Should pilot holes be used when drilling concrete?

5002 Views 16 Replies 13 Participants Last post by Emmabern, 3 mo ago

Cyrax

Discussion Starter · Jul 4, 2018

I'm installing a lift and the instructions say to use a 3/4" bit for the anchors. Is it best to start with smaller holes, or can I just use the 3/4" bit only?

1 - 17 of 17 Posts

Tizken

· #2 · Jul 4, 2018

I've never needed a pilot hole for concrete, unless it's to check location on a wall or for a core type bit.

I bet you hit rebar in 75 % of the holes. &#55357;&#56833;

bgaidan

· #3 · Jul 4, 2018

Not needed for anchor holes.

I'll use them for through-wall holes to help control the blow out spalling on the back side.

RANGERROD

· #4 · Jul 4, 2018

^^^this. And if you hit rebar stop and get the right bit. Rebar eater put the drill on drill only and not hammer drill. Lots of pressure don’t move the bit side to side you’ll egg the hole out and then your fucked. You could use the pilot bit to see if you’ll hit rebar?

#1SomeGuy

· #5 · Jul 4, 2018

Not every slab has rebar in it (nor is it a requirement for most residential construction or for most lifts). When I drilled for my anchors I did straight through the slab with the 3/4" bit and it went fine. I drilled with the lift in place through the actual holes such that it was spot on, and installed each anchor as I went.

tracyb

· #6 · Jul 4, 2018

if you can drill thru the mounting plate good to go.

i drill alot of holes for handrail mounting plates and when i can go thru the mounting plate i use a smaller pilot hole to help keep it from walking on large aggregate.

i only go about an inch deep with it, i figure its not much help after that.

Twankie

· #7 · Jul 4, 2018

Just start with the 3/4"

To help with the layout without standing up the lift you can make a template of the base plates out of metal or 3/4" plywood. Install anchors as you go.

bdkw1

· #8 · Jul 4, 2018

Drilling a pilot hole is a good way to get your big bit stuck in the slab. A small bit will graze a piece of rebar and keep going. Your big bit will then hit the rebar on the side and get wedged in the hole. If you don't have the pilot hole it will just bounce off the rebar. Got a rebar cutter?

_ogre

· #9 · Jul 4, 2018

never used a pilot bit in the many thousands of holes i've drilled in concrete
i will say drill thru the slab, this way if you have a problem or ever need to move the hoist, you just hammer them down
i've only installed 4 lifts in my life, the same 4 in 4 different shops

Cyrax

Discussion Starter · #10 · Jul 4, 2018

#1SomeGuy said:
Not every slab has rebar in it (nor is it a requirement for most residential construction or for most lifts). When I drilled for my anchors I did straight through the slab with the 3/4" bit and it went fine. I drilled with the lift in place through the actual holes such that it was spot on, and installed each anchor as I went.

Were you the guy with the Bendpak lift?

It doesn't look like I can hook up the hydraulic lines without extending the scissors. Is it safe to use a cherry picker, and will the locks engage to keep it extended?

total newb

· #11 · Jul 4, 2018

Not in a floor, in hard walls with multi layers of bar or hard rock ive done it plenty.

Maybe if you have a shit drill like a sds or hammer drilling cordless. Any sds2 or spl drive will rip 3/4 like its nothing

#1SomeGuy

· #12 · Jul 4, 2018

Cyrax said:
Were you the guy with the Bendpak lift?

It doesn't look like I can hook up the hydraulic lines without extending the scissors. Is it safe to use a cherry picker, and will the locks engage to keep it extended?

Yeah that's me...

Basically what I did, without the lines hooked up I got a prybar in to spread it enough to get a strap through the middle. Used my engine hoist on full extension to pick up just the top half until it reached the first lock. Once on the lock, I put a ratchet strap through to the bottom side of the X of the scissors and around the top (basically to keep it from spreading any further). Then just lifted the whole unit up and dropped it in the pit that way. Was super easy...then after anchoring, just ran the lines with the power unit side unhooked, dropped the platforms down with the engine hoist manually releasing the locks with a prybar, hooked up the power unit side, and bled.

Here's without the ratchet strap after I dropped them in:

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Cyrax

Discussion Starter · #13 · Jul 4, 2018

#1SomeGuy said:
Yeah that's me...

Basically what I did, without the lines hooked up I got a prybar in to spread it enough to get a strap through the middle. Used my engine hoist on full extension to pick up just the top half until it reached the first lock. Once on the lock, I put a ratchet strap through to the bottom side of the X of the scissors and around the top (basically to keep it from spreading any further). Then just lifted the whole unit up and dropped it in the pit that way. Was super easy...then after anchoring, just ran the lines with the power unit side unhooked, dropped the platforms down with the engine hoist manually releasing the locks with a prybar, hooked up the power unit side, and bled.

That really helps, thanks. Was your motor 220 or 110? This lift has been revised so many times I don't even know what voltage my motor is. The manual says 220, but the motor has a standard 3-prong plug....

There's a placard listing different voltages, but none of the boxes are checked for a specific one. Other online specs say it's 110?

#1SomeGuy

· #14 · Jul 4, 2018

Cyrax said:
That really helps, thanks. Was your motor 220 or 110? This lift has been revised so many times I don't even know what voltage my motor is. The manual says 220, but the motor has a standard 3-prong plug.... There's a placard listing different voltages, but none of the boxes are checked for a specific one. Other online specs say it's 110?

Mine is 110...IIRC they can be rewired to be 220 but ship from the factory as 110. If it's got a standard edison on it, plug er' in and give er'

[email protected]

· #15 · Jul 9, 2018

Open the junction box on the motor and see how it's wired. USUALLY there will be a diagram on the inside showing what wires to hook up where.

firutaarnold

· #16 · 3 mo ago

If you're drilling into concrete, it's generally a good idea to start with a smaller pilot hole before moving up to the final size. This will help prevent the bit from wandering and ensure that the anchor is properly seated.

Emmabern

· #17 · 3 mo ago (Edited)

I'm new here, but I think I can help with your question. From my experience, it's always best to use pilot holes when drilling concrete. You want to make sure you've got a secure anchor because you said you're installing a lift - that's no joke! Think of it like this: if you're driving a nail into a wall, it's always easier to start with a smaller hole and make it bigger. The same logic applies to drilling concrete. So, in your case, I'd recommend using a smaller bit first to create the pilot hole before moving up to the 3/4" bit. That way, you'll avoid any cracking or breaking in the concrete from the bigger bit. You can also check out upet.com for more drilling options.

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