BHC 18 => 18 mm diameter is max. for concrete?

[threesixright]

Hi,

I read on the Festool site (BHC 18), that the max. diameter is 18mm for drilling concrete. Compared to other drills that seems a bit on the low side.

Should I read this as a recommended value? or really is it a red-line-threshold (do not cross) ?

Thanks!

 

[mrboult]

I've had my BHC for about 3 years. I have to say that I don't do holes that big much if ever. . . 18mm simply can't be a red line because things don't work that way. But if 18mm is what you are doing most of the time I have to believe that the BHC is not the right choice in drill. I drill 10mm holes into reinforced concrete and love how this light little SDS does it with ease, but I can tell it does not have the power of units twice it's size.

 

[AlexThePalex]

18 mm max for this size drill is not that uncommon, concrete is hard stuff. You can always try to drill a bit bigger holes, but you have to take it slow and make sure you don't overheat the drill.

 

[threesixright]

Thanks!

I understand if you do regular  big holes your better off with something bigger.

I just need to drill a few holes 20-24mm (400 mm deep).  I saw that other vendors have listed a recommended diameter, so I was curious. Wanted to buy a new BHC, but don't want to wreck it on it first holes

So if i take it easy (i.e. not too much pressure) it should be OK?

 

[six-point socket II]

Hi,

I don't see any problem using the BHC for 24mm diameter holes in (non-reinforced) concrete. Going 400mm in will require to pull out the drill bit a couple of times to clear the hole, go easy - don't rush & don't push too hard, let the BHC do the work. BHC will do just fine for a couple of holes.

If you need to do a couple of holes every so often, get something bigger.

Kind regards,
Oliver

 

[threesixright]

I don't see any problem using the BHC for 24mm diameter holes in (non-reinforced) concrete.

Hi, thanks!

It is reinforced (floor)  [scared] , now that one is slightly thinner (~ 250mm).  The other holes are for wall (~ 3600 mm), could be maybe 20-22mm DIA. I saw youtube movie of Peter, he was drilling without issues 20mm. But don't think it was reinforced concrete. My floor is for sure (reinforced).

Do I get it right: as long I don't overdo it, the biggest concern would be overheating the motor?  Was planning to buy a decent Bosch SDS-Plus-7 drill.

As you said the length is more a issue of pulling it out, so the dust is freed.

 

[AlexThePalex]

Do I get it right: as long I don't over due it, the biggest concern would be overheating the motor? 

Yes, as always with drills, overheating is the main issue here. If they say 18 mm is the maximum size, that means a professional user can drill those holes with a certain comfort and ease, in an acceptable timeframe and without endagering to overheat the motor. But if you're willing to take your time so the motor won't overheat you can drill holes that are a bit bigger.

I have never used a BHC, but if it has the standard Festool electronics inside, it will start to beep at you anyway when you ask too much from the drill. But use your common sense and give the drill some rest after each hole because the electronics don't always work as advertised.

 

[threesixright]

Do I get it right: as long I don't over due it, the biggest concern would be overheating the motor? 

Yes, as always with drills, overheating is the main issue here. If they say 18 mm is the maximum size, that means a professional user can drill those holes with a certain comfort and ease, in an acceptable timeframe and without endagering to overheat the motor. But if you're willing to take your time so the motor won't overheat you can drill holes that are a bit bigger.

I have never used a BHC, but if it has the standard Festool electronics inside, it will start to beep at you anyway when you ask too much from the drill. But use your common sense and give the drill some rest after each hole because the electronics don't always work as advertised.

Thanks, got it, WICO.

Now lets order a BHC

 

[neeleman]

Why not dril the holes in 2 stages: Ø10/12 and then Ø22/24.
You only need 2 drills which are long enough.

 

[threesixright]

Why not dril the holes in 2 stages: Ø10/12 and then Ø22/24.
You only need 2 drills which are long enough.

Ah, thats a great plan! That will obviously take the 'load' of it.

Thanks.

 

[Gregor]

Should be no problem, should you worry about overheating you always can pull back a little and let it run free for a moment (so the fan can do it's job without the motor generating much heat in the meantime).

Great machine, sadly not fully perfect as that would require the ability to disable the rotation so chisels could be used.

 

[pingvinlakrits]

Why not dril the holes in 2 stages: Ø10/12 and then Ø22/24.
You only need 2 drills which are long enough.

Ah, thats a great plan! That will obviously take the 'load' of it.

Thanks.

I would advice against this as the risk of the drill binding in the hole is far too great! You risk a kick/throw if the drill gets stuck and that is a real risk drilling in hard concrete, you only need to be a little off in angle for it to happen! The risk is probably a bit higher doing so long/deep holes.

The BHC does not have RFC or similar tech to avoid binding related wrist wrangling.

Has happened to me, with the BHC 18, trying to enlarge existing holes. Can happen with any drill.