Making cutters for molding

Old molding, like in the picture below, can get full of old paint, gouged and ruined over time. If a piece it not salvageable, it is a possibility to remake the molding. Some special equipment is needed, but if you have access to a shop it is fairy easy to replicated molding.

The first step is to make a custom knife. Get high speed planer steel, usually ordered from a machine supply company like Belsaw.

Draw, in permanent ink, the contours of the molding on the steel .Next using a grinder, with a thin cutting wheel, make relief cuts into the steel to help make cutting away excess steel easy.
After you have removed the excess steel, use a wide grinding wheel to start moving toward the lines you drew on the steel. Make sure to keep your steel against the stop at a 45 degree angle, in order to create a sharp cutting edge. The blade will get very hot, so have a bucket of water next to you to dunk the cutter in often.

Here you see the cutter's edge bevels downwards to make a sharpen cutting surface.

Check back often with the original molding to make sure you are staying on course and not cutting too wide or deep. Once knife is done, it is set up in a molding planer , which is a planer that takes custom blades. Be sure to read and follow instructions for that specific planer, because most are different and have compacted balancing system. Next test the blade, line up a scrap board (set up some kind of guide) then test. Once you have the kinks straighten out , send your good board through the planer.

The result is custom molding identical to your old molding and made by you. After the grinding of the knife and set up of the machine, it is easy to make multiples.