Any engineers, architects or designers out there know what the pull out values are for a t-nuts through a 3/4 in piece of plywood?
Pull Out Values for T-Nuts
(8 posts) (4 voices)-
Posted 1 year ago #
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Too many factors involved for a blanket answer, i.e.: type and rating of plywood, distance from last stud or other framing member, diameter of hole in plywood (7/16" or 1/2"?), footprint of hold mounted on T-nut, diameter of base plate on T-nut, integrity and age of plywood, etc.
What are you trying to mount that you're worried about the strength? Slack line? Lead anchor? These types of connections are best placed where they can be connected directly to the framing of the structure.
Posted 1 year ago # -
....LOL should have known that was coming! Let me take a couple of steps back. Aside from being a climber and setter I'm an architect that's designed and built a couple of gyms so I've got a little more background than gym staff trying to attach a lead anchor. I've always taken for granted the use of t-nuts as 'tried and true' industry standards. I've gone looking through all of the standard wood design manuals for pull out values for fasteners of 1" diameters through 3/4" plywood but the standard building design manuals don't address this 'reverse' direction that is found with the fastening of holds to t-nuts.
My interest is two-fold:
First I'd like to start building some volumes (potentially big ones) but also make them removable ie. fastening them via T-nuts. So I wanted to be able to calculate the forces and volume (given its particular size) exerted on the wall in order to determine how many fasteners would be required. This thought process also got me wondering about the forces/torque that was generated just by some of the monster holds/volumes that already exist; but that's just me over analyzing it, but curious none the less.Secondly, (I was going to post another topic about setting systems but its all related) the gym I'm setting @ has no floor anchors. I hate having both the climber end and the grigri end tied into my harness. Not only is it too much stuff it make ascending slow b/c you have to pull twice the amount of rope. So I wanted to calculate how many tnuts you'd have to bolt into (equalized of course) in order to build a safe anchor. Unless I'm just being a dumb ass and missing the obvious answer.
Yes granted some of the things you mentioned above are factors and some are negligible. But like with any good design (sarcasm) assumptions are made and in this case I would use the lowest or a low median for any published design values.
So the million dollar question... Are there any pull out values for t-nuts in plywood?
Thanks
Disclaimer-typed on a BB please excuse any type os, spelling or grammar mistakes.
Posted 1 year ago # -
Wasn't trying to be sarcastic at all - sorry if it read that way.
I know of no pertinent data for our application of t-nuts, sorry.
When I'm setting off a rope, I'll usually place bolt hangers into (2) different t-nuts and equalize those for attaching the other end of my rope. Most setters I know go with that type of set up also.
Let me (us) know if you do find any strength info though - I'd be curious to see what it might be.
- Louie
Posted 1 year ago # -
EN norm 12572-1 says that the tnuts should be tested Axial with a force of 5kN for 1 minute.
Furthermore there are limitations to the integrity and dimensions of climbing holds in norm 12572-3. in essence the climbing hold must not turn or fracture if a force of 1,5 kN is placed on the worst possible place. Second the dimensions of the climbing hold must be so that this 1,5kN force will never result in more than 5kn force on the Tnut. Therefore the part of the climbing hold below the bolt (tnut) must be atleast 1/3 of the other dimensions.
Let
d1 = distance that the climbing hold extends below the bolt (along the wall).
d2 = distance that the climbing hold extends above the bolt (along the wall).
d3 = distance that the climbing hold protrust from the wall
Then:
d2/d1 >3 and d3/d1 >3That should help you along.
Posted 1 year ago # -
400 lbs
Posted 1 year ago # -
@ offroute,
Just ty a figure of eight knot in to one end of the rope. This knot should'nt go through the top rope protection points so you can just pull the other end of the rope. This way you have an instant "fixed rope".
I always put a karabiner in the figure of eight and clip this around the other end of the rope. After setting you can climb the route while pulling through the rope. At the top clip the karabiner onto your harness and descent.
Posted 1 year ago # -
for a system that fixes volumes in place see:
http://www.altissimo.fr/shop/popinfo.php?tips=macrosm_conseil_3The TD+ system for volumes is composed of a polyester shell and an adjustable steel frame that acts as an interface between the wall and the shell. This system is not only useable on any kind of wall (concrete, wood, breeze-block, brick...), it also ensures maximum secutity in terms of fixation. This is of special importance for fixing very large volumes such as stalactites (sizes M and L) and rounded volumes (sizes L, XL and XXL).
Thanks to the steel interface, the shell can pivot through 90° thus creating 4 configurations. With 2 volumes, the shells can not only pivot on their own axis but are also interchangeable. Please note: the steel interface exists in size 50x50 cm or 100x100 cm according to the size of the shell. Ony shells with identical interfaces are interchangeable.Posted 1 year ago #
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