There's no need to have split bottom bars if you're not going to use foundation - but that's the cheapest format from the supply houses, so that's what I buy as frames 'for sale'. I use 2x verticle bamboo skewers per frame to support the comb, rather than monofilament fishing line, the acceptance of which was always a little erratic.
I drill holes in the top bar (using a simple jig to ensure accurate positioning) and feed the skewers through the top bar and down to the divided bottom bar, where they are trapped between the split bars, and held in place (if necessary) with large clothes-pegs. Wood glue is coated onto the top 2" of skewer prior to insertion into the top bar - that's straightforward enough.
Gluing the skewer to the split bottom bar is a bit of a faff, but I think worth the trouble. With the clothes-pegs holding the bottom bar tight, trapping the skewer, a dab of glue is placed where the skewer contacts the bottom bar, and allowed to dry. When dry, excess skewer length can then be cut-off, and more glue added to either side of the skewer at the bottom-bar contact point. Finally, popsicle sticks are glued into the foundation groove between the skewers. This is typical of the results:
I'm finding that this method of making foundation frames is the best I've found so far - it would be nice to speed the operation up a little - if anyone has any ideas .... ?
BTW - for my 'not for sale' frames, I use solid bottom bars and drill holes in them exactly the same as the top bars - thusly:
Makes assembly a whole lot easier.
LJ
PS - are you in a position to make your own frames, or do you need to buy ?