Corner Problems

[Ash the Framer]

Hi All,

I have a slight problem with my corners! i have recently had my Morso blades sharpened (sawrite), when they returned i put them on in the usual way did some test cuts and mitre checks and these seem fine when i dry fix them. When i pin them the tops are fine (see 1166) but the corner are splitting at the base (see 1165).

This has not happen before, i have checked the Morso, checked the underpinner and can see nothing wrong.

Any ideas??

Thanks

Ash

IMG_1165.jpg

IMG_1166.jpg

[prospero]

Looks like classic 'not enough pressure on top' to me. On hard wood, when the wedge starts to penetrate and push against the pad, if there is any give all it will tend to lift and separate the join at the back. The deeper the moulding the worse. As the wedges go in they will pull the face together but the gap at the back will remain.

You could also have the wedges too near the back of the moulding.

What pinner are you using and what wedges?

[Ash the Framer]

Hi Prospero,

I rarely use hard woods but i think this one was. I use the rule of thirds to pin.

The pinner is an m3 and the wedges are a universal softtype.

I did a few frames last week which highlighted this problem, some were the dreaded polymer and some were softwoods.

I really noticed it on a reverse scoop slip where the pinner seamed to be pushing down and when the pinner pinned the top would open up!! It really is a frustration.

When you say not enough pressure on top how would i go about increasing this?

Thank you again, and also thanks for being so speedy to come to my rescue.

Ash

[Kevlar]

Hi Ash, from your post and in my limited knowledge you may need to be using hardwood wedges rather than the soft ones you state you are using. Hardwood wedges for hardwood. It may not be the answer but given you are using a hardwood when you don't normally and you are only now experiencing the problem with the mitre's it might be worth considering. The underpinner you have, has both soft and hardwood wedges as suppliable items. I guess the hardwood wedges will go into the hardwood easier and therefore possibly prevent the mitre opening up, whereas a softwood wedge in hardwood will not have the same strength to pull the mitre together or go through hardwood as easily. Just a thought.
Kev

[Graysalchemy]

Definitely as Prospero says a problem with it being hardwood and if you are not using hardwood wedges it is going to struggle. I bet if you cut a softer piece of wood you will have no problem.

[Ash the Framer]

Thanks all for your help and suggestions, i will look into using hardwood wedges with hardwood mouldings and see i this helps.

However, annoyingly i have just made a frame up with soft wood 1"x1" and the same problem occurred.

I am starting to think that my Morso might be at fault and not cutting true, could this be the case or is it solely down to my pinner?

Not a great start to a day!!!

Ash

[AllFramed]

When I have had problems like this it has always been down to the under-pinning. As you said it is fine when lined up dry.
I find the problem tends to go away with not only top pressure on the joint and correct wedges but also by ensuring plenty of downwards and outwards pressure against the under-pinner fences so the whole moulding stays flat.