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thewall
Jun 23, 2004, 4:27 PM
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Registered: Jun 23, 2004
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What is hte tool that you use to save your t-nuts. Is it a attatchment that will fit on a standard drill and can we get it at the hardware store, and what size will we need? Thanks in advance
The Wall
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steamboatclimber
Jun 23, 2004, 4:44 PM
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The tool you are looking for is a tap. But I wouldn't trust t-nuts that have been re-threaded. I might be off-base, but I think you are asking how to save a t-nut that has been stripped out, or cross threaded. If thats not what you are asking, just disregard my comments.
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atomic
Jun 23, 2004, 4:45 PM
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You will need to get a tap the same size as the bolts you are using. Standard t-nut are usually 3/8" by 16 thread pitch.
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thewall
Jun 23, 2004, 5:41 PM
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Exactly what im talking about, whynot rethread them...are you taking away some of the metal of the threads and comprimising the ability ot hold the bolt?
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rrrADAM
Jun 23, 2004, 6:02 PM
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T Nuts are what... .10 cents each ??? Buy a new one. That, and they are really thin to begin with, so removing more metal is not gonna be wise.
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thewall
Jun 23, 2004, 6:31 PM
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Thats what we have been doing for 4 years. Simply looking into other options. Some nuts are in places that are extreamly hard to get into, like short of taking hte panal out. The thin argument seems a good reason to rethink it that idea though. Thanks.
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j_ung
Jun 23, 2004, 6:37 PM
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In reply to: T Nuts are what... .10 cents each ??? Buy a new one. That, and they are really thin to begin with, so removing more metal is not gonna be wise.
I disagree. I re-tap t-nuts all the time. And though I'm not certain, I've probably re-tapped t-nuts that have already been re-tapped. But then, I'm usually up a ladder or on rope, and climbing/rappelling down, walking behind the wall, climbing up its innards and changing out the t-nut just isn't a good option for me. If I were talking about a home woody, I might consider changing it out, but don't worry so much about destrying the t-nut. You'd really have to (ahem) screw it up for that to happen.
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overlord
Jun 23, 2004, 6:43 PM
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In reply to: T Nuts are what... .10 cents each ??? Buy a new one. That, and they are really thin to begin with, so removing more metal is not gonna be wise.
well, i would agree with that, unless you cant easily gain acess to the back of the wall.
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anykineclimb
Jun 26, 2004, 10:00 AM
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just be careful not to cross thread the Tnut in the 1st place.
I usually screw it backwards until I feel it catch, then screw it in.
and NEVER use power tools to bolt on holds!!
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dorkmaster
Jun 26, 2004, 10:47 AM
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I'm gonna have to agree with rrradam on this one... :roll:
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socalbolter
Jun 26, 2004, 2:59 PM
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lots of good information and misinformation here already.
there's two main types of t-nuts out there. the hammer in (3 or 4 prong) are thinner metal and cost less. these can only be retapped a couple of times. unless the threads are really jacked up, all you're doing in most cases with the tap is cutting and realigning the existing threads; not always cutting new ones. it's your perogative to replace them instead, but unless the back of the panel's hard to get to it's really not the only option. also, with hammer ins you have to be careful not to push the t-nut out of the back while tapping. for this reason, if it's badly cross-threaded, you may not be able to salvage it.
screw in t-nuts (those used in most bigger commercial gyms) are made from thicker stock and cost more (about 25-30 cents each). these are designed to be able to be tapped several times. they also have a much longer barrel, equalling more threads overall.
a few thoughts on tapping:
- use the tap handle, not a power drill. the extra torque of the drill can snap or "weld" the tap into the t-nut.
- don't force the tap. once it starts to bind back it back out of the t-nut and blow out the cut metal shavings. you may have to repeat this a few times. if you continue you will only destroy the threads further (and shorten the life of the t-nut) by pushing all the shavings along with the tap's cutting edges.
- keep the tap handy when setting. don't wait until a t-nut's really messed up to use it. when caught early enough the tap is only straightening and realigning the threads, with a small amount of recutting being performed to these threads alone, versus recutting the entire t-nut's threads. this can be done several times (even with cheaper t-nuts). it's not until you start actually cutting new threads that you shorten the life of the t-nut.
hope that helped.
edited to correct spelling.
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boku
Jun 26, 2004, 3:51 PM
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In reply to: ...when caught early enough the tap is only straightening and realigning the threads...
I disagree.
I've worked in machine shops with taps and dies, and I've designed threaded fastenings for aviation applications, and I'm well nigh sure that concentional taps are not "straightening" and "realigning" tools. They are cutting tools; they are made of hardened steel and are carefully sharpened for the purpose of removing metal.
The only reason I think that it's OK to be re-tapping gym T-nuts is because there is a huge safety margin inherent in the use of 3/8" nuts and bolts.
Consider that even a cheese-hardened 3/8" bolt will have a tensile strength of at least 55000 psi, and a shear strength of 55% of that. So evaluate (3/8*.5)^2*pi*55000=6075 lbs tensile strength, *.55=3340 lbs of shear strength. A good quality T-nut will probably be capable of developing that full tensile strength with only a few good threads.
Thanks, and best regards to all
Bob K.
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socalbolter
Jun 26, 2004, 4:00 PM
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boku took my quote out of context. maybe if he had extended the quote a few words more in either direction?
i agree with him. of course the tap is a cutting tool. if however, the person cross threading the t-nut realizes this and doesn't continue to force it. the tap will only cut (read: realign) the damaged thread(s).
there are also far more threads in the t-nut than the amount required to be "strong enough." even if a singular thread (or a couple) is damaged beyond repair, a tap will cut away the portion of that thread posing an obstacle and realign what's left of it with the remaining threads to keep the bolt moving parallel through the t-nut. in all but the most extreme cases the remaining threads will work just fine.
again, good luck with your efforts.
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