Wexmar provides custom fixtures and jigs machining for manufacturers that need workholding, drill jigs, assembly fixtures, weld fixture components and inspection fixtures built to their designs. Our Canastota, New York shop has a tool room alongside production, and we use the same fixturing practices on our own machines every day.
What fixtures and jigs do and who buys them
A fixture holds a part in a known, repeatable position for machining, assembly, welding or inspection. A jig does the same and also guides a tool, most often a drill through hardened bushings. Good fixtures reduce setup time, cut scrap and make results independent of the operator. Buyers include manufacturing engineers at OEMs, contract machine shops that need extra fixture capacity, assembly and welding operations, quality departments building check fixtures, and defense and aerospace programs with dedicated tooling requirements.
How we machine CNC fixtures
Fixture plates, tombstone faces, sub-plates and fixture bodies are machined on our six Mazak horizontal machining centers: two FH4800s, a PFH4800, a Nexus 4000-II and two Nexus 5000-II machines with pallet changers and 4th-axis rotaries. The horizontal lets us machine locating features on several faces of a fixture body in one setup, so every locator, clamp pad and bushing hole is in position to a common datum. These are 3- and 4-axis machines, and compound-angle features are handled with angle plates and setups we plan with you.
Locating pins, rest buttons, drill bushings, clamp studs and diamond pins are turned on our Mazak and Doosan lathes or our Maier Swiss machines, then ground to size on our centerless grinder. Fixture plates and wear pads are finished flat on our surface grinder. The tool room handles fitting, assembly and adjustment. See horizontal CNC milling and capabilities.
Fixture materials
- Aluminum: 6061-T6 and MIC-6 cast plate for light, stable fixture bodies.
- Steel: 1018, A36 and 4140 pre-hard for rigid fixture bases and tombstone faces.
- Tool steels: O1, A2, D2 and S7 for locators, bushings and wear components, hardened through outside processors.
- Others: bronze for wear strips, and engineered plastics such as acetal, UHMW and nylon for non-marring nests.
Critical fixture features and how we hold them
- Locator position: dowel and locator holes bored or reamed in one setup and verified on CMM.
- Datum surface flatness: rest pads and base plates surface ground after machining.
- Drill bushing location: liner and bushing holes bored to position for press fit, with bushings to ASME B94.33 styles or custom.
- Repeatability: ground dowels and slip-fit diamond pins so the part or fixture locates the same way every time.
- Clearance and chip control: relief cuts and drainage paths so chips do not interfere with locating.
Typical tolerances and finishes
| Feature | Typical tolerance | Tighter on request |
|---|---|---|
| Locator hole position | ±0.001 in | ±0.0003 in |
| Reamed dowel hole | +0.0005 / -0.000 in | +0.0002 / -0.000 in |
| Rest pad flatness | 0.0005 in | 0.0002 in (ground) |
| Ground locating pin diameter | ±0.0002 in | ±0.0001 in |
| Parallelism of base | 0.001 in | 0.0003 in |
| Ground surface finish | 16 Ra | 8 Ra |
Secondary operations
Heat treat for tool steel locators and bushings, black oxide, anodizing, nitriding and welding of fixture bases are performed through qualified outside processors. Wire EDM, when a design needs it, is also arranged through qualified outside processors. We grind hardened components after heat treat in-house and assemble and check complete fixtures in our tool room.
Quantity patterns
Fixtures are usually one-off or small sets: a single machining fixture, duplicate fixtures for multiple machines, or a family of fixtures for a product line. Replacement locators, bushings and wear pads are ordered in small quantities as fixtures age.
Inspection
Complete fixtures are measured on our Brown & Sharpe CMMs to confirm locator positions relative to datums, with CMM reports supplied on request. Ground components are measured with calibrated micrometers and gage blocks. See inspection and quality.
Getting a quote
Send fixture drawings or a 3D model, along with the part it will hold and the process it supports. You can upload a drawing for an instant estimate, and an estimator will confirm pricing. Or call (315) 400-2654. Related: tooling components and dowel pins.