Hydraulic Reference Charts & Resources

Free reference charts for hydraulic hose, fittings, O-rings and cylinder seals. We built these because we get asked the same questions every day at the counter: what thread is this, what size O-ring do I need, and what seal kit fits my cylinder. Bookmark this page — everything here is free to use, no sign-up.

Reference charts

Hydraulic Thread Identification Chart

Identify JIC 37°, SAE O-Ring Boss, ORFS, NPT/NPTF, BSPP, BSPT and metric DIN 24° threads by dash size, thread size and outside diameter. Includes the pairs that get mixed up most often.

O-Ring Size Chart (AS568)

AS568 dash numbers with inside diameter and cross section for the 1/16″, 3/32″, 1/8″ and 3/16″ series, plus how to measure an O-ring you already have.

Hydraulic Seal Measurement Guide

How to measure rod seals, piston seals, wipers and wear rings, how to read a rod-by-bore seal kit specification, and what the part number prefixes on our seal kits mean.

Hydraulic Hose Size Chart

Dash sizes with inside diameter in inches and millimetres, a plain-English comparison of the SAE and DIN hose types we stock, and how to measure a hose you need to replace.

Still not sure?

Bring the old part or a photo to the counter and we will match it. You can also contact us with the numbers stamped on the fitting or the cylinder tag.

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