This section is from the book "Cassell's Cyclopaedia Of Mechanics", by Paul N. Hasluck. Also available from Amazon: Cassell's Cyclopaedia Of Mechanics.
The sketches show how the several parts of a top sash are formed with the mouldings scribed so as to fit together. At A in the above drawings is shown the tenon and mortise of top rail and stile, C is a joint between the bars, and D is a dovetailed joint between meeting rail and stile. At E is shown the joints between the bars, tenoned and scribed ready for fitting together. If desired, these joints can be made more secure by strengthening with dowels, as shown. The scribing should be done with a scribing gouge.
Scribing and Fitting Sash Bars and Rails.