Thread: Lock Mitre Joint

...and here is another link: http://www.wealdentool.eu/reviews/review_04.html

Still looking for a reply from a few of the forum's 95,715 members.

I'm surprised you can get a lock mitre bit as big as 89mm diameter! From the look of the specs of the bits on the Wealden link you will need a bit all of 100mm diameter. That's a mighty big router bit. Having said that I can't imagine a tungsten carbide tipped bit having too much trouble lasting a looong time cutting Western Red cedar. Due to the nature of this wood it would probably be a good idea to give the bit a thorough clean at the end of each session though. Can't help you with where to get a lock mitre bit that big though.

What is your friend trying to do?

Lock mitre joints are really a box makers joint -- and require a degree of precision when setting up the router table

also, with 40mm thick wood your friend should be using some form of structural joint.

so if you can tell us what your friend is trying to achieve we may be able to suggest an alternative that dfoesn't require him spinning a 100mm diameter cutter

There is a very simple solution.....use 36mm timber instead of 40mm

Originally Posted by ian

What is your friend trying to do?

Lock mitre joints are really a box makers joint -- and require a degree of precision when setting up the router table

also, with 40mm thick wood your friend should be using some form of structural joint.

so if you can tell us what your friend is trying to achieve we may be able to suggest an alternative that dfoesn't require him spinning a 100mm diameter cutter

He is making hundreds of square boxes to house Australian Stingless Bees. Each box has an internal measurement of 150mm.

Originally Posted by mark david

There is a very simple solution.....use 36mm timber instead of 40mm

I broached that matter with him and he does not want to have the wastage of cutting the material down to that size.

Given that that the boxes are more utilitarian than decorative, there are much simpler and more cost effective methods of jointing the boxes.

Making hundreds of mitre lock cuts is a major undertaking and given the fact that he is not prepared to use thinner material and that a larger mitre lock bit is seemingly not available then there are few other options.

Do you have a drawing or photo of what he is trying to make?





Q

Originally Posted by Kidbee

I broached that matter with him and he does not want to have the wastage of cutting the material down to that size.

Originally Posted by ian

What is your friend trying to do?

Lock mitre joints are really a box makers joint -- and require a degree of precision when setting up the router table

also, with 40mm thick wood your friend should be using some form of structural joint.

so if you can tell us what your friend is trying to achieve we may be able to suggest an alternative that doesn't require him spinning a 100mm diameter cutter

Originally Posted by Kidbee

He is making hundreds of square boxes to house Australian Stingless Bees. Each box has an internal measurement of 150mm.

Originally Posted by mark david

There is a very simple solution.....use 36mm timber instead of 40mm

Originally Posted by Kidbee

I broached that matter with him and he does not want to have the wastage of cutting the material down to that size.

I'm sorry to have to say this but your friend is crazy.

As I mentioned earlier, the lock mitre joint is a box maker's joint -- it requires timber accurately machined to a consistent thickness with square edges for all the hundreds of boxes he wants to make. Machining the quantity of timber required for "hundreds of square boxes" is an industrial scale task.


Can I suggest that you friend gets his 40mm thick timber sliced into 2 approx 20mm thick boards, which after skip dressing will finish around 18mm thick.
His bee boxes can then be assembled with butt joints nailed together.

100's of boxes using a mitre lock bit. Would have to fall into the "it seemed like a good idea at the time" category.

40mm timber, a quick, cheap and dirty idea, but fast, either butt join and screw or nail the boxes or if needing to replace bits, aluminium angle on the outside and screwed into the timber, if bits need to be replaced the aluminium can be reused and should also form a protective edge. As these boxes are to be used and shifted around they probably should be looked at as an expendable item requiring minimum cost and time to construct.

can someone check my maths, I'm getting 4 to 5 kg for a 150 x 150 (internal dimensions) box made with 40mm thick wood (including base and top.

These would seem on the very heavy size for a bee box.

Originally Posted by ian

I'm sorry to have to say this but your friend is crazy.

As I mentioned earlier, the lock mitre joint is a box maker's joint -- it requires timber accurately machined to a consistent thickness with square edges for all the hundreds of boxes he wants to make. Machining the quantity of timber required for "hundreds of square boxes" is an industrial scale task.


Can I suggest that you friend gets his 40mm thick timber sliced into 2 approx 20mm thick boards, which after skip dressing will finish around 18mm thick.
His bee boxes can then be assembled with butt joints nailed together.

'Crazy' you may say, but he is an extraordinary fellow, a doer and thinks outside the circle. Where you or I would think something is too difficult and give up, he just powers on ahead. He has patents pending and is in the throes of revolutionising the Australian Stingless Bee Industry, and I dare say, soon to become the bigggest ASB keeper in Australia.

Yes the boxes can be a bit on the heavy side as the 40mm thickness is required for insulation purposes. Once the daily temperature reaches 40 degrees C these little bees are in big trouble and meltdowns occur with subsequent colony fatalities. Big losses occurred in Queensland's South East area more than a year ago. The consequences of taking them out of well insulated tree cavities and putting them in thinner walled artifical boxes.

Below is a photo of one of his older hive setups made of Tallowwood.

image.jpg

OK a bit more relevant information puts some context around what your friend wants to do.

So I suppose the first question revolves around -- does 40mm provide enough insulation, or does the box need to be double walled?
given the number he wants to make, it would pay to experiment somewhat to determine this

I like the simplicity of the box you posted -- both for ease of construction and function.

Originally Posted by ian

OK a bit more relevant information puts some context around what your friend wants to do.

So I suppose the first question revolves around -- does 40mm provide enough insulation, or does the box need to be double walled?
given the number he wants to make, it would pay to experiment somewhat to determine this

I like the simplicity of the box you posted -- both for ease of construction and function.

Thanks Ian. I wonder if you or others know much about double walled boxes or thermo regulation using an air gap for that matter and things like: suggested timber thickness, air gap or air gap ratio, and how you would assemble such a box. A lot to ask but hopefully with the amount of members on this forum, someone may just know.

Also does the air gap have to air tight, so to speak, to be effective?