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5-Axis CNC Machining Robot Joint Holes to Tight Tolerance

Sendot Engineering Team· Custom ManufacturingJuly 28, 2026

This is 5-axis precision milling of a robot joint — 3D programming through to a finished workpiece, with the joint holes held to a tight tolerance so the joint runs true and the robot moves without play. On an articulated robot, the bore accuracy and position of the joint holes decide how repeatably the arm moves, which is why they are machined on a 5-axis setup that reaches every face without re-fixturing. See our 5-axis CNC milling service and send your CAD for a fast quote.

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Key takeaways

  • Why joint holes matter: a robot joint's repeatability depends on the bore accuracy and hole position — play in the joint becomes error at the end of the arm.
  • 5-axis, one setup: tilting and rotating the part reaches every hole and face in a single clamping, so the holes stay referenced to one datum and their positions hold.
  • Tolerance: ±0.05 mm on critical features, with tighter control on specific bores confirmed at quotation; surface to Ra 0.2 µm where a bearing or bushing seats.
  • Materials for robotics: aluminium for light structural parts, alloy & stainless steel and titanium where strength and wear matter — 30+ in total.
  • No MOQ — one prototype through repeat low-volume production; samples in 3–5 working days, quote within 12 hours. Backed by 20+ years (founded 2003) in precision hardware.

Why robot joint holes are machined on 5 axes

A robot joint carries a bearing, a bushing or a reducer, and its holes have to be both accurate in size and correctly located relative to each other. If a joint hole is bored slightly off, the error does not stay local — it is amplified along the length of the arm, so a few hundredths of a millimetre at the joint can become a visible position error at the tool. Machining the holes on a 5-axis machine lets the part be reached from every angle in one clamping, so all the holes are cut against the same datum. Re-fixturing to reach a second face would reset that reference and introduce exactly the position error a joint cannot tolerate. Learn more about our CNC machining services.

Custom robotics parts we machine

  • Joint and reducer housings — bores and hole patterns held to tight position tolerance
  • Structural links and brackets — see high-rigidity robot structural components
  • Materials: aluminium 6061/7075, alloy & stainless steel, titanium — 30+ in total
  • Tolerance: ±0.05 mm on critical features; CMM inspection and FAI reports on request
  • Volumes: no MOQ — one prototype or low-volume production

Frequently asked questions

Why machine robot joint holes on a 5-axis machine?
Because a robot joint's holes must stay accurately located relative to each other, and 5-axis machining reaches every face in one clamping. That keeps all the holes referenced to a single datum, so their positions hold. Machining them across multiple setups would reset the reference each time and introduce position error — which a joint amplifies along the arm into visible movement error.
What tolerance do robot joint holes need?
It depends on the bearing or reducer they carry, but joint bores are typically among the tightest features on the part. Sendot holds ±0.05 mm on critical features, with tighter control on specific bores confirmed at quotation, and surface finish to Ra 0.2 µm where a bearing seats. Tell us the fit class on your drawing and we will confirm what is achievable.
What materials do you machine for robotics parts?
Aluminium 6061 and 7075 for light structural parts where weight matters, alloy and stainless steel where strength and wear resistance are needed, and titanium for the highest strength-to-weight. That is part of 30+ materials in total. The right choice depends on load, weight target and duty cycle — tell us the application and we will suggest options in a DFM review.
Can you machine a complete robot joint from 3D programming?
Yes — from your 3D model we program the toolpaths, machine the part on a 5-axis setup, and inspect the critical bores and hole positions, with a CMM report and material certificate on request. Send a STEP file with a 2D drawing marking the joint holes and their tolerances, and you will have a quote and DFM review within 12 hours.
Is there a minimum order for custom robotics parts?
No. Sendot has no minimum order quantity on CNC machining — a single prototype joint or bracket is a valid order, and the same process scales to repeat low-volume production. CNC samples typically run 3–5 working days. Sendot has machined precision hardware since 2003, over 20 years.

Get your robotics parts quoted

Have a robot joint, housing or structural part that needs multi-axis machining to tight tolerance? Upload your CAD file on our Request a Quote page. Our engineers return a DFM review and price within 12 hours, with global shipping from prototype to low-volume production.

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