Moulding substrate and a caul on the CNC

For Ogee clock replicas there are two specialized moldings. One is the Ogee and the other is the door molding. My first clocks used Ogee moldings I had made to order (which is expensive). I cut the door moldings with a table saw (cutting diagonally, which is tedious). When I applied the veneer to either, I had to press urgently with a dowel while the vacuum bag started, so that the veneer adhered to the deepest parts. This is a finished clock, made before the Onefinity:

I had about 25% failures, because the veneer (mahogany) broke at the edges of the substrate. I didn’t have a caul to pre-form them, because I couldn’t justify paying for a molding cutter that only made a mirror image of my project piece.

But this month I learned about Vectric’s “moulding tool”!

The images (below) are door moldings. These aren’t flat; they’re coves, 1/16" deep, on a 7/8" width. They’re 1/2" thick but after veneering they are rabbeted to hold the glass and to fit within the clock opening. So once all that milling is done, they’re delicate. The images below show the earlier stages of production, when the veneer is shaped and then glued. The piece on the left is a pair of molding sections held in place by the vacuum (not yet glued). It’s shiny because of the bag. That molding pair, and the veneer on it is concave. On the right is a mirror image, but it takes effort to see that it’s convex. I use it to compress the veneer after using GF-20 (veneer softener). It’s shiny because I use packaging tape to keep water or the veneer softener from reaching it (and causing warping).
Moulding

It takes about 40 minutes to make the blanks for two door moldings. It took 2 hours to make the convex version, but it will be re-used with each veneer session. When I get better at this I’ll find a way to index the two pieces so that they fit together in one consistent way. I think this is an example in which a CNC isn’t a substitute for traditional woodwork, it’s a tool to improve the quality and reduce waste.

5 Likes

VERY nice clock!!!

Good use of the moulding tool path

How about dowel holes for alignment?

Pony

1 Like

Dowel holes could work nicely, and they can be programmed into the toolpaths.

Excellent…techniques.