Splitting/separating corners

[shiltonphoto]

Hi all,

I have a rather annoying corner separating issue which I'm a bit puzzled about. I've tried typing this post a few times trying to quickly sum up the problem, so please forgive the rather uneducated explanation below...

Essentially, when looking at the outer corner of the frame, the corner seems to open towards the bottom (the side that would be against the wall when hanging). Looking at the frame from the front, it all looks fine - the corners are perfect, but from the side, they look pretty poor - like: /\ but not quite as exaggerated!

I'm using an Alfa M1 foot operated underpinner and have tried altering the arm height for less pressure, the type of wedge (softwood/hardwood) and position, but I cant seem to eradicate the problem. When I try a dry run before assembling (laying out the frame on the workbench to check everything's fine), the corners appear fine.

Does anyone have any suggestions?

[prospero]

What type of wood and how wide the moulding?

Could be two things: You might have the outer wedge too near the outside. This will split the wood. Or, not enough pressure and the hammer is lifting the two halves before the wedge penetrates.

Both these things will tend to be worse the denser the wood.

[shiltonphoto]

I've been playing about with Lion's new sundea/sunday (not sure of the spelling) moulding, which is quite a light wood. However, as its only about 20mm wide, if that, so it might be as you suggest, that I'm putting a wedge in too near the outer edge.

Also, the hammer is resting nicely in the wood, and its not allowing the moulding to lift, so I'm happy that it shouldn't be that.

I'll have another play today and see.