Placing 3/8" Bolts, How Many Turns?
|
I am using 3/8" five piece Rawl Power bolts and am wondering if someone can give me a good rule of thumb regarding the max number of cranks or a rough description of how it should feel with a standard box wrench. I dont have a torque wrench and could not find info regarding turns on the Fixe or Powers web sites for 3/8". Muchas Gracias! |
|
John Wilder wrote:It's not number of turns (which will be different depending on the type of rock), it's torque and it's important. For a 3/8" stainless bolt, you'll want to use a small box wrench for tightening, and hold three fingers right up against the bolt side of the wrench and turn until its snug (not super tight)- that should be about 12lbs. You'll want to be very careful about over-tightening the 3/8" stainless bolt- they snap super easy, and if you over torque them, you are weakening them substantially.I know that you have replaced a lot of bolts John, but seriously, do you really think your suggestion has any amount of accuracy? Probably not. How about Blommerz goes out and buys a torque wrench and does it right. Unless you are doing something ground up, I don't see any good reason not to carry a torque wrench (you're already carrying all sorts of other bolting gear so its not a big deal to toss in the wrench). |
|
Let's hope you're placing SS but in the case of 3/8" 5-piece carbon steel, the spec is 25 ft-lbs. Most would be surprised to learn just how 'light' 12 ft-lbs (for SS) feels, which explains the natural inclination to over-torque. |
|
John Wilder wrote:Oh, I would much prefer that he go get a torque wrench, but I'm also realistic about the likelihood of some random off the internet buying a torque wrench because some random people told him to. As to the accuracy, I would argue that the method I suggest will get you somewhat close, which is better than cranking it down- it was shown to me by a guy who has placed way more bolts than most of us combined. That said, I use a torque wrench when I place mechanical bolts, and I always use 1/2" Stainless.I hear you John, the guy who taught me to bolt (who like your guy, has placed a ridicules number of bolts) also uses both a short box and a torque wrench depending on the situation. But I really think that if someone asks, it is probably best to arm them with the idea of "best" practices, i.e. use SS, some LocTite, and a torque wrench. Anyway... |
|
12 ft/lbs is 25 pounds at the end of a 6" wrench. |
|
rocknice2 wrote:12 ft/lbs is 25 pounds at the end of a 6" wrench.Or 24lbs :-) |
|
Jim Titt wrote: Or 24lbs :-)LOL yeah but not all three fingerrs for at the very end of the wrench. |
|
Only $22. Get one. |
|
Powers 3/8" 5-piece SS bolts come with a built in device which indicates proper torque. There is a little, grey plastic washer between the bolt head and the SS washer. Tighten the bolt until the grey, plastic washer deforms and is visible as it is squeezed out the side of the washer. |
|
Locker wrote:"Muchas Gracias!" Muchas n00bias is more like it. How many turns? Really? YIKES! "Yer GONNA die!!!"Sadly, with an over-torqued bolt, it is probably someone else who is gonna die. |
|
Why not teach the novices to do it the right way with a torque wrench. I even have one id donate to make the public safe that's in the lower range. Leave the three finger touch for the wizards. |
|
Aric Datesman wrote:Only $22. Get one. harborfreight.com/3-8-eight…I would be more inclined to start a n00b out with one of these- sears.com/craftsman-3-8-in-… the clickers are not easy to read/set properly and besides that I would never consider buying tools where accuracy may equate with life or death from China Freight Tools this thread is funny and scary all at the same time |
|
Yeah just do it by hand because you want 24 foot-pounds at 6 inches exactly from the center of the bolt so that means you need to be at 21 pounds at 7 inches exactly from the center of the bolt or 28 pounds exactly if you are 5 inches from the Super Bowl yes this is totally easy to do I am by a total inexperienced person this is freaking awesome I love it just one more reason why sport climbing is really scary. |
|
Look at the label on the Powers box. 3-5 turns: |
|
Fixe says 3 to 4 turns past finger tight. 12 ft*lb for 3/8", 25 ft*lb for 1/2"
This is the spec sheet from Fixe: fixehardware.com/specs-manu… 12 ft*lb for 3/8" 25 ft*lb for 1/2" |
|
People must have missed reading this the first time around:-) |
|
I agree that the bolt should not be overtightened, and a torque wrench is the best way to ensure that happens. But I do not agree with John that they break easy, at last not the old RAWL 3/8" stainless ones. |
|
Harbor Freight has a perfectly serviceable 3/8 inch torque wrench for $25. Get one. Not the 1/2 inch, sorry. |
|
I'd rather climb runout choss on ballnuts than trust a China Freight torque wrench with my life, YMMV |
|
Do everyone a favor and flip for a torque wrench. Until then you are probably under torquing on Rawls no matter how many knuckles you scrape with an open end wrench greasing off the head. |
|
Do it right or don't do it at all. If you have to ask this question, you need to go out with someone who knows and learn before placing any bolts. |