[aandrews]

Approximately how far down from the top bar will the comb extend? If it varies, what's the maximal?

 

[Akademee]

Practically until it hits the bottom, they will leave some space for them to get through to the other side. Bees can make comb that is several feet tall if you give them the space, just ask someone who has pulled bees out of someone's wall.

 

[GregB]

Approximately how far down from the top bar will the comb extend? If it varies, what's the maximal?

The real issue is - how much weight the comb can hold when only attached at the top bar.
Once the comb exceeds about a foot and is full of honey, it is likely to tear off - not something you want.
That is what you should think about.

Otherwise the bees will build down few feet over time and if not limited and supports are provided.
But this does not apply to you if running a TBH.

 

[ursa_minor]

Practically until it hits the bottom, they will leave some space for them to get through to the other side. Bees can make comb that is several feet tall if you give them the space, just ask someone who has pulled bees out of someone's wall.

 

[aandrews]

View attachment 63097

I guess my question was more like a strength of materials thing. How far can comb suspended from a top bar extend without breaking? Normally, in a cool, temperate environment. (I'll guess it's about a foot.)

 

[ursa_minor]

I know, I just thought I would post a picture of how long comb can get.

 

[mtnmyke]

Practically until it hits the bottom, they will leave some space for them to get through to the other side.

Exactly. Very close to the bottom and will often attach the comb to the sides. I had to use a long bread knife to cut the comb free so I could get the bars/comb out. I even tried different angles with no luck to that problem. Since they even attach to the sides of foundationless lang frames there likely isn't a solution to that, just get a good bread knife.