Butchers Block type things . .

[Dewy]

Real butchers blocks always had steel bars bent round the corners which were held on with coach screws.
These held the corners together.
I saw one made with holes drilled through the blocks in both directions with holes in the one plane lower than in the other.
Long threaded bolts were threaded through them then tightened with nuts on each end.
It's a problem if th ecustomer wants wood and nothing else.
In this case angled sides of the apron allow for movement while the mitred corners dont move.

 

[mudman]

It seems to me that the problem is to stop the mitred corners from blowing apart which is what the metal brackets would have been for. This would then leave the frame to move with the expanding and contracting block. It would be forced to bow out as the block expands and then should spring back as it contracts. That way you should never get a gap between the block and the frame and everything is held in place but allowed to move freely at the same time. You probably need to choose the wood for the frame carefully, something strong and resilient, ash maybe?

 

[ike]

Didn't Norm use Poplar for his?

 

[Rattie]

Hard Maple I believe

Martyn

 

[Anonymous]

It seems to me that the problem is to stop the mitred corners from blowing apart

It would seem to me that this is the problem fullstop.
As I read this thread, the actual block is tapered and suspended inside a mitred skirt, if it was left to rise and fall from natural movement, it might be ok, but a butchers block is designed to take a pounding from meat cleavers etc, so the first thing you will do is drive it deeper and the wedging effect from the tapers will drive the mitre joints apart without any help from contraction/expansion.
Even keyed mitre joints will open at the top as the first key will have to sit down from the top of the mitre joint to gain its strength on its registering faces.
Dovetails will lock the skirt in one direction, but the other way will try and force apart for the same reason, but I would still say is a better joint all round for a framed job like this.
Mind you, I might have misread the thread completely, so if I'm barking up the wrong tree, please feel free to tell me i'm an idiot! :?

Andy

 

[ike]

Hard Maple I believe

Yeh...for the slab. I thought he used different timber for the frame/legs? I'm probably getting the facts twisted as usual though :roll:

 

[ike]

Dovetails will lock the skirt in one direction, but the other way will try and force apart for the same reason, but I would still say is a better joint all round for a framed job like this

.

Maybe this is a job for <rushes into phone box...rustle, rustle.. :shock: > twisted dovetails! . Now that'd be one purty butchers table!

 

[Dewy]

Norms version used hard maple for the block and poplar for the frame and legs with no iron brackets shown.
http://www.newyankee.com/getproduct3.cgi?510

 

[Anonymous]

Well, plenty to think about so far! I guess it goes to show that there are solid reasons why 'proper' butchers blocks have heavily reinforced corners and threaded bars.

My original reason for asking the question was that I had actually already made one, with the timber parallel grained (it won't be used for chopping on) and a keyed mitred frame. I gave it umpteen coats of 'OSMO Top Oil' to hopefully keep moisture out as this is the most hard wearing and waterproof oil finish I've come across, then plonked it in place and crossed my fingers.

It's obviously not an ideal design, I did it 'cos it was quick and I couldn't come up with a better idea in a hurry, but it's been in use in our kitchen for a couple of months now with no movement, so watch this space! If I do another I'll certainly try a variant on the 'angled/reduced point of contact theme'

 

[Dewy]

Tommy Walsh and The Salvager have both made 'butcher block' tables from 2-3" square pine glued to make a panel instead of blocks of endgrain.
These only look like a butchers block without having the benefits of end grain.
End grain allows any blood to go into the top which stops any bacteria because timber has antibacterial properties.
Bacterial food poisoning has increased dramatically since plastic has been used instead of the old fashioned butchers blocks that used to be scraped clean then scrubbed every night.

 

[SimonA]

Right then, could you not build the endgrain block with a large lip on it so that it can line up with the outer side of the frame but still have enough room to expand and contract on the inside. If you added a dowel to the very centre of the endgrain block, this would stop the block from moving around.

I just hope you can understand what I'm on about....

SimonA

 

[Taffy Turner]

That was the exact same solution I was working up to try and describe.

Any tapered system is bound to run into problems, as unless the angle is greater than 45 degrees, any force is going to push the frame out rather than allowing the block to rise up.

 

[Anonymous]

Hi SimonA,

the only problem I can see here is that as the blocks are end grain up, then the amount of timber removed in your drawing for the rebate area leaves very short grain so is likely to break away even under light use.
The principle is spot on though, but I would be inclined to do it by taking out a smaller rebate so that the strength is retained.

Andy

 

[SimonA]

Cheers Andy......I should have put on that the image is for illustration purposes only :wink:

SimonA

 

[frank]

just how much will the block expand ???

 

[Bean]

In order to solve the short grain problem why not replace the rebate with a taper! The blocks will slide when they expand, not forcing the frame apart and without being loose in the frame, as a rebated block would be.

Bean

 

[Dewy]

just how much will the block expand ???

Wood expands far more across the grain than with the grain.
This means that the expansion of a butcher block top can be enough to force the surround apart.
All wood contains water regardless of how dry it appears.
It naturally absorbs water from the atmosphere then gives some of it up in warm central heated rooms.
You always have to take this movement into account when making anything.

 

[Chris Knight]

In order to solve the short grain problem why not replace the rebate with a taper! The blocks will slide when they expand, not forcing the frame apart and without being loose in the frame, as a rebated block would be.

Bean

Déjà vue all over again?

 

[Johnboy]

 

[Chris Knight]

Aaahh - the light dawns! Sorry Bean

Thanks John.