I just finished assembling the frame for a gravel pad where I plan to put a shed. Because I put it into the side of a slope, I needed to use 5 layers of 4x4's to get the proper depth. Currently everything's held together with decking screws, but I have read that it is best to lock everything together with 1/2" rebar. So basically I have to drill an 18" hole through the 5 layers of 4x4 (pressure treated). Today I tried to place the rebar using a 7.5Amp 1/2" corded hammer drill (Genesis brand) with a 24" inch 1/2" bit and a 3/8" shaft, and I got down to about 12" and the bit got stuck and the motor on my drill started smoking.

I'll admit I had overpowered the drill once before and saw smoke with a previous DIY task, so the drill could have been damaged to begin with, but my real question is this: I don't want to buy a new drill, I can rent a 4.2AMP corded makita hammer drill from Home Depot for about $40 for a day, but that's way less amps than the one I was using. I'm afraid of it either not getting the job done or possibly getting damaged. Do you think that that will cut it? Or is there a better approach to this?

Thank you

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    Were you cleaning out the hole as you drilled down? What type of bit did you use?
    – crip659
    Jul 30, 2023 at 20:14
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    18" deep wood hole... chip clearing is imperative, did you do the up down motion to pull chips out as you went? probably need a vacuum every once and a while too.... I've drilled 10" with just my makita cordless..... I like the bosch spade bits with the self feed. Jul 30, 2023 at 20:23
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    i do like to use an sds max with a ground rod driver to pound rebar into the ground for this though so you might just want to rent an sds max drill with the intention of using it for pounding the rebar down as well. How far into the ground will you go with the rebar? Jul 30, 2023 at 20:24
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    7.5 amps from a brand I've never heard of that might not have been around last year and might not be next year .vs. 4.5 amps from a reputable company....
    – Ecnerwal
    Jul 30, 2023 at 21:09
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    That bit would have worked if you had pulled it out regularly to clear chips, even with a basic drill. (I'm assuming you were in drill mode, not hammer mode.) This is a bit of a rathole/aside, but amp ratings aren't really a useful way of comparing power tools. Personally, I'd spend a little more on its replacement and get a known brand: Makita, Dewalt, Milwaukee to name a few. Even Ryobi is apt to perform decently. Jul 30, 2023 at 22:13

1 Answer 1


The shown drill bit is a bit sketchy: The extremely short flutes require you to do frequent in-and-out passes to clear out the chips. Blocked flutes block the drill bit and ruin both drill bit and drill.

I would do as following:

Given that the drill has already sustained an overheated motor, I'd try it one last time with your current setup. After all, your current drill has already sustained damage, so the worst that can happen is that it gives out now, instead of the next heavy job.

But this time you move it out for every inch you drill. Keep the drill on speed, even when moving out. This helps clear the chips, and the full speed helps to cool the motor. Electric drills don't like reduced speed on high load, as the cooling fan is directly attached to the motor.

Should the drill not survive this: For frequent heavy drilling I'd get a multiple gear drill from an reputable brand. The amperage of an motor isn't really helpful. An better indication would be a reputable brand, the rpm range and max. hole diameters in the manual.

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