TL;DR
For high-strength bolted joints within the RCSC Specification’s scope, mechanically guided thermally cut holes are permitted in statically loaded joints and cyclically loaded slip-critical joints when their surface-roughness profile is no more than 1,000 microinches; connection details and project requirements still govern.
- Check the project’s joint designation: “pretensioned” and “slip-critical” are distinct. Written EOR approval is required for freehand thermal cutting of bolt holes and for thermal cutting in cyclically loaded pretensioned joints.
- A CNC beam drill line is a production option, not a code requirement. For a PBD 13, verify the offered configuration against actual member profiles, sizes, weights, hole locations, tooling and programming needs; product features alone do not establish job fit.
- Compare drilling and thermal cutting on the same representative jobs, including processing, finishing, inspection, setup and material movement. Shop-specific data is needed to establish cycle time or cost.
For high-strength bolted joints within the RCSC Specification’s scope, mechanically guided thermally cut holes are permitted in all statically loaded joints and cyclically loaded slip-critical joints if the holes meet the specified surface-roughness limit. The connection details and applicable project requirements govern; a CNC beam drill line is a production option, not a universal code requirement.
Thermally cut holes have defined limits
The June 5, 2025 RCSC Specification supersedes the June 11, 2020 edition and places the thermal-cut-hole surface-roughness limit in Section 3.3. That section sets a maximum surface-roughness profile of 1,000 microinches, as defined by ASME B46.1, for mechanically guided thermally cut holes.
Two approval conditions matter: freehand thermal cutting of bolt holes requires written Engineer of Record (EOR) approval, as does thermal cutting in cyclically loaded pretensioned joints. RCSC uses “pretensioned” and “slip-critical” as distinct joint classifications, even though slip-critical joints rely on pretensioned bolting assemblies. Check the joint designation in the project documents rather than inferring it from how the bolts will be installed; send an unclear classification to the EOR.
When complete connection design is not shown in the design documents, the party responsible for connection design, fabrication, or erection, as applicable, must notify the EOR of the hole types and dimensions to be used. Hole-making convenience does not authorize a different hole type or override project-specific requirements.
Where a CNC beam drill line fits
A CNC beam drill line gives a structural fabricator a dedicated drilled route for specified connection-hole patterns. The PBD BEAM DRILLING MACHINE is the assigned machine example; whether it fits depends on the actual member mix, hole requirements, and workflow, not on a general preference for drilling.
The Prodevco PBD 13 has three drilling heads and sub-axis positioning for simultaneous drilling on all faces, including when holes are not aligned; its software uses DSTV (.NC1) files. Treat those as PBD 13 product details, not a guarantee that every configuration or job is suitable. Confirm the offered configuration against representative member profiles, sizes, weights, hole locations, tooling, and programming requirements.
Drilling and thermal cutting also place different demands on the operation. A thermally cut route must achieve and verify the applicable surface quality, and finishing may be necessary if a cut does not meet the limit. A drilled route requires appropriate tooling and machine capacity. For recurring work, compare both permitted routes using the same representative jobs, including processing, finishing, inspection, setup, and material movement; shop-specific data is needed to establish cycle time or cost.
Let the connection detail shape the production decision
Start with the specified hole type, joint classification, loading condition, and any project-specific restrictions. Then establish whether the thermal-cut method is mechanically guided, which surface-quality limit applies, and whether written EOR approval or notification is required. If the project documents do not resolve those points, settle them before assigning the hole-making route.
Once the permitted process is clear, compare the actual member envelope and pattern mix with the proposed drill-line configuration and the shop’s current cutting, drilling, finishing, inspection, and handling sequence. A dedicated beam drill line can be worth evaluating for recurring profiles and patterns, but neither the standard nor the machine name alone establishes the right route for a particular job.
I’m Dave Graf, Mac-Tech’s Regional Sales Executive for Arizona, Colorado, New Mexico, California, Utah, Nevada, Idaho, and Oregon. Call me with representative connection drawings, the specified joint classification and hole type and dimensions, member profiles and weights, expected quantities, and your current hole-making route. I can help assess PBD configuration and workflow fit; the EOR and responsible project professionals determine design requirements and approvals.
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