Been drilling some 10mm holes in concrete with my hammer drill. One particular hole would not go any further. Don't know if I hit some aggregate or steel, but I was going nowhere. Full body weight leaning on the drill was making 1mm progress in 15 minutes.

Borrowed my neighbours rotary drill. With no pressure applied from me at all, was through the slab in about 3 seconds.

Damn, someone told me they were good, but I wasn't expecting that.

If you're about to spend your dough on a hammer drill, think again. Rotary worth it's weight in gold.

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Harrow said..
Been drilling some 10mm holes in concrete with my hammer drill. One particular hole would not go any further. Don't know if I hit some aggregate or steel, but I was going nowhere. Full body weight leaning on the drill was making 1mm progress in 15 minutes.

Borrowed my neighbours rotary drill. With no pressure applied from me at all, was through the slab in about 3 seconds.

Damn, someone told me they were good, but I wasn't expecting that.

If you're about to spend your dough on a hammer drill, think again. Rotary worth it's weight in gold.

I was looking for an rotary impact drill to also use to lift up bathroom tiles. Bunnings and Supercheapauto seem to have cheap models that come on sale and do a good job. I can't remember which one I bought or even what it cost (not much), but the thing drills itself through holes - you just sit back and hold the button while it pulls itself through.

How do they work?

The standard hammer drill uses a cam or toothed plate that rubs against the chuck to provide the hammering action. You need to lean on the drill to provide force against the cam to create the hammer action. A rotary drill has a reciprocating piston driven system that positively drives the chuck in and out as it rotates, so you don't need to provide any pressure yourself. The hammer action of the rotary drill is so strong that special slotted shank drill bits are needed that are shaped to lock into a special chuck. You can also turn off the drilling mechanism, and use the rotary drill as a small electric chisel or jack hammer.

Here's a good comparison...watch from 2:30 onwards.



The guy makes a good comment that by the time he makes the hole with his hammer drill it's so messy and oversize that the Hilti bolt won't bite, but with the rotary drill, the hole is so fast and clean, that the Hilti bolts always grab well. See at the end he does it easily one handed with no pressure applied.

Add a cardium tipped 3/4 tooth bit and it's even easier, I generally put 2 to 300 in at times on houses, even though it's only 120mm deep external and 80/90 internally I use a 600mm bit, easier on the old back, had my hitachi for approx 6 years doing this type of work
Don't use a rotary going through tile though

So you didn't destroy your pool rim in the process?

Did you end up using ankabolts, nylon plugs or something else?

The rotary hammers are good. So much cheaper than 10 years ago too, even the good ones.

Clarence

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clarence said..
So you didn't destroy your pool rim in the process?

Did you end up using ankabolts, nylon plugs or something else?

The rotary hammers are good. So much cheaper than 10 years ago too, even the good ones.

Clarence

No, it's all still in once piece, and seems pretty secure. Looks great too.

I used the nylon ramplugs with 8mm stainless steel coach bolts, all mounted with nylon washers and spacers to stop any cathodic interactions. Also made sure the rivets I used had aluminium mandrels. Drilled the cleat and flange holes out to 12mm, so there is play for expansion. Also, I used some 25 x 32 angle to mount the panels to the posts, and I drilled the holes on the mounting angle 1mm larger than it needed to be, so there is some extra play on every panel. (I got paranoid when I read that aluminium has twice the expansion of steel....worked out that the 10m fence will get 2mm longer for ever 10 deg C rise, and it's black!)

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cauncy said..

Don't use a rotary going through tile though

Ah, thanks for the tip. Yeah, I guess it's kind of obvious once you say it, it would smash the tile to bits instantly.

I'll sell you a cordless one second hand Hitachi one for $600... hilti they are the best. smallest and lightest but like 5 grand new . dewalt are the worst . massive units . . . IMO .

Cordless and the price is massive. Compared to pug in all