Rotary hammer choices...Milwaukee M12 5/8" SDS or 18v Bosch?

I'm looking to pick up a rotary hammer that'll take advantage of one of the battery systems I've got, either 18v Bosch or 12v Milwaukee.

We're not going to be going nuts, but have a couple projects in mind.  Some of it will mean bolting on lead, so lighter is better.  Mostly half inch bolts in southern sandstone.

I love the M12 stuff I own, but are 1/2" holes out of a 5/8" drill too much to ask?  Would I regret not getting one of the brushless Bosch 18vs?  Which?

I have the M12 and have put a few 1/2 inch holes into limestone. It eats batteries and I wouldn’t call it a workhorse, but for on lead bolting for a pitch, it can’t be beat! Lightweight and pretty small.  

If ya ever start rap bolting and doing a lot of drilling, you will eventually wish you had an 18v set up.  They really are two different systems, so I say, buy both ;)   

Whatever you get make sure you get a high amp hour battery.  I have a 18v Bosch and use a 6 amp hour or 6.3 and I usually only take one battery with me. I get easily 20 3/8x3” bolts with just the one battery while drilling in granite or quartz monzonite.  

Hello,

Get an 18v should you ever decide to do glue ins or want to run a blower.

Milwaukee makes an M12 blower now.  

Hello,

Is the m12 blower as powerful as the 18v ones and have similar runtimes?

m12 for just a few holes.  Otherwise Brushless 18v SDS all the way.  As mentioned, get the big 6 amp hour batteries.  Slightly heavier but significantly better run time.  I’ve got the Makita version and love it. 

Fishy Boi wrote:

Hello,

Is the m12 blower as powerful as the 18v ones and have similar runtimes?

I haven’t looked up the specs. I am sure they are on the Milwaukee site.  I currently use the smallest M18 blower for cleaning as I use the M18 platform for home/bolting and it’s perfect.  

12v ain't gunna cut it man. Especially if your doing more than 2 holes a month lol.
either get a 18v Milwaukee set up or a 18v Bosch.
and if you’re looking for small and light. The little black 18v makita is super nice for limestone and sandstone. Its 12v size with 18v power. 

If you already have Bosch 18v battery tools this is the hammer I have.  It’s compact and light, great for ground up ascents.  I abuse the heck out of it and it keeps going.  
https://www.partswarehouse.com/Bosch-18V-Compact-Rotary-Hammer-Bare-Tool-w-L-Box-p/bsh-061190431g.htm?gclid=EAIaIQobChMI2rm_l4Xd9AIVxdzICh1qVgAVEAQYDCABEgIQ2_D_BwE&Click=365719

I’ve heard really good things about the m12.   Contrary to popular belief it can definitely drill to good affect.   I want to say it hits with .9 or 1 ft/lbs with my bosch doing 1.3 or so.  

But it weights 30 % less. I’m strongly considering one for lead bolting.   

I've used my 5/8" fuel M12 a fair bit in concrete/construction, no use on rock yet. Even though I've been just standing on the ground and weight isn't a big deal, I haven't found any reason to use my much bigger roto hammer unless I'm going really deep or bigger than 1/2". I'd probably stick to the 4 or 6 Ah M12 batteries. I don't find battery life to be a problem at all. Even so, the batteries are very light weight so taking a second one with you is no big deal.

I don't understand the concerns about the M12 above. Maybe you'd save 10 seconds per hole with a roto hammer that weighs twice as much? Maybe people are used to old equipment? With modern tools (li-ion, brushless, etc), drilling a 1/2" hole in rock is really not a big deal.

Milwaukee service has been fantastic by the way. I've sent two tools in this year, including my SDS Max roto hammer for the standard service interval (beat the hell out of it for 3-4 years), and they serviced both at no charge. They pay for FedEx both ways. Not that I need it very often...

Lately I've been an M12 user. 1/2 works fine, definitely eats batteries. I bolt mostly granitic rock and gneiss, so I opt for 3/8 most of the time and it's totally fine for that. 

I also own the new blower, which is pretty nifty combo for developing.  A 4 mah battery keeps the blower going for 20 minutes of sustained use. Spot blowing it generally lasts all day. 

Hello,

There are 2 things with the m12 drill.

The first is the low impact force, which itself is not a 12v issue. The makita subcompact 18v has the same 1.1-1.2 joules. Makita UK recommends up to 10mm in concrete all day, with higher occasionally. For harder rock or deeper holes 1/2" becomes quite slow with both the makita subcompact and the m12. 

The new dewalt subcompact that came out this year is more powerful at 1.4 joules and 20v (18v nomimal). You can tell the difference even on 3/8" holes. I have used all 3 side by side.

Once you get to glue ins, you will be doing all 1/2" or even up to 11/16" for the larger twisted legs. And possibly 6" or deeper depending on the rock. A subcompact drill may not be the best for this.

The second issue is basic physics. There is no way around the energy difference between a 12v and 18v battery. 

6 Ah x 12v = 72 Wh

6 Ah x 18v = 108 Wh

For the 12v equivalent of an 18v battery you would need 1.5x the amp hour rating. I bbelieve that the m12 tops out at 6 Ah, the bosch 18v go higher. You can do the math for their respective energy.

As to blowers, I go through 2 5 Ah 18v batteries every scrubbing session on lower angle climbs. It depends on the amount of dirt and vegetation you need to clean. I have tried using the cheaper 18v snail blowers and they just don't cut it. I suspect a 12v blower would not be much better for my uses. Your needs may differ.

On the positive side milwaukee does have a 5 year factory warranty, and their quality is quite good.

pat a wrote:

I'm looking to pick up a rotary hammer that'll take advantage of one of the battery systems I've got, either 18v Bosch or 12v Milwaukee.

We're not going to be going nuts, but have a couple projects in mind.  Some of it will mean bolting on lead, so lighter is better.  Mostly half inch bolts in southern sandstone.

I love the M12 stuff I own, but are 1/2" holes out of a 5/8" drill too much to ask?  Would I regret not getting one of the brushless Bosch 18vs?  Which?

The more powerful drill will give you better holes. Go with the m12 only if you can't do the ground up with the bigger drill but you're just tag lining the drill anyway right?

Double J wrote:

I haven’t looked up the specs. I am sure they are on the Milwaukee site.  I currently use the smallest M18 blower for cleaning as I use the M18 platform for home/bolting and it’s perfect.  

+1 on this! Nothing better than a leaf blower while you're cleaning. I've been using a gas powered model with a gazillion hp and I love it! But the convenience of bringing an extra battery or two that also works with your drill sounds amazing. In addition to the lower weight, this would definitely be a bit more quiet. 

Fishy Boi wrote:

I bbelieve that the m12 tops out at 6 Ah, the bosch 18v go higher. You can do the math for their respective energy.

9ah m12 battery

With this battery, I've done 28 3/8" holes with my m12. 

I've only drilled a few 1/2" holes with the m12 and it worked fine, but not sure I'd want to do it all day, as has been said. 

Brian Prince wrote:

9ah m12 battery

With this battery, I've done 28 3/8" holes with my m12. 

I've only drilled a few 1/2" holes with the m12 and it worked fine, but not sure I'd want to do it all day, as has been said. 

Hello,

That is a knockoff battery, not a milwaukee one.

The genuine m12s top out at 6 Ah, which is the energy equivalent of a 18v 4 Ah battery.

The knockoffs use no name chinese 18650 batteries. The genuine big brand ones use samsung, panasonic or LGs which last longer over the time.

Also the knockoffs lack load balancing circuits so that over time the voltage in the batteries become unbalanced. This leads to earlier dead cells at best or a fire hazard at worse.

The knockoffs also lack the electronics to communicate with modern fast chargers which often have fans and temperature sensors to regulate the charge rate.

Personally I would never buy knockoffs, and if I were to charge them it would be outside the house.

People have had issues with then going dead earlier, or even fires.

You can often find genuine name brand batteries on sale, and mikwaukee ones come with a 3 year warranty.

If it’s strictly sandstone, the M12 gets it done. Even @ 1/2”.

Fishy Boi wrote:

Hello,

That is a knockoff battery, not a milwaukee one.

The genuine m12s top out at 6 Ah, which is the energy equivalent of a 18v 4 Ah battery.

The knockoffs use no name chinese 18650 batteries. The genuine big brand ones use samsung, panasonic or LGs which last longer over the time.

Also the knockoffs lack load balancing circuits so that over time the voltage in the batteries become unbalanced. This leads to earlier dead cells at best or a fire hazard at worse.

The knockoffs also lack the electronics to communicate with modern fast chargers which often have fans and temperature sensors to regulate the charge rate.

Personally I would never buy knockoffs, and if I were to charge them it would be outside the house.

People have had issues with then going dead earlier, or even fires.

You can often find genuine name brand batteries on sale, and mikwaukee ones come with a 3 year warranty.

Definitely don't buy the knock off batteries. Good call.