Gear racks and pinions · Module 4–5 induction-hardened alloy steel racks, 20° pressure angle, HRC 50–60 teeth, about 1 m sections joined end to end, specified by module, face width, precision grade, backlash and strength
A rack and pinion turns rotation into straight-line motion: a pinion gear on a driven shaft meshes with a straight toothed bar, the rack, sold in sections such as the 1,005.31 mm racks reviewed here. Ask three things first: what force and speed the axis needs, which module, material and hardening carry that load, and what precision grade and backlash the positioning allows.
Spur and helical gear racks with their mating pinions for linear drives in machine tools, gantries, automation, lifting and door drives. Gear reducers (see gear reduction unit and planetary gear reducer), ball screws (see ball screws and linear motors), linear guides (see precision linear motion guide rail) and quarter-turn rack-and-pinion valve actuators (see pneumatic actuator) are outside this page except where compared.
01
KHK lists its SRFD4-1000HJ hardened rack at module 4 with 80 effective teeth, standard full-depth teeth at a 20° pressure angle, SCM440 (AISI 4140) alloy steel with tooth surfaces induction hardened to HRC 50–60, a 1,005.31 mm total length, 40 mm face width, 45 mm height and 41 mm height to the pitch line, six M12 mounting holes, a surface durability rating of 8,310 N·m, bending strength of 13,900 N·m and a weight of 12.6 kg. [1]
The module 5 version, SRFD5-1000HJ, has 64 effective teeth on the same 1,005.31 mm length, 50 mm face width, five M14 mounting holes, surface durability of 13,200 N·m, bending strength of 21,800 N·m and a weight of 17.2 kg, with the same material, hardening, pressure angle and precision grade. [2]
Editorial calculation: the circular pitch is π × module, 12.57 mm for module 4 and 15.71 mm for module 5, so 80 × 12.57 mm and 64 × 15.71 mm both give the listed 1,005.31 mm length; moving from module 4 to module 5 raises bending strength by about 57 % and weight per section by about 37 %. [1] [2]
Give the supplier the axis layout and travel, moving mass and forces, speed and acceleration, required positioning accuracy and backlash, module or strength needed, rack material and hardening, section length and joining, mounting surface and holes, pinion bore and fixing, lubrication, and quantity of sections.
02
Both KHK racks are made to KHK R 001 grade 5 precision with stated backlash ranges of 0.06–0.26 mm (module 4) and 0.07–0.28 mm (module 5), and are supplied with mounting holes for M12 or M14 screws. [1] [2]
Ask whether a precision grade is quoted to the maker's own standard, as KHK R 001 is, or to an international gear standard, and request the pinion's grade, the measured backlash for the pair and the method for aligning joined rack sections. [1]
03
ATLANTA Drive Systems' rack data, published through its distributor Bibus, lists its racks by quality class with total pitch error per 1,000 mm, tooth thickness tolerance and maximum feed force. All three classes below come in lengths up to 2,000 mm with 19°31'42" helical or straight teeth, hardened with ATLANTA's high-performance hardening process and ground on all sides. [3]
Q6 is offered in case-hardening or heat-treatable steel, while Q7 and Q8 are listed in heat-treatable steel. Set these class figures against the KHK module 4 and 5 racks above, which are specified by grade, backlash range and induction-hardened tooth surfaces rather than by feed force. [3] [1] [2]
Editorial calculation: Q7 allows about 1.5 times the pitch error of Q6 (0.052 / 0.034), and the Q6 maximum feed force is about 4.5 times that of Q8 (409 / 90.5 kN).
| ATLANTA rack class | Total pitch error GTf per 1,000 mm | Tooth thickness tolerance | Modules | Max. feed force |
|---|---|---|---|---|
| Q6 HPR (high precision) | ≤ 0.034 mm | −20 µm | 1.5–12 | 409 kN |
| Q7 | ≤ 0.052 mm | −36 µm | 2–10 | 287 kN |
| Q8 PR (precision) | ≤ 0.060 mm | −58 µm | 2–6 | 90.5 kN |
State the axis length, required positioning accuracy and feed force, and ask for the rack quality class, total pitch error per metre, tooth thickness tolerance, maximum feed force for your pinion and the joint alignment method between rack sections.
04
WITTENSTEIN alpha publishes its racks in three segments and states that the linear drive's technical data come from the interaction of gearbox, pinion and rack, not from the rack alone. Its racks span modules 1.5 to 8 mm, lengths of 167 to 2,000 mm and maximum feed forces of 2.3 to 135 kN, with helical teeth as standard and straight teeth only on request. [4]
All figures in the table are from WITTENSTEIN's racks page; the feed force and accuracy columns are for the complete Value, Advanced and Premium linear systems, and the 62.5 mm bore spacing is tied to its highest feed-force level. Lengths are available in intermediate steps depending on module, and custom lengths and bores are on request. [4]
Editorial calculation: the Value segment's ≥ 140 µm positioning figure is about 4.7 times the ≥ 30 µm stated for Advanced and Premium (140 / 30). Set these system figures beside the rack-only data above — ATLANTA's Q6 class at ≤ 0.034 mm (34 µm) total pitch error per 1,000 mm and KHK's grade 5 racks with 0.06–0.28 mm backlash — and ask each supplier whether a quoted accuracy belongs to the rack, the pinion pair or the whole drive. [4] [3] [1] [2]
| WITTENSTEIN segment | Rack modules (mm) | Rack lengths (mm) | Bore spacing (mm) | System max. feed force | System positioning accuracy (single drive) |
|---|---|---|---|---|---|
| Value | 1.5; 2; 3; 4 | 500–2,000 | 125 | 1.89–8 kN | ≥ 140 µm |
| Advanced | 2; 3; 4; 5; 6; 8 | 167–2,000 | 62.5 or 125 | 1.37–21 kN | ≥ 30 µm |
| Premium | 2; 3; 4; 5; 6; 8 | 167–1,000 | 62.5 or 125 | 5.45–112 kN | ≥ 30 µm |
When the rack is bought with a gearbox and pinion, ask for the system feed force, feed velocity and positioning accuracy for your exact module, pinion and gearbox combination, plus the rack bore spacing and length steps.
05
No manufacturer record has been confirmed for this product yet. Send your specification and CNFX will match it against manufacturer records.
Ask any supplier for module and pressure angle, helical or straight teeth, material and heat treatment with hardness, precision grade and its standard, section length and end machining for joining, mounting holes, strength ratings, pinion dimensions and bore options, backlash, surface treatment, and drawings.
06
This is a functional reference built from the sources cited; it is not one maker's specification.
07
A rack and pinion quotation needs values for your axis. The table explains each field, gives published values where a reviewed source states them, and says what to obtain from the supplier.
| Field | What it means and published values | Ask the supplier for |
|---|---|---|
| Module (mm) | e.g. 4 or 5. [1] [2] | Module. |
| Number of Teeth | e.g. 80 or 64 per 1,005.31 mm rack. [1] [2] | Rack and pinion teeth. |
| Pressure Angle (°) | e.g. 20°. [1] | Angle. |
| Face Width (mm) | e.g. 40 or 50 mm. [1] [2] | Width. |
| Tooth Hardness (HRC) | e.g. HRC 50–60, induction hardened. [1] | Hardness; depth. |
| Accuracy Grade (DIN) | Not stated in the reviewed sources. One maker quotes its own KHK R 001 grade 5. [1] | Grade; standard. |
| Max Linear Speed (m/s) | Not stated in the reviewed sources. | Speed limit. |
| Max Load Capacity (kN) | Not stated in the reviewed sources. Strengths given as 13,900–21,800 N·m bending. [1] [2] | Allowable force. |
| Operating Temperature (°C) | Not stated in the reviewed sources. | Range. |
| Material | e.g. SCM440 (AISI 4140). [1] | Grade. |
| Surface Treatment | Not stated in the reviewed sources. | Treatment. |
| Weight (kg/m) | e.g. 12.6 kg and 17.2 kg per 1,005.31 mm section. [1] [2] | Weight. |
| Quality class and feed force | Q6: ≤0.034 mm/1,000 mm, 409 kN; Q8: ≤0.060 mm, 90.5 kN (ATLANTA). [3] | Class, pitch error, feed force. |
08
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Axis: [travel; layout; mounting] Load: [moving mass; force; acceleration] Speed: [m/s] Accuracy: [positioning; backlash] Rack: [module; material; hardening; length] Pinion: [teeth; bore; fixing] Grade: [precision; standard] Quantity: [sections; pinions]
No manufacturer record has been confirmed for this product yet. Send your specification and CNFX will match it against manufacturer records.
Its website lists precision gear racks and rack-and-pinion drive sub-assemblies.
Product scope checked 2026-10-12
Its website lists a gear and rack series.
Product scope checked 2026-10-12
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
It sets tooth size; KHK's module 4 rack has 80 teeth and module 5 has 64 on the same 1,005.31 mm length. [1] [2]
KHK induction-hardens SCM440 rack teeth to HRC 50–60. [1]
KHK lists 0.06–0.26 mm for module 4 and 0.07–0.28 mm for module 5. [1] [2]
ATLANTA's Q6 high-precision rack lists a total pitch error of ≤0.034 mm per 1,000 mm, against ≤0.052 mm for Q7 and ≤0.060 mm for Q8. [3]
Sources checked 2026-10-12. KHK makes standard metric gears and racks. WITTENSTEIN alpha's racks page adds a third rack maker's module, length, feed-force and positioning data for complete linear systems.
Ask for use case, specification boundaries, supplier type, and RFQ preparation information for this product.
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