Electric (corded) hammer drills

[ga-hvac-tech]

Last week, I did an HVAC job where I had to cut two 10x4 vent holes in the floor of rooms, through 4" of concrete. I do not do this often, however when I do it takes a LONG time (the first one was a little over an hour... the second was almost 2 hours due to rebar).

While I was drilling, the chuck head (SDS style bit) loosed its grease seal and started throwing grease. I did finish the holes... however my gut instinct is this hammer drill is almost history (it is many years old).

Generally, I use the hammer drill to cut holes for condensing furnace flues, ducts, and vents. I have been doing this with lots of 1/2" holes and use the chisel feature to chip out between the holes. I would like to use a hole saw for the PVC furnace vents though. I have lots of SDS bits.

I was in HD today and looked at Makita, Bosch, and Hilti. The Hilti (HD is selling them off, they will not handle that brand anymore) is just too much $$$ for the amount I will use it.

I kinda liked the Makita... yet am not sure if I want the 1" or 1-1/4"... The smaller one is a conventional design... straight drill with D handle at the back. The larger one is the angle design and appears more rugged. Price is $200 and $300... both come with a bonus 4-1/2" grinder.

Does anyone have experience with these Makita hammer drills, are they durable, is the heavier one worth the extra $100, is the angle design a good idea or difficult to use?

And if there is another brand I should look at, please suggest it.

THX in advance for any suggestions.

[eddiegoodfellar]

Bosch makes very good corded tools. You should look into " Rotary Hammer Core Bits".

You could also look at a smaller Core set up. We had a Shibuya at my old company and it worked very well. You can find them for $1000 on ebay every now and then. They weight very little and are very easy to use and you can just go right through the rebar.

[jpsmith1cm]

I did a 4 1/2" hole in my home for a bathroom vent.

Rented a core drill and bit from the local tool rental place.

Was about $85 bucks. Did the job in under 10 minutes and made a perfect hole.


As for replacing your drill, I used to work with a guy who had a Bosch. He was quite happy with it. I never had much opportunity to use it.

[jeep6275]

A buddy of mine has a tool repair business.... he swears by the bosch, but he does fix all of the rest... the bosch I picked out was the splined style (heavier duty) and was about 4 hundy.

[philjafo]

I have a Makita cordless hammer drill for the small stuff, works good, I've used a masterforce (menards store brand) drill worked well lots of power but the chuck wore out after a couple months and would not stay tight only used it on holes less then 1". For cored holes for vents and such I have a Milwaukee rotary hammer 3 and 4 inch core bits no problem and fast to, but core bits really slow down when you hit rebar

[nsula_country]

I have gone Bosch for all corded and cordless tools. 3 year warranty, even for commercial. I stripped low range out of my 18V Brute Drill with about 40 days left on warranty. I abuse it pushing much larger bits and hole saws than it is designed for. Called, sent it in, they paid freight back, 1 week turnaround. I was impressed!

CT

[socotech]

Anybody used a Bosch Bulldog Extreme? I have had my eye on one of these, but never used one.

[ga-hvac-tech]

Anybody used a Bosch Bulldog Extreme? I have had my eye on one of these, but never used one.

This is one of the ones I am looking at... the 1-1/8" rated unit... not sure what that means. My current unit (about to die) is a 7/8" rated unit.

HD has it for about 2-1/2 bills.

[socotech]

Ebay has refurbished bulldog extreme for $150. My company replaces our tools when they wear out/break so thats good enough for me.

[ga-hvac-tech]

Update... finally had time to do some online research... came across this item:

http://www.amazon.com/Bosch-RH328VC-8-Inch-Rotary-Hammer/dp/B003DQO7ES/ref=sr_1_1?ie=UTF8&qid=1351126610&sr=8-1&keywords=bosch+rh328vc

Anyone have experience with this drill?

THX in advance for any posts.

[ryan1088]

We have a few bulldogs that we use but I don't know if they would do 4" of concrete.... The guy I ride to work with says the bulldog is as good as any of them.
The Hilti we have is a beast but who can afford that?

[mstx]

Well i have owned this little puppy 7.5 amps of pure joy and power always served me very well always never got a problem. Higly suggested :whistle:
http://www.amazon.com/Makita-HR2475-1-Inch-D-Handle-SDS-Plus/dp/B002SSUR28/ref=sr_1_14?s=hi&ie=UTF8&qid=1351127265&sr=1-14&keywords=makita+drills+corded

[ga-hvac-tech]

We have a few bulldogs that we use but I don't know if they would do 4" of concrete.... The guy I ride to work with says the bulldog is as good as any of them.
The Hilti we have is a beast but who can afford that?

Agree... Hilti are just too much $$$. HD quit carrying them in my area... there were a few discounted ones... still lots of $$$.

[neophytes serendipity]

Update... finally had time to do some online research... came across this item:

http://www.amazon.com/Bosch-RH328VC-8-Inch-Rotary-Hammer/dp/B003DQO7ES/ref=sr_1_1?ie=UTF8&qid=1351126610&sr=8-1&keywords=bosch+rh328vc

Anyone have experience with this drill?

THX in advance for any posts.

That is an SDS-Plus drill, and it will do more work than a regular SDS drill.

Still no comparison to a spline drive or hex shank rotary hammer.

If you plan to cut through 4" of concrete more often, or want to cut 4-1/4" holes in concrete with a percussion coring bit, then you want spline drive.