Hi all,

Credit Chris Chapman for bringing to attention the use of plumbing brass
tees,
elbows; and hobby shop brass tubing some time back! They are VERY handy
and useful for a variety of hinge/boom setups of various designs of
seismometers!

There is a new variation of such, which I believe is even more use variable=
,
that
is coming out on the American market.

Too review a plumbing compression tee, and the old style, go to:

http://plumbing.hardwarestore.com/52-330-compression-tees.aspx

On the upper left hand photo corner is a representative of the older style,
that
comes in a variety of tube/pipe sizes. Press/click, on the green "view
options"
oblong box. That box will show various sizes that will fit therein. Other
tees,
can come in various other configurations to reduce, etc., the sizes. These
tees
are unlike most plumbing "sizes" are they are instead a more exact size of
the
tube/rod used; i.e., plus or minus afew thousandths of a inch. Hence, a
common hobby (or hardware store) with a K&S precision brass tube of say,
1/4" diameter, can be easily compression fitted into a like diameter
compression
tee.

I've failed to find a good representative web image of the new style.
Basically
it looks like the old style, except, the new style will have what looks lik=
e
a small
loose brass tube protruding aways from the ends of the tees and angles
opening
holes. I've found such at Home Depot (chain) stores. No...Ace Hardware
(chain)
only has the old style at the present.

I've used both varietys of tees for my recent hinge/suspension tests. The
old
style will work for joining a rod to a boom where two hinge contacts were
needed.

The new variety is more variable in that it can be used for both a double
contact
hinge, and/or, for containment of a ball bearing, should one wish to use
such for
a seismometer hinge/suspension. For a ball bearing use; the little loose
tube is
extracted from the assembly and is turned around, and inserted into the
compression
nut end, where the broad funnel shaped end goes over the slightly extruded
lip of
the new tee variety. By lightly pressing down, the small tube will lightly
lock (click)
onto the extruded lip of the inner compression mechanism. I simply put
various
ball bearings in the "funnel", and held it while turning it over to mount o=
n
a variety
of test contact surfaces. For your ball bearing use; it can of course be
glued down
with epoxy or whatever, and will likely hold the position quite well.
Similar elbows,
with the same small tube therein can of course be adopted for ball bearings
setups
(or two contact hinges) where other boom configurations may be more
desireable.

Use of these tees and elbows isn't a totally alignment free method, as the
internal
oval shaped compression loose tubes is designed to give a variety of angles
to
fit together. You will have to make sure your directional alignment with an=
y
boom
is correct for your design. If it isn't, unscrewing the nut will allow
readjustments,
then tighten the nut/s again. On the sides of these tees and elbows there i=
s
a
flat area, which with whatever other fixtures you wish to use, can be
anchored
down on a like flat surface, clamped, adjusted, and then have the nuts
tightened;
the alignment/s will be much better this way.

Use of the 3 outlet/inlet compression tees, for a double hinge, or say, a
crossed
rod hinge/suspension assembly, should entail drilling out the internal bras=
s
that
obstructs your rod going entirely through the parallel openings for which i=
t
will be
used; then, installing the internal oval compression ring and/or nut...just
to retain
the straight shape of the rod. With the new tee variety, the compression
locking
mechanism is lightly attached to the compression nut itself. If you don't
drill and
just use the separate ends to install acouple separate rods, they will be
assuredly
not aligned...and your double hinge, or crossed rod hinge may suffer
somewhat
from that misalignment effect. Yes, they are alittle work, but alot less
than trying
to homebrew your own "T" joints.

Take care, Meredith Lamb
Hi all,



Credit Chris Chapman for bringing to attention the use of plumbing brass te=
es,

elbows; and hobby shop brass tubing some time back!  They are VERY han=
dy

and useful for a variety of hinge/boom setups of various designs of seismom=
eters!



There is a new variation of such, which I believe is even more use variable=
, that

is coming out on the American market.



Too review a plumbing compression tee, and the old style, go to:



=
http://plumbing.hardwarestore.com/52-330-compression-tees.aspx



On the upper left hand photo corner is a representative of the older style,=
 that

comes in a variety of tube/pipe sizes.  Press/click, on the green &quo=
t;view options"

oblong box.  That box will show various sizes that will fit therein.&n=
bsp; Other tees,

can come in various other configurations to reduce, etc., the sizes.  =
These tees

are unlike most plumbing "sizes" are they are instead a more exac=
t size of the

tube/rod used; i.e., plus or minus afew thousandths of a inch.  Hence,=
 a

common hobby (or hardware store) with a K&S precision brass tube of say=
,

1/4" diameter, can be easily compression fitted into a like diameter c=
ompression

tee.



I've failed to find a good representative web image of the new style. =
 Basically

it looks like the old style, except, the new style will have what looks lik=
e a  small

loose brass tube protruding aways from the ends of the tees and angles open=
ing

holes.  I've found such at Home Depot (chain) stores.  No...Ace H=
ardware (chain)

only has the old style at the present.



I've used both varietys of tees for my recent hinge/suspension tests. =
 The old

style will work for joining a rod to a boom where two hinge contacts were n=
eeded.



The new variety is more variable in that it can be used for both a double c=
ontact

hinge, and/or, for containment of a ball bearing, should one wish to use su=
ch for

a seismometer hinge/suspension.  For a ball bearing use; the little lo=
ose tube is

extracted from the assembly and is turned around, and inserted into the com=
pression

nut end, where the broad funnel shaped end goes over the slightly extruded =
lip of

the new tee variety.  By lightly pressing down, the small tube will li=
ghtly lock (click)

onto the extruded lip of the inner compression mechanism.  I simply pu=
t various

ball bearings in the "funnel", and held it while turning it over =
to mount on a variety

of test contact surfaces.  For your ball bearing use; it can of course=
 be glued down

with epoxy or whatever, and will likely hold the position quite well. =
 Similar elbows,

with the same small tube therein can of course be adopted for ball bearings=
 setups

(or two contact hinges) where other boom configurations may be more desirea=
ble.



Use of these tees and elbows isn't a totally alignment free method, as the =
internal

oval shaped compression loose tubes is designed to give a variety of angles=
 to

fit together.  You will have to make sure your directional alignment w=
ith any boom

is correct for your design.  If it isn't, unscrewing the nut will allo=
w readjustments,

then tighten the nut/s again.  On the sides of these tees and elbows t=
here is a

flat area, which with whatever other fixtures you wish to use, can be ancho=
red 

down on a like flat surface, clamped, adjusted, and then have the nuts tigh=
tened;

the alignment/s will be much better this way. 



Use of the 3 outlet/inlet compression tees, for a double hinge, or say, a c=
rossed

rod hinge/suspension assembly, should entail drilling out the internal bras=
s that

obstructs your rod going entirely through the parallel openings for which i=
t will be

used; then, installing the internal oval compression ring and/or nut...just=
 to retain

the straight shape of the rod.  With the new tee variety, the compress=
ion locking

mechanism is lightly attached to the compression nut itself.  If you d=
on't drill and

just use the separate ends to install acouple separate rods, they will be a=
ssuredly

not aligned...and your double hinge, or crossed rod hinge may suffer somewh=
at

from that misalignment effect.  Yes, they are alittle work, but alot l=
ess than trying

to homebrew your own "T" joints.



Take care, Meredith Lamb