Impact Hammer vs Rotary Hammer Drill

I need some clarification on the whole masonary drill thing and am not even sure if I am using the right terminology. I have only ever owned a normal hammer drill but have used SDS rotary impact drills. From what I have read and what I have experienced the SDS rotary drills are far superior. This leaves me with two questions. What is the actual difference in the mechanics of the two types and if SDS is so much better, why do Hitachi, Bosch Makita etc still make high end impact drills, that are in some cases more expensive than the SDS equivalent?

Q: What’s the difference between a Rotary Pneumatic Hammer drill and a standard impact hammer drill?
A: They are constructed using a pneumatic cylinder that is more effective in a hammer action, around three times quicker than normal hammer drills which use a mechanism to push the chuck and bit forward and backwards to create the hammer effect.

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Originally Posted by manoftalent

Q: What’s the difference between a Rotary Pneumatic Hammer drill and a standard impact hammer drill?
A: They are constructed using a pneumatic cylinder that is more effective in a hammer action, around three times quicker than normal hammer drills which use a mechanism to push the chuck and bit forward and backwards to create the hammer effect.

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Thanks, without the technical part, that is what I understood. So this begs the question, why would you want to buy a regular impact hammer drill if it was the same price as the equivalent rotary one? From looking at the various brand sites, it appears they can all be used without the hammer function to drill steel and timber so why?

sorry Burnsy, this doesn't answer your question but I just thought I'd comment. I have a pretty good makita hammer drill which I was going to use on the weekend to put some dyna bolts in. My mate happened to be there with his work ute and pulled out a $69 Ozito rotary hammer drill and within 5 minutes the holes were done so I'm wondering the same thing? He uses the cheap Ozito cos he says it seems to be reliable and if he leaves it on site or someone knocks it off, big deal he gets another one. I'm wondering the same thing. Have these things made the quality/expensive hammer drill redundant??

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Originally Posted by notenoughtoys

sorry Burnsy, this doesn't answer your question but I just thought I'd comment. I have a pretty good makita hammer drill which I was going to use on the weekend to put some dyna bolts in. My mate happened to be there with his work ute and pulled out a $69 Ozito rotary hammer drill and within 5 minutes the holes were done so I'm wondering the same thing? He uses the cheap Ozito cos he says it seems to be reliable and if he leaves it on site or someone knocks it off, big deal he gets another one. I'm wondering the same thing. Have these things made the quality/expensive hammer drill redundant??

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This has been discussed before in quite a few threads and the big Ozito has a good rep. I have a huge Dewalt Jack hammer (comes in handy for digging stump and post holes in the hills here) so don't need the no rotation chiseling capacity offered by the Ozito and GMC. What I do want though is a high performing small light hammer drill so am leaning towards the Bosch I have mentioned in the other thread. Until today I had not put two and two together and realised that the SDS drills had a different mechanism nad that is why they drill so quickly.

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Originally Posted by Burnsy

So this begs the question, why would you want to buy a regular impact hammer drill if it was the same price as the equivalent rotary one?

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Well you wouldn't, not if you were getting comparable quality. Lot of people on here seem quite happy with the GMC rotary hammer, I bought a Metabo. Plenty in between, and even beyone. Bosch have a good one in the middle of that range...lots of choice. But for concrete, you'll want Rotary Hammer...

I also bought a cheap ozito rotary for a small job I had to do, and ended up using it on another job ( drilling coach bolt holes through redgum)...in application I can see why a rotary is used mainly for concrete work .....the rotary does not have the rev range a normal hammer drill has .....it does have heaps of grunt, just drills slower .....so if you were to drill through steel for instance ....it would probably take a little longer than usual .....

Burnsy

The Rolls Royce of Drills both Rotary and Impact would be Ramset and Hilti.

Have a look here and see the differences in them all the different models they make. I used to work for Ramset and also own a Hilti. Certainly they have a Rolls Royce price unlike the Ozitos and GMC which have a Holden price or less but Ramset and Hilti were the originators of Rotary Hammer Drills.

http://www.ramset.com.au/public/arti...lID=5&menuNo=0


http://www.hilti.com.au/holau/module....jsp?OID=-8714

There are two types of hammer drill:

1. Pneumatic
2. Impact

Pneumatic:
These drills use a piston action to compress air which works in combination with hardended striking parts. Concrete for example, should only be drilled with this type of hammer drill.

Impact:
These drills use a clutch to engage two grooved hardened plates against each other. The impacts created (Blows Per Minute) are in the thousands, but the force is minimal and these drills are designed for softer materials such as bricks or solid plaster. The manufacture of such drills is cheaper than pneumatic and if they are subjected to concrete the parts will wear quickly.

SDS is a Bosch-developed shank system used almost exclusively by pneumatic drills.

Damien

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Originally Posted by Barry_White

Burnsy

The Rolls Royce of Drills both Rotary and Impact would be Ramset and Hilti.

Have a look here and see the differences in them all the different models they make. I used to work for Ramset and also own a Hilti. Certainly they have a Rolls Royce price unlike the Ozitos and GMC which have a Holden price or less but Ramset and Hilti were the originators of Rotary Hammer Drills.

http://www.ramset.com.au/public/arti...lID=5&menuNo=0


http://www.hilti.com.au/holau/module....jsp?OID=-8714

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I would like to correct a statement I made. Although I said Ramset was one of the originators of Rotary Hammer Drills in fact Bosch used to manufacture the original Ramset Dynadrill under the Ramset name in the Ramset orange colour. At the time Bosch used to sell an identical drill in the Bosch Blue.

Here in Australia Ramset sold the Dynadrill 10 to 1 of Bosch.back in the early 80's

Burnsy,

Damien has summed it up to a Tee. The Rotary Hammers are slower but pack a hell of a punch - too much in fact for brick... I use my Ozito Rotary Hammer in concrete, but won't let it go anywhere near bricks, which it would most definitely bust apart. I leave drilling in bricks to my normal Impact drill.

But in case you're thinking ":rolleyes: Well, I'll just get an Impact Drill so that I can do both concrete and bricks without destroying the bricks...", the trouble is, the Impact Drills take forever and a day in concrete. You could end up burning the darn thing out drilling just one or two holes!

Now the other thing is, the Rotary Hammers (the cheap ones at least) are not very fast or precise, and you have to throw in the Chuck-with-the-SDS-Shank before you can load normal drill bits into it too. So unless the more expensive Mak, Bosch, and Metabo Rotary Hammers are a different "Kettle of Fish", you might find it hard to do normal drilling into timber and wood with any Rotary Hammer, cheap or dear. One of the cheap Rotary Hammers, plus a fairly decent Impact Drill (get something with metal gears, not just a metal-looking gearbox housing) therefore seems to be a popular combination.

Now, if you're not a Tradie, think twice before grabbing a cordless Impact Drill because battery performance will probably end up letting you down. NiCads and NiMH rechargeables both self-discharge even just sitting around on a shelf. Chances are that they will therefore be flat when you go to pick up the drill. Even worse, if they discharge too much or you use the darn thing when it's nearly flat, you might end up driving one or more of the multiple 1.2v cells inside the battery into Reverse Polarity, from which it will never recover, and the battery will be permanently and adversely affected thereafter. It's not an issue for the Tradies because they charge up and use their batteries every day or week, etc. Lithium batteries don't self-discharge, but Lithium drills are very expensive (Mind you, I haven't looked into the price of the new range of Ozito Lithium cordless drills, but again - make sure what you get has metal gears inside :cool:)

Final Tip - I noticed at Bunnings Carseldine on Monday that there were no Triton Cordless Plunge Drills on the shelf. I remember that when I told the Head Dude at the Triton stand at the Woodwork Show that I'd buy one of the darn things if it had a Lithium battery, he replied "I think it's long overdue..." It has 2 speeds, metal gears, a little light, and a plunge "thingy" on the front that makes it work something like a portable drill-press. Would be "To Die For" if it had a Lithium Battery... Therefore, wait and see, Grasshopper, wait and see... :rolleyes:

Best Wishes,
Batpig.