Wexmar provides custom knob and handle machining for equipment builders, instrument makers and government programs that need controls with a specific feel, fit and finish. Our Canastota, New York shop produces CNC machined knobs, pull handles, crank handles and grips on CNC lathes, Swiss-type machines and horizontal machining centers, from prototype sets through production releases.
What knobs and handles do and who buys them
A knob or handle is the part of a machine the operator touches. It must transmit torque or pull force without slipping, locate correctly on a shaft, and hold up to handling and cleaning. Typical buyers include:
- Instrumentation and test equipment makers needing precision control knobs
- Industrial OEMs building machine tools, valves and fluid power equipment
- Medical hardware builders with cleanable stainless or plastic grips
- Defense and government build-to-print programs with ruggedized controls
How our custom knob and handle machining works
CNC lathes with live tooling
Round knobs, knurled thumb screws and turned pull handles run on our Mazak and Doosan lathes. Live tooling and Y-axis add set screw holes, flats, indicator lines and finger scallops in the same setup, so the grip features stay aligned to the shaft bore. See our CNC turning page.
Swiss machining for small knobs
Small instrument knobs and thumb screws up to 32 mm diameter run on our Maier MLK-32 Swiss-type machines, where a knob can be turned, knurled, drilled, tapped and parted off complete.
Horizontal milling for handles
Bridge-style pull handles, offset crank arms and non-round grips are milled on our Mazak horizontal machining centers. The 4th axis indexes the part so both mounting holes and the grip profile are cut from one datum.
Typical materials
- 6061 and 7075 aluminum, the common choice for anodized knobs and handles
- 303 and 316 stainless for washdown, medical and marine use
- Brass for decorative or instrument controls
- Carbon steel for heavy crank handles, usually black oxided or plated
- Engineered plastics such as acetal and PEEK for insulated or lightweight grips
Critical features and how we hold them
- Shaft bore and D-flat: bored to fit the control shaft without play; D-flats and splines are checked with mating gages.
- Set screw and thread: tapped holes are gaged to class and positioned relative to the bore flat.
- Knurl quality: diamond or straight knurls are formed to a consistent pitch and depth, with clean ends.
- Mounting hole spacing: on pull handles, hole centers are held by the machining center so handles drop onto panel holes without binding.
- Cosmetic surfaces: tool paths and edge breaks are planned for anodize, so visible faces are uniform.
Typical tolerances and finishes
| Feature | Typical tolerance | Tighter on request |
|---|---|---|
| Shaft bore | +/-0.001 in | +/-0.0005 in |
| Outside diameter | +/-0.005 in | +/-0.002 in |
| Mounting hole spacing | +/-0.005 in | +/-0.002 in |
| Tapped threads | Class 2B | Class 3B |
| Bore to OD concentricity | 0.003 in TIR | 0.001 in TIR |
| Cosmetic surface finish | 63 Ra | 32 Ra |
Values are typical for knobs and handles. Your quote will state what we hold on each feature.
Secondary operations
Anodizing in clear or color, black oxide, plating, powder coat, passivation and laser marking are completed through qualified outside processors. We plan machining around the finish, including masking notes and thread allowances.
Design notes for knobs and handles
Generous outside radii and consistent wall thickness reduce machining time and give anodize a more even color. Specifying a set screw at 90 degrees to a D-flat, rather than on the flat itself, often gives better holding. For pull handles, blind tapped mounting holes keep the grip face clean, and a thread depth of about 1.5 times the diameter is usually enough. If a knob carries an indicator line or scale, tell us whether it is machined, engraved or marked after finish so we can plan the sequence.
Quantity patterns
Knob and handle orders range from sets of 10 to 50 for a new machine design to repeat production of a few thousand per year. Programs are saved so repeat runs start quickly. Sibling parts often ordered with controls include levers, links and clevises.
Inspection
Bores, threads and hole positions are checked with gages and our Brown and Sharpe CMMs, and knurl profiles and edge breaks with the Mitsubishi optical comparator. FAI in AS9102 format, CMM reports and material certs are available.
Getting a quote
Send the drawing with material, finish and color callouts and quantity. You can upload a drawing for an instant estimate, and an estimator will confirm price and lead time. Call (315) 400-2654, Monday through Friday, 7 to 4 Eastern.