I e-mailed this question to Gareth before I was able to post on here. Now that I can post on Simple Bees I thought I’d repost it here with the reply in case it’s useful to anyone else …
I met up with my allotment neighbour to site the hive ready for hopefully getting a swarm. She’s done a fantastic job at building the Warre but she hasn’t put the grooves in the under the top bars. We agreed that I would do this and that I would do the modifications that you showed us on the course. I just wanted to check a couple of things about the modification. I thought my memory and the quick doodle I did would be enough but I’m not quite sure of a couple of things.
You recommended putting a piece of wood about 3mm wide and about 7mm proud along the underside of the top bar to act as a guide. I’ve forgotten whether or not you said you glued this in. I would think this wouldn’t be a great idea on the inside of a hive. If it’s not glued how is it fixed in? Are the dowels on each end of the top bar glued in? Also, should there be a gap between the dowels (or the ends of the guide if dowels aren’t being used) and the inner wall of the hive or should they be as close as possible? If there is a gap how large should it be?
This is the reply I received from Gareth ….
For comb guides, many use lolly sticks (Tesco, Lakeland etc). If they are put into a tight grove, glue is not needed. If not using a groove, then use waterproof PVA adhesive. Without a groove, the sticks will need some tape or pins to hold them in place while the glue dries. Or try superglue!
Dowels: 6mm wide (no wider) located about 3-4mm inboard of the hive wall – enough space to put a knife between the dowel and the hive wall should you need to remove the comb for detailed inspection. Glue as for the comb guides although I don’t always bother if the dowels are a tight fit.