# Sloped vs. vertical sides



## Antero (Jan 9, 2005)

Discussion of Bee Biology <[email protected]>
From: Chris Allen <[email protected]>

"These hives are wider across the
top than they are across the bottom. The sides are sloped about 30 degrees
from the vertical. This is the same slope that bees use when they build
honey comb out in the open. Using that slope in the hive discourages the
bees from attaching their combs to the side of the box.

If you make the box as deep as a typical "free form" honey comb, it should
be just right."


Terry


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## Michael Bush (Aug 2, 2002)

I did a straight sided (TTBH) one that was just a deep Langstroth box (double wide though). It was in full shade and in the heat of summer I had a complete comb collapse. I did another striaght sided one that was a medium Lanstroth box (triple wide) and it has done wonderfully. I also did a slope sided (KTBH) where I went the same depth as the deep Lanstroth but with a shorter bar and sloped and I had no problems with comb collapse with it. I think as the comb gets deeper it's more helpful to have the sloped sides. What I haven't tried yet, is to do a slope sided one with the 19" bars and see how those hold up. The lower corner of the heavy comb on a deep comb, seems to add a lot of stress to the comb.

I'm still experimenting and can't say I have a total understanding of all the issues involved, but the smaller lighter combs have been easier to handle and have not had problems. I see no real difference in problems with either the KTBH or the TTBH as long as the comb doesnt' get too large.


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## BWrangler (Aug 14, 2002)

Hi Guys,

I haven't seen any difference in comb attachments based on the slope of the sides. I've tried 22.5 degrees, 19 degrees and 8 degrees off vertical. The bees can sense which combs need reinforcement and will attach them to the sides regardless of the slope.

But there is an advantage of sloped sides for the beekeeper. When combs are cut free of the attachments and removed, the remanents of the attachments toward the bottom of the comb can easily clear those above it in a sloped hive. In a square sided hive, the lower attachments can catch or snag those above it when the comb is removed. Extra caution is needed when removing combs in a square sided hive.

Regards
Dennis


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## Dick Allen (Sep 4, 2004)

Thanks for that Dennis. I'm just starting the process of making one and was fretting over those slope angles myself.


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## Scot Mc Pherson (Oct 12, 2001)

Dick,
I have made many several TopBarHives, my operation works exclusively on TopBarHives. Angle DOES make a difference, but you have to find the right angle which I believe I did, since none of my bees (mostly swarm captures or their progeny) seem to attach much at all. The angle is 28.5 degrees. Its just slightly off the 30 degree perfectly divided 360 degree vector, this is due to comb cells not being built to exactly 30 degree vectors. The vertical vector is slightly longer than the angled vectors.

If you build your hive sides to 28.5-30 degrees, you will see that the edges of the combs are almost perfectly a single line of cells, and the attachments will be very few to none.

You can find the enormously successful dimensions I use on the BeeWiki http://beewiki.linuxfromscratch.org 

I am trying to standardize TopBarHive dimensions so that we will hopefully sometime in the future have some sort of product that can be relied upon like the langstroth. I am also going to try and sell them when asked.

I do not think one size fits all climates, but I do think that one size fits a climate range, and another size fits another climate range. That being said, perhaps the standards can encompass 2, 3, or maybe 4 or 5 ranges of measure.


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## BWrangler (Aug 14, 2002)

Hi Scott,

Maybe I changed the angle in the wrong direction:>)

When I designed my first tbh, I selected a top bar length and then constructed a series of catenary curves based on that length. A 17 to 20 degree slope accomodated most of the curves of varying heigth. I used 22.5 as a construction expediant. At the time, I had planned on building only a single tbh.

But the tbh idea captured me and I've since optimized the design for efficiency and economy. That's resulted in the different slopes which are shallower than the initial one.

Regards
Dennis


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## Michael Bush (Aug 2, 2002)

>you have to find the right angle which I believe I did, since none of my bees (mostly swarm captures or their progeny). ??? The angle is 28.5 degrees. Its just slightly off the 30 degree perfectly divided 360 degree vector, this is due to comb cells not being built to exactly 30 degree vectors.

I put the question marks in where there appears to be something missing. Could you complete the first sentence for me? "Since none of my bees" what?


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## Scot Mc Pherson (Oct 12, 2001)

Michael,
Thanx for pointing out the ommision. I fixed the ommision in the original post. I guess it happened when I digressed parenthetically. 

For clarity: ??? should have == seem to attach much at all

I bought a PDA in december which also has a low grade camera but suitable for general use. I should take more pictures of my bees now that I don't have to get the film developed, pay for CD or scan manually. I can just snap and transfer now. I'll take some photos of my hives and the combs. I just did splits of nearly all my hives, so they won't be impressive strength wise, but you will get to see what the combs look like with the rows being parallel to the comb edges. You guys all might remember that I deliberated over hive design for most of 2003 and early 2004. Took a lot of reading, study and thought to come up with what I did, and I believe I got lucky and hit the nail on the head and drove it in with one smooth hit. I have refined the actual design of the hive several times as I build them and get new ideas, but the basic design and dimensions haven't changed one tiny bit.


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## Michael Bush (Aug 2, 2002)

Thanks.


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## Dick Allen (Sep 4, 2004)

Antero and Scott: interesting information for the 30º slope. I had already cut the boards to dimmensions given in the plans I have. The angle given in those plans is 23º. So, that's about what I'll end up with (give or take according to my lack of carpenter skills). Eva Crane says in her book bees were less inclined to attach combs to the hive walls at any of the slopes tested (10º to 45º) than to the vertical. She also writes that 33% of the combs were completelly unattached, whatever the angle of the sides, and that as the angle to the vertical increased any combs that were attached had their highest point of attachment lower down. 

I'm also curious about what you other TBH guys are finding.


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## Michael Bush (Aug 2, 2002)

I have one at 22 1/2 degrees and one at 90 degrees. Not much attachment on either.


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## Cinnamon (Feb 1, 2004)

Hiyas,

A couple of things to consider in rectangle vs. triangle is:

1) a Triangle gives you the nearly the same size 'broodball' as the rectangle shape, but at about half the weight for the comb to have to hold(and for the beekeeper to lift)

2) The resulting space inbetween the combs is smaller, and so easier to temperature control for the bees.

Now for the wild guess bit: 

3) the bees can make a more temperature efficient winter grape shape in a triangle hive because it allows a bigger, and hence, more round and compact ball. (I wonder, how big is the avg. colony in winter?)

Now, I am wondering about 3) a bit, do you feel that the shape of the bee grape in winter is a significant factor? I have a feeling that a grape that can shape ovally vertically is more efficient than one that spreads out (I'm thinking of this like an eggshape, picture the egg on its side or standing up).

Cinnamon


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## Michael Bush (Aug 2, 2002)

I've overwintered both and they both did fine. I didn't notice any difference.


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