Pumps, motors and hydraulic blocks often use SAE flange connections instead of threads. There are two series that look alike but do not interchange: standard pressure (SAE 3000 psi, code 61) and high pressure (SAE 6000 psi, code 62). This guide explains how to tell them apart with a caliper.
Code 61 and code 62
| Code 61 | Code 62 | |
|---|---|---|
| Common name | SAE 3000 psi, standard pressure | SAE 6000 psi, high pressure |
| Standard | SAE J518 | SAE J518 |
| Maximum port pressure | 5000 psi (345 bar) up to 1"; 4000 psi (276 bar) at 1 1/4"; 3000 psi (207 bar) at 1 1/2" and 2" | 6000 psi (414 bar) in all sizes |
| For the same size | smaller bolt pattern and thinner bolts | larger bolt pattern and thicker bolts |
Indicative information. Check the marking on the part or the manufacturer's data sheet.
The flange size (1/2", 3/4", 1"…) is the nominal bore size, not a dimension you can measure on the part. To find the size and the code, measure the distance between the bolt holes.
Port bolt pattern (distance between bolts)
Measure centre to centre of the holes, on the long side (B) and on the short side (C).
| Size | Code 61: B × C (mm) | Code 61 bolts | Code 62: B × C (mm) | Code 62 bolts |
|---|---|---|---|---|
| 1/2" | 38.10 × 17.48 | M8 or 5/16"-18 | 40.49 × 18.24 | M8 or 5/16"-18 |
| 3/4" | 47.63 × 22.23 | M10 or 3/8"-16 | 50.80 × 23.80 | M10 or 3/8"-16 |
| 1" | 52.37 × 26.19 | M10 or 3/8"-16 | 57.15 × 27.76 | M12 or 7/16"-14 |
| 1 1/4" | 58.72 × 30.18 | M10 or 7/16"-14 | 66.68 × 31.75 | M14 or 1/2"-13 |
| 1 1/2" | 69.85 × 35.71 | M12 or 1/2"-13 | 79.38 × 36.50 | M16 or 5/8"-11 |
| 2" | 77.77 × 42.88 | M12 or 1/2"-13 | 96.82 × 44.45 | M20 or 3/4"-10 |
Indicative information. Check the marking on the part or the manufacturer's data sheet.
Bolts may be metric or UNC: the same flange exists with both threads, so also check the thread of the holes in the pump or block.
Flange head diameter on hose fittings
On hose fittings with a flange head, the head diameter also separates the two codes:
| Size | Code 61 (mm) | Code 62 (mm) |
|---|---|---|
| 1/2" | 30.2 | 31.8 |
| 3/4" | 38.1 | 41.3 |
| 1" | 44.5 | 47.6 |
| 1 1/4" | 50.8 | 54.0 |
| 1 1/2" | 60.3 | 63.5 |
| 2" | 71.4 | 79.4 |
Indicative information. Check the marking on the part or the manufacturer's data sheet.
The flange O-ring
SAE ports seal with an O-ring in the groove of the flange head. Sizes 1/2" to 2" use O-rings with a 3.53 mm cross-section and an inside diameter from 18.64 mm (1/2") to 56.74 mm (2"); the same O-ring fits code 61 and code 62 of the same size. You will find them under O-rings.
Indicative information. Check the marking on the part or the manufacturer's data sheet.
Step by step
- Measure the distance between the holes on the long side and on the short side.
- Compare with the table to find the size and the code.
- Check the bolt thread (metric or UNC).
- Choose the part: flanges and split flanges, flange hose fittings or adaptors with the same code.
Can't identify the flange? Send us a photo with the distances between holes. The Hidro Orfão technical team will help you find the right flange, hose fitting or adaptor.
See also
Sources
- FOR, Catalogue 1, rev. 9, 2017: dimensions for SAE flange ports; SAE 3000 and 6000 psi flanges.
- Hydro Holding / Tieffe, HH catalogue: SAE code 61 and code 62 flange fittings (SAE J518).