I had a closer look at my No. 83, little odd to say the least. I drew a rough trace of the briar to show better. The wide mortise is in correct alignment with the stummel, but they drilled the draw hole angling away as shown, probably because of the sharp angle the mortise is to the bowl. The highlight shows the position of the filter. The effect is that the smoke bypasses about 1/4 of the total length of the filter, plus the filtering process itself is pretty shoddy, nowhere near as effective as the typical filter set-up, where the smoke is drawn from one end of the filter to the other, mostly through the filter, in the case of Medico and Dr. Grabow, and around the filter in the case of the Savinelli.
The Falcon or the Sav styles might work better, except the mortise is so wide, doesn't look like filtering will get done, because the mortise opening and tenon holding the filter is much wider than the diameter of the filter. If the filters were shorter they would still slip down to the end of the mortise, on my particular model. Pretty wide open draw, even if the draw hole is in line with the mortise/tenon opening since it is really wide. Have no idea whether this architecture is similar on other models...?
The set-up doesn't bother me much, but if I didn't want to buy the Falcon filters for this pipe, the only option is to go with Sav, and figure out a way to keep it from slipping down to the end of the mortise, because they're quite a bit shorter than the other filters.
