Overview
A star knob gives the fingers a firm hold on a threaded fitting, so a clamp, a jig or a machine cover can be tightened by hand and released again without a wrench. Six recesses run around the rim, which lets the fingers sit in the gaps between the lobes and turn the knob with the fingertips or the palm. A metal threaded insert is set into the centre of the body, so the knob turns onto a stud and takes the load on a metal thread rather than on plastic.
The insert sits below the top rim, which keeps the thread clear of the hand and leaves the flat top of the knob free.
Because a star knob is molded around the insert, the six lobes and the centre bore are formed in one cycle, so the insert stays concentric with the rim and the lobes keep the same shape on every knob.
Our threaded insert knob carries a diamond knurl band rather than a lobed rim, which suits a smooth round grip, while this star knob uses the six recesses to take a heavier hand load. Our plastic control knob is the smaller grip that mounts onto a shaft with a plain bore and no insert at all.
Key Features & Benefits
– Six-lobe rim — fingers sit in the recesses
– Metal insert — internal thread at the centre
– Hand tightening — no tool needed
– Recessed top — keeps the insert below the rim
– Size range — molded in several diameters
Customization Options
Body diameter, body height, lobe depth, lobe count and insert depth are all set by your 3D file, and the insert thread is cut to the specification your stud calls for. We mold the body in PA6, ABS, POM and glass filled nylon in any colour, and set the insert in during molding so the thread stays square to the body. A revised star knob usually needs only a tool insert change, so a new diameter keeps the same insert.
Quality & Delivery
Each star knob is checked for body diameter, body height, lobe depth and insert depth, and the insert is gauged for concentricity with the rim before packing. First articles are sent for approval, so a star knob arrives ready to fit. Send your 3D file through our quotation page and we will confirm material, colour and lead time.
Related Capabilities
A star knob is molded in the same shop as our threaded insert knob, which uses a knurled band for the grip, and our large knurled knob, which is the wide disc version for a stiff turn. All of them are produced in house under our injection molding service.
