@Dave Shepard: Here there is no cleanup. It helps that the standard tenon in traditional French carpentry is 30mm (so a bit over 1") which corresponds nicely to the standard chain size. Tenons are rounded by hand on their long edges to ensure that they don't foul the rounded bottom of the mortise which is, in any case usually cut to 75 / 80mm depth for a 70mm tenon. In modern construction we're usually working with treated commercial pine 75x225mm (referred to as an 8/23 and very roughly equivalent to a 3"x9").
I wholly agree with the cost issue (factor in also the fear factor of the chainsaw). But that is factored out here by the time saving. Since we're not 'roughing out' but just cutting with the mortiser, our time saving is very real. To take TIMBEAL's example from above: Let's say that 8 mins is a realistic time for cleaning out a bored mortise, and that boring that mortise took another 4 mins (from memory, that seems generous), that's 12 mins from layout to mortise being cut. I would count maybe 2 mins to set up the mortiser (assuming that your using a guide and not just freehanding), and another 3 to cut it. So a time saving of 7 mins per mortise. For a standard truss there are at least 6 mortises so 42mins per truss. Let's say 3 trusses in a house (Fairly normal for a house with "traditional" roof carpentry), so just over 2 hours. At a total cost of employment per hour of around 20€ for a newly qualified carpenter (just to pay the wages), that's at least 40€ extra labour per house. Each extra minute taken per mortise costs an extra 6€ per house.
What I've been wondering for some time (and am now wondering out loud) is what is the fundamental difference between our countries that makes for this difference in working practice? Is it simply employment cost? Or is it a more subtle difference in attitude.
Please don't take this as a criticism. I'm trying (in my own way) to push a more "artisanal" model where the work is valued not simply for its cost, but for how it was made. That is to say, that there is a value for the future owner in knowing the care and precision that went into the cutting of a mortise, even if they will never see the mortise itself.
@TIMBEAL: Already watched nearly all of your videos over the last few years. I'm more tempted by a modified boring machine, than by a chain mortiser, but a few years of trying to sell this idea to clients may cause me to drift off-piste on this one.
