Descrição
Precision Ground Helical Rack
Helix Angle 19°31’42” | Four-Side Ground + Tooth Surface Ground | High-Load Linear Transmission
Trusted by UK automation engineers, machine builders and OEMs across Europe
When a linear drive system has to deliver both accuracy and sustained load capacity, the choice of rack becomes the most consequential engineering decision on the machine. Our Precision Ground Helical Rack is manufactured to DIN6 Grade 5 tolerances, combining a precisely controlled helix angle of 19°31’42” with a four-side flat-ground body and a fully ground tooth flank surface. The result is a helical rack that delivers noticeably lower noise, smoother motion and higher torque transmission efficiency compared with standard cut or milled alternatives — without adding complexity to the mounting arrangement.
The rack is produced in two core material grades — S45C medium-carbon steel for general industrial use and 42CrMo alloy steel for demanding high-load or shock-heavy applications. Both are heat-treated to achieve a surface hardness of HRC 48–55: the S45C variant through induction hardening and the 42CrMo grade through carburising and case hardening. After hardening, every rack undergoes precision four-side flat grinding followed by dedicated tooth-face grinding to restore geometry and eliminate distortion introduced during heat treatment — a production step that separates genuine precision racks from those simply labelled as such.
Available in modules from 1.5 to 12 and in standard lengths of 500 mm or 1,000 mm, these helical racks are widely used in CNC gantry systems, high-speed linear axes, robotic transfer units and heavy-duty portal structures. Drill-hole patterns are included as standard; no-hole variants (suffix “N”) are available on request. Custom dimensions, materials and special configurations can be arranged directly with our engineering team.
Response within 24 hours · Custom sizes available · UK & EU delivery
Why Engineers Choose This Helical Rack
Material, Design Principle & Application Scenarios
▶ How the Helical Rack Works
A helical rack converts rotary motion from a mating helical pinion into precise linear displacement. Unlike a straight rack where the full tooth width engages instantaneously, the angled tooth form of our helical rack (helix angle 19°31’42”) allows engagement to progress gradually across the tooth face. This overlap increases the contact ratio, spreads load more evenly, and suppresses the impulse forces that cause vibration and pitch error accumulation in high-speed or high-load straight rack drives. The right-hand helix direction is consistent across all standard models, making the mating pinion selection straightforward.
▶ Material Selection Guide
S45C (Induction Hardened, HRC 48–52): Medium-carbon steel with good machinability and adequate toughness for the majority of general automation, gantry crane travel, and conveyor drive applications. Cost-effective for high-volume machine builds where ultra-high-cycle fatigue is not the dominant failure mode.
42CrMo (Carburised, HRC 50–55): Chromium-molybdenum alloy steel providing superior core strength and impact toughness alongside the highest surface hardness available in this product range. The preferred choice for heavy CNC machining centres, forging transfer lines, stone-cutting portals and other applications subject to shock loads or abrasive environments.
▶ Typical Application Sectors
- CNC machining centres — X/Y gantry and cross-slide axes
- Automated storage and retrieval systems (AS/RS)
- Industrial robots and servo-driven transfer units
- Wood and stone processing portal machines
- Plasma, laser and waterjet cutting tables
- Large-format 3D printing and additive platforms
- Wind turbine pitch adjustment mechanisms
- Overhead crane and gantry crane travel drives
- Agricultural machinery steering columns
- Semiconductor wafer-handling linear stages
Key Product Specifications
Technical Specification — Full Dimensional Data
Pe (End Face Pitch) = Module x pi / COS(19°31’42”) | Fp = Total Pitch Error | Unit / Dimension: mm
* Racks without drill holes: add suffix “N” to the model code (e.g. 552-010-050N). Different sizes and materials available on request — contact our engineering team for customisation.
* All specifications and model parameters are subject to change without prior notice. Please confirm with us before placing your order.
Related Products in Our Rack Range
For projects where a helical tooth profile is not required, or where budget-conscious procurement is a priority, we offer two complementary straight rack products that share the same manufacturing standards and supplier network. The Q&T Straight Rack is a quenched-and-tempered option suited to medium-precision linear applications where hardness uniformity and dimensional stability after heat treatment are the primary requirements. For applications demanding the highest geometric accuracy in a straight tooth form, the Precision Ground Straight Rack delivers a ground tooth profile comparable to our helical model but without the helix angle — commonly specified for applications where axial (thrust) forces on the pinion shaft need to be kept to zero.
Customer Success Story
West Yorkshire CNC Machine Builder — UK · 2024
Upgrading Gantry Axis Drives on a 5-Axis Machining Centre Range
A West Yorkshire-based manufacturer producing five-axis heavy-duty machining centres for the UK aerospace and defence sector had been experiencing progressive positioning drift and elevated noise levels on the X-axis gantry drives of their flagship machine line. The existing straight rack-and-pinion setup, sourced domestically, was producing pitch-error accumulation beyond the 0.05 mm threshold that their aerospace clients required. After a two-week qualification trial with our Module 6 Precision Ground Helical Rack (42CrMo, HRC 50–55), their metrology team recorded cumulative pitch errors below 0.02 mm across a 3-metre travel span. Noise levels dropped by an estimated 40% at rated traverse speed, removing the need for acoustic enclosures that had been under consideration. The manufacturer has since standardised on our helical racks across all gantry axis variants in their machine range.
~40% noise reduction
Standardised across machine range
What Our Customers Say
“We’ve fitted these helical racks to 14 gantry machines over the past two years. The dimensional consistency between batches is excellent — our fitters rarely need to adjust the pinion mesh depth after installation, which saves real time on the shop floor.”
CNC Machine Tool OEM, West Midlands, UK
“The 42CrMo grade with HRC 50–55 hardness was exactly what we needed for our stone-cutting portal — the previous racks were showing wear within three months. These have now run for over a year with no measurable tooth surface degradation. Good price, quick delivery from stock.”
Stone Fabrication Equipment, Edinburgh, UK
“We specified these for a large-format laser cutting table build. The DIN6 Grade 5 accuracy gives us confidence in the interpolation, and the noise level is noticeably lower than the milled helical racks we used previously. Enquiry to delivery was straightforward and the technical team answered our questions about matching pinion selection promptly.”
Laser Systems Integrator, Manchester, UK
Manufacturing Capability & Custom Orders
Our production facility operates dedicated CNC gear grinding lines specifically configured for helical rack manufacture, capable of maintaining DIN6 Grade 5 tolerances across modules 1.5 through 12 as a standard process — not an exception. Each production batch undergoes gear measurement centre inspection with full dimensional reporting available on request.
Beyond the standard range, we actively support custom engineering requirements. Whether your project calls for a non-standard module, an unusual cross-section profile, a specific mounting hole pattern, an extended or shortened length, a helix direction change, stainless steel or other alloy material, or a specialised surface coating such as black oxide or hard chrome, our engineering team works directly from your drawing. We have supplied custom helical racks to UK, German, Italian and Australian machine builders and are experienced in meeting CE marking documentation requirements for machinery directive compliance. If you cannot find the exact specification in the standard table above, that is the best time to get in touch.
Email: sales@farm-equipment-parts.com · Custom drawings welcome
Frequently Asked Questions
Ready to specify Precision Ground Helical Racks for your next UK project?
