Features
- Embedded magnets for attachment to mild steel to aid setup
- Crosshairs on die surface for alignment
- Punches up to 10 gauge mild steel and 12 gauge stainless steel
- Laser-etched size markings for identification
Specifications
| Size | 3-1/2 in. |
| Material Capacity | Up to 10 gauge mild steel; up to 12 gauge stainless steel |
| Alignment Aids | Crosshairs on die surface |
| Positioning Aid | Embedded magnets for attachment to mild steel |
| Markings | Laser etched size markings |
| Intended Use | Works with hydraulic knockout tools (tool sold separately) |
Related Articles
Die intended for use with a hydraulic knockout tool to create 3-1/2 inch conduit holes. Designed to cut through up to 10 gauge mild steel and 12 gauge stainless steel. Includes features to aid alignment and positioning.
Project Ideas
Business
On-site panel knockout service (3 in conduit)
Offer a mobile service to add 3-1/2 in knockouts to existing electrical panels, MCCs, and enclosures for 3 in trade-size conduit. The die’s magnets/crosshairs speed precise layout, minimizing shutdown time. Market to industrial facilities, OEMs, and contractors needing fast retrofits.
Rack and enclosure cable entry upgrades
Retrofit server racks, AV cabinets, and machine enclosures with 3-1/2 in openings for brush grommets, split boots, or cable glands. Sell fixed-price packages per hole (including hardware), with optional sealing and labeling that leverages the die’s clean, repeatable cuts.
Stainless pass-throughs for food/biotech
Specialize in punching 12 ga stainless control panels and equipment skins to add sanitary pass-throughs for sensors and conduits. Provide on-site service with wipe-down protocols and deliver flush-mounted fittings that meet facility hygiene standards.
Pre-punched gland plates and blanks
Manufacture and sell standard-size gland plates for common enclosure brands with 3-1/2 in holes positioned for 3 in hubs or boots. Offer custom layouts using the die’s alignment features to turn around short runs quickly without CNC setup costs.
Tool rental + operator package
Rent a hydraulic knockout set with the 3-1/2 in die and offer an operator-on-call option for precise work on heavy-gauge steel. Bundle with layout templates and grommet kits, and charge per hole or per day to serve small contractors and makers who don’t own the tooling.
Creative
Custom cable pass-through plates
Punch 3-1/2 in holes into brushed steel or aluminum plates to make clean cable pass-throughs for home theaters or studios. Pair with 3 in trade-size bushings/boots or grommets. The die’s magnets and crosshairs make centering on narrow rack panels easy, and the clean shear edge looks professional without secondary deburring.
Smoker and grill vent mods
Add precise intake/exhaust ports to smokers or grills by punching 3-1/2 in openings in 10 ga mild steel or 12 ga stainless. Mount adjustable dampers or 3 in pipe collars for controlled airflow. Use the crosshairs to align multiple vents symmetrically around a barrel or kettle.
Sheet-metal dust collection manifold
Build a compact dust manifold from sheet steel and punch 3-1/2 in ports to accept 3 in PVC or metal duct stubs. The magnets hold the die on curved mild-steel duct sections while you align with the crosshairs for evenly spaced takeoffs.
Metal pendant lamp housings
Create pendant or sconce housings from thin-gauge steel and punch crisp 3-1/2 in openings for diffusers, glass globes, or decorative grill inserts. Use repeated, evenly spaced holes to form light patterns; the alignment aids keep patterns consistent.
Compact speaker projects
Punch 3-1/2 in driver or port openings in thin steel speaker enclosures or retrofitted ammo cans. The die produces a tight, round opening for mounting small drivers or round port tubes, with minimal finishing needed for gasket sealing.