Sorry Martin Gibson but I don't think you've understood the position - and a couple of others likewise.

I didn't buy this instrument. Daughter's boyfriend did.

The next thing he did was take it to a shop to get it "set up". The shop put tension (not thrust, tension) into the co-ordinator rod (probably until it produced cracks in the rim). It thereby altered the neck angle until it was unplayably low. The shop will of course say it was like that when it first received it. The manufacturer will say it was all right when it left him. The shop that first sold it will say it was either the manufacturer of the person who did the setup.

I actually am a lawyer and I'd certainly not advise a client to litigate where proof of the facts is so difficult.

Also as it happens I do know a thing or two about truss rods - from guitars. It's quite rare for me not to be able to improve the action on a guitar fairly substantially, setting saddle height, nut height, and truss rod, and lightly dressing frets.

Also this is a six-string, not a 5, as some seem to have assumed.

Anyway, I had a chat with Andy Perkins who I know from years back, and who also sells "Countryman" banjos as one of his cheaper lines. He told me that the Countryman is so light that even 10s are too heavy and it should only have 9s on - and that because of the small head diameter he prefers to use Nashville tuning (see thread on Nashville tuning).

He also told me a bit about head tension, and co-ordinator rods and the tailpiece lever, and the bridge. On this machine the Phillips screw in the shoulder of the neck attaches the neck to the co-ordinator rod, and Andy likes to add a woodscrew through from the inside of the rim into the inside of the shoulder (where the dovetail joint would be on a guitar) to prevent the neck rotating around the co-ordinator rod.

So I took all the tension off the strings, and then all the tension off the co-ordinator rod, and re-set the head (skin) tension. The advice here about the skin tension and the fact that owner of machine is a drummer and used to setting drumskin tensions helped quite a bit, and it now makes a sort of snare like noise, evenly around the head.

Put (on Andy's advice) a dribble of superglue in the small cracks in the rim, and put a spot of thrust in the co-ordinator rod to push the cracks together. Neck angle looking more hopeful! Rim still oval so that seems to be a permanent feature now!

Tightened (on Andy's advice) tailpiece lever to bring strings almost to the skin (be careful of bending it, he said) then positioned bridge by measurement, treble side one mill back from twice the distance from nut to octave fret, bass side two mill, and brought instrument up to pitch. Feet of bridge not making a nasty dent any more. Fiddling with harmonics seems to indicate the octave is about right, and insofar as any banjo ever tunes it pretty much seems to tune even fret-to-fret.

Action now a bit too high, so remove a tiny bit of thrust from co-ordinator rod (superglue in cracks seems to have set and be doing job). Still too high, but the neck has a significant forward bow, so much leaning on the truss rod, and eventually it's nearly there. Any lower and I'd have to dress the first couple of frets to avoid fret rattle on open strings.

The action is now about a pound coin under the bass string at the octave (that's 3.5 mm, or 140 thou, a little over 1/8th of an inch for those using inches) which I reckon is reasonable for a banjo. There's no real effort in it with those light strings.

I quite like the sound, but three things (apart from oval head) bother me a bit. First, the G string "honks" a bit louder and ,well, sort of "honkier" than the others and I note it's an unwound "G". I might try a very light wound G and see if it gives a more balanced tone. Second these light strings are so light already that if you're used to 13s on an acoustic guitar, you tend to pull the string down tothe fretboard, rather than just enough to fret it properly, so it's really easy to pull individual notes sharp, rather like the problem you can get if you take a guitar down to open C tuning without going to heavy guage strings. Third, the rim it is easy to put a little bit of push or pull in the neck, particularly as the top end of the strap attaches to the headstock, not the other side of the rim from the tailstock, so again making things go a bit sharp or flat.

Anyway, it's a huge improvement, and I'll bully a real banjoplayer I know into trying it in a day or so and see what he thinks.