OK, I had a go at this today. I didn't take many photos (and those I did take are poor quality) which is a shame as it would have produced a few laughs. Anyway I will post what I have. Now, where did I put that list of excuses ...
I made a couple of decisions to start with.
I started by cutting off the 8 inch piece, but decided to keep the 3 inch and 4 inch pieces in one until I had cut all the joints. I figured it would be easier than trying to cut joinery on the end of very small pieces. I think that was a good decision, but it did come back to bite me later. (There, that has built up some suspense to keep you reading).
My next decision was to mark everything up before going any further. Busy work perhaps but, this being a schoolboy project, I was anxious to avoid schoolboy errors. Also I found this surprisingly ... not difficult exactly, but not the way I have become used to working. I rarely measure anything on actual projects, I just lay things out so they look right and cut things to fit each other. Making things to a fixed size seems alien to me now. Take the dovetails for example. I normally lay them out by eye, or use dividers. Either way I neither know nor care what size they are. For this exercise that would not do, so I had to change the way I work.
Here are the marked up pieces:
At this point I checked the clock for the first time. Yikes! I had spent 30 minutes piddling about with a pencil & marking knife and now I was way behind schedule.
I started by cutting the dovetails, and here I made my first mistakes. I don't own a dovetail saw. I usually use a tenon saw but I recently bought a 32 TPI Zona saw and I decided I would use that. Here's a tip for you: in an exam, don't use tools you have not used before.
The Zona saw produces a smooth cut and a fine kerf. Very fine. Too fine. The blades on my coping saw and my fret saw would not go into the Zona saw kerf which complicated the removal of the waste. I decided chopping it out with a chisel would take too long, so I used my tenon saw to put a thicker kerf down the middle of the waste and used a coping saw from there. Not a big issue, but stupid to have to sort out issues like that in an "exam".
Having cut the tails, they were visibly wrong despite the time I had spent on the layout. How did that happen? I don't know but you can see the 2 tails are nowhere near the same size. So I had to waste time trying to correct that. I got it better, but not 100%, before moving on to cut the pins.
Another mistake on the tails was that the angles were not consistent. I was unable to track properly with the Zona saw. I did find it difficult to make adjustments to a cut using a comparatively flimsy saw. Again, I should have stuck to tools I am familiar with. Not a fault in the saw, the fault was in my use of the saw.
After rough-cutting the waste from between the pins with the coping saw, and before cleaning out the last of the waste from the shoulders, I quickly tested the fit of the two boards to get an idea of how much clean up & fettling I was in for. First look was promising so I just cut out the rest of the waste and carried on without tackling the fit any further at this stage.
I was now over half way through at this point, 100 mins frittered away and 80 minutes left. One joint done and two to go.
Next up I tackled the bridle joint. I don't remember cutting a bridle joint before so made up the technique as I went along. I decided to cut the recesses in the horizontal piece entirely with a chisel, as they were not deep. I made exagerated knife walls at the sides and then pared out the waste between them with a 25mm chisel. That seemed to go OK. The joint goes together lovely, feeling "just right" when pushed together by hand, but it is gappy at the top. Oh well, I don't know how to fix that on a joint that is not glued, so move on.
At least the bridle joint didn't take too long, so I had 50 minutes left for the M&T.
The mortice & tenon is another example where my usual "make it fit" approach didn't work for this exercise. Usually I size the mortice to suit the chisel I will cut it with, but here I had to select a chisel to suit the required size of the mortice. Also I normally cut the mortice and clean it up (possibly changing its size) before cutting the tenon to suit. Again, that doesn't work when their required sizes are specified. Not big issues, but more care was called for.
I chopped out the mortices, and then compared this to how I had originally marked out the tenons:
Quite close but I would need to make some slight adjustments to my cut lines. 30 minutes left so I have to press on but I don't feel too pushed for time.
After cutting the tenons I found they didn't fit at all and I had to spend precious minutes adjusting things with a chisel. Not an impressive sight, I assure you, and when they went together there were definite gaps. Disappointing. I normally do better with this type of joint.
At this point I had 15 minutes left. Lots of time, so decided to clean things up before final assembly and this is where things started to go awry. I rubbed a plane over the wood to remove the worst of my marking out lines. When I came to the vertical part of the bridle joint I realised I had forgotten to cut the chamfers. I tried doing one with a No. 4 plane and it was not good so I adopted Andy's technique and used a chisel. One of the corners split off quite badly so I ended up with a bigger chamfer and bigger mess on that corner. I was spoiling the job right at the end.
Then came the biggest comedy moment of all when I came to assemble everything. I had never got back to testing the fit of the dovetails so I was grateful that they went together without needing fettling, but I couldn't find the tenon piece to assemble the M&T. How is that possible, I had it a couple of minutes ago. I was searching in the shavings under my bench when I remembered that it was still attached to the pins part of my dovetail joint. I had to quickly cut them apart and trim the tenon piece to length. So I went from being fairly relaxed to a bit of a flap over the last 10 minutes, and only time for a minimal final clean up with a plane.
The final result is not too bad. Not what I would want on a piece of furniture, but no really major mistakes. Some gappy joints and innaccurate chamfers but there we are.
I did learn a lot from this. As I mentioned, I have drifted into working methods that are more pragmatic than accurate and working to a drawing now seems a bit odd. Working to a timetable is something I never do so that was also strange. Taking the time at the start to lay everything out and mark up the joints was beneficial in the long run but it was a bit of a shock how long that took, so for much of the time I felt I had to play catch-up.