The making of a frame, with side discussion of frame rests, bee space, and Langstroth
I'm going to post most of what I have learned about frames over the course of 46 years. Some of this might be useful to someone sometime in the future.
Frames revolve around the concept of bee space. Get it wrong and the bees will glue the frames in place so that you can't possibly pull them out. Get them too wide and bridge and brace comb will drive you nuts. What exactly is bee space? It is a gap from 1/4 to 3/8 of an inch that bees will not normally propolize over or build comb in. Langstroth recognized this space and applied it first by leaving a gap above his primitive frames to keep the bees from gluing the cover down. When he thought about this a bit, he realized that a frame could be made with a bee space on each end, at the top and below the bottom. He then designed and patented a hive that incorporated the principle of bee space. This hive is the basis of most U.S. beekeeping today. Takeaway: Beespace is 1/4 to 3/8 of an inch!
Lets start with discussing frame rests. These are normally called Rabbetts in the U.S. or Rebates on the other side of the pond. Frame rests can be made various sizes depending on manufacturer. Standard is supposed to be 3/8 inch wide and 5/8 inch depth. Some manufacturers also offer 7/8 inch depth which is intended to be used with metal frame supports nailed onto the frame rest. I've seen homemade boxes with 1/2 and 3/8 inch frame rests. These are entirely inadequate to maintain proper bee space. Takeaway: Verify that your frame rests are 5/8 inch deep!
The frames we use today were not designed by Langstroth. They were designed by a guy named Hoffman. The major difference was that Hoffman used a thick top bar where Langstroth used a thinner strip of wood. The advantage of the Hoffman top bar was such that most frames made today are based on the Hoffman design. The problem is that dimensions of frame parts are NOT standard among the various manufacturers. You can't buy a frame from Betterbee and expect to interchange parts with a frame from Kelley. Takeaway: buy frames from one supplier to make your days simpler!
Frames can be assembled with nails, staples, glue, made from plastic, combinations of plastic and wood, etc. I prefer wood frames for a lot of reasons most of which involve durability and easy acceptance by the bees. Plastic frames can cause various problems with severe cross combing being the worst. For this discussion, I will only address wooden frames. Takeaway: I don't like plastic frames!
So what are the most common errors in frame manufacture? The first is a design flaw. 9 5/8 inch depth Langstroth deep hives are fitted with 9 1/8 inch deep frames. This leaves 1/2 inch gap when two boxes are stacked. So this is a big gotcha and causes problems with comb built in the too-wide gap. Takeaway: 9 1/8 inch frames in a 9 5/8 inch box do not provide a bee space!
Another common problem is getting the lugs/ears of the frames wrong, either too thick or too thin. A frame full of honey can be dropped and break off the ear which requires repair or replacement. Too thick and it messes up spacing in other areas of the hive. This is one area where mixing frames from different suppliers is a distinctive problem. Lets say you get frames from Mann Lake with 7/16 inch thick lugs and then you buy some frames from Kelley that are cut on a slant so the frame sits on the rest where the wood is 1/4 inch thick. Now we have a problem because putting the Mann Lake frames in a box on top of Kelley frames gives a gap 3/16" thicker while putting Kelley frames on top of Mann Lake frames will be less than a bee space! Takeaway: Know the + and - of the frame lugs from the manufacturer!
Groove top bars are a real pita when they are cut wrong - as most of them are. Foundation sheets are cut to exact sizes that allows for exactly 1/4 inch of foundation to be in the wedge area. Most top bars are cut between 5/16 and 7/16 of an inch deep. This leaves the foundation barely sticking down into the bottom bars or in some cases not even touching them. I've used other styles of top bars such as grooved, slotted, etc, but my preference is the wedge because of the way wired foundation with hooks fits and stays secured. Takeaway: the wedge area should be exactly 1/4 inch deep, no more!
End bars are a real issue for me. Have you noticed that they get thinner year by year? I saw some Kelley end bars a few weeks ago that were not even 5/16 of an inch thick! The wood is so thin that you can't wire the frame and expect it to stay straight. The correct thickness of an end bar is 3/8 of an inch. This is not maybe, not possibly, and I'll prove it. The interior dimension of a Langstroth hive is 18 5/16 inches. Foundation is precisely 16.75 inches wide. Add the width of the foundation plus the width of two end bars at 3/8 each plus the bee space at the end of the frame plus 1/16 of an inch expansion space inside the frame and you should get exactly 18 5/16 inches! 16 3/4 plus 3/4 plus 3/4 plus exactly 1/16 and you get voila 18 5/16! Why is it important to have an extra 1/16 inch inside the frame? Because it is difficult to get a frame exactly square so when the foundation is inserted, there has to be a bit of room for it to adjust to the frame size. Takeaway: a properly made frame should have a 3/8 inch thick end bar, yet none of the commercial manufacturers currently cut 3/8 end bars!
How many holes should be in an end bar? Well, that depends. If you are using foundation strips, who cares. If you are using plain wax foundation, then at least 4 and preferably 5 in a 9 1/8 inch Langstroth frame. For vertically wired wax, only 3 are needed. How many am I making? I'm building Dadant depth 11 1/4 inch frames with 3 holes in each end bar spaced 2.5 inches apart from the bottom of the end bar going up. This leaves a bit over 3 inches between the wedge at the top and the hole below it. This spacing works just about perfect with wired wax foundation with hooks. Takeaway: end bars need 4 or 5 holes to wire plain wax or 3 or 4 holes for wired foundation!
What is the right width for an end bar? This question caused no end of controversy in the late 1800's and early 1900's. Dadant and several early beekeepers said 1 1/2 inches. Beekeepers using Italian stock said 1 1/4 inches. Mixed mutts could build worker size combs anywhere in between! This was really important when bees built some drone cells on a frame because they are deeper than worker cells. A frame could be difficult to remove and/or crush bees if there was a lot of drone brood around the edges. There are some advantages to a 1 1/4 end bar but only if fitted with perfectly straight sheets of foundation. In other words, wire them and keep them straight or suffer serious consequences. The controversy ended in a compromise with 1 3/8 end bars which is what all major manufacturers build for Langstroth equipment today. Takeaway: 1 3/8 is a good compromise, 1 1/2 works, 1 1/4 works but requires expertise!
What kind of wood should a frame be made of? If you had asked me 6 months ago, I would have given you an answer of White Pine. I now know that this is not the best answer. White pine is relatively soft and flexible. It is the best material for top bars and bottom bars, but spruce is a better choice for end bars. Spruce is a bit stiffer and more brittle than white pine. This is a distinct advantage with 1 1/4 inch wide end bars when the frames will be wired. There are other wood species that make perfectly acceptable frames. The key traits are that the wood must be soft enough not to split when nailed or stapled and it must be stiff enough to stand up to years of use in a high moisture environment. Takeaway: White pine is a good choice for all frame parts, but I prefer spruce for end bars!
Now I am going to describe the perfect frame with 1 1/4 inch end bars in terms of cuts and I will add pictures in another post. All measurements are in inches
The top bar blank should be 19 X 7/8 X 3/4 and cut from straight grain white pine. The wedge should be cut precisely 1/4 inch deep and such that the foundation will be exactly centered in the mid-line of the top bar. The lugs should be cut so they are tapered to 5/16 inch thick at the end and 1/2 inch thick where the end bar attaches, a 17 degree angle is just about right. The end bar notches should be cut to leave exactly 16 13/16 inches for the foundation and the notches should be exactly 3/8 inch wide so the end bars fit properly. I cut top bars from white pine planed to 3/4 of an inch thick.
The bottom bars should be cut 3/8 X 3/8 X 17 17/32 inches for divided bottom bars, 3/4 X 3/8 X 17 17/32 for a grooved bottom bar. A small slice should be cut on each end of the divided bottom bars so they fit properly into the end bars. I cut bottom bars from scrap pieces of white pine left over from cutting top bars.
The end bars should be cut to the exact vertical size of the finished frame, 11 1/4 for Dadant, 9 1/8 for standard Langstroth, 7 1/4 for Illinois, 6 1/4 for Mediums, and 5 3/8 for shallows. I'm going to waffle on one item here by saying that the finished end bar should be exactly 1 1/4 inches wide, but in the process of cutting, you may want the blank to be wider so a propolis cutter can be made on one side of the end bar. The notch for the top bar should be cut 1/2 inch deep by 3/4 inch wide. the notch(es) for the bottom bar(s) should be cut 3/4 of an inch wide by 3/8 of an inch deep. If using divided end bars, two notches should be cut 5/16 wide with 1/16 of an inch between the notches. This is best done with a double stacked dado so both notches are cut at the same time.
Last edited by Fusion_power; 05-26-2016 at 01:16 AM.
NW Alabama, 50 years, 20 colonies and growing, sideliner, treatment free since 2005, 14 frame square Dadant broodnest