OK here's one for you mechanical engineers out there........... I want to
screw two (2) screw eyebolts into an overhead 2x4 rafter. Then I will
attach a 3' long chain to each one so that they hang down. Assuming that
the wood of the rafter is excellent and structurally sound as well as any
other hardware, such as the chain ...... "Would these two screw eyebolts
hold up to 400 pounds (share 200 pounds each)? I have no real good idea of
shear factor for this type of fastener........ ie. Would the screw break
before the wood?????

The eyebolts that would be used are 3/8" diameter and 3 1/2" - 4" long. The
eyebolts would be just standard Home Depot mild steel with galvanized plate
plate I suppose. I am thinking that these two bolts would equally share the
load and probably be fine but......... The weight of 400 pounds might strip
them out of the 2x4s....... Is this likely or would the threads be strong
enough ??
Not looking for any promises.... just some good swags. And yes, I am
intending to hang from this but I weigh a little over 200 pounds.... safety
factor you know..... :~)

Thanks for any help!

Oh, oh, let me guess... Trapeze in the bedroom?

Clint

"buck" wrote in message
ervers.com...
OK here's one for you mechanical engineers out there........... I want to
screw two (2) screw eyebolts into an overhead 2x4 rafter. Then I will
attach a 3' long chain to each one so that they hang down. Assuming that
the wood of the rafter is excellent and structurally sound as well as any
other hardware, such as the chain ...... "Would these two screw eyebolts
hold up to 400 pounds (share 200 pounds each)? I have no real good idea
of shear factor for this type of fastener........ ie. Would the screw
break before the wood?????

The eyebolts that would be used are 3/8" diameter and 3 1/2" - 4" long.
The eyebolts would be just standard Home Depot mild steel with galvanized
plate plate I suppose. I am thinking that these two bolts would equally
share the load and probably be fine but......... The weight of 400 pounds
might strip them out of the 2x4s....... Is this likely or would the
threads be strong enough ??
Not looking for any promises.... just some good swags. And yes, I am
intending to hang from this but I weigh a little over 200 pounds....
safety factor you know..... :~)

Thanks for any help!

buck wrote:
OK here's one for you mechanical engineers out there........... I want to
screw two (2) screw eyebolts into an overhead 2x4 rafter. ...
"Would these two screw eyebolts
hold up to 400 pounds (share 200 pounds each)? ...
The eyebolts that would be used are 3/8" diameter and 3 1/2" - 4" long.
....

I don't have any doubt about the bolt itself, and it would likely hold
200 lb in tension on a 3/8" lag bolt (that's essentially an eyebolt),
but I'd first be concerned of the span of the 2x4 rafter (or lower
truss chord). I'd not trust it as a mounting technique if I were
hanging from it or underneath a suspended load, though.

If I were doing somethng similar, I'd go _through_ (or even better
over) the rafter w/ a 3/8" bolt and a couple pieces of strap iron and
go through the bottom ends w/ a second bolt for the chain mount. AFTER
verifying what the actual 2x4 structure looks like--

I'd consider what you're suggesting for half the load if the load
weren't me or there were nobody ever under it, but it's definitely not
adequate safety margin in my view for the stated purpose (even w/o
looking up actual values). (Your numbers don't account for any dynamic
loading, for example.)

....... Now there's a thought!


"Clint" wrote in message
news:2fINg.532144$Mn5.522456@pd7tw3no...
Oh, oh, let me guess... Trapeze in the bedroom?

Clint

I don't have any doubt about the bolt itself, and it would likely hold
200 lb in tension on a 3/8" lag bolt (that's essentially an eyebolt),
but I'd first be concerned of the span of the 2x4 rafter (or lower
truss chord). I'd not trust it as a mounting technique if I were
hanging from it or underneath a suspended load, though.

If I were doing somethng similar, I'd go _through_ (or even better
over) the rafter w/ a 3/8" bolt and a couple pieces of strap iron and
go through the bottom ends w/ a second bolt for the chain mount. AFTER
verifying what the actual 2x4 structure looks like--

I'd consider what you're suggesting for half the load if the load
weren't me or there were nobody ever under it, but it's definitely not
adequate safety margin in my view for the stated purpose (even w/o
looking up actual values). (Your numbers don't account for any dynamic
loading, for example.)


dph........ All good points and I certainly appreciate it. Might be iffy
for sure. Will see what others have to say too. Thanks again!

dpb wrote:
buck wrote:
OK here's one for you mechanical engineers out there........... I want to
screw two (2) screw eyebolts into an overhead 2x4 rafter. ...
"Would these two screw eyebolts
hold up to 400 pounds (share 200 pounds each)? ...
The eyebolts that would be used are 3/8" diameter and 3 1/2" - 4" long.
...

I don't have any doubt about the bolt itself, and it would likely hold
200 lb in tension on a 3/8" lag bolt (that's essentially an eyebolt),
but I'd first be concerned of the span of the 2x4 rafter (or lower
truss chord). I'd not trust it as a mounting technique if I were
hanging from it or underneath a suspended load, though.


I agree the bolt should be fine but I would thru-bolt with a washer and
nut on top or one of the ideas dpb gave. But not with a 2x4 rafter!

What is the distance the rafter is spanning?
what is the slope of the roof?
is the rafter realy a ceiling joist that is part of a truss?
Is it a finished ceiling (drywall)?
Could you put a beam perpindicular to spread the load over several
rafters?
Could you sister a larger rafter like a 2x6 or 2x8 to the 2x4?

buck wrote:
OK here's one for you mechanical engineers out there........... I
want to
screw two (2) screw eyebolts into an overhead 2x4 rafter. Then I will
attach a 3' long chain to each one so that they hang down.
Assuming that
the wood of the rafter is excellent and structurally sound as well
as any
other hardware, such as the chain ...... "Would these two screw
eyebolts
hold up to 400 pounds (share 200 pounds each)?
snip

I wouldn't touch this one on a bet.

"Why?", you ask.

Because you know ZIP about that 2x4.

What is it's unsupported length?

What existing loads does it support?

What is the condition of that 2x4. (checks, cracks, knots, etc)

There are other considerations, but those above are enough to reject
the idea.

Lew

buck wrote:
OK here's one for you mechanical engineers out there........... I want to
screw two (2) screw eyebolts into an overhead 2x4 rafter. Then I will
attach a 3' long chain to each one so that they hang down. Assuming that
the wood of the rafter is excellent and structurally sound as well as any
other hardware, such as the chain ...... "Would these two screw eyebolts
hold up to 400 pounds (share 200 pounds each)? I have no real good idea of
shear factor for this type of fastener........ ie. Would the screw break
before the wood?????

The eyebolts that would be used are 3/8" diameter and 3 1/2" - 4" long. The
eyebolts would be just standard Home Depot mild steel with galvanized plate
plate I suppose. I am thinking that these two bolts would equally share the
load and probably be fine but......... The weight of 400 pounds might strip
them out of the 2x4s....... Is this likely or would the threads be strong
enough ??
Not looking for any promises.... just some good swags. And yes, I am
intending to hang from this but I weigh a little over 200 pounds.... safety
factor you know..... :~)

Thanks for any help!



My mom's porch swing hangs from two screw-eyes just like that. It's been
swinging 2 or 3 adults off and on, plus the weight of the swing, since
1957. The 2 by is different, it was salvaged from the old house built
around 1910. My porch swing hangs from two screw-eyes in an ordinary 2 x 4.

To me, an eyebolt implies machine threads and a nut, a screw-eye implies
wood threads. But that may just be my idea.
--
Gerald Ross
Cochran, GA

A pessimist is a person who mourns the
future.





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buck wrote:
OK here's one for you mechanical engineers out there........... I want to
screw two (2) screw eyebolts into an overhead 2x4 rafter. Then I will
attach a 3' long chain to each one so that they hang down. Assuming that
the wood of the rafter is excellent and structurally sound as well as any
other hardware, such as the chain ...... "Would these two screw eyebolts
hold up to 400 pounds (share 200 pounds each)? I have no real good idea of
shear factor for this type of fastener........ ie. Would the screw break
before the wood?????

The eyebolts that would be used are 3/8" diameter and 3 1/2" - 4" long. The
eyebolts would be just standard Home Depot mild steel with galvanized plate
plate I suppose. I am thinking that these two bolts would equally share the
load and probably be fine but......... The weight of 400 pounds might strip
them out of the 2x4s....... Is this likely or would the threads be strong
enough ??
Not looking for any promises.... just some good swags. And yes, I am
intending to hang from this but I weigh a little over 200 pounds.... safety
factor you know..... :~)

Thanks for any help!

Calculus anyone?
http://www.awc.org/pdf/NDSCommentary...pp115to123.pdf

there is a table near the end of the document that should answer the
pull-out question.

Tue, Sep 12, 2006, 6:14pm (EDT-2) (buck) doth query:
snip "Would these two screw eyebolts hold up to 400 pounds (share 200
pounds each)? snip

No prob. Try it, and if it dumps you on your ass you'll know you
screwed up.

Me, I wouldn't do it that way, but that's only because I wouldn't
trust them to not pull out rom that much weight. That's just me tho.

I'm going on the theory that you're talking about screw-in
eyebolts, because that seems to me to be so. Me, I'd use longer ones,
that take a nut on the end, and I'd use a large washer under the nut.
I'm a candy-ass and I'd reinforce the 2X4s too.

Whatcha making anyway? Sumthin' kinky?



JOAT
I am not paranoid. I do not "think" people are after me. I "know" damn
well they're after me.

buck wrote:
OK here's one for you mechanical engineers out there........... I want to
screw two (2) screw eyebolts into an overhead 2x4 rafter. Then I will
attach a 3' long chain to each one so that they hang down. Assuming that
the wood of the rafter is excellent and structurally sound as well as any
other hardware, such as the chain ...... "Would these two screw eyebolts
hold up to 400 pounds (share 200 pounds each)? I have no real good idea of
shear factor for this type of fastener........ ie. Would the screw break
before the wood?????

The eyebolts that would be used are 3/8" diameter and 3 1/2" - 4" long. The
eyebolts would be just standard Home Depot mild steel with galvanized plate
plate I suppose. I am thinking that these two bolts would equally share the
load and probably be fine but......... The weight of 400 pounds might strip
them out of the 2x4s....... Is this likely or would the threads be strong
enough ??
Not looking for any promises.... just some good swags. And yes, I am
intending to hang from this but I weigh a little over 200 pounds.... safety
factor you know..... :~)

Thanks for any help!

I do chin ups from a bar that hangs from 1 eye bolt in the ceiling and I
weigh around 225. It's in a 2X6 though. I'd be much more worried about
the 2X4 breaking than the eye bolt coming out. If the span is not too
long it might not be a problem though. I also have a porch swing hanging
from two eye bolts and it frequently has around 400 pounds in it. They
are in 2X6's too though.

Bruce wrote:

I do chin ups from a bar that hangs from 1 eye bolt in the ceiling
and I
weigh around 225. It's in a 2X6 though. I'd be much more worried about
the 2X4 breaking than the eye bolt coming out.
snip

The moment of inertia for a rectangle is: (b*h^3)/12 where b=base &
h=height.

The moment of inertia is a measure of a beam's resistance to bending.

Do the math and you will find a 2x6 rectangle has a moment inertia of
4.5 times that of a 2x4 rectangle, thus 4.5 times stronger in
resisting bending.

Lew

OK.... OK....... I THINK I SCREWED UP THE TERMINOLOGY ....... I said RAFTER,
but what I should have said was that it is the lower horizontal 2x4 of a
common TRUSS. The trusses are 24" on center. I was thinking about lagging
in a 2x6 board with lag screws across "three trusses" ..... and then screw
in my two eyebolts ....... so all the weight should be spread across the
three rafters. The problem is that the ceiling is in the garage and has
wallboard on it but I can see that the span is 24" between the trusses. A
lot of the townhouses here have wallboard ceilings on 2x4 trusses so I would
imagine they are holding up a lot of weight already with no apparent effect.
So now that I have everybody thinking about a horizontal 2x4 truss rather
than a rafter....... Is this more acceptable or even a worse idea?
-sorry for the wrong verbage.
Thanks for all previous responses..... Appreciate it!

buck wrote:

OK.... OK....... I THINK I SCREWED UP THE TERMINOLOGY ....... I said RAFTER,
but what I should have said was that it is the lower horizontal 2x4 of a
common TRUSS. The trusses are 24" on center. I was thinking about lagging
in a 2x6 board with lag screws across "three trusses" ..... and then screw
in my two eyebolts ....... so all the weight should be spread across the
three rafters. The problem is that the ceiling is in the garage and has
wallboard on it but I can see that the span is 24" between the trusses. A
lot of the townhouses here have wallboard ceilings on 2x4 trusses so I would
imagine they are holding up a lot of weight already with no apparent effect.
So now that I have everybody thinking about a horizontal 2x4 truss rather
than a rafter....... Is this more acceptable or even a worse idea?
-sorry for the wrong verbage.
Thanks for all previous responses..... Appreciate it!


What I have done is not to put the supporter through the 2x4 but use
hammok rings (a hammok ring is aboit 8mm steel wire and 90mm dia) and
rope round the 2x4. Three times round the 2x4 and through the ring with
6mm or 68mm polly. or nylon means that the knot has less stres and the
swing is less likly to damage the supporting roap

--
replace spamblock with my family name to e-mail me

"Lew Hodgett" wrote in message
ink.net...
Bruce wrote:

I do chin ups from a bar that hangs from 1 eye bolt in the ceiling and
I
weigh around 225. It's in a 2X6 though. I'd be much more worried about
the 2X4 breaking than the eye bolt coming out.
snip

The moment of inertia for a rectangle is: (b*h^3)/12 where b=base &
h=height.

The moment of inertia is a measure of a beam's resistance to bending.

Do the math and you will find a 2x6 rectangle has a moment inertia of 4.5
times that of a 2x4 rectangle, thus 4.5 times stronger in resisting
bending.

Lew

Close. As you state, given a constant value for "b", moment of inertia is
proportional to the cube of the height. (5.5/3.5)^3=3.9, not 4.5. If you
meant a literal 2x6 vs. a 2x4 rectangular cross-section, the ratio would be
3.4.

todd

buck wrote:
OK.... OK....... I THINK I SCREWED UP THE TERMINOLOGY ....... I said RAFTER,
but what I should have said was that it is the lower horizontal 2x4 of a
common TRUSS. The trusses are 24" on center. I was thinking about lagging
in a 2x6 board with lag screws across "three trusses" ..... and then screw
in my two eyebolts ....... so all the weight should be spread across the
three rafters. The problem is that the ceiling is in the garage and has
wallboard on it but I can see that the span is 24" between the trusses. A
lot of the townhouses here have wallboard ceilings on 2x4 trusses so I would
imagine they are holding up a lot of weight already with no apparent effect.
So now that I have everybody thinking about a horizontal 2x4 truss rather
than a rafter....... Is this more acceptable or even a worse idea?

Do you mean sleepers-- short horizontal members toenailed to joists?
They support the subfloor?

Have you considered a clevis instead of an eye fastener?

boorite wrote:

Have you considered a clevis instead of an eye fastener?

....or a U strap or something?

When I say truss..... I mean that in my garage there are 2x4s that are part
of the truss framework that go horizontal across the entire length of the
garage and they are on 24" centers. My ceiling drywall is nailed to them.
There is no second story over the garage..... just the roof. I can't get to
anything other than the side of the 2x4s since they have been wallboarded
over...... So I can't loop wires over the top or drill holes in the side of
these 2x4, etc. I can either screw into the width of the 2x4 (1.5 inches)
or don't do anything. So far, from what I am hearing, is.... Don't do it
may be the answer, although I don't know why the ceiling truss 2x4s will
hold up a ton of wallboard but not an extra 200 pounds..... puzzled!

buck wrote:
OK.... OK....... I THINK I SCREWED UP THE TERMINOLOGY ....... I said RAFTER,
but what I should have said was that it is the lower horizontal 2x4 of a
common TRUSS. The trusses are 24" on center. I was thinking about lagging
in a 2x6 board with lag screws across "three trusses" ..... and then screw
in my two eyebolts ....... so all the weight should be spread across the
three rafters. The problem is that the ceiling is in the garage and has
wallboard on it but I can see that the span is 24" between the trusses. A
lot of the townhouses here have wallboard ceilings on 2x4 trusses so I would
imagine they are holding up a lot of weight already with no apparent effect.
So now that I have everybody thinking about a horizontal 2x4 truss rather
than a rafter....... Is this more acceptable or even a worse idea?
-sorry for the wrong verbage.
Thanks for all previous responses..... Appreciate it!

Buck,

I'm a Registered Architect, so let's see if I can lend a little clarity
here...

Terminology:
If your house was 'conventionally framed' (that is, the old 'stick'
method), the sloped members that support the roof deck would be called
"RAFTERS" and the horizontal members that are supporting your ceiling
are called "CEILING JOISTS".

If (as it appears) your roof structure is framed with wood trusses,
these members are called "CHORDS" - the 'top chord' being that which
support the roof deck and the 'bottom chord' being that which supports
the ceiling.

As you've described this as '2x4' framing, it sounds pretty clear this
is, indeed, 'trusses' - as a normal ceiling joist would be quite a bit
bigger (like 2x8 or so).

The important point about 'trusses' is that they are designed and
assumed to carry their load at the 'panel points' (that point where
some of the diagonal members frame into either the top or bottom chord
(usually with those little 'prickly' metal plates on each side). Add to
this the fact that a truss will resolve the forces into axial ones
(i.e. running down the length of the member) and this is why the chords
of trusses are smaller - they're not 'bending' as much (other than
carrying the actual load of the ceiling or roof decking) -- a truss is
just simply more efficient in doing this (that's why they're used).

Another important point to consider when adding some additional load to
a truss is to get it as close to one of the 'panel points' as possible
- that way, you are not loading the chords in 'bending' (which they
were not assumed to be doing initially). A 200 or 400 pound load is
not that much when carried at one of these 'panel points' - but might
get 'iffy' if you applied this load midway between two 'panel points'.

Your idea of laying a 2x6 across 3 (or so) truss chords is a good one -
but, to improve it a little more, I would suggest making a 'strongback'
- and, by that, I mean laying your 2x6 horizontal across the 3 bottom
chords but also nailing (at least) a 2x4 VERTICAL to one side of this
2x6 (better yet - use a 2x6 vertical here, as well). It is difficult
to put a bolt through the long axis of a piece of lumber - better to
go through the short dimension (like drilling through that flat 2x6) -
but this is also the 'weak axis' of the member (the "Moment of Inertia"
mentioned earlier) - which is why I suggest turning (and nailing) that
vertical 2x6 to it -- making it a 'strongback'. Nail these together
with 16d nails about every 8 to 12" (no more) and use machine thread
eye-bolts, not the 'lag thread'. One thing I didn't see mentioned is
the fact of the eye-bolt opening up under load -- you can get forged
eye-bolts (i.e. with a 'closed eye') that is 10 times (or more) stonger
that would give you a lot of insurance at only minor cost increase.
Lowe's (etc) may have it - or McMaster-Carr online surely does. I
might would suggest using those forged ones -- because they are (truly)
at least 10 times stronger and if this is a 'human' hanging off of
these eyebolts, that about cinches the decision (in my mind).

Main points:
Put your load as close to a 'panel point' as possible
Add that vertical 'strongback' to the side of your framing member
Use forged (closed eye) eyebolts
Be careful and look for signs of fatigue when loading it - wood
won't fail immediately, it gives warnings (assuming you're paying
attention).

-- john.

In article rs.com,
buck wrote:
OK here's one for you mechanical engineers out there........... I want to
screw two (2) screw eyebolts into an overhead 2x4 rafter. Then I will
attach a 3' long chain to each one so that they hang down. Assuming that
the wood of the rafter is excellent and structurally sound as well as any
other hardware, such as the chain ...... "Would these two screw eyebolts
hold up to 400 pounds (share 200 pounds each)? I have no real good idea of
shear factor for this type of fastener........ ie. Would the screw break
before the wood?????

The eyebolts that would be used are 3/8" diameter and 3 1/2" - 4" long. The
eyebolts would be just standard Home Depot mild steel with galvanized plate
plate I suppose. I am thinking that these two bolts would equally share the
load and probably be fine but......... The weight of 400 pounds might strip
them out of the 2x4s....... Is this likely or would the threads be strong
enough ??
Not looking for any promises.... just some good swags. And yes, I am
intending to hang from this but I weigh a little over 200 pounds.... safety
factor you know..... :~)

Thanks for any help!




I am guessing you mean a joist and not a rafter? And you are talking
about an "eyebolt" that has a thread like a lag bolt, correct? If so,
I have always called these "screw eyes" and use the term "eyebolt" for
a bolt with machine threads that goes in a through-hole, with
a nut on the end. Maybe someone here can verify what the correct
nomenclature is.

At any rate, if the wood is sound and the pilot hole sized properly
to the eyebolt/screw eye, it should able to support 200lbs dead load
without pulling the threads out of the wood.

Some thoughts and concerns: You mention that you will be "hanging"
from the eyebolts. That's probably OK but if you are "swinging"
from them, maybe not, especially in soft wood. No way for instance,
that I'd hang a kids swing from a screw eye.
--

Larry Wasserman Baltimore, Maryland

Hey John................. Thanks for the great info. Appreciate the time
that you spent. I think you nailed it perfectly. I have come to the
conclusion from what was said in most of the replies is that there is
"considerable doubt" as to whether this is safe or not. I will error on the
safe side and pass on this idea.
As a final note................ Thanks to All for your super replies,
concern and time spent. I will now start on my new Rube Goldberg idea....
:~)

-buck

In article rs.com,
buck wrote:
OK.... OK....... I THINK I SCREWED UP THE TERMINOLOGY ....... I said RAFTER,
but what I should have said was that it is the lower horizontal 2x4 of a
common TRUSS. The trusses are 24" on center. I was thinking about lagging
in a 2x6 board with lag screws across "three trusses" ..... and then screw
in my two eyebolts ....... so all the weight should be spread across the
three rafters. The problem is that the ceiling is in the garage and has
wallboard on it but I can see that the span is 24" between the trusses. A
lot of the townhouses here have wallboard ceilings on 2x4 trusses so I would
imagine they are holding up a lot of weight already with no apparent effect.
So now that I have everybody thinking about a horizontal 2x4 truss rather
than a rafter....... Is this more acceptable or even a worse idea?
-sorry for the wrong verbage.
Thanks for all previous responses..... Appreciate it!



I missed the 2X4 part when I made my first reply. I was thinking you
meant a 2X6 or 2X8 or larger joist. Anyway, since you are talking
about a truss made of 2X4s, I'd say it's not a good idea. Trusses are
usually engineered to support a roof and little else, they have
a definite limit on safe loading of the lower horizontal and will not
take additional loading to the same extent that stick-built framing
joists will.

With your idea of laying a 2X6 across 3 trusses and
spreading out the load, you might be OK depending... If you know who
manufactured the trusses you could checki with them for allowable
loading, or look at similarly sized and constructed trusses if the
manufacturer is unknown. If this will just be a "dead" load, not
swinging or subject to shock or impulse loads, you could just do a
test; Lay the 2X6 up there, then s l o w l y do a pull up on it. If
your comfortable with the degree of flexing (or lack thereof) let your
conscience be your guide.


--

Larry Wasserman Baltimore, Maryland

Larry...... Thanks for the come back. Me thinks I will not take a chance on
a questionable idea. Probably will save me some grief down the road.
Appreciate your advice.
-buck

"jcatora"
I'm a Registered Architect, so let's see if I can lend a little clarity
here...

Terminology:
If your house was 'conventionally framed' (that is, the old 'stick'
method), the sloped members that support the roof deck would be called
"RAFTERS" and the horizontal members that are supporting your ceiling
are called "CEILING JOISTS".

If (as it appears) your roof structure is framed with wood trusses,
these members are called "CHORDS" - the 'top chord' being that which
support the roof deck and the 'bottom chord' being that which supports
the ceiling.

As you've described this as '2x4' framing, it sounds pretty clear this
is, indeed, 'trusses' - as a normal ceiling joist would be quite a bit
bigger (like 2x8 or so).

The important point about 'trusses' is that they are designed and
assumed to carry their load at the 'panel points' (that point where
some of the diagonal members frame into either the top or bottom chord
(usually with those little 'prickly' metal plates on each side). Add to
this the fact that a truss will resolve the forces into axial ones
(i.e. running down the length of the member) and this is why the chords
of trusses are smaller - they're not 'bending' as much (other than
carrying the actual load of the ceiling or roof decking) -- a truss is
just simply more efficient in doing this (that's why they're used).

Another important point to consider when adding some additional load to
a truss is to get it as close to one of the 'panel points' as possible
- that way, you are not loading the chords in 'bending' (which they
were not assumed to be doing initially). A 200 or 400 pound load is
not that much when carried at one of these 'panel points' - but might
get 'iffy' if you applied this load midway between two 'panel points'.

Your idea of laying a 2x6 across 3 (or so) truss chords is a good one -
but, to improve it a little more, I would suggest making a 'strongback'
- and, by that, I mean laying your 2x6 horizontal across the 3 bottom
chords but also nailing (at least) a 2x4 VERTICAL to one side of this
2x6 (better yet - use a 2x6 vertical here, as well). It is difficult
to put a bolt through the long axis of a piece of lumber - better to
go through the short dimension (like drilling through that flat 2x6) -
but this is also the 'weak axis' of the member (the "Moment of Inertia"
mentioned earlier) - which is why I suggest turning (and nailing) that
vertical 2x6 to it -- making it a 'strongback'. Nail these together
with 16d nails about every 8 to 12" (no more) and use machine thread
eye-bolts, not the 'lag thread'. One thing I didn't see mentioned is
the fact of the eye-bolt opening up under load -- you can get forged
eye-bolts (i.e. with a 'closed eye') that is 10 times (or more) stonger
that would give you a lot of insurance at only minor cost increase.
Lowe's (etc) may have it - or McMaster-Carr online surely does. I
might would suggest using those forged ones -- because they are (truly)
at least 10 times stronger and if this is a 'human' hanging off of
these eyebolts, that about cinches the decision (in my mind).

Main points:
Put your load as close to a 'panel point' as possible
Add that vertical 'strongback' to the side of your framing member
Use forged (closed eye) eyebolts
Be careful and look for signs of fatigue when loading it - wood
won't fail immediately, it gives warnings (assuming you're paying
attention).

-- john.


Finally, an accurate, well thought out response.

Thanks

Dave

"buck" wrote in message
ervers.com...
Hey John................. Thanks for the great info. Appreciate the time
that you spent. I think you nailed it perfectly. I have come to the
conclusion from what was said in most of the replies is that there is
"considerable doubt" as to whether this is safe or not. I will error on
the safe side and pass on this idea.
As a final note................ Thanks to All for your super replies,
concern and time spent. I will now start on my new Rube Goldberg idea....
:~)

-buck

Why not cut a hole in the ceiling just enough to get Johns strongback idea
up on top of the truss chords (ceiling joist). Patch and paint it back to
the way it was. The way I'm reading it, you was just going to put your 2 by
6 across 3 joists on the outside-underside of the sheetrock ceiling?

buck wrote:
Hey John................. Thanks for the great info. Appreciate the time
that you spent. I think you nailed it perfectly. I have come to the
conclusion from what was said in most of the replies is that there is
"considerable doubt" as to whether this is safe or not. I will error on the
safe side and pass on this idea.

There's always this...

http://www.amishoutdoorfurniture.com...es/A-Frame.gif

Tim.... Just when I think I am not going to do it...... You and John come up
with these good ideas...... :~)
-thanks but I no longer have a good feeling about this idea.





"Tim Taylor" wrote in message
...

"buck" wrote in message
ervers.com...
Hey John................. Thanks for the great info. Appreciate the time
that you spent. I think you nailed it perfectly. I have come to the
conclusion from what was said in most of the replies is that there is
"considerable doubt" as to whether this is safe or not. I will error on
the safe side and pass on this idea.
As a final note................ Thanks to All for your super replies,
concern and time spent. I will now start on my new Rube Goldberg
idea.... :~)

-buck

Why not cut a hole in the ceiling just enough to get Johns strongback idea
up on top of the truss chords (ceiling joist). Patch and paint it back to
the way it was. The way I'm reading it, you was just going to put your 2
by 6 across 3 joists on the outside-underside of the sheetrock ceiling?

"buck" wrote in message
ervers.com...
Tim.... Just when I think I am not going to do it...... You and John come
up with these good ideas...... :~)
-thanks but I no longer have a good feeling about this idea.

LOL!!! Follow your gut feeling brother!!! It usually turns out to be right.
I know I sure wish I'd have listened to mine more than a thousand times!!!
In other words, DAMN I wish I hadn't done that!!!

-thanks pardner! Roger That!

"Tim Taylor" wrote in
m:


"buck" wrote in message
ervers.com...
Tim.... Just when I think I am not going to do it...... You and John
come up with these good ideas...... :~)
-thanks but I no longer have a good feeling about this idea.

LOL!!! Follow your gut feeling brother!!! It usually turns out to be
right. I know I sure wish I'd have listened to mine more than a
thousand times!!! In other words, DAMN I wish I hadn't done that!!!



Then, after I've learned my lesson, it changes to "If I did that this
way... perhaps it would work." (Curse of the engineer?)

Puckdropper
--
Wise is the man who attempts to answer his question before asking it.

To email me directly, send a message to puckdropper (at) fastmail.fm

LOL ....... sounds like an ME talking.

Buck,

I wouldn't let the comments (mine or anybody else's) give you that
'bad' feeling. I feel pretty confident that a solution is there - but
I would add this one caveat...

If you were thinking of attaching this 2x6 from the *underside* (i.e.
on the ceiling - visible from below), I would caution against doing
that. If you lay your 2x6 ON TOP of the bottom chords of the trusses
(i.e. from the attic space), then those members are transferring their
loads to the bottom chords through simple 'bearing' -- any anchorage
you use (nails, lag bolts, etc) are simply holding the 2x6 in place so
that it wouldn't shift depending on the loading from the eye-bolts.

If, on the other hand, you *were* thinking of anchoring this from
below, then you are relying on the lag bolts to carry ALL the load into
the truss bottom chords. This might actually could be workable -- the
AITC (Amer. Inst. of Timber Construction) "Timber Construction
Handbook" has loading values for lag bolts in exactly this kind of
loading case -- so there are *real numbers* that can be determined as
to how much load they would carry. BUT, if you're talking about
hanging some bicycles or other 'hardware' from these eye-bolts, that's
one thing. Placing a 'human load' on them (in this arrangement) is
something else - and I wouldn't do that if I had to rely on lag bolts
only to do it. There's just better ways when you are putting someone's
health and safety on the line.

If I were detailing such an arrangement for a client, I would -- as
noted -- place the 'structure' ABOVE the bottom chords (i.e. in the
attic) to get that 'bearing' type of load transfer. That will,
obviously, complicate the situation for 'already built' conditions --
tearing a hole in the ceiling and patching back.

But, the bottom line is that this *could* be done - and I wouldn't let
any comments dissuade you if you really want to pull this off. Just do
it the right way and you won't have any problems. Invariably, folks
tend to 'rewrite the laws of physics' (without thinking things through)
and that's when they get burned.

-- john.


buck wrote:
Tim.... Just when I think I am not going to do it...... You and John come up
with these good ideas...... :~)
-thanks but I no longer have a good feeling about this idea.





"Tim Taylor" wrote in message
...

"buck" wrote in message
ervers.com...
Hey John................. Thanks for the great info. Appreciate the time
that you spent. I think you nailed it perfectly. I have come to the
conclusion from what was said in most of the replies is that there is
"considerable doubt" as to whether this is safe or not. I will error on
the safe side and pass on this idea.
As a final note................ Thanks to All for your super replies,
concern and time spent. I will now start on my new Rube Goldberg
idea.... :~)

-buck

Why not cut a hole in the ceiling just enough to get Johns strongback idea
up on top of the truss chords (ceiling joist). Patch and paint it back to
the way it was. The way I'm reading it, you was just going to put your 2
by 6 across 3 joists on the outside-underside of the sheetrock ceiling?

ARGGGGG! ...... Darn it John! Now you got me thinking again. What you say
makes sense too, putting the 2x6 above the bottom chords. I guess it is
very similar to John and Tim's ideas......... As far as 'rewriting the laws
of physics' ...... I have a tendancy to always think there is a better way -
And I'm usually right about 15 percent of the time.... LOL! Thanks John for
your good info and I will certainly accept your expertise as well
................. As far as other opinions go, I know that they all are
wanting to error on the side of safety and I appreciate that for sure. See
Puckdropper, I am like a rudder-less ship!!!!
-buck

ps........... Please stop adding to this thread, cause it is making me
crazy..... :~)