You are here: Through-hole and Blind-hole Rivet Nut Operation Points and Pre-drilled Hole Processing Requirements - BISUDI
Through hole and blind hole (closed) are the two most common rivet nut end structures, with different processing requirements and operation details. Many on-site problems such as uneven bulge, screw that cannot withdraw, and leakage stem from mixing the two or failing to machine the pre-drilled holes as required. This article organizes the operation points and processing requirements into a version that can directly train workers.
I. Differences between through-hole and blind-hole types
| Comparison Item | Through-hole Type (open) | Blind-hole Type (closed) |
|---|---|---|
| Structure | The shank is open, the screw can pass out of the tail end during pull riveting | The tail end is closed into a dome, the screw does not pass through |
| Pre-drilled hole | Machine round or hexagonal holes per the specification table | Also per the specification table, but more sensitive to hole diameter tolerance |
| Sealing performance | Does not prevent leakage | The closed end blocks liquid and moisture, usable for liquid/gas-tight positions |
| Typical uses | General connections such as cabinets, brackets and internal appliance parts | Water tanks, oil tanks, piping, outdoor cabinets, chassis parts |
| Inspection focus | Bulge, thread go/no-go, plate surface | In addition to the above, check the closed end for puncture or leakage |
II. Pre-drilled hole and plate thickness requirements
Rivet nut outer diameter D, mounting hole diameter d and plate thickness G correspond one-to-one, and each specification catalog gives the recommended hole diameter and plate thickness range. Note during machining: control hole diameter to the recommended value - too large means the nut loosens and follows rotation, too small means it will not insert or the bulge is abnormal; the plate thickness a given nut fits has upper and lower limits, and the total stacked thickness must fall within the range; the hexagonal hole's six-sided dimensions and orientation must be accurate, for which a dedicated punch is recommended; the hole perimeter must be free of burrs, obvious edge collapse and weld spatter, otherwise seating is incomplete. The equipment only provides stable pull riveting, and unqualified holes cannot be compensated by the equipment.
III. Standard operation steps
1) Install the screw and rivet head matching the nut specification, and confirm the gun is switched to the corresponding program; 2) the nut automatically screws onto the screw (for manual models, screw it into place by hand); 3) keep the gun head perpendicular to the plate surface, insert the nut into the pre-drilled hole and seat it tightly - no angled insertion and no gap; 4) start pull riveting, and the equipment automatically completes pulling/bulging, setting and screw reversal/withdrawal; 5) visually inspect the bulge and plate surface, and check the thread with the corresponding screw or go/no-go gauge; 6) for blind-hole parts additionally confirm the backside closed end is intact. Throughout, "perpendicular, seated, no gun wobble" are the three basic action requirements.
IV. First-article inspection and in-process sampling
After each shift start, nut batch change, specification change or worker change, the first piece must undergo first-article confirmation: rivet 3-5 consecutively, check whether the bulge is symmetric, whether the plate surface is depressed, and whether the thread go/no-go passes, and do leakage or closed-end inspection for blind-hole parts; in mass production, sample at fixed intervals and do necessary pull-out/torque tests. Stop immediately upon a single-piece anomaly and troubleshoot per the fault table; common faults are inRivet Nut Gun Common Faults and Installation Problem Troubleshooting。
V. Common operation defects and prevention
| Defect | Cause | Prevention |
|---|---|---|
| Bulge skewed, nut crooked | Angled gun, large hole, not seated | Seat the gun perpendicularly, control hole diameter, use a positioning fixture |
| Plate surface crush/depression | Rivet head mismatch, excessive pulling force, countersink too deep | Change to a matched rivet head, adjust stroke/pulling force, verify countersink |
| Blind-hole end puncture and leakage | Excessive pulling force, plate thickness below lower limit, wrong specification | Select by plate thickness, do leakage inspection on the first article |
| Screw withdrawal damages threads | Screw wear, withdrawal before setting | Replace the screw, confirm the full pull-riveting stroke |
Operation Points FAQ
Through/Blind Hole FAQ
For the same thread specification the same screw can generally be used, but confirm the rivet head and program by type; the blind-hole stroke setting differs, so do a first article on changeover.
It must be tightly seated to the plate surface so the closed end forms correctly and sealing is ensured; a gap causes incomplete bulge and a leakage hazard.
Watch three points: whether the gun is perpendicular to the plate, whether the rivet head is seated, and whether the gun wobbles during pull riveting; the manufacturer teaches these item by item during on-site training.
Trial-rivet with real plate-thickness coupons, do thread go/no-go, appearance and pull-out/torque tests, add leakage verification for blind-hole parts, and only mass-produce after passing.
Unsure about through/blind hole process? On-site trial riveting
The manufacturer can bring machines to verify forming and sealing on-site with customer workpieces, consultation hotline +86 13556668682.
VI. Positioning fixtures and error-proofing measures
In mass production, hole position consistency is ensured by fixtures: for regular parts such as door panels and mounting plates it is recommended to make positioning fixtures or profile tooling, so that once the workpiece is placed the holes naturally align with the gun head and the worker only needs to seat the gun and start, preventing angled riveting and reducing labor intensity; at stations mixing multiple nut specifications, use color or marking distinctions on screws, rivet heads and trays, and confirm item by item against a checklist on changeover to prevent through/blind hole mixing and M5/M6 misassembly. For stacked plate connections, confirm the two layers' holes are coaxial and the mating faces are seated, as gaps let the bulge form in the seam and cause looseness; for blind-hole parts it is recommended to add backside support to the fixture to avoid plate deformation when the closed end forms.
The closed and open ends are distinguishable to the naked eye; it is recommended to store them in specification-specific bins with markings, use independent channels for different specifications on auto-feed equipment, and have the team leader double-check at first article and changeover to error-proof by process.
Further reading:Pull Rivet Nut Types and Selection Comparison · Maintenance Items and Wear Parts · Automatic Rivet Nut Gun
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