On Mon, 24 Oct 2005 16:41:56 -0700, "Key Bored"
wrote:

What are some methods to fit the door frame and casing to the arch? Should
I make a series of cross cuts (but not all the way through) so that the
stock will bend, and then spackle and sand? Or should I rip the stock into
thin strips, bend them on a form, and glue together? Other ideas???


I've never tried to make an arched jam from MDF.
When using hardwood I always rip thin strips and bend it on a form.
You can either make a form of the entire radius or use L shaped
brackets made from plywood for the form and screw them down to a line
with your radius. Then glue and clamp it up. If your MDF won't bend
without breaking you could make the arch out of something else maybe
poplar if it paints.
When I make casing for arches I normally cut it out from pieces of
solid wood. In your case I guess MDF. I cut a pattern from 1/4"
plywood or hardboard with the router (and homemade circle jig) then
rough cut the stock and use the pattern with a pattern bit to make the
casing. When using stock for the casing I would have to cut this
radius from two pieces but with the MDF you wouldn't have to do that.

When we have the millwork make arches (for custom casing), they
actually rip thin strips of hardwood to the width of the casing and
bend the casing too. I think this helps with grain direction when
cutting the detail with their machines. They always come out in one
piece.

Mike O.