39 (10) |
SR-RM-3216-BR | M32 x 1.5 | M16 x 1.5 | 1.34 (34) | .31 (8) | .34 (11) |
SR-RM-3220-BR | M32 x 1.5 | M20 x 1.5 | 1.34 (34) | .31 (8) | .43 (11) |
SR-RM-3225-BR | M32 x 1.5 | M25 x 1.5 | 1.34 (34) | .31 (8) | .43 (11) |
SR-RM-4020-BR | M40 x 1.5 | M20 x 1.5 | 1.46 (43) | .31 (8) | .47 (12) |
SR-RM-4025-BR | M40 x 1.5 | M25 x 1.5 | 1.46 (43) | .31 (8) | .47 (12) |
SR-RM-4032-BR | M40 x 1.5 | M32 x 1.5 | 1.46 (43) | .31 (8) | .47 (12) |
SR-RM-5025-BR | M50 x 1.5 | M25 x 1.5 | 2.17 (55) | .35 (9) | .51 (13) |
SR-RM-5032-BR | M50 x 1.5 | M32 x 1.5 | 2.17 (55) | .35 (9) | .51 (13) |
SR-RM-5040-BR | M50 x 1.5 | M40 x 1.5 | 2.17 (55) | .35 (9) | .51 (13) |
SR-RM-6332-BR | M63 x 1.5 | M32 x 1.5 | 2.56 (65) | .39 (10) | .55 (14) |
SR-RM-6340-BR | M63 x 1.5 | M40 x 1.5 | 2.56 (65) | .39 (10) | .55 (14) |
SR-RM-6350-BR | M63 x 1.5 | M50 x 1.5 | 2.56 (65) | .39 (10) | .55 (14) |
Reducers – Metric to Metric Threads | |||||
PART NUMBERS | THREADS | DIMENSIONS IN INCHES (mm) | |||
Male Thread | Female Thread | W | T | H | |
A | B | Wrench Flat | Thread Length | Height | |
SR-RN-3412-BR | 3/4″ NPT | 1/2″ NPT | 1.18 (30) | .71 (18) | .87 (22) |
SR-RN-1034-BR | 1″ NPT | 3/4″ NPT | 1.30 (33) | .98 (25) | 1.14 (29) |
SR-RN-5410-BR | 1-1/4″ NPT | 1″ NPT | 1.69 (43) | .98 (25) | 1.14 (29) |