when drilling large hole(20mm) in brick wall is it best to use fast or slow speed.any other tips thanks?

Question

want to put plastic conduit through wall to let areial co ax (2 or 3) wires into house

Answer 1

Use a carbide tipped SDS hammer drill set on a SLOW speed. High speed will just burn the edges on the drill. You need to just apply enough pressure to the drill to keep it cutting. Best plan would be to hire a trade quality drill from a tool hire shop if you don't own one. There are not many DIY quality drills that will handle 20mm.

Answer 2

1

Answer 3

Neither go and buy/borrow/rent a decent SDS hammer drill then you will actually be able to get through that wall with ease. And buy the way if its a 20mm conduit u will need a 25mm drill bit.Im guessing that because you are talking about speeds u r using a crap drill that isn't ment to take a 20/25mm drill bit. When youve got the proper tools for the job drill the hole when u start getting near the end of the hole the drill will shudder turn off hammer action and this will stop u taking half a brick off

Answer 4

The bigger the hole, the slower the drill speed. The extremities of the business end of a 20mm drill will be moving over 3 times as fast as those on a 6mm drill run at the same rpm, and hence will develop much more heat.

But why not drill two or three holes at 6mm (or whatever - to suit the coax)? That way, you may be able to get them through the mortar beds in the outside brickwork without damaging the bricks, and making restoration much easier than a 20mm hole if you ever remove the cables.

Answer 5

Slow speed with an SDS drill is best. One thing to watch is to avoid breaking out a big hole on the exit side as you could break out half a brick with a powerful tool. To avoid this drill from the face side and slow right down before the drill comes through. You could drill a pilot hole say 6mm then use a 20mm drill from each side to keep it neat.

By the way 20mm is not really very large.

Answer 6

Yes... they make regular drill bits that long and longer. Make sure you get a masonry bit. I am not sure that you will easily find a 3 inch masonry "hole saw" though.... not a common hardware store item. That is really a professional-type tool would require carbide or diamond cutting tips... and would cost a fortune for someone who needs to drill just one hole. The person that suggested you hire a professional is absolutely right. If you want a "clean" hole you will not be happy with your own DIY results. Honestly, for a hole that size... the "cleanest" way of doing it may be to simply remove an entire brick. This is not difficult, mortar is relatively soft and can be removed by hand with a chisel. If it is 10 inches thick it is probably two brick walls (i.e. two bricks thick) separated by a narrow space. Hope this helps.

Answer 7

If the brick is not brittle you can use a hammer drill with a good masonry bit and drill at high speed. If the brick is brittle then you need to slow it down and possibly not even use the hammer drill. The hammer drill would be the easiest way to do it, but it is also the most likely to crack the surrounding brick.

Answer 8

I'd go slow with a large bit and have a constant source of water dripping onto the bit as you are drilling.
Just like a water saw for cutting stone

Answer 9

If bricka nd mortar are in good shape, hammer drill, and a good moderate speed. Depends on your drill. Go as fast as you can, so long as the bit "bites".

Answer 10

Slow speed keeps the bit from heating up a small squirt bottle with water will help