[LenInNorCal]

Build TBHs. Math whiz, my daughter (so proud) tells me that an angle of 25.18 degrees is the correct one to get a 19" bar with 1x12" stock for side walls and a base of 9".
What do others use to get a bar length of 19" so swapping can be standardized? I know there's a difference between paper math and the real world, so that's why I am asking.
TIA,
=

 

[odfrank]

Did she take into consideration the true size of lumber?

 

[LenInNorCal]

Well I told her 11 1/2" but i know as a math nerd I could have made it easier and rounded off to the nearest 10 thousanths.

 

[Sam-Smith]

12" boards are to expensive for me, I just clamp up 2x 6" and a slice since they are more like 5.5" ea.

 

[LenInNorCal]

Yeah, was considering that myself. But what is the angle you cut? And how big is your bottom board that you line them up with?

 

[Michael Bush]

A one by twelve is 11 1/4" wide... sorry.

 

[LenInNorCal]

OK. You know, I've gotten a lot of stuff n' nonsense, but none has given up the angle of the cut! I've got to wonder, what's up with that?

 

[Shazam]

I think we went with 18" at top and 6.75 at bottom for the initial test? That's external dimensions and a 30 degree off vertical angle.

We're going to be doing a little cad version up, but will likely go with 19.25" top external or 19" to allow for playing around with supering using a Lang body on top of the TBH in future versions. Keeping the same angle is simple by just adding the same width to the bottom. We're also not using a bottom board at the moment, just a screen. Will be building a 'pillow' top ala Warre style when we get to fall.

Here is a useful site for figuring trapezoid angles if you want to be lazy and not just work it out


Anyway, there is no single correct angle. Most everyone has their own angle. I have noticed most hives go more vertical than ours, with as little as 8-12 degrees off vertical. I have yet to find two designs that use the same angles that I've noticed. (Unless one is an explicit derivative of the other).

I'll let you know how the 30 degree works in a year. I figure if the theory is that by having a sloped wall, it more resembles a floor, so they are less likely to attach the comb, then more of an angle is is better, within reason.

 

[WLC]

Unless you use the exact same sized lumber, and set the exact same dimensions for things like the size of the top bars, then it can become a bit of a hassle.

I've got a 19 inch top bar with the inside dimension set at 17 1/2. My bottom board is 10" X 48", my side boards are 10 3/4" X 48", and my end boards are 19" X 10 1/2".

I was going for a 30 degrees angle at the bottom board. You know, 3, 4, 5; 30, 60, 90.

But you know what? If you are even a little bit off, you won't be able to easily swap bars with full comb between KTBH hives.

However, you probably can swap from the TBH to a standard nuc box (which is one of my goals w/ the 19" bars) but not the reverse.

I can see why someone might argue that a Tanzanian TBH built to Lang specs would be a better idea.

We can all do 90 degrees (more or less).

 

[Shazam]

That is probably why some people use two follower boards as 'forms'. They lay the sides on the follower boards and nail/glue in place. Since all their hives are formed using the same two follower boards to provide angle and spacing they get a consistent result.

We're going to try a different automated approach, if we make more KTBH. My next hive or two will be Langs just to compare the process of tending the bees. That said, a Tanzanian or rectangular TBH at 19", that can take top bars or foundationless frames is intriguing too. Not sure the advantage really over a Lang box in that case, other than the fact it can be longer.

 

[raosmun]

For what it is worth. 25 degrees. I built my KTBH with 3/4 exterior 7 ply plywood. YA, I know "weight" your not going to move a full one without a fork-lift anyway. go to a big box store and get a precut 2' X 4' piece of ply, rip it on center at 25 deg., flip the pieces and rip again = the two sides that are very close to 12" (less 1 saw kerf).

I put a swarm in last year, the bees loved it, I did not. My falt! did not keep up with the girls and got cross comb, what a mess:doh:. Anyway they did not make it through our winter. So I took the thing apart and will go with long Langs. this year TTBH. I did get a lot of good comb to frame-up.

 

[Sam-Smith]

I tried using follower boards as the reference, I found this to be a bit to inaccurate for me, what I do is make an inside template, draw those lines on my square ends and router slots for the walls and floor to slip into. This makes a very strong hive with nice straight walls that if I router properly almost perfectly matches my form. I drew up my plans in a pdf if anyone wants to take a look message me with your email address and I'll shoot you the plans, I based them off of the bio-bees hive design with a unique lid.

Sam.

top is the hive floor

template I use:
A trapezoid 38.3cm at bottom, 13.8958cm at top 66deg on both bottom corners, 114deg on both top corners, sloped sides
are 30cm long, make sure its perfect since it is a template.