THKBTK1404V-3.6ZZBall Screw Nut Only — 14 mm Shaft, 4 mm Lead, Flanged, Brush-Sealed, No Preload (Screw Shaft Not Included)

Product Description

What this part is

A THK ball screw nut, model BTK1404V-3.6ZZ, from the BTK rolled ball screw series. This is the recirculating ball nut half of a ball screw drive: hardened balls circulate through a return path in the nut and roll in the helical groove of the screw shaft, so the shaft turns and the nut travels with rolling friction instead of the sliding friction of an Acme or trapezoidal nut.

Decoding the order code

BTK is THK’s rolled precision ball screw series. 14 is the screw shaft outside diameter in millimetres. 04 is the lead — the nut advances 4 mm per revolution of the shaft. V identifies the nut variant within the BTK range. 3.6 is the number of loaded ball turns, arranged here as a single circuit of 3.65 turns. ZZ is the contamination protection code: brush wipers at both ends of the nut. No preload symbol appears, which means the no-preload build, supplied with a nominal 0.1 mm axial clearance rather than a set preload.

Scope — what is in the box

The nut only. No screw shaft, no end journals or end machining, no support bearings, no bearing blocks, no nut housing and no coupling. A ball nut does not include a screw and cannot be fitted to an arbitrary shaft — it needs a 14 mm BTK-series rolled shaft of 4 mm lead and matching hand, because the groove radius and ball diameter are specific to the series. This nut will not run correctly on a ground precision screw of the same nominal 14 x 4 size.

Published specifications

Series: BTK, rolled ball screwScrew shaft outside diameter: 14 mmLead: 4 mm per revolutionNut flange outside diameter: 50 mmNut overall length: 40 mmNut form: flanged, double-chamfered flangeLoaded ball circuits: 1 x 3.65 turnsPreload: noneAxial clearance: 0.1 mmSeal: ZZ, brush wipers both endsNut running tolerance class: P5 (ABEC 5 equivalent)Material: bearing steel, hardened and ground racewayMass: 0.23 kg

What these specs mean in practice

A 4 mm lead on a 14 mm shaft is a fine-lead combination: 4 mm of travel per revolution gives good resolution and good static holding, and the low lead angle makes the screw much less likely to back-drive under a suspended load than a large-lead screw. The trade-off is traverse speed — you need high shaft rpm for fast motion, and 14 mm is a slender shaft, so critical speed and column buckling set the practical length rather than load rating. The single 3.65-turn circuit keeps the nut short at 40 mm, which is exactly why this size is used on small stages and instrument slides. The no-preload build with 0.1 mm axial clearance is right where drag torque and cost matter and a few hundredths of backlash are acceptable; a reversing contouring axis wants a preloaded nut instead.

Fitting notes

Keep the nut on its shipping mandrel until it is transferred onto the shaft. Running the balls off the end of the circuit drops them, and a nut short of balls feels notchy immediately and fails early. Bolt through the flange with the flange face square to the shaft axis — a cocked mounting loads the single ball circuit unevenly and shortens life sharply on a one-circuit nut. Charge with a lithium-soap ball screw grease before first motion; the anti-rust oil it ships in is not a lubricant.

Interchange guidance

Also written BTK1404V-3.6ZZNUT (the nut-only order code), BTK1404 V-3.6ZZ, BTK1404V-3.6 and BTK1404V. The code AJF03502 carried on the earlier record is a THK internal or lot reference rather than a catalogue model number, and is retained here only as a search term. Related builds in the same series are BTK1404V-2.6ZZ (fewer loaded turns, lower rating) and BTK1405-2.6ZZ (5 mm lead) — different parts, not substitutes. Ball nuts are not interchangeable across manufacturers: an NSK, Hiwin, Kuroda, Rexroth or TBI nut of nominally 14 x 4 will not share the groove profile or ball size and will not run on a THK BTK shaft.