SDS Rotary Hammer specs...

[DamnYankee]

I had to install the letters shown in the attached photo to the stone-faced monuments. Each letter has 3 or 4 studs, so I have to drill a 3/16" hole for each stud. There are 6 sets of these letters altogether, so when drilling that many holes, my mind always wanders to whether or not I'm using the best tool for the job.

I currently have a bunch of the DeWalt 20v stuff including the SDS rotary hammer which works great and is what I use for installs like the above one. I'm always reading up on new tools, specs, etc. though just to see how everything compares. So I figured this morning while I'm laid up sick, I would compare the various cordless SDS rotary hammers.

I know there's a lot of brand loyalty out there, but based on specs, I wonder which would be the better performer. Hilti has a loyal fan base, but given their price, heavier weight, and (some) lower specs, it definitely wouldn't be my choice based on given specs. Milwaukee kills it in IPM and RPM but the Impact Energy is significantly lower than everything else. So that makes me wonder if there is a perfect combination of IPM, RPM and Impact Energy when it comes to rotary hammers or would the best one be the one with the highest RPM, most IPM, most Impact Energy....? It really makes me wonder how these would shake out in a head-to-head comparison. Take all the tools listed below, use the same brand bit in each, and drill twenty ¼" holes then twenty ½" holes....who wins?


Hilti TE 4-A18

Weight: 7.3 lbs.
RPM: 1090
IPM: 5200
Impact Energy: 1.5 ft. lbs.

DeWalt DCH253

Weight: 6.4 lbs.
RPM: 1200
IPM: 4500
Impact Energy: 1.7 ft. lbs.

Milwaukee M18

Weight: 5.5 lbs.
RPM: 1300
IPM: 7000
Impact Energy: 1.0 ft. lbs.

Makita X2 LXT (specs are if using 2 batteries I believe)

Weight: 7.3 lbs.
RPM: 1200
IPM: 4800
Impact Energy: 2.21 ft. lbs.

Bosch RHH181-01
Weight: 5.7 lbs.
RPM: 1400
IPM: 4500
Impact Energy: ?? Not Published ??

Bosch RHS181K

Weight: 4.6 lbs.
RPM: 1050
IPM: 4950
Impact Energy: ?? Not Published ??

 

[Danglerb]

The stuff looks like ti would crack so easy to me, get a good answer from somebody with experience on that type of stone facing.

 

[Philbert]

I have the Bosh Bulldog extream. I used the Bosh when I worked construction. Allways seemed to do the job for me. So that iswhat i bought for myself when I needed one.

 

[DamnYankee]

The stuff looks like ti would crack so easy to me, get a good answer from somebody with experience on that type of stone facing.

It does crack pretty easily if near an edge or a weak point (see photo brlow). A lot of time is spent repairing cracks like this with silicone and fortunately most of the repairs are usually covered by portions of the sign.

And I have plenty of experience on stone, stone veneer, concrete, etc. I was just interested in seeing how the various cordless rotary hammers compared on paper. I'd love to get a hold of each of the models I listed and do a true comparison.

I have the Bosh Bulldog extream. I used the Bosh when I worked construction. Allways seemed to do the job for me. So that iswhat i bought for myself when I needed one.

People swear by those....you can't really find a bad review about them. Bosch has a couple of cordless rotary hammers, but I can't find the Impact Energy specs anywhere.

I use my DeWalt enough that I would consider switching brands if I found one that was significantly better. That's kind of what got me gathering all of the specs.

 

[giavra]

Since the stone's crack even in the middle area of them the problem may be in the impact energy that sds plus rotary hammer do.So if you want to try to drill with the common hammer drill without pneumatic hammer action mechanism the classic one without sds chuck.Also the quality of the drill bit itself may crack them so you can try dewalt extreme drill bit so the hole open more easily without more push power from you.

 

[DamnYankee]

Since the stone's crack even in the middle area of them the problem may be in the impact energy that sds plus rotary hammer do.So if you want to try to drill with the common hammer drill without pneumatic hammer action mechanism the classic one without sds chuck.Also the quality of the drill bit itself may crack them so you can try dewalt extreme drill bit so the hole open more easily without more push power from you.

The one that cracked in the center isn't typical, thankfully. Mostly, the cracks happen when near the edge. A hammer drill isn't an option - it would just take too long. As far as the bits, I use DeWalt Rcok Carbide bits. They're a German-made bit as are Bosch. Wouldn't be surprised if they were made by the same company.

The stone finish was just a bad choice....originally the faces were supposed to be EIFS. Somewhere along the line it got changed. There's going to be quite a few tenants on the monument as well and those letters will be smaller with the studs/drilling closer together. Not to mention it's hard to read due to the stone being so busy.

 

[Thumper68]

For cost/value/performance I would go with the bosch bulldog, I had a used hilti and it worked awesome but the weight working overhead drove me to sell it and buy the bulldog.

If you watch the ads you can get the bulldog for around $180 with a hard case and a bit set.

 

[rlitman]

There's going to be quite a few tenants on the monument as well and those letters will be smaller with the studs/drilling closer together. Not to mention it's hard to read due to the stone being so busy.

Smaller letters = smaller studs, maybe? Smaller studs = smaller holes = less cracking.

If your drilling speed is acceptable, don't get something with more impact energy or you'll get more cracking (and blow out in the back side). More energy will drill faster, but should only be necessary when drilling bigger holes. I've found that my Bosch 11236 SDS+ is amazing on 3/8" - 3/4" holes, but is often too powerful on 5/32" holes for tapcons.

 

[DamnYankee]

For cost/value/performance I would go with the bosch bulldog, I had a used hilti and it worked awesome but the weight working overhead drove me to sell it and buy the bulldog.

If you watch the ads you can get the bulldog for around $180 with a hard case and a bit set.

Yeah, that's a great price for a great tool. My cordless DeWalt works just fine though, I'm not really in the market for a different tool. A lot of my installs aren't near electric, so the cordless beats lugging around a generator.

I was more curious about how the different specs come into play...like is there a perfect combination of RPM, BPM, and IE that results in the best performance. My thinking was that Hilti would have been the highest RPM, BPM, and IE....but it's not. Makes me wonder if there's a reason. Without head-to-head testing, I guess it's hard to say.

Smaller letters = smaller studs, maybe? Smaller studs = smaller holes = less cracking.

If your drilling speed is acceptable, don't get something with more impact energy or you'll get more cracking (and blow out in the back side). More energy will drill faster, but should only be necessary when drilling bigger holes. I've found that my Bosch 11236 SDS+ is amazing on 3/8" - 3/4" holes, but is often too powerful on 5/32" holes for tapcons.

99% of the letters I install use 3/16" studs. The only other size stud used is 1/8" but that's rare - especially with masonry applications. The reason being is in masonry, the studs almost always have to be bent/tweaked because the holes aren't always perfectly straight or the hole location may be slightly off due to the bit wandering on a jagged surface, etc. 1/8" studs tend to strip/break out of the tapped area of the letters if you tweak them at all. In a .250" aluminum letter, there's only about 1/8" hole drilled and tapped in the back. So there's not much for the stud to grab on to. But when they do use 1/8" studs, the smallest SDS bit (that I've found anyway) is 5/32" which isn't a whole lot smaller than the 3/16" bits.

As far as the impact energy, your comments kind of go along with my response to Thumper68, above. The Impact Energy of the Milwaukee is "low" compared to the other cordless rotary hammers, but I wonder if that means it's less efficient at drilling....?

Wish I had the capability of getting one each of the various brands and doing a head-to-head. I'm really curious what the results would be.

 

[bcradio]

Don't forget the other 36v contenders like bosch and Dewalt. My Dewalt 36v roto hammer works great. However for the smaller holes, you may want to look at M12 fuel roto for reduced cracking of the stone.