masonry vacuum drill bits

[jfoldbar]

im wondering if anyone has any experience with using hollow masonry vacuum drill bits? if so, how were they for you? i have bought a few and so far having a hard time with them.

 

[Ron]

What is your problem with them? What brand are you using? Do you have a problem with both small diameter and larger diameter? Is your vacuum system strong enough to prevent clogging within the bit? Are you noticing moisture clumping?

 

[Enable]

I have only ever used such products from Hilti (up to 1" diameter) in combination with their vacuums. They work quite well but can be slow if you have a lot of holes to drill.

 

[jfoldbar]

thanks for the replies guys.
first up i tried Milwaukee 18mm by 250 long. in both concrete and sandstone. using a 2000w vacuum. works great. i timed it and its almost twice as quick.
the problem is when i used bits 400mm long. they just simply block up after a few holes. first time i was able to unblock the bit. drilled a few more holes and blocks up again.
im at a loss as to why it blocks up and what i can do about it?
and now, i have a bit that i cant unblock. annoying as it costs $250.

 

[Ron]

It is likely blocking up because you are not evacuating the dust from the bit quickly enough as more gets packed in. Increase the vacuum air flow and slow down your feed rate on the bit.

To clear your existing bit, use a piece of stiff wire (coat hanger type). Cut the end with wire cutters to give you a slanted cut profile. Chuck the wire into a drill and push into the cutting end of the bit while the vacuum is on. Should be able to clear it out.

 

[Enable]

I try to avoid Hilti products where possible due to their relative expense. However, in situations like these I have found them to be the only manufacturer to produce reliable products - that actually work as intended. 400mm is rather shallow and I have gone well beyond that with the Hilti drill / vacuum combo without any issue.

Should you not want to admit defeat Ron has it. Slow down the feed rate.

 

[jfoldbar]

i dont see how i could increase suction as im already using a really powerful vacuum.
what do you mean by "slow down feed rate". im assuming you mean the slower the drill hammers, the more chance the vacuum has to suck up.
while drilling, i wasnt applying any pressure to drill, purely letting the weight of the machine do the work. to drill slower i would have to actually lift the drill off the concrete, meaning it wouldnt drill any more.

i tried the wire in the hole. a combination of wire and air compressor. no luck

 

[hokie66]

Bosch says they clog if the concrete is too green...too high moisture content.

https://thetoolpig.com/2017/07/28/bosch-speed-clean-dust-extraction-bits/