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Excess Bolt Threads On Top?


Original Post
Bill Lawry · · New Mexico · Joined Apr 2006 · Points: 1,637

Novice bolter here.

Hand drilled and placed my first bolt today - practicing in practice rock.

When I torqued the bolt, I reached the prescribed torque with about 3 or 4 threads showing above the nut. Photo included.

I had started torquing with the bolt top flush with the top of the nut. Am not surprised at threads showing.  But I am wondering if experienced folks  tend to start with the top of the bolt recessed a thread or two below the top of the nut.

Cheers!

Bill Lawry · · New Mexico · Joined Apr 2006 · Points: 1,637

Two drawbacks to pre-recessing the bolt:

First, any hammer action to insert the bolt shocks the threads. Felt not bad.

Second, recess the bolt too far and one may wind up with less than 100% thread engagement - though this seems easy to control

?

Bill Czajkowski · · Albuquerque, NM · Joined Oct 2008 · Points: 30

I haven’t put in many bolts but, as a bolting effort consumer,  personally I prefer this (and it doesn’t seem unusual in degree) to those instances where the last threads are barely engaged (or aren’t).

Bill Lawry · · New Mexico · Joined Apr 2006 · Points: 1,637

Good point, Bill. It is indeed the consumers I had in mind. :)

bus driver · · Unknown Hometown · Joined Aug 2009 · Points: 1,165

In construction applications,  I think you need to have two or more full threads showing for full spec. Someone else can confirm. 

Jeffrey Constine · · Los Angeles, CA · Joined May 2009 · Points: 643

2 to 3 threads must show.

Bill Lawry · · New Mexico · Joined Apr 2006 · Points: 1,637

These are great reminders for me.

The contrary thought I’d had about the consumer was that the bolt sticking up might interfere once in a while with clipping. But the points being made here rule the day. 

And credit goes to the drill / bolt designers for making it simply happen as part of the typical installation steps and proper torque

David Gibbs · · Ottawa, ON · Joined Aug 2010 · Points: 2

That looks like a normal and expected installation to me.

Alexander Stathis · · Athens, GA · Joined Jan 2016 · Points: 401

I've never placed a bolt, but this looks like pretty much every wedge bolt I've ever encountered in the wild. It's actually a lot better than a lot of them, since it doesn't have like a half inch of bolt sticking out. It's a huge pain in the ass to stick clip draws and clean draws when too much of the bolt is showing and in the way. 

Bill Lawry · · New Mexico · Joined Apr 2006 · Points: 1,637
Alexander Stathis wrote:.... It's a huge pain in the ass to stick clip draws and clean draws when too much of the bolt is showing and in the way. 

.... and I’ve banished any thought of dealing with a shallow hole that way. :)

Oddest thing I ever saw along this topic were belay anchor bolts on Y2K at Red Rocks. Wish I’d taken a picture. There were hefty stacks of washers underneath the hangers.  Am hopeful the bolts themselves were really long.
Alexander Stathis · · Athens, GA · Joined Jan 2016 · Points: 401
Bill Lawry wrote:

.... and I’ve banished any thought of dealing with a shallow hole that way. :)

Oddest thing I ever saw along this topic were belay anchor bolts on Y2K at Red Rocks. Wish I’d taken a picture. There were hefty stacks of washers underneath the hangers.  Am hopeful the bolts themselves were really long.

I know what you're talking about. I still run across them occasionally. They're an old style of bolt that is no longer used, and should be treated with caution since I thought I remember reading somewhere on this forum that they're kinda junk.

Guideline #1: Don't be a jerk.

Fixed Hardware: Bolts & Anchors
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