The Framers Forum

Hi,
I am relatively new to the framing game - i've been having some issues joining some oak mouldings with my Framer's Corner M3 underpinner - where the mitred edges meet - the joins are fine at the front but are coming apart on the side. I'm using mouldings cut with a chop service so they are all spot on and i'm using 12mm hardwood wedges (the moulding is 18/19mm) - i'm sure its user error - just wondering if I can summon the help of all of you and your experience! Hopefully i'm doing something blindingly obvious and easily remediable!
Thanks!

Budget priced underpinners don't cope with hard woods like oak so easily, as the topend more professional underpinners. I not saying that you can't make the budget priced underpinners do what you want, but sometimes it takes some extra know how and maybe a fewtrick of the trade. At one time most framers had underpinners without rebate clamps, which are a relatively new thing, compared to the early underpinners.

Joining hard woods like oak, will test both the performance of the underpinner and the framer. There are forces to be overcome to prevent the two lengths of the moulding moving apart, while they are being joined. I have small pine corner pieces which have been joined and strips of abrasive paper press into the rebate of the moulding that i am joining.

The rebate clamp on my machine has it's limitations, so I help it along a bit and use the machines rebate clamp to push the abrasine paper on the little corner piece to grip the mouldings that I am joining via the fine abrasive paper. This stops the two pieces of moulding pushing apart. iIt works for me, maybe it will work for you too!

Just had similar issues, although I have a Cassese underpinner so no experience of the Framers one.

Overcame by gluing and clamping the frame first, leave overnight. Use plenty of downward and inward pressure when pinning to help wood stay in place.

I've been making frames for nigh-on 40 years and if I tried to join that moulding on an underpinner that's the result I would expect.
It's tall and narrow and very dense.
Unless you want to splash out on a Hoffman router the best way I've found is to put a shallow (7mm?) v-nail in, not too near the outer edge and then
cross-nail it nearer the top with conventional pins. Use a hard pad on the pinner.
OK, there are some divots to fill in but that's no great problem on Oak.
If you can get a strap clamp around it as well then all the better.