The Framers Forum

I recently ordered two differnt mouldings as samples that had sloping back edges but when it came to making them up I struggled not only to cut them but joining them on the underpinner failed completely. The join was continually pushed open because of the slope on the back edge. Any ideas anyone or is it just a moulding design to avoid? Thank you. A customer choose it so I used a clamp glue and then underpinned it but was time consuming.

Some mouldings are just not underpinner-friendly. The thing is to get the point where the pressure pad contacts
directly above the nail insertion point. Not always easy. If the two opposing forces are offset then the moulding will tip.
Often you can make little auxiliary pressure pads that conform to the moulding shape and put them on top of the join
so as to spread the force.

Any chance of a moulding ref for the one you are struggling with? Or a photo? Might be able to suggest a sneaky trick.

with this sort of moulding I sometimes reverse a small piece cut the opposite way and put it on top so that the top edge is flat eliminating the offset problem....does that make sense sense??

Here's one I made earlier.....



The profile is effectively levelled out and the pressure bears on the whole joint equally.

It works best on mouldings with grooves and reeds.

thanks for the picture Prospero

OOps! mis read your posting and was thinking of slope on front, I see it is a slope on the back which shouldn't present problems, if it opens up as you underpin I would suspect it is the underpinner at fault

Looking at the profile and wood type I suspect I know the supplier of these two mouldings.

I too have had difficulty cutting and joining them, if they are what I think they are! The wood itself, the density, varies considerable in a 3m length and is generally of poor quality IMHO. The back continually breaks out because of the grain.

Because I thought it was down to my cutting I also order on chop, but the joining was still problematic.

Chevrons binned, no longer use.

I would agree that it's the wood rather than the shape that is the prob.

That piney stuff can vary a lot along the length and at best it doesn't like underpins.

The second one is tricky even with nice wood. If I had to use it i would put in a shallow pin first, toward the inside, then
cross nail it near the top by drilling pilot holes and with good ol' hammer and panel pins. Strap clamping was well would be good.
OK, you have little nail holes to fill but at least you know you have sound join.

Easy!

Trim the lip off a small piece, cut it backwards and make an anti Chevron this can the be used upside down behind the moulding effectively creating a flat back, I can post a picture next time I go in the workshop

Is there an echo in here?

You misunderstood how I meant it to be used, not the same as other suggestions, a picture will work, that's the umbra range, I use lots of it, pinned right it's fine.

Took me time but here are the pics of how to do it reight like.