Moulding knives are used to create many different things, but cutting custom profiles into wood to recreate classic moulding shapes is the most common use. For recreating historic moulding or details in a restoration project, a set of custom made moulding knives may be required. There are many suppliers that can help.
Custom made moulding knives are typically tool steel that is ground into a specific profile so that when the knives are installed in a moulding machine or a rotary planer, they cut a specific shape in the wood you are running through the machine. The moulding knives are cut as a negative for the moulding profile that you need, so they remove specific elements of material and leave the pattern you want in the material.
While moulding knives are available from most suppliers that cover a wide variety of different shapes and profiles, if you are looking for custom made moulding knives that will produce something specific, you will most likely need to have the knives made for you. The simplest way to do that is to take a piece of the original moulding you are trying to reproduce and send it to the company making your knives.
The moulding can be scanned then digitized to make a pattern that can be loaded into a CNC machine, and the knives can be cut out precisely as you need them. Once the custom made moulding knives are cut, they need to be ground so that the cutting edges are sharp. This is usually done by hand and requires an artisan that knows precisely how to grind the bevels on the edges so that the knives cut perfectly and wouldn't ripping out the material.
Durability and Materials
When the knife maker is producing a set of custom made moulding knives for you, they may ask if you want the knives made from any special material. While tool steel is often strong enough, if you are using the moulding knives to produce a lot of moulding, you may want to consider having the knives made from an alloy or even stainless steel to increase the life of the knives.
Custom made moulding knives will dull over time, but if the knives begin to dull too much, you can send them in and have them sharpened by the manufacturer. Many times the company that made the knives for you will keep the profile on hand so they can make a new set very quickly for you if you need them as well.