SDS vs hammer drill

[Deleted member 174758]

Statung the obvious?: TBH the only practical way to gauge how quickly an SDS will drill a hole is to look at the impact strength in Joules, then look at the rotation speed. In practice given two drills of identical impact power the faster of the two will generally perform better simply because it can clear waste material from the hole faster. The power (Input or output) has absolutely no bearing on it in my experience - the efficiency of the hammer mechanism, however, does (e.g the original Kango 422 and 426 designs in the early 1980s were actually less powerful on paper than the equivalent Bosch SDS drills of the period but the superior design of the hammer mechanism meant that they were faster at drilling multiple holes, at least once you'd warmed the grease in the box up. Things have moved on a lot in 40 years however).

As to 6kg, that's a ridiculous weight for an SDS drill. Far better to have a 2 to 3 kg tool with less power that you can actually use at shoulder height or above In my experience. It'll do most of the things that people want IMHO

On a side note, as an alternative, got rid of my last 2kg corded SDS 3 years or more ago and went 90% cordless (18 volt Makita brushless) - when you are working up a ladder, or on a scaffolding tower or worse still on a scissor lift or cherry picker the cordless is a far better option. Never used more than 2 no 5Ah batteries in a day yet. Still have my 3kg corded (Milwaukee) hammer for the odd task, but the cordless will happily drill 16mm holes in dense concrete or stone for resin anchors so I don't often need much more. For breaking out I simply hire a 5kg or 10kg SDS Max hammer for the odd occasion that I need one

 

[delmel]

Its not just the quality of the tool, its the quality of the drill bit that counts for much. A cheap bit could easily be knackered after 7 holes of tough drilling

 

[Nige F]

Can we have a forum section for people wishing to state the obvious?
.

And then to argue about it

 

[Deleted member 174758]

Its not just the quality of the tool, its the quality of the drill bit that counts for much. A cheap bit could easily be knackered after 7 holes of tough drilling

OK, so I was making an assumption that anyone spending the money for an SDS would at least buy half decent bits. TBH you often see the biggest differences with 12mm an above drill bits where tri or quad bits (I.e bits with 3 or 4 carbide "teeth" as opposed to the two "teeth" of cheaper bits ' note that some tri jets are available as small as 6mmm from Heller) will cut faster than basic bits. Hardness of carbide and flute design (generally better on industrial bits) make some difference to.performance as well. Worth noting that in trade use we don"t expect to get hundreds of holes out of an SDS bit, either, simply because even the best bits round off at the end, albeit more oy than cheapies