Large Barrel Nuts for connecting timber?
Discussion
Hello,
Can you get large barrel nuts, like the kind you get in flat pack furniture, but scaled up? Search engines don't seem to be helping, but maybe the forum hive mind knows better.
I'm building a timber frame in our garden. I could use heavy duty timber screws, but for some reason I like the idea of something that could be unfastened and refastened without risking 'drilling' the hole that the screw goes into. I'm also mindful that timber cracks and changes shape, and wonder how much purchase the screws retain when this happens.
Cheers
Can you get large barrel nuts, like the kind you get in flat pack furniture, but scaled up? Search engines don't seem to be helping, but maybe the forum hive mind knows better.
I'm building a timber frame in our garden. I could use heavy duty timber screws, but for some reason I like the idea of something that could be unfastened and refastened without risking 'drilling' the hole that the screw goes into. I'm also mindful that timber cracks and changes shape, and wonder how much purchase the screws retain when this happens.
Cheers
Cheers for the replies. It turns out that the fixings I mean are called cross dowel barrel nuts. The largest diameter I can find is 16mm though, with an M10 thread, so seems a bit small for beefy pieces of timber.
My thinking was that if you could get really large diameter ones, use a router or forstner bit to make a pocket for it, then the radius spreads the load on the surrounding wood, so is less likely to tear out or be affected by cracking/rotting/changing of timber over time compared to a screw. Of course, that method requires removing a lot of wood, which probably weakens everything in the first place. There is no science to this, just thoughts in my head. It's a head that went through an engineering degree, but none of that was learning about timber fastening.
My thinking was that if you could get really large diameter ones, use a router or forstner bit to make a pocket for it, then the radius spreads the load on the surrounding wood, so is less likely to tear out or be affected by cracking/rotting/changing of timber over time compared to a screw. Of course, that method requires removing a lot of wood, which probably weakens everything in the first place. There is no science to this, just thoughts in my head. It's a head that went through an engineering degree, but none of that was learning about timber fastening.
Prawo Jazdy said:
Cheers for the replies. It turns out that the fixings I mean are called cross dowel barrel nuts. The largest diameter I can find is 16mm though, with an M10 thread, so seems a bit small for beefy pieces of timber.
My thinking was that if you could get really large diameter ones, use a router or forstner bit to make a pocket for it, then the radius spreads the load on the surrounding wood, so is less likely to tear out or be affected by cracking/rotting/changing of timber over time compared to a screw. Of course, that method requires removing a lot of wood, which probably weakens everything in the first place. There is no science to this, just thoughts in my head. It's a head that went through an engineering degree, but none of that was learning about timber fastening.
I think you could usefully look at vaguely similar joints and guess how things scale?My thinking was that if you could get really large diameter ones, use a router or forstner bit to make a pocket for it, then the radius spreads the load on the surrounding wood, so is less likely to tear out or be affected by cracking/rotting/changing of timber over time compared to a screw. Of course, that method requires removing a lot of wood, which probably weakens everything in the first place. There is no science to this, just thoughts in my head. It's a head that went through an engineering degree, but none of that was learning about timber fastening.
For instance, these barrel nut thingamies are used in a pine bedframe we've got.
The barrel nut and screw pulls the joint tight, while a couple of wooden dowels are in shear, taking the actual weight of the persons in the bed.
I'm sure designing this kind of joint to the n'th degree of efficiency is quite hard.
But doing an adequate job, testing it, then adding more fasteners usually works?
I've had thoughts about building a wooden-framed house using large cross dowel barrel nuts (M20?). I'm pretty sure no such exist as stock items. You would have to find a manufacturer who could make you a batch, preferably in stainless steel. Used properly, they do make immensely strong joints to connect wooden structures together.
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