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Frames, to suit the Kirchhain Type Mating Hive

This drawing shows the dimensions of a Kirchhain frame and the space that it occupies. The three types of top bar that are depicted by the coloured outlines are illustrated in the drawings below. I used a drawing similar to this to devise the layout of the large frames that will fit into a B.S. National hive.

	This is the frame that I developed to overcome the floppy comb breaking off. The rods were cut from hardwood kebab skewers and they varied a little in diameter. In order to overcome this variance a special very slow spiral 3.5 mm twist drill bit with original shape as shown in grey was ground to the profile shown in red and arranged to drill at the 76° angle using an industrial die grinder at a very high speed, but slow feed rate, with a constant jet of damp compressed air clearing the chips and cooling the bit. The drilling speed of 10,000 rpm resulted in stepped holes that were very clean.

I use the word frames quite loosely here as most of the Kirchhain frames are just top bars, but some developed by Peter Springall have wire rims and some others have wooden dowels to stiffen the sloping sides. This latter type was developed by myself, when I used the plywood forerunner of the Kirchhain nuc, because I found that the row of cells that were immediately below the wooden top bar were often left empty by the bees, which made this line of cells very weak and prone to break of if there was any weight in the bulk of the comb.

This drawing shows the dimensions of a Kirchhain frame and the space that it occupies.

The three types of top bar that are depicted by the coloured outlines are illustrated in the drawings below.

I used a drawing similar to this to devise the layout of the large frames that will fit into a B.S. National hive.

The plain topbar is often supplied without the central groove, that can be used for starter strips or just a bead of melted beeswax. If grooves are desired it is fairly important that they are cut in a 'blind' fashion otherwise the comb can be joined to the top of the sloping sides of the box. The lug recesses that the bars are located in are 10 mm deep and so bars of up to that thickness can be used.

Using the stepped form shown here the setting up for the grooving is simplified, but the notches need to be cut in a separate operation.

The form with the scalloped recesses is sometimes supplied as standard with the nucs and has the benefit of being easier to remove if you have thick stubby fingers and the gap that occurs between adjacent recesses is a useful place to put a queencell.

This is the frame that I developed to overcome the floppy comb breaking off.

The rods were cut from hardwood kebab skewers and they varied a little in diameter. In order to overcome this variance a special very slow spiral 3.5 mm twist drill bit with original shape as shown in grey was ground to the profile shown in red and arranged to drill at the 76° angle using an industrial die grinder at a very high speed, but slow feed rate, with a constant jet of damp compressed air clearing the chips and cooling the bit. The drilling speed of 10,000 rpm resulted in stepped holes that were very clean.

The 100 mm rods had their tips dipped in pva glue and were forced into place so that the end was flush with rim of the hole at the point nearest the end of the top bar. After the glue had dried the slight protrusions were sliced off using a curved knife blade and a quick touch on a belt linnisher, did the final smoothing.

The grooves that are faintly outlined in grey were also made with a special cutter, which was developed so that the starter strips required less molten beeswax to fix them in position. This cutter started life as one that would cut a plain 5 mm wide groove... The cross section of it's original form is shown at extreme right. To modify it I mounted it on a spindle and placed it in the chuck of a lathe and fitted a die grinder onto the slide. The 30 mm grinding wheel was spun at 10,000 rpm and gradually traversed into contact with the spinning cutter. The tip width was reduced to 2 mm and as a result of removing the material the cutter ended up 4 mm wide at it's maximum thickness and of the profile shown in the inner right view. For ease of drawing the cutter is shown with eight teeth, but the actual cutter has nine teeth at 40° intervals.

Grooves for fitting foundation normally have a 3 mm width... Using this cutter the bottom of the groove is 2 mm wide, but the sides of the groove flare outwards. The groove has a wider effective width the deeper that it is cut. This means that you can set it to produce a shallow groove 2 mm wide or if you require a groove 3 mm deep then the mouth of the groove is 3 mm wide, because of the progressive curvature of the sides of the groove, foundation is easily deformed into the narrower bottom of the groove which then requires less liquid wax to fix it in place.

Peter Springall's version

Originated... February 2003, Revised... 10 March 2003,