Hi everyone, hope you are all well. I recently bought a used Chester bench top mill and I’m really pleased with it. One of the attractive parts other than the price was the fact that it had been fitted with a DRO – nice little blue thing, inexpensive but works well. I have been persuaded to purchase a larger head unit, one that’ll do various calculations, bolt rings, trigonometric calcs etc etc. But, when purchased over the internet, no mention of scale types was made. My machine has the magnetic type and I hope that it is compatible with the new head. Does anyone have any experience of swapping types on their setup? Further, there will have to be some minor butchery in the workshop as the cable that comes out of the magnetic reader terminates in an RJ-11 plug, whereas the new head requires the DB-9 interface – there is therefore an obvious question about pin outs. Again, has anybody had experience of doing this particular piece of surgery? If my eyes weren’t fading I’d leave well alone – the magnetic scales have been fitted so well by the previous owner (alas a silent key) that I am loathe to change them if I can avoid it. So any help, at all, will be gratefully received. Aye, Peter.

Les, Chris and Stuart – thank you for your excellent input. As Captain Darling would say – Oh Bugger. I think I’m going to have to get me a pair of magnetic scales and fit them after all. It leaves me with a perfectly serviceable, albeit second hand, Arceuro system. I may try to adapt it to fit my ‘35 Drummond M lathe, but I’m having difficulty in imagining the value of that – it may end up on eBay. Thanks once again for your help, it is much appreciated. Peter.