I have a platform tree house supported by 4 4x4 pressure treated
posts. I want to build a rope cargo net between 2 of the posts. To
do so, I either need to drill about 4 holes in two of the posts, or
use eye bolts. Because of the size of the rope, I would need to drill
one inch holes in the 4x4's. Will they retain their strength if there
are 4 one inch holes drilled through them about one foot apart? Or
should I bite the bullet and buy the eye bolts?
Assuming they're not loaded to capacity, 1" hole won't make a lot of
If it's a wet area, might have some concern about a hemp rope in the
hole retaining water and failing in an unseen place (inside the hole)
while what's visible still looks fine.
But, a bent eye bolt isn't real good choice either imo unless it is
_well_ oversized so there's no possibility of it straightening out under
load. A forged eye or similar would be best imo...
> I have a platform tree house supported by 4 4x4 pressure treated
> posts. I want to build a rope cargo net between 2 of the posts. To
> do so, I either need to drill about 4 holes in two of the posts, or
> use eye bolts. Because of the size of the rope, I would need to drill
> one inch holes in the 4x4's. Will they retain their strength if there
> are 4 one inch holes drilled through them about one foot apart? Or
> should I bite the bullet and buy the eye bolts?
As a sailor, my major concern with line, (rope to non sailors), is chafe.
I don't like either of your choices for that reason.
Much prefer to use pad eyes and thimbles for the line.
Mount the pad eye with 4, 1/4" bolts, then use a clevis to attach the
rope thimble to the pad eye.
You don't need S/S hardware that you would find on a sailboat,
galvanized will do a good job.
If you don't recognize any of the above items, go to Jamestown
Distributors and search their web site using the above terms.
On Tue, 10 Jul 2007 20:49:23 -0000, email@example.com wrote:
My "gut instinct", which usually gets my ass kicked, says to not bother
I sort of picture a bit of notching of the corners and running the rope around
the posts... easier to inspect the rope occasionally and no drilling required..
Being a turner, I picture the notch as if you had put a 4x4 in the lathe and
rough-rounded a small section..
Please remove splinters before emailing
Most of the tension and compression occur on the outside of the post so
drilling through the center post would be the best bet. You would loose some
strength but not all that much - don't remember how to calculate it, its
been a long time. On the other hand if you notch or drill 1" anywhere near
the outside of the post, you've effectively turn a 3.5" post into a 2.5"
post. See this all the time where electricians and plumbers notch and
butcher a 12" beam into a 6" beam in building construction.
Right. Look how airplane wing ribs are skeletonized to cut as
much weight as possible without reducing strength. The resulting
braced structure transfers stresses to the top and bottom. Aircraft
crash for a variety of reasons. This is seldom one of them.
If I were to follow your method I personally would attach the net at six
points (3 on each vertical side) on the premise that if one point chafes
through the kid(s) won't fall through the net so readily.
The sailor is correct though, from a long term perspective. His method
will last almost indefinitely. Yours, through-drilled and figure-eight
knotted, will last for a few to perhaps several years depending on the
amount of time the kids have at it, but will eventually wear through and
break in at least one place. When that occurs, you replace the whole net.
Bottom line is that it's your choice as to where you want to make the
tradeoff between cost and absolute safety.
Thanks to everyone for your input. The sailor's option certainly
would last a long time, but since I am using relatively think rope
(line), and don't need it to last that long, have decided to go
through the posts - I believe 13/16 inch holes for 3/4 inch line. I
will be attaching it at 4 points on either side, and probably about 6
points on top, through the 2x6 beam. Also, the net is only 5 to 6
feet high. I usually test everything in the yard often and look for
wear, so will keep an eye on the line as well.
Again, thanks for the advice.
> Thanks to everyone for your input. The sailor's option certainly
> would last a long time, but since I am using relatively think rope
> (line), and don't need it to last that long, have decided to go
> through the posts - I believe 13/16 inch holes for 3/4 inch line.
3/4" line is nothing.
Let me know when it chafes thru.
I did something similar on the play structure I built two years ago.
Inspected the ropes last month and did not find any noticable wear. I
figure that by the time the rope wears out, the kids will have out-
grown the swingset.
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