I see Chronos do a Soba 6" rotary table with dividing plates and tailstock
for 139 quid. Any comments on the quality of Soba stuff? Anyone have one of
these rotary tables?
Cheers,
I haven't seen one of their rotary tables but if their milling vices are
anything to go by, I wouldn't hesitate. I have a small tilting milling vice
from them that is beautifully finished and thoroughly accurate - a nice
piece of kit to look at and use. I suspect therefore that their quality is
very good. ISTR that I got it from Chronos.
Mark
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Thanks - I'll take that as an indication that the Soba stuff isn't grotty,
then. :-) Just did the 'click buttons, stuff shows up' thing on the
Chronos eBay store.
I bought one a while ago. I've not used the dividing set up yet but
have had no real problems with the rotary table and tailstock.
General quality is good and, although the graduations are untidy, they
are accurate.
One minor niggle is that the mounting surface for vertical mounting
projects slightly above the level of the table when used horizontally.
Thus large work mounted on the table has to be spaced off a little to
clear it. When I have a few spare moments I intend to machine a
little off the mounting to rectify this.
Russell.
I have the 6" Soba RT and it seems nicely made and is an absolute snip
at the current price. Mine does not have the problem mentioned below
with the mounting base protruding above the table, but I am still
going to need to machine the vertical base because the T-slots on my
VMC are not far enough apart to fit when used in vertical mode.
I haven't used it enough to give you an opinion on it's accuracy but I
don't anticipate any problems based on my playing so far. If you
intend fill in the gaps in the dividing range by making your own plates
then you should allow for making new sector arms as well because ISTM
the ones supplied won't be very practical for plates with more than
about 50 holes.
I also bought the Soba 4" modular milling vice and it seems also nicely
made and quite accurate but jaw lift is a bit of a problem - any
parallels near the moving jaw come loose straight away under even light
cuts. I don't mean to hijack your thread, but if anyone knows a cure
for this I'd be interested to know it.
Cheers,
David
Maybe this is an issue which the makers have addressed.
That's something I'll need to check when it arrives. What are the spacings
on the rotary table?
I'll cross that bridge when I come to it. No plan for custom dividing plates
just now - don't even have any specific plans to use the ones that come with
it (apart from maybe making an abney level at some point). I just reckoned
that the price for the full kit was very good compared to almost any other
6" table on its own, that it was worth the small extra splurge.
Tap the job down with a hammer while tightening? Or, shim appropriate bits
of the vice, or replace it.
Use a 'pull-down'.
You will need to use a fixed font to see the workpiece below resting on
two parallels, with a parallelogram shaped packer between the job and
the moving jaw. This is a 'pull-down'. Use another parallel to rest it
on while you initially grab everything, then slip this parallel out and
tighten up. If the proportions of the pull-down are right, the friction
will hold things in place and the offset forces (a moment) result in a
downward force on the job. If the proportions are wrong, the whole thing
goes poing in your face as you apply pressure.
If the pull-down is too thick, you can cheat by tilting it a bit,
clockwise in the diagram. It does not need to, and should not, have
sharp corners. You can take a bit of flat stock and file a bevel on
opposite corners for just over half the thickness.
Another narrow packer can usefully be placed between the fixed jaw and
the job, opposite the pull-down. This ensures that a
not-perfectly-square job is sitting flat for making the top parallel to
the bottom.
Conversely, where the job is pushed directly against the fixed jaw, you
are making a face square to an existing one, and one parallel underneath
is theoretically sufficient.
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Dunno, I'll have a look when I get home tonight...
Tried tapping it down, I'll have to have a look at the vice. Maybe
there is provision for adjusting the tightness that the moving jaw is
held down.
Cheers,
David
This sounds useful - how much of a bevel do you need ? I'm guessing a
millimeter would be enough ?
Also useful...
This may actually have been part of the problem - I'm not certain the
faces I was gripping were parallel to each other and it might have been
an idea to put a bit of round bar between the work and the moving jaw.
Thanks for the help,
David
parallel to
underneath
Trap a piece of 16 gauge aluminium welding wire horizontally between
the jaw and the work. It will deform as you tighten the vice and allow
for non-parallel workpieces.
AWEM
No need - it doesn't fit the mill's slots when vertical.
Worth a look. That said, I tried to 'fix' a cheap drill press vice that had
bad jaw lift by removing some material here and there. It ended up with the
moving jaw sitting too low and the leadscrew was binding. It's now in the
'experience' box...
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