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Page 4 of 5 The Search for Nirvana
These models are all fine and good, but I tend to be a bit of a
perfectionist and really wanted something that "looked" more like the
original. Delrin, seems to be the product of choice these days
for dive gear so I looked up on McMaster-Carr's website and found that
they had it as well. I picked out a nice block of the stuff that
measured ?" X 1 & ?" X 12. I ordered it
and promptly placed it on my workbench as one of those projects to get
around to one of these days!
CSS-1 (Citelli Spring Strap, Model 1)
There it sat for almost a year until I got an e-mail from Joe Citelli
saying he had an idea on making the blocks out of delrin! I
responded that great minds think along the same track and decided to
revive the project. While I was still thinking about it, Joe
knocked out a set of the blocks that are the closest things to the
originals that I have seen yet. He reversed and re-used the
original Jet Fin hardware. You can also buy this hardware new as
previously mentioned from Global, which is probably the easiest route
to take and is very secure. The only downside to the CSS-1 is
that Joe made them on a Bridgeport milling machine so unless you
currently have access to one of those (or about $20,000 to buy one) you
still have a problem. They are VERY slick looking and I could
hear the girls swooning all the way up in MD when Joe took his fins out
the first time! (Figure K1 and Figure K2).
DSS-2 (Dalton Spring Strap, Model 2)
I decided that I was going to get left in the dust on this project if I
didn't get back in the game so I decided to get out my block of delrin
and replicate what Jim did on an inexpensive tool, a table mounted
router.
In 1989 I decided to put away my "badge & credentials" and try
making a living as a custom cabinet maker. The economy turned
south and I found that it was a good way to go broke and returned to
the warm, yet smothering embrace of the Federal Government.
However, I did manage to acquire some nice tools in the process and had
a table mounted 3 hp router to utilize for this project.
I would suggest that if you are going to try this, first work with a
piece of wood cut to the same dimensions as your block of delrin
(?" X 1 & ?" X 12"). That way you can figure out exactly what
depth to cut, and "fit" the block of wood to
your fin, making any mistakes in the wood, a material that is
CONSIDERABLY less expensive than delrin. Also shape the profile
in the piece of wood/delrin while it is still 12" long. It will
be easier to handle and you are less likely to lose any parts of your
hand!
If neither you or any of your friends have a table mounted router you
can mount most any router to a piece of ?" plywood, screw a
piece of 2 X 4 to it for a "fence" and clamp or screw the whole thing
to your deck for a one time use. If you have no earthly idea what
I am talking about or think that a router is a piece of computer gear
used in T-1 & T-3 hookups, go find a woodworking dive buddy to do
this for you.
Basically you want to cut the end down to about half of it's thickness
and then shape it to fit in the notch in your fin. All fins are
not the same and I noticed considerable differences in the Scuba Pro
Jet Fin and the IDI Turtle Fin (Figure L). You could use any
number of bits for this so just look and see what you have available
and how you might cut it. You could use a round over bit, a
beading bit, a Roman Ogee bit or even a Classic Roman Ogee bit which is
what I had handy (Figure M). The trick is to just use that portion
of the bit that will cut the profile you are after. The shape is
not really critical, remember the Jackie Smith version is just a
?" rod.
After you get the basic profile you want (Figure N)
you can cut the strip of delrin into blocks that are the same height as the block on your
fin, which is about 1". I found this easiest to do on a power
miter-box saw but it could be done on a table saw or even with an
inexpensive had miter-box saw as well. If you use a power saw it
is best to use a plain steel blade instead of a tungsten tipped blade
because the blade is thinner. Delrin cuts very easily.
After you cut the four pieces you will need to make your straps, it
will be necessary to drill holes in them. The first hole you
should drill is either a ?" dia or a 9/16" dia. The
difference will be whether or not you trim the springs and how you form
the end loop in the spring if it is trimmed. I found that with my
drysuit boots (Si-Tech) and 9 ? foot size, with the Scuba Pro
X-L Jet Fin, I needed the whole 11" of the spring. When I made
straps for use with wetsuit booties and Swimaster Mark X fins, I had to
cut about 1 & ?" off of the spring. In trimming and
reforming the loops, they were hard to get into the ?" hole so I
opened it up to 9/16". The holes in the blocks on the original
F/O are 17/32" but I couldn't find a bit that size locally. I also had to trim the spring when making the straps for use on my
Turtle Fins. The length of spring needed should be checked by
tying the spring onto the existing fin hardware with nylon line as
described in the instructions for the QAD-1. Also check the
length of the inside nylon line you will use to limit the length of the
spring. The original F/O straps used a brass grommet to secure
the nylon line to the spring loop. You may wish to do the same
(Figure O).
If you will require the entire length of the spring then you will be
using the existing loops and can drill a ?" hole into which the
spring will fit. Using a 1 ?" length of delrin and a normal
?" twist drill bit, hole "A" should be centered and drilled
1.25" deep. The depth is measured at the center of the hole. Next
drill hole "B" with a 1/8 drill bit 1" from the top of the delrin
block. The reason that you drill the hole "A" first, is that if
you drill hole "B" first, the ?" drill bit will grab when you
drill through hole "B". Trust me, I know! (Figure P)
After you drill the holes you can dress the edges on the router, with a
dremel, a belt sander or even with a file. Delrin is very easy to
work.
Next you need to decide if you want to go the Global hardware route or
go with SS wire/rod. Either way you will first need to remove the
original hardware by cutting it off with a hacksaw or wire cutter or a
grinder. If you use a grinder make sure you don't let the brass
get too hot and burn the rubber of the fin.
If you decide to go with the Global hardware you will need to remove
the sliding bar from the buckle so it forms an open "D" (Figure Q).
Then squirt some hand dishwashing detergent like "Dishdrops" or "Joy"
or "Ivory Liquid" into the hole in the fin block. Then push one
end of the buckle into the hole. Take a thin needle nose pliers
and grab the end of the buckle from the other side and pull it through
the hole. After that you will just attach the "pin" through the
delrin block securing the spring (and nylon line - don't forget
that!!!) and "stake" the pin into the buckle and you are done
(Figure R).
If you decide to go with the SS rod you will find that it works well
because you can bend it against the Delrin which was very difficult to
do with the rubber blocks. Before trying to bend it, first find a dowel
that is about ?" in dia. Cut half of it away at one end to
form a "halfround" (Figure S). Place the delrin block in a vise,
insert the spring with nylon line in hole "A" and insert the SS wire in
hole "B". Let approximately 2 ?-3" of the wire extend
from the top. Grab the wire with a pair of pliers and bend it
over the ? dowel (Figure T). Then slide the block down a bit
and put the newly formed loop in the vise and squeeze it until it
completes a 180 degree turn. Now slide the block back on the wire
and reverse the wire in the vise. Bend the long end of the wire
as far down over the ? dowel as you can (Figure U). Place it back in the
vise for a final squeeze (Figure V). Now use an angle grinder, a dremel
cutoff wheel or wire cutters to cut the wire off. Spread the ends a bit
to work it onto the fin blocks. Then use a Channel Lock type of pliers to
clamp them on your fins (Figure W). Sit back and admire them (Figure X) and
then go diving!
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