I have slowly been replacing my Jacobs keyless chucks with the 0 -13 mm ones from ARC. I got 4 Jacobs chucks with a new lathe and I don't know whether I got a bad batch but all so far have overtightened themselves and exploded. At first glance it looks as if the jaws are too brittle, over hardened ?
The Arc ones are OK but you have to give them a quick twist as you start to drill with the larger drills, sometimes you have to use a strap wrench on them to release on the larger sizes if you get all excited but they do release OK Or perhaps it me getting weaker in my old age.
Got keyless all round now, twin spindle drill, 3 different sizes on the Bridgy and 6 between two lathes, still got a couple of Jacobs keyed chucks but these are useless and only good for reducing plain round drill shanks into ploughed fields.
Sorry but I think Jacobs should have stuck to making cream crackers.
I've had a Validus Super 3mm to 16mm for about 10 years and wouldn't be without it on the BP mill. I've never had occasion to question its quality or accuracy. Personally I've never heard of locking or non-locking version so can't answer that. The only time I've had a problem with the Validus is if the drill has slipped, which isn't often, and it can self tighten a bit and need some assistance to loosen, I believe that's par for the course with keyless chucks in general. Years ago, maybe 32, a machining instructor did say they could be prone to locking on when worn and used near maximum capacity, I've not had that problem yet.
Can't find a source of Validus chucks in the UK. Think I'll probably go for a 16mm chuck, rather than 13mm, from AET.
My thinking is that while I won't be using it at capacity (I have better holding systems for that, eg ER collets) a 16mm chuck is wider then a
13mm and thus easier to turn. Also using a bigger chuck at below capacity may mean it doesn't need as much force to undo - my hands are not strong, I need to use extension sleeves for many of those tools which are sized so that strong hands will just not break them.
AET, reasonable chinese quality, should be okay, as it's for the X3 mill which isn't hugely accurate anyway (unlike the BCA, which is getting better every day :)
Though I did see an unusual keyless chuck in a US training film, which I can't find a reference or name for. You pushed a ring ?up and it opened fully, then inserted the drill and pulled the ring ?down, and the jaws closed on the drill no matter what size it was. Then a half turn of a ?different ring clamped or unclamped the drill.
Very quick to operate and seemed entirely tight - didn't slip even on large blacksmith drills in mild steel.
If anyone knows what that type of chuck is called then please can they let me know. I can't find it on Google, it's too overwhelmed with keyless chucks for handyman drills. Thanks,
I'm sure I got the Validus from J&L but they don't seem to sell them anymore. They do do a number of other makes, some with good names as I understand it and pricey, some more unknown and cheaper, so a difficult choice maybe without further feedback from others.
Regarding the US film, it sounds vaguely like the Coventry tool holder quick change unit I have on the Denford Triac regarding the ring rotation but not the up/down action.