Not to mention the small cell debacle.....
This type opinion is based on a false premise, that the foundation cell size we use today is correct for all situations.
Current foundation is mostly made with 5.3 rollers. By the time the wax stretches a tad in the process, it is often 5.4 or even 5.5 in the direction the rollers turn. This invites the question, is this the right size for the bees to use? When I stopped treating my bees in 2005, I changed over to 4.9 foundation as there was quite a bit of discussion that smaller cells reduced varroa reproduction. It was difficult to get my bees to accept the small cells, but after a couple of years, I had most of my bees on 4.9. What did I find? Well, there was no appreciable effect on varroa either good or bad. I still had mites in abundance in susceptible colonies. But what about other effects?
When I subscribed to Gleanings in Bee Culture in 1977, the January issue had an article by Charles Koover on using 31mm end bars for narrower frames along with some discussion of the advantages. Not knowing any better, I built a bunch of new frames using 31 mm end bars. As you may guess, there were problems. I goofed by using a standard frame with 35 mm end bars as a pattern reducing the joints to make it fit. It turns out that frames with reduced dimensions are not strong enough to withstand the pressure of wire to hold foundation in place. The joints were not strong enough to stand up to years of use. Add in the abundance of drone cells built around the edges and you can guess they worked up to a point but not exactly the way I thought they would. What did I do? I designed a frame specifically to meet the requirements of 31 mm spacing. You can read about it in this thread.
https://www.beesource.com/forums/showthread.php?325985
Turns out, using small cells in narrow frames had an unexpected benefit. The bees built up earlier in the spring. I eventually figured out the reasons why by studying what was happening compared to bees on 5.3 foundation in 35 mm frames. A cluster of bees of a given size can cover a certain amount of comb. If you put more comb in the cluster, the bees produce more brood earlier. This is especially significant when the cluster is tight at temps below 7C. The combination of narrow frames with small cells gives a 27% advantage in terms of number of cells a cluster can cover. The resulting brood cycles shortened my normal 10 to 12 week spring buildup from 10 to 12 weeks to 8 or 9 weeks. That sounds lovely, but remember that bees love to swarm in the spring so what I achieved was colonies ready to swarm 2 or 3 weeks earlier that expected. I adapted by inspecting my bees in late march and pulling a 3 frame split from any near swarm strength.
But that was not the end of the story. My bees still did not like the 4.9 foundation and would re-work it over time to a mix of worker cells and drone cells. I don't like such mixed combs as they are a pain to remove for inspection and there was often brood on one face of the comb but not on the opposing comb.
When I decided in 2016 to convert my operation from Langstroth deeps with shallow supers for honey, I decided to also do something about the 4.9 foundation. I contacted Dadant and was told that in late 2016 they would do a special run of foundation at 5.1 mm as they market it in that size. I had to purchase 200 pounds to get it made both with 5.1 mm cells and Dadant frame size. I ended up with square Dadant hives, 31.5 mm end bars, and 5.1 mm cell size. The result has been abundantly satisfactory. The bees readily accept the 5.1 mm cells. Very little drone brood is produced in the frames. Each frame has 3 wires to hold the foundation in place and since the foundation is also wired, the entire sheet stays flat and properly positioned. The bees readily build brood cells on both sides of the comb and preferentially do not convert it to drone cells. If I want drones from a colony, I put a shallow frame in a deep box. The bees build drone comb on the bottom of the shallow frame. When the season is over, I remove the shallow frame and replace with a regular Dadant frame.
If you want to speed up buildup of a colony, use 31.5 mm end bars. 35 mm frames will slow down buildup. 38 mm end bars slows it down still further. This affects preparations for swarming such that Dadant originally chose 38 mm spacing for his hives based on the reduction in swarming. Unfortunately, neither Dadant nor Brother Adam ever tumbled to the concept of using end bar spacing to enhance spring buildup. In my climate, faster spring buildup is a very real advantage.
But what about uses for 4.9 foundation? Small bees love it. Africanized bees love it. Just don't expect it to help with varroa.
