This is a line of Cnc Machined Knurled Knobs Handles produced on 3-axis and 5-axis CNC lathes, with straight and diamond knurl patterns that give you a non-slip grip under torque or oily shop conditions. You get a repeatable tolerance of ±0.005 mm on the bore and shank, a surface finish of Ra 0.8 µm, and a hardness range of 28 to 45 HRC depending on the material you choose. Every knob is deburred, passivated (for stainless), or black-oxide treated (for steel), and standard orders ship from our Dongguan factory in 7 days.
Knurl Patterns That Hold Up Under Repeated Torque
We cut knurls using CNC single-point rolling or cut knurling, not cheap press-forming. That means the diamond or straight teeth are burnished into the surface, so they do not peel or flatten after 5,000 cycles of hand tightening. Standard pitches are 0.5 mm, 0.8 mm, and 1.0 mm, but we can cut custom pitches down to 0.3 mm if your application needs ultra-fine grip. The knurl depth is held to ±0.05 mm, so you get consistent texture across every piece in the batch.
Materials and Heat Treatment We Use
We stock 1215 free-cutting steel, 303 and 316 stainless steel, 6061-T6 aluminum, and C36000 brass. For steel knobs, we offer induction hardening on the knurl area only, bringing the surface to 45 HRC while keeping the core at 28 HRC for toughness. Stainless and aluminum knobs are left at natural hardness but receive electropolishing to Ra 0.4 µm on the grip if you need cleanroom compatibility. Brass knobs are available with a matte nickel plating that adds corrosion resistance without changing the thread fit.
Bore and Shank Tolerances for Press-Fit or Set-Screw Mounting
If your knob mounts onto a shaft with a set screw, we hold the bore to H7 tolerance (e.g., 6 mm +0.012/0). For press-fit applications, we machine the bore to a custom tolerance of ±0.003 mm and can add a knurled drive ring on the inside diameter for extra pull-out strength. We also machine keyways, D-flats, or cross-holes for roll pins—send your drawing and we will lock the datum structure to your shaft spec. Runout between the bore and the outer knurl diameter is held to 0.02 mm TIR, so your knob spins true without wobble on high-speed adjustment spindles.
Inspection Before Every Shipment
Every batch gets a first-article inspection report (FAIR) with a CMM check on bore diameter, knurl pitch, and runout. We also do a 100% visual check for tool marks, burrs, or damaged knurl teeth under 2x magnification. For critical lots, we add a surface roughness test with a profilometer and a hardness test on the knurl teeth—if the teeth are too soft, they will deform under a 5 Nm torque wrench test, and we reject those parts before packing. Photos of the inspection results are emailed to you within 24 hours of shipment.
| Specification | Value / Range |
|---|---|
| Materials | 1215 Steel, 303/316 SS, 6061-T6 Al, C36000 Brass |
| Knurl Types | Straight, Diamond, Cross-cut (custom pitches 0.3–1.0 mm) |
| Knurl Depth Tolerance | ±0.05 mm |
| Bore Tolerance | H7 standard, ±0.003 mm for press-fit |
| Runout (bore to OD) | 0.02 mm TIR |
| Surface Finish Ra | 0.8 µm standard, 0.4 µm optional |
| Hardness (Steel) | Induction hardened 45 HRC (teeth), core 28 HRC |
| Size Range | OD 10–80 mm, length 10–120 mm |
| Lead Time | 7 days standard, 3 days for prototypes |
| MOQ | No MOQ (1 piece accepted) |
How We Handle Prototypes and Small Batches Without MOQ
Our CNC lathes and turning centers are set up for quick changeover, so we run 1-piece samples at the same cost per part as 100 pieces—only the setup fee changes. For a prototype, you pay a flat setup fee of USD 50, and we ship the part in 3 days via DHL. If you then place a production order of 200 pieces or more, we refund the prototype setup fee. This is our way of saying we trust our process and we want you to test the knob before you commit to a volume order.
Surface Finishes for Corrosion and Grip
Steel knobs get black oxide (MIL-DTL-13924) for a matte look that resists rust up to 96 hours of salt spray. Stainless steel knobs are electropolished to remove micro-burrs and improve passivation. Aluminum knobs get hard anodizing (Type III, 50 µm) that raises surface hardness to 60 HRC equivalent—this is your best choice if the knob will be used in a food or chemical washdown area. Brass knobs can be nickel-plated (5 µm) or left raw for a natural brass color that patinas over time.
Threaded Inserts and Custom Inserts for Molded Handles
If you are inserting a metal knob into a plastic or rubber molded handle, we can machine a threaded insert (brass or stainless) with an internal thread (M4 to M12) and an external knurl for anchoring into the molded material. The insert is machined with a blind or through bore, and we control the external knurl OD to ±0.05 mm so it locks into the mold cavity without flash. This is a common request for medical device handles and automotive shift knobs—we have tooling for 16 standard insert sizes and can make custom ones in 5 days.
What is the minimum order quantity?
No MOQ—we accept 1 piece for prototyping and 10 pieces for test runs, with the same tolerance and finish as a full production batch.
Can you customize the knurl pitch or shape?
Yes, we cut custom knurl pitches from 0.3 mm to 1.0 mm, and we can machine straight, diamond, or left-hand helix patterns by changing the CNC program or rolling die.
How do you guarantee quality on small orders?
Every order, even 1 piece, gets a CMM inspection and a visual check under magnification; we email the inspection report before packing.
What is the lead time for 5,000 pieces?
Standard production is 7 days, but for 5,000 pieces we add 3 days for full batch inspection, so expect 10 days door-to-door for DHL express.
For more on tool selection that affects knurl tooth quality, see our CNC cutting tool selection guide. To understand how we hold ±0.005 mm on bores and runout, check the CNC machining tolerances guide.
Send your knob drawing or sample for a firm quote within 12 hours. Email: sc@bquq.com. WhatsApp: +86 13713157787. We are a precision manufacturing company made in China, and we ship worldwide with no MOQ.
