Anyone make tiny (1/8" or less) carbide SDS bits?

[BQuicksilver]

Placing a ton of crowded raceway track in our 1946 poured concrete basement and I don't have room for tapcon heads.

I understand 1/8 or smaller SDS bits likely break a lot (buy in bulk), but I've honestly not found anything smaller than 5/32 out there.

I found a non-carbide Makita on Amazon, but shipping is 1-3 months.

 

[seber]

Considering how easily they break, I can't imagine using a carbide sds that small.

 

[rlitman]

SDS just has too much impact energy for a shank that thin. Just get a bulk pack of carbide masonry bits and use a standard hammer drill.

 

[BQuicksilver]

The 5/32" do just fine over about 150 holes thus far. I understand thin bits will break more often.

Does anyone know of someone who produces them?

 

[MoonRise]

Instead of an SDS rotary hammer, try just a hammer drill?

Bosch 1/8" diameter BlueGranite carbide hammer drill bit, 25 pack

https://www.boschtools.com/us/en/bo...carbide-hammer-drill-bits-hcbg01b25t-36386-p/

Smallest SDS-Plus bit I see with a quick look on the Bosch site is 5/32"

https://www.boschtools.com/us/en/boschtools-ocs/sds-plus-bulldog-rotary-hammer-bits-hc2001-30101-p/

One posted review from 2 years ago, user complained that the bit bent after ~15 holes (slight pause after every 5 holes to let the bit 'cool') and then broke at ~20 holes. With how fast a decent SDS rotary hammer is, I can see how hot drilling even 5 holes 2" deep into concrete will get a bit. Personally, I think that the user was just blasting through the crete and working the bits darn hard (and hot).

25 pack is at

https://www.boschtools.com/us/en/bo...bulldog-rotary-hammer-bits-hc2001b25-30102-p/

call Bosch at 1-877-BOSCH99 and ask them for advice and options?

And what are you anchoring that a 5/32" hole in concrete is no good but a 1/8" (aka 4/32") hole is just fine? With the way the bit is slamming around and the concrete and aggregate is chipping out, I usually think that within 1/32" is pretty close for a drilled hole in concrete. YMMV and all that.

Maybe go to powder-driven pins?

 

[BQuicksilver]

The concrete I'm drilling into is very dense. No joke, our 1946 basement was designed as a bomb shelter.

I've broken scores of small bits with my hammer drills. I'll go through about 3 to get 1/2" deep in this stuff with my M18 Hammer drill. The 5/32 Bosch SDS carbide goes through it easily and has made countless holes without issue, hence wanting a smaller one. The raceway is VERY tight with the 12ga Romex and I'd really like to hang it with smaller screws.

That bit you linked is exactly what I'm using. It's outstanding. I wish it had a little brother.

 

[rlitman]

The 5/32" do just fine over about 150 holes thus far. I understand thin bits will break more often.

Does anyone know of someone who produces them?

I've had terrible luck with the 6" long 5/32" bits that they sell at HD. They all seem to bend before they're otherwise worn out.

However, my local tool store has 4" long Bosch 5/32" bits that hold up extremely well. But I still don't think I've ever seen these in 1/8".

 

[GRB]

Hammer Drills work better for old concrete up to 3/16". At 3/16" in old concrete, 1/4" in new concrete and 5/16" in cement block, SDS starts to work better. It is a difference between rotation speed and impact strength. This is why we have small SDS, large SDS, mid size SDS Max, big SDS Max that only gets used for the big stuff.
This becomes important when you are drilling lots of holes.

 

[Bretny]

They do make a hand chuck to sds adapter. Amazon has it for $35. Just saw it this morning.

 

[Lasu]

Hawera / bosch sells here sds-plus carbide 4-cutter 3,5mm and 3mm 2-cutter. Those are the smallest.

 

[BQuicksilver]

They do make a hand chuck to sds adapter. Amazon has it for $35. Just saw it this morning.

I think this is the direction I'll be going. Great idea. Thanks!

 

[BQuicksilver]

Hawera / bosch sells here sds-plus carbide 4-cutter 3,5mm and 3mm 2-cutter. Those are the smallest.

I'll give those a look. Didn't even think of checking the metric side. Thanks!

Edit: Also purchased a few 3mm bits.

 

[spike99250]

How about using 1/4" and using plastic anchors with a pan or lath head screw.