Selecting Best Wedges For Cassese Underpinner?

[christopher777]

Hello All,
I have a Cassese CS79..Can anyone tell me if x2 stacked 10mm hard wood wedges would be adequate for a 30mm depth moulding. Or do the wedges have to penetrate more than 2/3 of moulding? What are the rules for the best joins?!!! Could someone tell me please...would two thirds be good enough

Thanks.

[Glimpse]

I have the same underpinner, stacking 2 x 10mm is fine in most mouldings - just don't go too close to the edge in case you get a misfire!

And from what I can gather, these pinners don't like the bigger wedges - I wish somebody had told me this before I wasted so much time dismantling the block to remove jammed 15mm wedges!

I just use 10mm for everything (5mm for skinnies). If it's a deep moulding like a box frame, I just clamp 'em up with band clamps and let the glue do its work...

[David McCormack]

You've mentioned hard wood wedges so I assume you are using hard wood, oak or ash? If so, I wouldn't want to try and stack any wedges in hard wood with a foot operated underpinner I think I'm right in saying that hardwood wedges don't stack successfully because of their shape anyway? Otherwise, stacking normal wedges in something like obeche will be ok.

For a 30mm moulding two 10mm wedges will be ok as they go past the half way mark.

If you are joining a 30mm deep hardwood then you need a different approach to joining... plenty of glue and cross nailing is one way.

[David McCormack]

A band clamp and plenty of glue as Glimpse suggests is also a good way, but I'd also glue some dowels in as well

[Jayvee]

I dunno...is it just me...or....do hardwood wedges stack better than normal wedges? I always find normal wedges veer off, whilst the hardwood are perfect nearly all the time (even with 5 or 6 stacked on really deep mouldings).

Obvs I'm talking about softer woods....couldn't even comprehend stacking wedges in something like oak or ash!

[prospero]

Something like deep, narrow oak or ash I would put in one v-nail toward the inside. 7mm probably.
Then cross-nail near the top using panel pins. A strap clamp is handy in some cases. OK, you have to
fill in the nail holes but it does save a lot of grief. Before about 1980 most frames were cross-nailed.

Stacking hardwood v-nails in hard wood is a bit problematic. You might get away with it in ash, but with
oak you are pushing your luck.


The best way to join this type of moulding is a Hoffman dovetail router which cuts a slot for a bow-tie shaped
key. If you do a lot of deep oak frames then think seriously about getting one. They aren't too dear.
Vastly stronger join than you can get using an underpinner.

[Steve N]

On 30mm deep I would use 2x 12mm stacked , near the inside, then 1x 15mm on the outer, plenty of glue

[Not your average framer]

What Steve N says is also what I would say, but also if you are doing this with a hard wood such as oak, then try to get the inside wedges really close to the rebate on the moulding, because stacking wedges in a hard wood such as oak, only works well if the wood has enough give when inserting the wedges.

Getting stacked wedges into the moulding with very little wood on one side of the wedge allows a bit more give as the wedges are inserted, because the thinner piece of wood between the wedge and the rebate has more flexibilty and moves over slightly as the wedges are inserted. Try it, you will be sorprised how well it works.

[christopher777]

Thats all great information, thank you. Glimpse..that is also very good specific advice to know the Cassese has its limitations.Your wedge choice has been noted

It is a hard wood Oak.

I have also learned that if the grain of the wood is a specific way the wedge can get pushed outwards if it follows the grain (causing a break out of the side of the moulding) The wedge follows the grain like a train on a train track..!

[Glimpse]

You do get the occasional skewed wedge, but I wouldn't worry about it - it's not so much of a problem that you need to check the grain before cutting. Just be mindful of how close to the edge you're putting your outside wedge - if you're putting a 10mm wedge less than 5mm from the edge, there's a possibility it could break out if it veers off course, more so if you're stacking.

Just use a bit of common sense and you'll be fine. Don't just rely on the wedges and glue all your joints well.