Why punch rather than drill?

It cuts in one stroke without swarf and leaves no burr; the sheet is not distorted, and for large diameters it is far faster than drilling.

What does a PG size mean?

A traditional thread and hole size system used for cable glands (PG9, PG16, PG21). In panel building the punch is chosen to match the gland.

Can stainless steel be punched?

Yes, but the capacity is lower than in mild steel and is quoted separately. Forcing beyond it breaks punches and draw studs.

When is a cordless punch driver worth it?

In production panel work and on site where many holes are made. For occasional use a hand-pump set is enough and much cheaper.

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Hydraulic Knockout Punches

A hydraulic punch cuts sheet with a punch and die rather than by drilling: the hole comes out clean and burr-free and the sheet is not distorted. The catalogue holds 14 sets and machines.

How a punch set works

A set has three parts: punch, die and draw stud. A pilot hole is drilled, the stud passes through it, and the hydraulic ram pulls the punch into the die, cutting a clean round (or square) hole.

Hole sizes follow panel and installation standards: PG sizes for cable glands, metric sizes for general use. Sheet capacity is marked on the set and is lower in stainless.

The pilot hole must match the draw stud.
Keep punch and die clean and lightly oiled.
Capacity drops in stainless steel.
Cordless drivers cut time in production panel work.

Frequently Asked Questions

Why punch rather than drill?
It cuts in one stroke without swarf and leaves no burr; the sheet is not distorted, and for large diameters it is far faster than drilling.
What does a PG size mean?
A traditional thread and hole size system used for cable glands (PG9, PG16, PG21). In panel building the punch is chosen to match the gland.
Can stainless steel be punched?
Yes, but the capacity is lower than in mild steel and is quoted separately. Forcing beyond it breaks punches and draw studs.
When is a cordless punch driver worth it?
In production panel work and on site where many holes are made. For occasional use a hand-pump set is enough and much cheaper.