Custom Machined Inserts
Resolute Precision Manufacturing produces custom CNC machined inserts threaded inserts, press-fit inserts, key inserts, and specialty retention hardware on Swiss CNC machines and bar-fed lathes. We manufacture inserts to your drawing in brass, stainless, steel, and aluminum from prototype quantities through high-volume production. Direct from the shop 24-hour quote response. Request a QuoteWhat a Custom Machined Insert Does
An insert is a machined component that is installed into a parent part typically pressed, threaded, or bonded into a drilled or bored hole to provide a feature that the parent material cannot supply directly. The most common application is a threaded metal insert in a softer parent material such as aluminum, plastic, or wood. The insert provides a durable metallic thread in the softer parent, enabling repeated assembly and disassembly without thread wear in the parent material.
Other insert types include press-fit pins, retention clips, bushing inserts for bearing housing, key inserts for spline and keyway applications, and specialty inserts for electrical conductivity or thermal management.
Our Services
Swiss CNC for Small-Diameter Inserts
Many threaded and functional inserts are small-diameter components M3 through M12 threaded inserts, for example, range from 4mm to 15mm in outer diameter. These are ideal parts for Swiss CNC machining: small diameter, complex features including external knurling, internal threads, external threads, and slotted drive features, all completed in one cycle.
Resolute Precision’s Swiss CNC machines in the 20mm and 32mm sizes efficiently produce inserts in this size range, delivering consistent dimensional quality across high-volume production runs.
Specifications
| Machines | Swiss CNC (20mm, 32mm, and 38mm) for small inserts; bar-fed lathes for medium-sized parts |
| Diameter Range | 3/8″ to 3.2″ standard bar-fed; smaller diameters on Swiss CNC machines |
| Internal Threads | Any thread form—metric, unified, pipe, or custom—machined on the ID |
| External Features | Knurled OD for press fit; slotted, hex, or Torx drive; grooved OD for bond-in inserts |
| Retention Features | Diamond knurl, straight knurl, serrated knurl, and grooves for epoxy or press-fit retention |
| Metals | Brass (360) — most common; stainless steel (303/304/316); steel (1018/4140); aluminum (6061) |
| Tolerance | External diameter: ±0.0005″ for press-fit inserts; internal threads: Class 2B or tighter |
| Volume | 1,000 to 5,000,000+ inserts per year |
| Certifications | ISO 9001:2015 |
Common Insert Types and Applications
Resolute Precision produces a complete range of insert types for diverse assembly and fastening applications:
- Threaded inserts for plastic and aluminum — brass or stainless with knurled OD for press or heat installation
Helical thread inserts (Heli-Coil style) — custom sizes not available in catalog form
Key inserts and Woodruff key slots — precision steel inserts for torque transmission
Press-fit dowel inserts — precision diameter stainless or steel inserts for hole reinforcement
Electrical contact inserts — brass or copper inserts for EMI shielding and grounding applications
Thermal insert slugs — copper or brass inserts for heat dissipation in plastic housings
Frequently Asked Questions
What is the most common material for threaded inserts?
Brass 360 is the most common material for threaded inserts installed in plastic, aluminum, and soft metal parent parts. It provides excellent machinability, good corrosion resistance, and adequate thread strength for most assembly requirements. Stainless steel is used where corrosion or higher thread strength is required.
What OD tolerance is required for a press-fit insert?
Press-fit inserts require the insert OD to be slightly larger than the parent hole — typically 0.001″ to 0.003″ interference depending on material combination and insert size. Resolute Precision machines press-fit insert ODs to ±0.0005″ to ensure reliable and consistent installation force across the production lot.
Can RPM produce inserts with knurled ODs for installation in plastics?
Yes. Diamond knurl, straight knurl, and custom knurl patterns are standard on our turning centers. Knurling increases the retention force of a pressed or molded-in insert by engaging the parent material across a larger surface area.
What is the minimum insert size RPM can produce?
Our Swiss CNC machines handle inserts from approximately 3mm to 38mm outside diameter. In practical terms, we regularly produce M2×0.4 threaded inserts with a 4mm OD on our 20mm Swiss machines.