I was tempted by the Chronos offer of 2 Soba toolholder for £26.40. A saving of perhaps £3 each compared the the genuine A&R ones but they are currently not listing them on Ebay.
I'd looked at this thread…
**LINK**
…but thought it might be worth a punt.
My QCTP is an A&R Precision one.
To get the toolholders to fit at all I had to grind the slot wider (Dremel with a cheap AlOx wheel) before the retaining block would fit. On the plus side the holders do seem to be file-hard so grinding was my only real option. The 30 thou mentioned in the above thread seems about right – it took quite a bit of work to get it to fit.
The worst draw-back IMHO is that the bottom ledge of the holder is at least 1mm thicker than my A&R toolholders which means that my normal 10mm tooling is unuseable – above centre when wound right down. There doesn't seem to be a good reason for this.
One of the set-screws for the height adjustment was bent and the other was cross-threaded but luckily the screws are cheap enough but the savings are soon eroded if you have to change the screws. The socket screws are marked 12.9 but this is quite feint and poorly formed. The flange on the knurled adjusters are also slightly too big but that's fixable with a quick slim.
So, these are about ok but if like me you're tempted expect them to need a bit of fettling and so they may not be that cheap in the long run.
HTH
Jon