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Ergonomics and optics advice


#1

I wonder if anyone can give me some advice as to proper height of
your seat at the bench? Where should the bench pin be pointing at on
the body? I am having a lot of trouble with my back lately and am
wondering if it is the height or the way I am sitting at my bench.

Also, I wear Optivisors to see- a # 5 lens for general and a #10 for
setting stones. Of course these have a tiny focal length which has me
all hunched over my work, trying to see it properly Any suggestions
as to optics?

Thanks, once again, for your help!
Mary Barker


#2

Bench pin should be about height of shoulder blade for sawing with
blade verticle.


#3

Hi Mary,

Most of it will depend on how you like to work, but I tend to keep
my bench pin about level with my upper sternum. (Or just below my
armpits.) That way you don’t have to bend your neck down to use the
optivisors. (remember to set this up while you’re sitting up
straight.)

I’ve also got a GRS mount on my bench, and one of their “level
adjustment” plates, with a couple of wedges on it at different
heights, so that I can play with the height of the pin if I need to.

As far as optics go, I’ve become a big fan of stereo microscopes.
Better depth of field, and massive magnification if you need it.
If you go that way, you really want one of the GRS acrobat stands.

FWIW,
Brian


#4
Also, I wear Optivisors to see- a # 5 lens for general and a #10
for setting stones. Of course these have a tiny focal length which
has me all hunched over my work, trying to see it properly Any
suggestions as to optics? 

There are 2 questions here. First one is the ergonomics.

Ideally, your back must always be straight. If one has to bend, it
should be for short periods of time. Experience shows that these
conditions exist when bench pin points to the middle of the chest.
When you change blade in the sawframe and have to compress it, the
handle should rest against the middle of chest bone. That implies
that all the work is done on the pin, and not on the bench top. If
one is not trained to work like that, it may take time to get used
to it.

The one problem with such body position is soldering. Soldering
requires more room than bench pin can supply, and surface should be
level. I solved this problem by adding another shelf to my bench, for
soldering. The shelf is retractable, so it is out of the way all the
time, except when I solder. I do not know if it’s clearly visible on
my videos, but that is what I do. I am not aware if anybody makes
such benches, but modification is quite easy, so it is not a big deal
to add this feature to any bench, with sufficient height.

Another question is proper magnification, which is directly linked to
ergonomics. When I was younger I used 1.75 magnification, now I use
2.25. I am not sure of the lens numbers. I use the same magnification
whether I do general work, or set stones. I guess I am going to hear
from setting microscope users, but the tendency to use higher
magnification for setting is trying to solve problem with less than
optimal solution. One does not need higher magnification, one needs
to see without reflections from stone tables. For ages, goldsmiths
lightly brush oil, or rub some beeswax, and dust with talcum powder.
Than, powder gets brushed off, and one has perfectly revealing
surface, which shows each and every detail, without strong
magnification.

Another detail, is that when working with white metals, is to shade
your lamp with a piece of transparent yellow film. It is not
necessary for gold, because of its natural color. Human eye sees the
most details in yellow light.

Leonid Surpin
www.studioarete.com


#5

I will be 70 in June and received good advice when working in
Denmark in 1964. Out seats were very low and hardish so the you sat
predominately on your backside. Your legs when vertical should hold
your femurs so your knees are slightly raised. The bench top and pin
for jewellers should be high, about mouth to nose height. This should
keep your back almost vertical and straight.

Try not to bend your back while working.

Setting is more difficult as the bench pin probably needs to be
somewhat lower. Also setting and jewellery generally are very very
asymmetric occupations. I have tried to do exercises to balance the
possible damage incurred. Lots of shoulder and back exercises and
frequent breaks standing up doing preparation or other work. Walking
is very helpful. I have never had serious problems and my back is
pretty straight.

jewellerydavidcruickshank.com.au


#6

Another thought regarding ergonomics:

I don’t solder at the bench. I’ve got a separate soldering area that
I have to get up and walk over to. Helps control both the mess and
the fire risks, as well as giving me an excuse to get up and
stretch. Not maximally efficient if all you care about is parts per
hour, but the “get up and move” aspect really helps keep me from
turning into a fossil.

FWIW
Brian.


#7

Hi David, Just wanted to say thanks for the tips and advice you
offer here now and before. If you never saw it I recently posted a
video of your tube coiling technique on the Benchtube here on
Ganoksin. I hope you don’t mind I credited you for sharing the
technique on your blog.

Coiling tube

Thanks,
Aaron
http://www.aaronwilloughby.com


#8

Thanks all!

I believe that I do have the bench pin at approximately the correct
height. Also I have modified some of the soldering set up and am
being very conscious of my back position. I do walk around to my
little “forming” station a fair bit and I added better lighting. All
that, combined with some better stone setting practices (thanks to
you all), and things are better. I was too tense I think too. But
this last weekend I set 9 stones with no breakage, cursing,
re-making settings or crookedness! So once again, my sincere thanks
to all of you for your generous advice. And thanks to Hanuman and
Ganoksin for hosting this list.

It can be lonely in the garage…

Mary Barker


#9

Hi Aaron,

That was a great and interesting video, thanks for taking the time
to do it. I often have to make specific sized circles out of tubing
for custom jobs and for a line of pendants I make, always in 14k
white or yellow. I tried several ways of doing it, practicing with
brass tubing. I settled on bending them around a dowel that I would
turn down smaller that the desired inside diameter of the finished
tube coil. I tried it filling the tube with frozen water, filling it
with super fine salt and leaving the tube empty (a few people
suggested using “woods metal” but I was afraid of residue screwing up
future soldering). I found that all three techniques worked equally
well, so I don’t put anything in the tube and they coil without
collapsing. I just put the dowel vertically in my bench vise, attach
the tube perpendicular to the dowel with a vise grippes and then use
my fingers to coil the annealed tube around the dowel. It has always
worked. I am alway using a 8" to 24" piece of tubing, so I have no
trouble with leverage. Using this method is a little easier for me
to get the coil diameter I’m looking for, but your demonstration of
David’s method is something I may try.

Thanks again,
Mark