A few of you may remember that last July members were good enough to comment on the cheapo coaxial dial indicator I had bought. It had a dangly probe and as such was quite useless. You might further recall that I compounded its uselessness by snapping the probe holder.

Having recovered it from the bin I managed to get it working by machining a new holder that was sufficiently thick to be gripped by the instrument's beam (See 'Limp Probe' if you're interested.) But to be honest, my replacement was not as elegant or accurately shaped as the original.

It was then that Jason, on this forum (16/7/21) suggested that if I had shortened the clamping screw on the beam (to modify the point where it 'topped out&#39, or fitted shims on either side of the holder, all might have been well. But, of course, I had already broken the holder!

As it happens, MSC Industrial in the US stock the holder that fits all these Chinese(?) indicators at $9 (I wonder whay!), but rather unhelpfully they won't send them to Europe. However, through great generosity, Tom Lipton of Ox Tool video fame, bought me one and sent it to France.

Lesson number one: The spare is no better than the original. PLEASE NOTE IF YOU CONTEMPLATE BUYING THESE INSTRUMENTS.

I now implemented Jason's shimming idea – I baulked at the screw-shortening as a bit fiddly. Fiddly! F-i-d-d-l-y! Try shimming the holder in the beam to discover what fiddly really is. It took me about two hours but with a 0.016" shim you can get sufficient tension – a bit too much, actually – to pre-load the probe i.e. it ceases to dangle uselessly. I subsequently got a flicker through about 0.01" on the needle when sweeping round an Austin Seven cylinder bore with the mill running at 100 rpm. (Thanks again to the forum on the advice on coaxial speed). This was about the same accuracy I achieved with the holder I made used around the inside of an A7 piston skirt.

ALL THIS SAID, I bit the bullet, as I suggested I might, and bought off ebay a used Blake Economy (god knows how old). It cost $200 plus taxes etcetera. What a difference! Straight-out-the-(patinated)-box, conspicuouslly smoother action and very slight flicker of the needle between two 0.005" graduations. Only two probes mind you, as opposed to about eight with its chinese cousin! And no special (crappy) spanners….or gibberish instructions or pedigree from someone who'd probably never seen it.

Lesson number two: You do get what you pay for; so pay the money.

Tip: Might be worth setting up on a cheapo and fine tuning on a decent instrument.

Best from Martyn for a peaceful and healthy 2022.