Stainless bolts and galling- dab of anti-seize lube?

Good old Ave has some words for us. 

Questions I have pondered: 

1. Would a tiny dab of anti-seize paste make for fewer botched installations on 5-piece bolts? (No!? Maybe??)
2. Would it make them more likely or less likely to loosen due to cyclical loading? (Probably more)
3. Would lube invalidate the torque specs by changing the assumed friction of the bolt and cone as shipped by the manufacturer? (Yes)
4.  Would the oily goop in that paste compromise the holding power if it were between the rock and the sleeve? (Probably a moot point)
   
   

Don't know. But it makes me think.

Carry on,

-gg

The galling (or spalling) problem is evident on wedge bolts too.  Nothing other than an extremely observant installation seems to avoid this problem.  On a wedge bolt, at least I can see when everything is spinning.  On a 5-piece, you're hosed, and out nearly 3X-5X the price of a wedge bolt.

Is the cone stainless? I never checked but they look like a different material (or grade of ss?) or have a coating. I think Ave missed the mark on this one.  Those fasteners were never installed correctly.  Pretty sure Powers has us covered but will to check next time I have one in hand. 

Cones are stainless. Slightly different material than bolt. 

Greg, are you talking galling in the threads?

1. I have placed more than 500 3/8 and 1/2 inch 5 piece without any known galling. I think a dry moly like Dow Corning molykote 321 might be a better fit? It dries like paint. Thin layer.

2. Maybe less trouble. Might achieve more cosistant expansion with a lubricated thead.

3. May need to reduce torque value to prevent stressing the bolt.

4. A light lube of the threads only should be the target? The dry moly mentioned above.

For me an extra clean hole is important for 5 piece. Ream the first 1/4" of the hole.

Botched 5-piece installations? How often do people have issues?

The cones are 303 stainless, but they are zinc plated - probably to avoid galling.

Greg Barnes wrote:

Botched 5-piece installations? How often do people have issues?

The cones are 303 stainless, but they are zinc plated - probably to avoid galling.

It happens occasionally that a 5-piece doesn't tighten down after hammering it in - it's not very common, tho.  The galling is more of an issue when attempting to remove a stainless wedge. The nut binds up when you try to unscrew it, and the collar likewise binds on the wedge when you try to spin and pull, breaking the bolt instead. 

Kind of a tangent, but how do those "crush washers" work on the Powers Bolt? How accurate are they?

My mental model says they should be accurate for measuring bolt tension even if you were to lube the threads and throw off the torque values.

Austin Donisan wrote:

Kind of a tangent, but how do those "crush washers" work on the Powers Bolt? How accurate are they?

My mental model says they should be accurate for measuring bolt tension even if you were to lube the threads and throw off the torque values.

if my torque wrench is correct, the stainless powers bolt torque washer breaks around 13-14Nm.

Before considering that as an option I would want to rule out the more obvious culprits...

The most common things I see people doing that cause problems installing 5 piece bolts are:

1. Initial expansion of sleeve prior to installation is either too expanded or not expanded enough. This is by far the most common error I see being made and can be compounded by the following point. 

2. Drill bit is too dull, making the hole smaller than spec. 

3. Improper cleaning, too much sand or dust left in the hole. Hand blower instead of tube and actually wire brushing it. I've seen people who are used to placing wedges blow the hole once and not brush at all and call it good then wonder why they're having problems getting 5 piece to tighten down. With the exception of bolting from precarious stances on lead, there's no reason not to get the hole as clean as you would for an epoxy bolt.

4. If you already have a spinner, putting back pressure on the hanger (claw hammer or wedge behind the hanger/pulling outward with a sling to the harness) and tightening at the same time. 

Short of the above issues, I've never had problems with 5 piece galling on me. 

Regarding sleeve bolts working loose, at one point we were recommended to use vibratight, a threadlocker that doesn't prevent future tightening like loctite. We found the more obvious solution was to simply do a second or third tightening to deal with the bolt/rock relaxation, and to use a (now officially recommended by powers) higher torque spec.

I wouldn't expect to have issues caused by galling when not using power tools to install the bolts, removing wedges this is obviously a more relevant issue.   

Gregger Man wrote:

 The galling is more of an issue when attempting to remove a stainless wedge. The nut binds up when you try to unscrew it, and the collar likewise binds on the wedge when you try to spin and pull, breaking the bolt instead. 

Yep that makes sense. I've seen stainless wedge bolts visibly stretched near the nut too - in that case they probably wouldn't unscrew regardless.

DrRockso RRG wrote:

Before considering that as an option I would want to rule out the more obvious culprits...

The most common things I see people doing that cause problems installing 5 piece bolts are:

1. Initial expansion of sleeve prior to installation is either too expanded or not expanded enough. This is by far the most common error I see being made and can be compounded by the following point. 

2. Drill bit is too dull, making the hole smaller than spec. 

3. Improper cleaning, too much sand or dust left in the hole. Hand blower instead of tube and actually wire brushing it. I've seen people who are used to placing wedges blow the hole once and not brush at all and call it good then wonder why they're having problems getting 5 piece to tighten down. With the exception of bolting from precarious stances on lead, there's no reason not to get the hole as clean as you would for an epoxy bolt.

4. If you already have a spinner, putting back pressure on the hanger (claw hammer or wedge behind the hanger/pulling outward with a sling to the harness) and tightening at the same time. 

Short of the above issues, I've never had problems with 5 piece galling on me. 

Regarding sleeve bolts working loose, at one point we were recommended to use vibratight, a threadlocker that doesn't prevent future tightening like loctite. We found the more obvious solution was to simply do a second or third tightening to deal with the bolt/rock relaxation, and to use a (now officially recommended by powers) higher torque spec.

I wouldn't expect to have issues caused by galling when not using power tools to install the bolts, removing wedges this is obviously a more relevant issue.   

all excellent points!

in terms of 2. i think the key is to seat the cone in the sleeve so that the sleeve overlaps the cone, but not so much that the sleeve expands beyond the circumference of the largest part of the cone.

I think some of the failures I have seen can be attributed to how the hole is enlarged after removing a previous 3/8" bolt. Volunteers cover a wide range of tool talent, and some don't have the awareness to follow the angle of the previous hole perfectly. That can lead to an enlarged cavity in just the wrong spot and the cone won't grip the walls very well. A light funking or pressure behind the hanger almost always fixes the issue and gets the cone to tighten down, but I have seen a few that just spun in the hole and refused to be tightened or unscrewed.