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Drilling out 3/8” to 1/2” hanger hole


Original Post
Kent Krauza · · Vancouver Island · Joined Dec 2018 · Points: 0

Up here in Canada, I am having trouble domestically sourcing 1/2” ring anchors. It’s super expensive to order them from the U.S., but 3/8” Fixe ring anchors are cheap and plentiful through MEC. Visually, it looks like they are identical other than hole diameter. Would it compromise the anchor to simply bore the hole out to 1/2”? I believe they are punched or stamped when manufactured, so would the heat generated by drilling affect the strength? I’m not trying to cheap out and re use old 3/8” anchors, they would be new ones. Thanks!

Ken Noyce · · Layton, UT · Joined Aug 2010 · Points: 2,415
Kent Krauza wrote: Up here in Canada, I am having trouble domestically sourcing 1/2” ring anchors. It’s super expensive to order them from the U.S., but 3/8” Fixe ring anchors are cheap and plentiful through MEC. Visually, it looks like they are identical other than hole diameter. Would it compromise the anchor to simply bore the hole out to 1/2”? I believe they are punched or stamped when manufactured, so would the heat generated by drilling affect the strength? I’m not trying to cheap out and re use old 3/8” anchors, they would be new ones. Thanks!

It won't do any damage to the anchors other than removing the passivation layer on the drilled out portion, but have fun trying to drill out the hole with all of the strain hardening of the material that will happen.

Josh Janes · · Unknown Hometown · Joined Jun 2001 · Points: 9,015

If the issue is that the hole in the hanger is 3/8" but you're using 1/2" bolts, my question would be what type of bolt are you using?

If they are 1/2" five-piece (Powers) bolts, you can use hangers with 3/8" holes: Only the sleeves of these bolts are 1/2" and the bolt itself is 3/8". The hanger will sit on the bolt instead of on the sleeve (in other words, between the washer and the sleeve rather than over the sleeve). I do this all the time and I simply remove the small metal spacer ring (if present - depends on length of bolt) to ensure that enough threads will still be in contact with the cone.

If you're using 1/2" wedge bolts you would obviously have to drill out the hole in the hanger but I have no idea how that would affect the hanger's strength.

CTB · · Cave Creek, AZ · Joined Jul 2015 · Points: 205

If you are going to do a lot of them just invest in two chucking reamer sizes 0.437" and 0.500". Just clamp the hanger in a vise or on the edge of a sturdy table and waller them out with a regular power hand drill on its SLOWEST speed..... Push HARD and drill SLOW......Start with the smaller one and then the bigger. Dunk them in WD-40 before and a couple times during each hole to keep them cool and lubed. If you are a gentleman and keep the cutting ends cool than you could probably open up a few hundred plated hangers before they need to be re sharpened... maybe 150 if they are SS.  Just make sure you buy ones with a 3/8" shank if you do not have a 1/2" chuck on your drill.

https://www.mscdirect.com/browse/tnpla/02290328?cid=ppc-google-New+-+Holemaking+-+PLA_s7rf5FeuY___164110844859_c_S&mkwid=s7rf5FeuY|dc&pcrid=164110844859&rd=k&product_id=02290328&gclid=EAIaIQobChMI3Nv-85Xz3wIVgR-tBh3LMwTyEAQYASABEgL_rPD_BwE

Zacks · · Unknown Hometown · Joined Apr 2015 · Points: 65
Josh Janes wrote:
If they are 1/2" five-piece (Powers) bolts, you can use hangers with 3/8" holes: Only the sleeves of these bolts are 1/2" and the bolt itself is 3/8". The hanger will sit on the bolt instead of on the sleeve (in other words, between the washer and the sleeve rather than over the sleeve). I do this all the time and I simply remove the small metal spacer ring (if present - depends on length of bolt) to ensure that enough threads will still be in contact with the cone.

I think this only works with the shorter (2 3/4"?) 5 piece bolts isn't the spacer on the longer bolts a longer spacer?  Climb tech recommends using their 3/8 hangers with 1/2in 5 piece sleeve style bolts (powers bolts) and not using the washer (the hanger is the washer) but the climb tech hangers are designed for use this way (although you must use the 3/8 hanger and must not use the washer on the 1/2in bolt for proper thread engagement.  Fixe hangers might be ok used this way but I have no experience or data with that.


In my very limited experience working with stainless steel and not in a climbing scenario the spit I cut or drilled tended to rust a little.  Not sure why

Also your on Vancouver island?  Ever get to squamish?  I'm sure you could get one of us yanks to truck up some hangers.  Although I'd be surprised to hear this stuff isn't available around squamish...  I'm in Seattle but I dunno when I'll be in Canada again might not be until summer.

My girlfriend heard about magic tufa pulling ion Vancouver island but it's such a pain with the ferry ect :(
Josh Janes · · Unknown Hometown · Joined Jun 2001 · Points: 9,015
Zacks wrote:

I think this only works with the shorter (2 3/4"?) 5 piece bolts isn't the spacer on the longer bolts a longer spacer?  Climb tech recommends using their 3/8 hangers with 1/2in 5 piece sleeve style bolts (powers bolts) and not using the washer (the hanger is the washer) but the climb tech hangers are designed for use this way (although you must use the 3/8 hanger and must not use the washer on the 1/2in bolt for proper thread engagement.  Fixe hangers might be ok used this way but I have no experience or data with that.

So that's the only length of 1/2" five-piece (stainless) that I use, and yeah, they have a small spacer. I believe that the longer versions do indeed have longer spacers which you couldn't remove. In that case I'd probably just remove the washer and use the hanger as a washer a la Climb Tech's recommendations. Actually, in my opinion the only reason you really need to make more room for more thread engagement with Fixe hangers is that they're made from such thick metal. With Climb Tech, Metolius, Mad Rock hangers you could probably get away without removing the washer or spacer and still have plenty of thread engagement. I can't remember how thick PETZL hangers are - I think somewhere in the middle? The reason I might remove the washer with non-Fixe hangers isn't actually for more thread engagement - it's that the large 1/2" five-piece washer won't sit flush against the curvature of those other hangers.

Kent Krauza · · Vancouver Island · Joined Dec 2018 · Points: 0

From what I can tell, a Cobalt or Titanium bit, with LPS or similar cutting fluid should do the job.  I’ll stop by the hardware store and give it a lash tonight.

Kent Krauza · · Vancouver Island · Joined Dec 2018 · Points: 0
Zacks wrote: Also your on Vancouver island?  Ever get to squamish?  I'm sure you could get one of us yanks to truck up some hangers.  Although I'd be surprised to hear this stuff isn't available around squamish...  I'm in Seattle but I dunno when I'll be in Canada again might not be until summer.

My girlfriend heard about magic tufa pulling ion Vancouver island but it's such a pain with the ferry ect :(

Yes we get over to Squamish quite a bit, but the standard there is still 3/8” Hilti KB3’s and corresponding hangers.  Very rare to see 1/2” hardware. Your girlfriend is talking about Horne Lake - magical indeed, but access is sensitive. Very important to abide by the landowner’s strata rules.

C. Williams · · the Climber Cave · Joined Jul 2013 · Points: 1,258
Kent Krauza wrote: From what I can tell, a Cobalt or Titanium bit, with LPS or similar cutting fluid should do the job.  I’ll stop by the hardware store and give it a lash tonight.

I use a Greenlee step bit and cutting oil. My bit is about 100 hangers into it and still going strong.

Kent Krauza · · Vancouver Island · Joined Dec 2018 · Points: 0
Bought a 1/2” Cobalt bit, and with vice grips and some cutting oil, I had a pretty easy time boring out a total of ten 3/8” hangers and ring anchors.  The hanger on the bottom is a store bought 1/2” hanger, and the one on the top is my handiwork. Thanks to everyone for the suggestions.
AKM1878 · · Unknown Hometown · Joined Jan 2012 · Points: 50

I find the easiest way to drill them out is with a step drill. They are made for drilling in sheet metal and will be a lot less likely to catch and bind up while drilling. The other nice thing is you can use the same bit to chamfer the edges of the hole easily. I would suggest running it quite slow on the RPMs.

I'm not a fan of using 3/8 hangers on 1/2 power bolts. I find it increases the chances of damaging the blue crush sleeve during installation. 

https://www.homedepot.com/p/Milwaukee-3-16-in-7-8-in-x-1-16-in-4-Step-Black-Oxide-Drill-Bit-48-89-9204/204312639

Guideline #1: Don't be a jerk.

Fixed Hardware: Bolts & Anchors
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