David, Howard et al,
I believe glazed doors in architectural work of the eighteenth century were often made using the same techniques joiners used for sash work. But, when it comes to the barred glass doors for high-style furniture, I believe cabinetmakers typically used the two-part construction being discussed in this thread. In which case, I'm a little puzzled about the relevance of a discussion of the differing sash tools/techniques used by joiners in England and the colonies/U.S.
But I do think it may be worthwhile discussing why cabinetmakers developed an approach to glazed doors which is so different from that used in sash work. I certainly don't feel I've arrived at any definitive answers to this, but think I can see some advantages when considering the variety of patterns of barred glass doors which seemed to abound in eighteenth century furniture.
For one thing, the separate "astragal" and "slat" pieces readily allow for differing joinery of the two parts as conditions require. For example, in the already discussed case of an hexagonal pattern where three elements meet at one point, the face astragal pieces can be neatly joined in full miters while the slat pieces can use a combination of miters and a V-joint for registration and rigidity. Same goes for simple grid work, as the slats can be cross-lapped while the astragals can be mitered. Some types of astragals with flats at the face might lend themselves to sash joinery, but many of them do not and really require full mitering. In line with this, Sheraton mentions lapping curved and straight slats, again allowing for registration/accuracy of the slats and mitering of the astragals.
Another, complementary, consideration might be strengthening/stiffening the astragal/moulded elements themselves. As already mentioned, the "astragal" portion of late seventeenth century walnut pieces were of cross-grained construction. In that case, long-grain slats definitely would be needed to give integrity to the whole structure. In fact, conjecturally, it may have been this particular situation which gave rise to the two-piece type of construction. I don't know if cabinetmakers of the eighteenth century followed up on this, but it would have been possible to re-enforce curved astragals (sawn-out and sent out to the turners) with glue laminated slats. Sheraton's text would seem to suggest this possibility, but Hayward appears to cast doubt on this being a common practice.
The final point is also interwoven with the previous ones. While the two-part approach has more individual pieces to assemble, I believe the assembly is simpler at any given point. In other words, if you start with the astragals, all you really have to be concerned with is keeping them flat on the backing board while following the pattern and fitting the miters. The slats can then be installed without worrying about the appearance of the astragals/miters at the face. Alternatively, if you start with the slats, you can concentrate on accurately following the pattern and keeping the joinery accurate/sound without worrying about the appearance of the astragals. Those can then be fit/mitered as dictated by the structure of the slats. In other words, there are fewer operative variables at any given step.
I'd be interested in other's thoughts on this.
As to the use of a plane or a scratch-stock, that is obviously Howard's choice. If he can find an older plane of the proper size/profile and all of his astragals are straight and relatively mild-grained, then it may well make sense for him to go that route.
Failing that, though, unless he is planning on making a number of pieces using this profile, I have to wonder if a scratch-stock doesn't make more sense than special ordering a moulding plane. (And, yes, I'm including a Stanley/Lie-Nielsen "beader" under this heading. They are, after all, simply commercial versions of scratch-stocks, in metal). And, if he follows the traditional practice of using a piece of saw blade or scraper for the cutter, it will already be properly heat-treated, needing "only" to have the profile filed in.
In the interest of providing a little more information on this approach, I've scanned a little more information from Hooper's _Modern Cabinetwork ..._. The PDF file can be found at:
http://www.planemaker.com/photos/s-stocks.pdfHope this may be of some help.
Don McConnell
Eureka Springs, AR