Stupid question #102

dogooder

dogooder

Well-known member
I might be able to find it on the web but...
I need to drill through a concrete block. Can a concrete block be stepped drilled like one might a piece of metal. By that I mean, drill with 1/4, then, 1/2, then 3/4 and so on? i need to run and electric line out of the basement to the shed. I intend to put a piece of PVC through the hole. I bought a set of masonry bits.
Thanx.
 
Cinder block is softer than you think... I wouldn't recommend step drilling, your larger bit may "catch" and rip out a large chunk.
Just set your drill on slow speed, be patient, use moderate pressure, and slowly warble the drill as you go. However, if the block is filled with concrete, then you're going to need a hammer drill.

Good luck ;)
 
I agree with JAPOV the drills will bind in the hole and could break, damage the drill mech' or indeed the driller!
I would use a small, 1/4" drill as a start, just to break the surface then steady does it with the big one. If you hit a Flint pebble you might have to smash it with a builder's chisel and lump hammer.

Dave.
 
JAPOV said:
Cinder block is softer than you think... I wouldn't recommend step drilling, your larger bit may "catch" and rip out a large chunk.
Just set your drill on slow speed, be patient, use moderate pressure, and slowly warble the drill as you go. However, if the block is filled with concrete, then you're going to need a hammer drill.

Good luck ;)
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I want to put the PVC through the wall. The outside diameter of 1/2 inch PVC is 5/8, almost to the thousandth of an inch. I would prefer to use three quarter PVC whose outside dimension is 1.050. I have a 5/8 and 1" masonry bit. I was thinking of drilling it 5/8 and measuring the hole with calipers and if it cuts over .050 oversize then I could step it up to the 1" drill and opening the hole up to accept the 3/4 inch PVC. If not, I could just leave it at 5/8 and get the 1/2 PVC through. I am going to have to run 6 THHN wires through and 3/4 would be much easier. I have never had to drill a hole in concrete that had to be a certain size. If I drill with the 1" drill and the 3/4 PVC won't go through, is there a way to open the hole another 1/16 of an inch. If it were metal I would just use a file. I highly doubt the block is filled with concrete. The whole 1400 sq ft basement is at least 12 cinderblocks high, that would have cost a bit of money. I will find out when I go at it. What am i thinking, all need to do is grind,sand or, turn, off .025 per side of the PVC to bring it down to 1" or less. Thats the ticket!
Thanx
 
Over here Dogooder all our PVC tubes are metric and although 'old' people talk about "quarter" and "three quarter ply" it is actually 6mm and 19mm and always has been because it all comes from the continent!
Just for me! Do your PVC tubes actually have "3/8" printed on them?

Dave.
 
If you're certain that the wall is not filled with concrete, then the cinder block will be soft enough to carefully "warble" your 1" bit from both sides of the wall enough to accommodate the 3/4 pvc.
Just take it SLOW!
 
A big chunk often breaks off on the exit side, but stepping has mileage.
Perhaps a narrow hole all the way through, then drill a bigger hole in from each side.
 
MDF in the UK still comes in 8 foot by 4 foot sizes, as does plywood - BUT IN 6/9/12/18 AND 24mm thicknesses!! Plasterboard comes in 1.2 x 2.4m sizes, and timber - like 2 x 4 sizes comes in typically 1.8, 2.4 or 3.2m lengths (but the 2" x 4" isn't how big it really is!! Drill bits, socket sets nuts and bolts are all metric, unless they aren't. Most socket sets use 1/2" square drive
 
JAPOV said:
I'm assuming that he didn't pay for a set of 10" drill bits lol ;)
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You are assuming wrong. I bought a set of of 1/4, 3/8, 1/2, 3/4 and one inch, 12 inch long masonry bits. The set was cheaper at one place than the single 1" drill in other places. I only need to use it once.
 
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ecc83 said:
Over here Dogooder all our PVC tubes are metric and although 'old' people talk about "quarter" and "three quarter ply" it is actually 6mm and 19mm and always has been because it all comes from the continent!
Just for me! Do your PVC tubes actually have "3/8" printed on them?

Dave.
Click to expand...
I don't have 3/8 PVC but both the 1/2 and 3/4 say 1/2 and 3/4 PVC on them
 
JAPOV said:
If you're certain that the wall is not filled with concrete, then the cinder block will be soft enough to carefully "warble" your 1" bit from both sides of the wall enough to accommodate the 3/4 pvc.
Just take it SLOW!
Click to expand...
Like I said, I don't know if they are filled with cement but I highly doubt it. I will find out when I go for it. No matter what, I have to get through that wall. It is either that or call the power company in and run a line from the pole to a new meter and that would cost me more than I want to pay. I was a machinist for over fifty years, drilling holes in metal and wood, no problem, just never tried to drill a cinder block and don't know what to expect.
 
You could drill thru a joint - solid all the way, less chance of breakage and no worries about lining up two holes on either side of a void.
 
JAPOV said:
Warms my heart to see so many "Do It Yourselfers" making music :D
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Indeed! In my case I don't "make music" I "make stuff to help musicians make music" (tho' I was a fair bass gitist many years ago) My son is the musician and dad soldered and payed!

Dave.
 
Okay, found out what I am up against. On the outside is one of those 4" thick solid blocks standing on its side. Behind that is your standard cinderblock. I am drilling and drilling thinking I should be through this wall by now, but no..... I finally break through I go inside, no hole. I go back out side and put the drill in there and it hits the next wall and I am about out of flute length. I have nine inches of drill in there now. I must have drilled through the solid block then the first wall of the standard cinderblock then the cavity in the inner cinderblock. I am not going to make it from the outside. I am near a window. I will have to measure from the lower right hand corner of the window and go inside and lay it out. This should be fun. If I had a lathe I could make an adapter to lengthen the shank length on the drill so I can get in there more. I probably only have an inch to go.
 
Draw a circle or trace the pipe. Small drill bit, drill a series of holes close together on the outside of the traced pattern. Tap it with a hammer or use a chisel or screwdriver. You'll get your circle while minimizing knock out on the inside of the block.
 
I am 11 inches into the wall now, out of flute length and still not through. It is either start from the inside or get a longer drill. I think I will go for a longer smaller drill just to poke the whole through so I know where it is from the inside.
 
Ah, so your tube is going outside? Don't forget to put in a 'drip bend' You make a down elbow with a hole in the very bottom of the U to allow watwer to drian out. or, if just goint up. use a T piece and leave the 'down' pipe open.

Applies to cables as well e.g. an aerial downlead going into a window or wall, otherwise water 'wicks' along the cable and ruins your carpet!

Dave.
 
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