Thanks a lot. I think Teng stuff is usually pretty good.

Decided to risk an ebay purchase, so if it turns out to be a fake it'll serve me right.

Company with the lowest price was called TW Tools, which MIGHT stand for Trans-World Tools, or Taiwan Tools (which would be ironic).

Even if it was made here, though (Teng are Swedish?) you wouldn't necessarily be able to buy it here.

However, going by some photos she sent me this morning, there isn't much movement on Scottish roads currently, so delivery may be delayed.

Edited by edlithgow on 02/03/2018 at 09:28

I used to use an impact screwdriver on the crosshead screws on jap bikes, simple but effective.

Got two. Sometimes they work, often they don't. Could be my technique of course.

A quick tip

pack the cross of the cross head fastener with course valve grinding past,

Now tap the bit into the fastener

Now put the impact onto the bit and gently hit the impact.

The grit in the paste grips and improve traction preventing cam out.

And from reading your posts I betting you have at least one pot of the stuff laying around.

I've heard of that trick but never tried it. Rather surprisingly, I think I have seen valve grinding paste for sale here. Might get some.

I've only ground valves once (1800 Marina B series). Probably didn't need it but I had the head off to replace a broken piston ring so thought I might as well.

I also used it on plate glass in the RE to true up some quite expensive but woefully abused (not unusual with the army and tools) Arkansas natural oilstones in the engineers stores. When finished they gave a very nice edge, and, used with a jig, a very accurate one.

My old Dad, a marine engineer, gave me the tip about using a file, when an oil pressure sensor sheared off leaving the thread behind. Worked a treat, but it was not a large threaded diameter, and a light alloy component in a cast iron block. The one and only time I've needed to do such a job.

Things can get much more tricky and I met someone in vintage circles who got a difficult item removed by spark erosion (iirc).

Spark erosion was the favoured method to remove broken taps in expensive components at the engineering factory where I worked, but not readily available these days (especially not in Thailand) and would,I guess, be fairly costly even here.