For general use I have found one of the cheap RDG 1-10mm keyless chucks
very adequate and when new I tested and saw a runout of chuck + arbor + machine
(old Meddings M2) was around 3 thou TIR.
For more exacting work I use an Albrecht 0-1.5mm
which is significantly better (and significantly more expensive).
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
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
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
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,
-- Peter Fairbrother
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.
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