You're far too kind Richard, as ever (and you too MG) - it's just that old 'Necessity Mother and Invention' thing plus I've plenty of time on my hands. The cutter is just a fly-cutter bit in HSS bought with a few others for a few pounds - but it's done a bit of work and I only sharpened it once I think.
The 'milled flat' description was a bit of short-hand really - there's a brass pad between the end of the screw with the (small) tommy bar and the flat side of the toolholder. It's there for the reason you give - to keep things square. What I did was part-tighten the pad against the holder to keep a bit of friction on when using it - not really a proper approach, as an adjustable D-shaped gib strip of some sort the whole length would have been better. And then some micrometer dials would have been nice, and and and! But hey, it did what I wanted on the day and it was only for private consumption.
By all means stick it in the tools section, hadn't thought of that - thanks.
I wasn't thinking of making any others, and I don't have a drawing - euphemism for 'actually, I can't draw' (I just did a rough sketch and then poked about for bits of scrap and took it from there). If anyone was really keen I could probably convince a mate who's truly competent to draw something up and maybe incorporate some of the improvements it needs. Be nice to think there was novelty in the thing, but think probably not (from the patents angle).
The problem with all these things is that the time taken to make them (by somebody properly-skilled using good materials rather than by optimistic lunatics out of farmyard scrap) makes them a worse financial proposition than the 75 pounds odd mentioned above for a perfect job + the right to complain afterwards! I have a whole box of things that took me a day or so to make and which work well for me, because I'm too mean to buy them, even if they exist. Clutch centre removers, bearing pullers, fork stanchion pullers and pushers, mag pinion and camshaft pinion extractors etc. I know many of us have the same or similar.
I was looking seriously the other day, guided by two better-informed others of our number, at those 'chuck pullers' for removing small bearing inner races that go tight up against stuff. . . they exist, but boy, at over 100 Euros and then needing some extra bits for the sorts of applications I had in kind (mag bearings in that case), I reckon it was better to have made my own ugly things to do the same job. And then there are things that just aren't really feasible at home for the want of tough enough materials - flywheel pullers for magnetic flywheels come straight to mind as I bust a newly-made mild steel item only yesterday trying to get the 'volant' off a (- very sorry -) classic Vespa scooter. Same story trying to make a tappet-guide puller for my Enfield twin - just not a sensible option. Sometimes you have to pay, or do without.
But I am tempted to make a nice valve guide remover having seen the brilliant torture chamber instrument posted on here recently! Personally, I enjoy playing in the shed, failures included, just as much as getting out there and breaking the toys on the road (just so they have to be mended). Funny thing is, BSAs don't seem to go wrong very often . . . I THINK that makes me happy.
