FAQHow to

Tools of my trade – calipers

tools of my trade calipers

Where would I be without my trusty calipers? They might be small, but I use them every day and they allow me to double check within seconds how thick a material is.

With laser cutting, the principle is to cut at maximum speed and the maximum power required for that speed for a clean cut through. Machine settings I select for 10mm perspex are different to the ones I’d choose for 1mm card.

If a material is a bit thicker than expected, even by a fraction of a millimetre, the chances of not getting a clean cut through increase. As a result, materials and production time are wasted.

Sometimes, production is successful, but if cut parts are designed to slot into each other and are too thick or thin, fit is not good. There’s a case study about this here.

Solid wood

It can be tricky to get sheets of solid wood cut to an exact thickness as they need to be cut with a saw and sanded down. They always need to be checked and I sometimes perform test cuts before starting a job. And as each piece of wood is unique with slightly different densities, tests are a wise precaution anyway.

Wood isn’t made in a standard process like perspex is. Tree type, where the wood came from in the tree, its growing conditions and how the wood was processed can all affect how the wood behaves.

measuring calipers


Perspex is usually pretty reliable in thickness as it’s either cast in sheets of a certain thickness, or it’s extruded through rollers set to a specified thickness. Some brands need to be cut a little slower than others. There’s a blog about perspex¬†here.

Birch plywood

When I buy birch plywood, the thickness described is nominal, not actual.

Nominal 3mm ply is usually 3.1 to 3.2mm, and 4mm is often 3.8 or 3.9mm. As it’s made of laminated layers, final thickness of a sheet depends on the thickness of its layers.

Some thicknesses of ply can look similar to others. I regularly use 3, 4, 5, 6 and 9mm. Sometimes, I’ve selected a piece of 4mm instead of 3mm, or 5mm instead of 6mm by mistake. Measure twice, cut once as a wise person once said!

If I pick a thicker piece by mistake, I don’t get a clean cut. If I select a piece that’s too thin, the work can burn on the back.

Cutting a material too slowly with too much a power damages final product quality. So checking before production makes sure products are right first time.


If you’ve got any questions about laser cutting and engraving, contact us and I’ll do my best to answer them.