[PSUBS-MAILIST] K-250 Angle Stiffener Web Question

[k6fee via Personal_Submersibles]

Reaching me.
Keith T 


Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> Date: 9/7/17  10:08 AM  (GMT-08:00) To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> Subject: Re: [PSUBS-MAILIST] K-250 Angle Stiffener Web Question 
Doesn't look like my posts are coming through. Anybody seeing them?Rick 
On Thu, Sep 7, 2017 at 9:32 AM Steve McQueen via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
Yes, I have some. I am planning on using them for the light weight stuff.  The holes I was contemplating were to help hold a little more weight than those devices might. I was hoping I was done with  all the welding but maybe not.



Thanks,

Steve



---- Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

> Steve,

>

> If you go to a hardware store you might find some little aluminum security

> devices for locking sliding doors. I'm sure TrueValue has better (wink wink

> for Scott) but at Home Depot I found some that fit the K250 stiffener

> flanges perfectly. They clamp on with a set screw, and give you a tab you

> can drill for attaching things.

>

> Best,

>

> Alec

>

> On Thu, Sep 7, 2017 at 10:24 AM, Steve McQueen via Personal_Submersibles <

> personal_submersibles at psubs.org> wrote:

>

> > Sean, thanks. I was hoping you would respond : )  I did have a clamping

> > approach in mind that I will revisit.

> > Thanks,

> > Steve

> >

> > ---- "Sean T. Stevenson via Personal_Submersibles" <

> > personal_submersibles at psubs.org> wrote:

> > > The minimum moment of inertia of the combined section of the stiffener

> > plus an effective length of the pressure boundary shell may be specified by

> > design, but in any case is to be calculated in consideration of the minimum

> > at the locations where any holes exist. Holes in the flange are far more

> > detrimental than holes in the web, with the mininum impact hole being a

> > hole which is coincident with the neutral axis across the combined section.

> > (i.e. holes drilled in the center of the web of an I-beam have the least

> > impact).

> > >

> > > Better than drilling holes would be to simply clamp to stiffener rings,

> > or weld on brackets or studs such that no material is removed from the

> > stiffener section. Otherwise you do have to account for the reduced moment

> > of inertia of the stiffener section at the hole location in your buckling,

> > inter-stiffener strength and stuffener tripping calculations.

> > >

> > > Sean

> > >

> > >

> > > On September 7, 2017 6:51:03 AM PDT, Steve McQueen via

> > Personal_Submersibles <personal_submersibles at psubs.org> wrote:

> > > >All, as most probably know a K-250 has internal angle stiffeners (L).

> > > >

> > > >In my rebuild I have avoided drilling any holes in the web portion of

> > > >these stiffeners (actually had some existing holes from the original

> > > >build welded up/filled).  However, I am finding it would be nice if I

> > > >could drill a few small (1/4") holes to help mount some interior parts.

> > > >I believe I am looking at 1 to 3 of these holes max. in any single

> > > >stiffener web.

> > > >

> > > >Calculating any reduction in functional strength that might result from

> > > >a few small holes isn't straight forward.  I guess I am looking for

> > > >some feedback from those who understand the web function of an L

> > > >stiffener better than I.

> > > >

> > > >My guess is this wouldn't be a significant issue and I an being too

> > > >anal.

> > > >

> > > >Thanks,

> > > >Steve

> > > >_______________________________________________

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> > > >Personal_Submersibles at psubs.org

> > > >http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles

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> >

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