I am brand new to this forum, although I have been lurking here for
many years. I had a question that I thought you guys might be able
to answer so today I joined.
I recently came possession of an old GRS BenchMate, it looks very
similar to what is now marketed as a “BenchMate Plus” model, the
only difference being that this one also has a heavy handheld
ringholder. It is missing the small U shaped holder for a ring, but
other than that, it is complete.
I have been trying to bead set stones for a while, with varying
degrees of success. I’m hoping that this devicewill help, as all I
was using before was a universal holder mounted on a piece of heavy
metal, which in turn was mounted in a large Craftsman Bench Mate
ball vise.
My question is this: The newer model comes with a 2 part holder
(making an L), mine is one piece. The newer holder looks as thoughit
gives one the ability to raise and lower the ring holder up and
down; mine does not. Here’s a link to show what I’m talking about;
the up and downmovement is shown in figure 5.
How important is this feature to you that have this device? I do not
have a jewelers bench; I use an old office style desk and it is
really alittle too low to mount this thing and I’m thinking that it
will really matter. If I ever decide to get a desk microscope being
too low would be good, because at that point it would be just about
at the right height. I’m getting old and ergonomics are really
beginning to matter to me. My space is limited in my little-bitty
studio and something would have to go if I’m forced to get a
jeweler’s bench. The guy I spoke to at GRS suggested that I might
could get an adjustable height bracket and turn it upside downto be
able to raise the thing; do any of you have one and use it this way?
My primary art is gemstone carving which is why I really want to
keepthe desk; it has a large formica top which is great for an easy
clean-up of rock-slurry and all the water drip or holders I might
have to use. Any input would be really welcome.
I have my Benchmate set up like Figure 4 and I just adjust my chair
as needed for the task at hand. Sometimes I’m higher to work on top
of a ring and sometimes I’m lower to evaluate side views, etc. The
raise/lower feature is solid set, not easily adjustable with out
unscrewing and rescrewing the bolts that hold it in place. I have
also used the adjustment plate when I was in an environment where
the chair adjustment just wouldn’t do.
It is also shown briefly in the video at 3 minutes 27 seconds,
though that one isn’t configured for a large change in working
height.
The bracket is quite stable. You can use it to raise or lower the
working height - high for a bench pin, low to hold an engraving
block. Consider it a semi-permanent adjustment, not something you’d
make frequent changes with, though you could. I suppose height
changes might take 5 minutes.
I looked at the instruction set you used to illustrate your
question, and couldn’t quite figure out what you were really asking.
What I think you were asking was why the support arm can be
adjusted through a limited range of angles. (the arm that links the
ring that holds the ring clamp, with the plate that attaches to the
rotary joint.) What that’s really for is to adjust where the center
of lateral rotation is in relation to the top of the ring clamp.
(There is a big rotary joint directly behind the ring clamp, on the
plate that the dovetail sidepieces fit onto.) What I’m talking about
is the center of rotation generated by that joint. The adjustment on
the arm lets you move the ring clamp support such that the center of
rotation relative to that joint can be either directly in line with
the top of the (normal) clamp, or slightly above or below, if you
prefer.
Most people never mess with it. It’s sometimes helpful to adjust it
if you’re using a microscope. If you get it in the right spot for
whatever you’re working on, it’ll keep the work piece from swinging
out of view if you rotate the clamp from right-to-left. But you’ve
still got tracking issues with fore-and-aft, so generally it’s not
worth fussing with. (You’ll lose your adjustment if you reclamp the
piece, so you’ll have to tweak it again. Really not worth fussing
with.)
For stone setting in rings, I use the "Inside Ring Mandrel". Its
very secure and rigid in use, which makes it ideal for hammering.
Great tool, I use the version designed for use in an engraver’s
block and I love it. One word of caution, however. It uses a split
collet and a tapered expansion screw to apply outward pressure on the
ring to hold it from the inside with friction. It is possible to
damage a ring with this tool, similar to the damage caused by using a
ring stretcher. If you put too much pressure to the expansion screw
in an attempt to keep it from turning, it can stretch the ring. If
the ring is delicate or has thin portions around stones or solder
joints in thin parts of the shank and so forth, you can easily rip it
wide open with a single twist of the allen wrench. It can generate a
lot more force than might be apparent to the casual observer.
If you find yourself with a ring that you might be uncomfortable
putting on a mandrel and trying to stretch a little with a leather
mallet, or if the thought of someone putting it on a ring stretcher
to ease it up a quarter size makes you break out in a cold sweat, it
is probably delicate enough to warrant caution when tightening the
expansion screw.
In any case, be aware of where the split in the collet is and index
the ring and collet so that the split is at the thickest / strongest
part of the ring, not under a stone seat or at a sizing joint or
other comparatively weak spot. The split is where the stretching
effect is greatest and the tighter the screw is, the greater the
force.
It is also wise to orient the ring so that any sideways or rotating
pressure is applied to the ring in the direction of tightening the
screw. Hammering or pushing in the direction the screw would turn to
unscrew can cause the ring to be released suddenly and without
warning, especially if the ring is delicate and therefore not
tightened down past just snug.
The GRS Inside Ring Mandrel is a wonderful holding tool. I bring
these limitations up not to scare anyone or down-grade this very
useful tool, just to point out to potential users the potholes in the
road that I found the hard way.
Thank you so much for posting this David as I have just recently
experienced it for the first time after years of using my inside
ring holder. I was doing my best to keep a ring very stable for
setting and engraving. I tightened it further as I was getting a bit
of rotation on the holder. I either revealed or created some small
cracks in the pierced under gallery by doing so which I then had to
repair. In the future for rings with delicate sections, I might
consider a different holding method just to be safe. Such a
wonderful, functional tool though. Cheers-Carrie Nunes
I agree with David, be gentle. The first time I used it I expanded
the ring too much and mis-shaped the bezel.
I use the U shaped piece to support some rings. But the extra inside
plastic pieces in the setters pack are great for setting wide rings.
OK benchmates are great but you need to trial and error as with
everything.
Still the benchmate is one of the best additions to my tools. Using
it the other day I thought about how I made rings before I had one.
Boring and hard and less accurate.
Newbies get a good torch then get a benchmate.
When I set a bezel into a ring band I cut out the space for the
bezel by clamping shank into benchmate then swivel benchmate at lowest
level to file shank to fit bezel profile.
These things are way far cool but need some practice, as do all
tools.
I’m not sure if I’m replying correctly; just wanted to thank you
guys for the replies. I put the plate on my desk and it’s apparent
that I’ll have to get the extension plate; everything will be a few
inches too low if I don’t.
I wondered about the inside ring mandrel; it does look pretty cool
and it’s nice to know that you guys recommend it.
I’ve already made an accessory for it; I had a universal holder with
a threaded hole and found a screw that fit it, cut it off to length
and soldered the screw to a heavy piece of brass bar which is held
by the jaws. It works surprising well.