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DAN
then you must have a different
roller then i have used.
plate 3
_______O____________
O O
1 2
SMALL PICTURE
once the plate passes the first roller all force on
it is lost. the only way to do that is if the rollers can be adjusted for
seperation. our big power rollers dont adjust that way
rick m
----- Original Message -----
Sent: Thursday, November 10, 2005 3:39
PM
Subject: Re: [PSUBS-MAILIST] Inner /
Outer support ribs.
Rick
It is possible to role without a flat spot.
After running the material through the rolls turn it end for end and role it
through again. The flat spot is on the leading edge first trip through
the rolls. The rolls form true to the last fraction if an inch on the
trailing edge. Turning the material around finishes what was the leading
edge the first time through.
Dan H.
----- Original Message -----
Sent: Thursday, November 10, 2005 1:58
PM
Subject: Re: [PSUBS-MAILIST] Inner /
Outer support ribs.
the problem with installing support frames is
that when rolling plate the first three to four inches can not be bent .
giving you a flat spot at the weld line in the tube.the easliest way to get
around this is to pre weld the frames inner web and true up to final size.
tack the outer web in place. do not weld the tube seam yet. Weld
in lifting eyes along the inside of the hull along the seam line and at
opposing points along the hull. set the frames inplace, and using chain
hoists pull the hull into roundness against the frames. note some triming of
the hull seam may be required for final fit.
rick
m
----- Original Message -----
Sent: Thursday, November 10, 2005
10:02 AM
Subject: RE: [PSUBS-MAILIST] Inner /
Outer support ribs.
Myles I should tell you getting those stiffeners in was far and
away the hardest part of building Solo. It took me three months of work to
get the first ring in. But it certainly worked as a method for stretching
the hull into roundness. This is a 3/8 thick hull of only 31" outside
diameter, so not very stretchy. If I remember correctly, the out of
roundness prior to inserting the stiffeners was about half an inch
difference between maximum and minimum diameters. With stiffeners in, I
can't detect any out of roundness.
My method was as follows: Roll the ring in along the
greater diameter, then try to straighten it until normal to the hull. I
tried hydraulics and failed. I tried icing the rings and heating the hull,
but that failed too. The latter is what Phil Nuytten does, but I presume
his hull cylinders are much higher quality (rounder) than mine. What
worked for me in the end was a very long lever built to hook onto the end
of the hull cylinder, chained to 1/2" holes drilled in the stiffener web.
I built a motorized table for my mill-drill machine, with which I
could gradually reduce the diameter of the stiffener by a few
thousandths after each unsuccessful attempt. I did this lots of
times, on each iteration getting closer to straightening the stiffener all
the way. Of course, the hard one is the first stiffener, and after
that they go fast.
rgds,
Alec
Dan,
The point I never considered
was using the rings to force the hull into roundness. I can
definately see where this would be easier when putting them on the
inside as they could be pounded / hammered / tapped into place, spot
welded, and then secured when all was well. That answers another
question in that the rings are to be pre made and not welded onto the
pressure hull when building them. In that way, the roundness of
the rings could be made true before installing. As for attaching
things to the rings inside the hull, is it safe to drill 1/4" holes for
bolts or is that comprimising the integretity of the ring too much
? ...or would welding mounting brackets to the rings and then
drilling the holes be preferable ?
On the K350, does the design
just eliminate the ring where the tower is, the tower collar providing
the strength in that area ?
Thanks for making my mind up
for me Dan.
Myles.
----- Original Message -----
Sent: Wednesday, November 09,
2005 9:10 PM
Subject: Re: [PSUBS-MAILIST]
Inner / Outer support ribs.
Myles,
A K-350 has ribs spaced 12 inches apart,
and at the ends where the hull tube meets the end caps, they are 10
inches apart leaving two inches of hull tube sticking past the
last frames to weld the end caps to.
True, the frame would be easier to
apply to the outside of the hull, for convenience of working, but it's
easier to spring the hull into better roundness when working from the
inside. No rolled tube is perfect round. You have to
work it as your installing the framing.
Ribs on the outside give you more places
for corrosion to attack, but do increase the inside room. Ribs
on the inside cramp the space in the sub, but are a convenient place
to clamp things that you want to add later on, without welding on the
finished sub hull.
Dan H.
----- Original Message -----
Sent: Wednesday, November 09,
2005 6:11 PM
Subject: [PSUBS-MAILIST] Inner
/ Outer support ribs.
I understand that support ribs offer
the same strength increase whether they are on the inside or outside
of the pressure hull. As I am planning on adding fairing, I am
also considering puting the ribs on the outside to free up interior
space. Is this a good idea ? In other words, is it
easier to install the ribs when they are on the outside ? Are
the ribs pre-made and then welded on or built right onto
the pressure hull ? I can't seem to figure out the ribs, how
they are made, and the best way to install them. My pressure
hull is of a similar design as the K350 36" x 1/4 " x 8'.
I am considering a rib spacing of 18".
Myles.
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