Precision Grinding

Why Precision Grinding Outperforms Machining on Critical Components

Machining alone has a ceiling. On hard materials like duplex stainless steel, ceramics, and high-performance alloys, it can fall short of the tolerance and surface finish a critical component actually needs. Grinding picks up where machining stops:

• Exceptional surface finish — essential for coating adhesion and minimizing wear
• Minimal runout — vital on bearing diameters, where even a slight imperfection turns into vibration
• Precision sizing — keeps fits tight and reduces vibration over the part's service life

Vibration is the threat that grinding exists to manage. The more perfectly a shaft or bearing spins, the longer everything downstream of it tends to last.

Precision Grinding Capabilities

Cylindrical Grinding

HFW's cylindrical grinding services, also called OD grinding, finish the outer diameter of shafts, rolls, and rotating components to final tolerance. We offer both conventional cylindrical grinding and precision CNC grinding services, particularly for turbine shafts where repeatability and cycle time matter.

• Conventional: up to 30" diameter swing x 288" long
• CNC: up to 12" diameter swing x 80" long
• Tolerances from 0.0002" to 0.001", depending on the application

Internal Diameter (ID) Grinding

• Up to 36" ID x 24" stroke (part geometry can affect capacity)
• Routinely holds 0.0002" tolerances across that full size range

Surface Grinding

• 12" x 24" table capacity
• Holds tolerances as tight as 0.0002"

Superfinishing & Honing

• Superfinishing down to 2 Ra
• Honing up to 36" ID

Across cylindrical grinding, ID grinding, and surface grinding, HFW holds tolerances as tight as 0.0002" on parts that never see a coating booth. Grinding doesn't have to be paired with another HFW service to get HFW-level precision. We precision grind components on their own as often as we precision grind them as part of a larger job, and we regularly take on custom precision grinding work that doesn't fit a standard spec sheet.

Grinding Thermal Spray Coatings

A lot of what comes through our grind department has already been through HVOF, plasma spray, or a hardfacing weld overlay. That changes the job. Thermal spray coatings, especially tungsten carbide and chrome carbide, can be significantly harder than the base metal underneath them, and grinding a coated surface to a fine finish without losing the tolerance or the coating integrity is a distinct skill.

It's part of why customers come back to our grind department specifically: we handle hard coatings over a softer substrate often enough that it's simply routine for us. Our recent investment in a Palmary CNC cylindrical grinder (12" swing, 80" centers, 660-lb capacity) added faster cycle times on exactly this kind of work, on top of the tighter tolerances and finer surface finishes it supports.

EMRO Testing: How Perfectly Do Your Shafts Spin?

Unwanted shaft movement causes vibration, wear, and premature failure, and precision grinding is the step that controls it. Mechanical runout measures shaft roundness. However, some applications like turbine shafts need a closer look at electrical runout too, which is affected by material chemistry and heat treatment, not just geometry.

HFW offers electrical mechanical runout (EMRO) testing, using proximity sensors to measure both mechanical and electrical runout for a complete picture of shaft condition after grinding.

Industries We Serve

Chemical Industry

We work with everyone from plant sub-suppliers to Fortune 500 manufacturers on:

• Mixer components
• Pump shafts and housings
• Extruders, seals, plungers
• Centrifuges and hydraulic rams
• Processing rolls

Power Generation & Turbomachinery

For utilities and OEMs alike, from routine maintenance to emergency turnarounds:

• Turbine and turbocompressor shafts
• Inlet pipes and valve components
• Seal and bearing housings
• Pistons, rods, and rotor assemblies

Oil & Gas

Our work in refining and upstream/downstream operations includes:

• Compressor rods and pistons
• Shaft sleeves and spacers
• Journal and thrust housings
• Seal housings and balance pistons

Our grind department sees the same components again and again: turbine shafts, processing rolls, and the rotating components that keep a plant running. That repetition is where the experience customers are paying for actually comes from.

One-Source Reliability, When Grinding Is Just One Step

Most of what comes through HFW's doors needs more than one process. When it does, precision grinding sits inside a one-source model: machining, thermal spraying, hardfacing, grinding, and assembly, all in a single facility with one quality system.

• We quoted an emergency shaft assembly job in 25 minutes. Our typical turnaround on standard quotes is 1 to 3 business days.
• When a power generation OEM needed to move a delivery date up by nearly two weeks, we hit the new date and still shipped a week early.
• We support emergency and rush grinding jobs on their own, not only as part of a larger combined order.

Case Study: How Grinding Factors Into Vacuum Pump Assembly

One example of HFW's one-source repair services was a pump assembly. After pump disassembly and cleaning, our steps for the project included:

• Shaft and Rotor Assembly: Machine drive, seal and packing sleeve diameters. Machine to prepare cone fits of rotor for coating. Thermal spray with nickel-based alloy and finish.
• Cones: Thermal spray with nickel-based alloy and finish grind to assure proper fit with rotor.
• Heads: Pressure test, machine inboard face and pilot diameter for coating and thermal spray with nickel-based alloy and finish.
• Assembly: Assemble complete including bearings, seals, gaskets and packing along with dynamic balancing and painting as required.

We don’t just grind. We finish, coat, assemble, and deliver.

Why Choose HFW as Your Precision Grinding Company

Many precision grinding companies can quote a tight tolerance. Fewer can back it up with the equipment and track record to repeat it. Choosing the right precision grinding company, or grinding shop, often comes down to exactly that. Here's what a precision grinding service should be able to show you, and where HFW stands on each:

• Precision: Tolerances down to 0.0002"
• Capability: Over 15 precision grinding/finishing machines, including a CNC grinding machine
• Speed: Emergency and short lead times available
• Standalone Service: Grinding alone, no coating or machining required
• One Source: Integrated grinding, coating, hardfacing, machining, and assembly when a job needs it
• Trust: Long-term relationships with OEMs and the Fortune 500

Ready to Discuss Your Project?

Whether you need a single critical part or an ongoing production run, our engineers are ready to talk through your precision grinding needs.

Explore HFW's Grinding Services

• CNC Precision Grinding Services — our CNC cylindrical grinding capability and how we hold tolerance on coated and uncoated parts
• Internal Diameter (ID) Grinding Services — a specialty within a specialty

Frequently Asked Questions

What is precision grinding used for?

Precision grinding brings a component's surface finish, geometry, and size to tolerances that machining alone often can't reach, especially on hard materials like duplex stainless steel, ceramics, and high-performance alloys, or on surfaces that have already been thermal spray coated.

What's the difference between cylindrical (OD) and ID grinding?

Cylindrical grinding finishes a part's outer diameter, while ID grinding finishes the inner diameter of housings, bearing seats, and inner seals. HFW holds tolerances as tight as 0.0002" on ID work up to 36" ID x 24" stroke, and 0.0002" to 0.001" on cylindrical work depending on the application.

Does HFW offer precision grinding without coating or machining services?

Yes. Grinding is a standalone service at HFW that doesn't require bundling with thermal spray, hardfacing, or machining. We can also grind parts that have already been coated elsewhere or machined in-house by the customer.

Can HFW handle emergency or rush grinding jobs?

Yes. Standard quotes typically turn around in 1 to 3 business days, and we've delivered emergency quotes in as little as 25 minutes when a customer's schedule demanded it.

What tolerance can HFW hold on surface grinding?

HFW holds tolerances as tight as 0.0002" on surface grinding, the same standard we hold on ID work.

What is EMRO testing, and how does it relate to grinding?

Electrical mechanical runout testing measures both the mechanical and electrical runout of a shaft using proximity sensors, giving a complete picture of shaft condition that complements precision grinding work.

What materials can HFW grind?

Our grind department works with duplex stainless steel, ceramics, high-performance alloys, and thermal spray coatings including tungsten carbide and chrome carbide, on components like turbine shafts, processing rolls, and bearing housings.