Cutting round gaskets yourself

The most common shape for a gasket is circular. Either as simple small washers with an Outside Diameter and Inside Diameter – or as larger pipe flange gaskets, and possibly with bolt holes around the flange.

While a set of compasses or dividers with a cutting blade can be used for cutting thin materials for smaller washers, many people struggle to cut larger rings. Here’s one of the simplest ways of cutting thinner gasket materials and rubbers etc using items most people can lay their hands on easily!

Take a piece of wood – say 50mm x 25mm baton, that’s longer than the radius of the largest circle you expect to cut. Using a hacksaw, make a cut about 100mm from the end from the outside approximately half way. Into this cut, press a new Stanley Knife blade (or similar !!). It needs to be a tight fit so you may have to hammer it in place.

Then mark the radius point of the circle, measuring from your blade cutting point – either knock a nail/pin in at this point or drill a small hole for a nail/pin to loose fit.

Now you have a simple scribing tool – press the nail into the material (or through it!) – apply a little pressure to the blade end and score the material as you rotate the blade. Some materials such as thin rubbers, will probably cut in one pass (water will help to lubricate the blade!) – other materials may need several rotations and more pressure to cut through.

Remember – always cut the OD first ! If you need to add bolt holes, you can scribe the Pitch Circle Diameter of the holes by changing the nail/pin radius point , and finish by cutting the ID  – again after changing the radius centre.

If you’re feeling confident, you can insert two blades and cut OD and ID at the same time !