Converting screw-on holds to bolt-on holds

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Converting screw-on holds to bolt-on holds

Postby mick » Wed Jul 23, 2014 10:07 am

I picked up about a dozen mid-to-large-sized screw on Metolius holds off kijiji and I want to convert a few to bolt-ons. I figure bolts will make it easier to turn them and move the holds around as needed. Does anyone have any experience doing this? They are not urethane, but rather the older, heavy resin style like these:

metscrewon.jpg

My plan is to drill a 5/32" hole all the way through with a masonry bit, then widen part of that hole to ~5/8" for the first 1/2". I'll glue a 3/8" washer in the countersunk portion to accept a standard socket cap screw.

Is this a good plan or will I break the holds somehow? Should I drill a pilot hole with a thinner bit first?

Feedback, advice, and spirited disagreement welcome.
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Re: Converting screw-on holds to bolt-on holds

Postby mick » Fri Jul 25, 2014 8:32 am

Update:

It worked! I used a 5/32" masonry bit and drilled through three of my screw on holds to fit them with bolts. Two I was able to go right through one of the screw holes, but the third I went in the middle of the four screws to keep it from spinning. Mounted them with external tooth lock washers (because that is what I had handy) and they were plenty secure. I have a couple more to do but I will wait until I get a hold of a larger bit so I can countersink the socket cap screw.

I'll post some photos when it's all done.
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Re: Converting screw-on holds to bolt-on holds

Postby chossmonkey » Sun Aug 31, 2014 12:01 pm

This is an interesting project. I'm usually drilling holes to make bolt-on's into screw-on's. I would be a bit worried about weakening the hold if the washer doesn't make full contact with the hold and creates a concentrated pressure point. Maybe a little epoxy to level out the washer if it isn't perfectly flat would help? Just drilling a largeish hole in a smallish hold could potentially weaken the hold and cause it to break.

Did the back of the hold blow out at all when you drilled thru? I have had that problem when making holds from rock.

Let us know how they work out.
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