High torque rotary hammer

My old 36v Bosch works well for drilling, but sometimes stalls when trying to spin old 3/8 studs during replacement. I want one with so much torque it can spin anything. Weight is also a factor, but cost not so much. What do I get ? I've done a lot of searching, and will bounce the locals too, but maybe you guys know. TIA !

Do you have a good 4.0 amp hr battery? 

My Compact 36v works great for spinning with the 4.0 battery. Not so much with small one.

I will add that 4.0 weighs less than 2 of the 1.3 amp hr. So it is a no brainer what i take for a work day. I can't drain the 4.0 completely in a day either doing normal replacement work. 

I use my subcompact Makita for ground up new routes.  The compact Bosch is a pig by comparison.

What you want is a cordless impact driver.

@Timothy... I'll try a 4.0 and see. Easy change.

I almost always do my bolt replacement work alone and usually have to hike pretty far carrying rope, rack, bolting gear and LRS gear.  I will typically bring a cheap ryobi drill because it’s the lightest and is actually a pretty awesome little drill.  That said it’s not the most powerful.  With a 4ah battery it will get the job done but occasionally it doesn’t have the torque to *start* the bolt spinning.  In this case I just leave the drill and spinner on the stud and with an open end wrench on the spinner tool, will turn the stud a couple of full turns.  This is usually sufficient to loosen things up enough to where the drill can handle it.  If it gets stuck while spinning (rare) I stop and spin it with the wrench a turn or two.  Make sure you’re squirting water + abrasive grit into the hole.  

Mitchell Goldmanwrote:

I almost always do my bolt replacement work alone and usually have to hike pretty far carrying rope, rack, bolting gear and LRS gear.  I will typically bring a cheap ryobi drill because it’s the lightest and is actually a pretty awesome little drill.  That said it’s not the most powerful.  With a 4ah battery it will get the job done but occasionally it doesn’t have the torque to *start* the bolt spinning.  In this case I just leave the drill and spinner on the stud and with an open end wrench on the spinner tool, will turn the stud a couple of full turns.  This is usually sufficient to loosen things up enough to where the drill can handle it.  If it gets stuck while spinning (rare) I stop and spin it with the wrench a turn or two.  Make sure you’re squirting water + abrasive grit into the hole.  

I'll pay more attention to the manual turning thing. I'm doing overhangs so squirting water doesn't seem like it would penetrate. Gravity.

jbak xwrote:

I'll pay more attention to the manual turning thing. I'm doing overhangs so squirting water doesn't seem like it would penetrate. Gravity.

I keep my grinding powder and water mixture in a condiment squirt bottle, so I can really blast it back in the bolt hole. It works well for me on the steeps. I find using a lot of the fluid important to prevent binding up when spinning. It also helps cool off the bolt.

Matt Miccioliwrote:

I keep my grinding powder and water mixture in a condiment squirt bottle, so I can really blast it back in the bolt hole. It works well for me on the steeps. I find using a lot of the fluid important to prevent binding up when spinning. It also helps cool off the bolt.

I got a condiment bottle for that very purpose, but didn't really try it on overhangs. I'll give it a go.

Good conversation here guys. A standard tool in my wedge bolt spinning kit is a 5/8 ratchet wrench. I always free the bolt in the hole with the wrench pior to spinning. Many of the bolts I deal with are in very hard rock. NC quartzite and WV sandstone. The holes tend to be undersize due to that. Occasionally i will find a bolt that will not turn without force. Rather than fuck my drill/battery up I now carry a 3/16 bit as standard. A single small hole next to the bolt will free the bolt and provide abrasive material.  That certainly would help to get the water in the back of the hole in steep terrain as well. Then you just have to upsize the hole. I also mostly am by myself. An additional few pounds for an impact tool in the pack is not something that is appealing.

timothy fisherwrote:

Good conversation here guys. A standard tool in my wedge bolt spinning kit is a 5/8 ratchet wrench. I always free the bolt in the hole with the wrench pior to spinning. Many of the bolts I deal with are in very hard rock. NC quartzite and WV sandstone. The holes tend to be undersize due to that. Occasionally i will find a bolt that will not turn without force. Rather than fuck my drill/battery up I now carry a 3/16 bit as standard. A single small hole next to the bolt will free the bolt and provide abrasive material.  That certainly would help to get the water in the back of the hole in steep terrain as well. Then you just have to upsize the hole. I also mostly am by myself. An additional few pounds for an impact tool in the pack is not something that is appealing.

Would that method leave glue-ins as the only replacement option? Sounds like the hole would be too large and asymmetrical to accommodate a 1/2"?

Andy Bwrote:

Would that method leave glue-ins as the only replacement option? Sounds like the hole would be too large and asymmetrical to accommodate a 1/2"?

Agreed, unless the 3/8 wedges are stubbies and you put in a long 1/2" mechanical. 

And in the case where you are not prepared for that,  the empty hole will patch nicely.

timothy fisherwrote:

Good conversation here guys. A standard tool in my wedge bolt spinning kit is a 5/8 ratchet wrench. I always free the bolt in the hole with the wrench pior to spinning. Many of the bolts I deal with are in very hard rock. NC quartzite and WV sandstone. The holes tend to be undersize due to that. Occasionally i will find a bolt that will not turn without force. Rather than fuck my drill/battery up I now carry a 3/16 bit as standard. A single small hole next to the bolt will free the bolt and provide abrasive material.  That certainly would help to get the water in the back of the hole in steep terrain as well. Then you just have to upsize the hole. I also mostly am by myself. An additional few pounds for an impact tool in the pack is not something that is appealing.

6/16+3/16 > 1/2. Plus would be asymmetrical like Andy says. Do they make a 1/8 SDS ? I'll Google.

jbak xwrote:

6/16+3/16 > 1/2. Plus would be asymmetrical like Andy says. Do they make a 1/8 SDS ? I'll Google.

The smaller 5/32 bit that is availible, the tips dont last long as they invariably rub agains the bolt. The 3/16 seem to deal with that ok.

Also as the bit will drift into the existing hole and rub the bolt it actually  may not be making the hole as big as you might think.  I have only done this to place glue ins at this point. 

jbak xwrote:

6/16+3/16 > 1/2. Plus would be asymmetrical like Andy says. Do they make a 1/8 SDS ? I'll Google.

I would expect the bit to bind catastrophically in the resulting figure 8-shaped hole.

Gunkiemikewrote:

I would expect the bit to bind catastrophically in the resulting figure 8-shaped hole.

You might be right, but worth some thought and experimentation. I've got a big rock in my backyard. Would allow water to penetrate for sure.

Gunkiemikewrote:

I would expect the bit to bind catastrophically in the resulting figure 8-shaped hole.

Well i did 7 bolts on a route last year that were 3/8 wedges. The holes had epoxy in them so i had no luck spinning them. I used a 1/4 in bit next to the bolt.  I pulled them all successfully with a Doodad tool. (Thanks Greg German). I up sized to only 7/16 to place 10mm glue ins. In good quality gniess. Had no issues with the bit binding. I think upsizeing to 1/2" would be even easier.

jbak xwrote:

You might be right, but worth some thought and experimentation. I've got a big rock in my backyard. Would allow water to penetrate for sure.

Mr Baker, I actually recall now that EFR and I replaced some old bolts using a 1/8" SDS bit (smallest they make, I believe) by just drilling in about 1/4". We were putting in longer 1/2" SS sleeves, so the small hole wasn't really (we thought) much of an issue (perhaps only in our super arid environment?). Not sure if this will help you in your specific case or not. YMMV

Andy Bwrote:

Mr Baker, I actually recall now that EFR and I replaced some old bolts using a 1/8" SDS bit (smallest they make, I believe) by just drilling in about 1/4". We were putting in longer 1/2" SS sleeves, so the small hole wasn't really (we thought) much of an issue (perhaps only in our super arid environment?). Not sure if this will help you in your specific case or not. YMMV

Andy, smallest I've seen is 5/32 but that may be okay. I would only do it as last resort. And then pound in a 1/2 x 4.5 wedge. I would only use the 3 inch 5-pieces when everything goes right (the normal case). If I used a 5/32, I would only go in an inch or less. Once the half inch wedge was in I would epoxy putty the auxiliary hole (which would end up under the washer) before final tighten. To seal against water.

jbak xwrote:

Andy, smallest I've seen is 5/32 but that may be okay. I would only do it as last resort. And then pound in a 1/2 x 4.5 wedge. I would only use the 3 inch 5-pieces when everything goes right (the normal case). If I used a 5/32, I would only go in an inch or less. Once the half inch wedge was in I would epoxy putty the auxiliary hole (which would end up under the washer) before final tighten. To seal against water.

It's been awhile since 9th grade math, but I'm fairly confident that 1/8" is smaller than 5/32" ...Just bought one yesterday...

Hmmm. I've heard epoxy can actually trap moisture and increase corrosion rates. But others more knowledgeable will have to weigh in. 

The holes we were drilling were like I said quite shallow. Not sure if they would help in your case or not 

Andy Bwrote:

Hmmm. I've heard epoxy can actually trap moisture and increase corrosion rates.

With a 5 piece or any mechanical bolt, you're never really sealing against water since it still can and usually will get in around the sleeve.  But moisture alone isn't going to increase corrosion for a stainless 5 piece.  So corrosion from trapping moisture shouldn't be a concern.  Erosion, maybe, for sandstone in certain environments, but I doubt that would be a concern most of the time either.  So it seems pointless to fill the small 1/8 or 5/32 hole with epoxy, except for aesthetics.