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Hydraulic & Pneumatic Cylinder Tie Rods
NFPA T3.6.7-spec tie rods for industrial fluid power cylinders, made-to-order in Northern Michigan.
Pick your cylinder duty tier (heavy-duty hydraulic, or light-duty hydraulic / pneumatic) and bore size below. The configurator loads NFPA-spec rod diameter, UNF thread designation, and minimum thread length per end. Total rod length is the one number you change — measure your old rod end-to-end and type it in. Material defaults to 1144 Stressproof (the industry-standard tie-rod alloy); 1045, 4140 annealed, 304, and 316 stainless are toggles. Cylinder repair shops can place an order in well under a minute.
Not sure which duty tier? Check the cylinder nameplate or OEM cut sheet for the operating-pressure rating, or just measure the existing tie rod's thread and diameter and match it to the right group. Same bore size carries different tie-rod sizes between tiers — a 4" bore heavy-duty cylinder uses 5/8-18 tie rods, while a 4" bore light-duty or pneumatic cylinder uses 3/8-24.
NFPA T3.6.7 cylinder bore sizes
Frequently Asked Questions
The bore size alone doesn't tell you. A 4″ bore cylinder rated for 2500 PSI hydraulic service uses heavy-duty NFPA tie rods (5/8-18 threads, Ø5/8″ OD); a 4″ bore cylinder rated for 250 PSI light-duty hydraulic or compressed air uses the lighter tie rod (3/8-24 threads, Ø3/8″ OD). Check the cylinder nameplate or the OEM cut sheet for the duty rating, or just measure the old tie rod's thread and diameter and match it to the right group.
NFPA T3.6.7 publishes separate dimension tables for each (Tables 25 and 40), but every tie-rod dimension is identical between them. The standard treats them as one structural tier. Showing separate listings would be the same product at two URLs.
Lay the old rod on a bench and measure end-to-end with a tape, including the threaded portions. That number goes directly into the configurator. We don't ask for cylinder stroke or cushion depth — the OEM-specific dead-length math (Parker 2H ≠ Atlas H ≠ Sheffer H) is more error-prone than measuring the part in your hand.
Each bore card loads with a representative starter rod: 6″ smooth middle body plus the NFPA-spec thread length at each end. That keeps the 3D preview compact and shows the correct rod-end proportions before you've typed anything. Drop your measured total length into the configurator and the middle stretches to match — threads stay at NFPA minimum unless you bump them up. The configurator accepts anything up to 48″ total.
Total rod length up to 48″, OD up to 12″. Every NFPA T3.6.7 bore in this folder sits well inside both — the largest tie rod we offer is the heavy-duty 8″ bore (Ø1-1/4″ × up to 36″ length). If you need a longer rod than the default length suggests, just type your measured number in; the configurator accepts anything up to 48″.
Rod OD is ±0.005″, the industry-standard tie-rod OD spec. Threads default to UNF class 2A per NFPA §6.4 — the form used by every major US cylinder manufacturer; class 3A is available for high-vibration / precision-mounting applications. Both ends are chamfered for nut start and thread protection in shipping.
Yes. The default thread length per end is the NFPA BB extension dimension (visible thread past the cylinder cap). Buyers stacking cushion-bolt + double nut, adding jam/lock/safety nuts for vibration service, or wanting fudge room during reassembly often run thread length longer than NFPA minimum. Price scales per inch of additional thread.
Default is 1144 A311 CL-B Stressproof — 100 ksi tensile, the industry-default tie-rod alloy used by every major NFPA cylinder OEM (NFPA T3.6.7 itself only specifies dimensions, not material — but 1144 Stressproof is the de-facto choice). Currently RFQ-routed so a human quotes the partner price; orders complete normally. Toggles for 1045 cold-finished (budget), 4140 annealed (high-pressure / shock duty / mining and presses), 304 stainless (marine, food, washdown), and 316 stainless (chemical, offshore, coastal) all auto-price.
Not in this folder. Mill-duty cylinders use a separate NFPA standard (T3.6.9 / T3.6.13 territory), with bigger rods (1/2″–3″ diameter), longer lengths, and 8 rods per cylinder. Real money in steel-mill rebuilds, but a different product surface. Contact us if you need one.