Fundamental Underpinner Question

[RobM]

Morning All,

Another silly question I should know the answer to by now...

Using the underpinner to connect the flat frame shown in the first picture, I have the feeling I'm using the wrong head. I think the yellow head is for non-flat mouldings (correct?).

The outcome is that the frame is lifting when I make use the pedal and the connection is loose, as the second picture.

For a flat frame, which of the heads shown in the third picture should I be using?

Or, is there something else I might be doing wrong?

[pramsay13]

I don't use that underpinner but if your moulding is lifting either the pressure from above isn't sufficient or the wedges can't go through the moulding.

If the coloured pieces are different sizes or density try different ones to check.

Make sure your wedges are the correct way round and that you are using the correct wedges for the type of wood you are joining.

[Justintime]

cs88 bungs.png Try adding the metal thing in the pic to the back of the rebates so that the bung does not press on the fences. [attachment=0]20240906_144510.jpg

[RobM]

Ah, so I need the "moulding spacer bars" (as they seem to be called on the Underpinned Spares website)?

That could make sense as I feel the bung does not sit cleanly over the frame, so maybe I need that extra space.

Thanks

cs88 bungs.png
Try adding the metal thing in the pic to the back of the rebates so that the bung does not press on the fences.
[attachment=0]20240906_144510.jpg

[StevenG]

Also, I'd bring the head as close to the moulding as possible - it'll help if you find the moulding lifting

[RobM]

This could be one of the fundamental setting issues that I haven't yet got right, so will have a look into it. Thanks Steven.

Also, I'd bring the head as close to the moulding as possible - it'll help if you find the moulding lifting