home made drill

[thistle]

I am rewiring my basement shop, and in order to run the conduit for my phase converter
wiring i needed to drill a hole for 1 1/4conduit ,through 21 inches of concrete,

-quite why i have a 21 inch thick concrete wall I dont know ,of course it is in my way.

I was horrified at the price of the appropriate masonry bit for 1 hole plus i didnt know if i was going to hit rebar so I delved into the scrap bin and welded a couple ofold 3/8 masonry bits into slots cutin a piece of 1 1/4 pipe,found an off cutfrom under the lathe that fited the pipe ,with a hole in it ,welded that and and a shank to grip the mess with and voila improvised core drill.

The wife is actually quite impressed!

Started a crater for it to start off in and away the drill went chewing through that
concrete.

ha!

would post a picture but its too ugly.

[egpace]

When did you find out the wall was 21" thick, before or after drilling?

[JCHannum]

Where there is a wall, there is a way.

[Norman Atkinson]

Couldn't buy one at Wall-mart?

Seriously, I did a similar job with nothing more than a bit of mild steel of the right size with a hammer drill.
The only temper was mine

Norman

[J Tiers]

Urrrr....

Another reason for a welder...... I have a 4" hole to cut through 14" of brick and hollow tile.... I figured to drill some smaller holes and knock out the stuff "on the dotted line", but it probably won't give nearly as nice a hole....

The core drill that size is $350 or so....

[Arbo]

Or you could just rent the right tool for the job. Around here, it costs 35.00 for a half day rental.

[J Tiers]

<font face="Verdana, Arial" size="2">Originally posted by Arbo:
Or you could just rent the right tool for the job. Around here, it costs 35.00 for a half day rental. </font>

That WOULD be good....... except in this case, there is a pretty decent chance of messing up the expensive bit because of the way the wall is, and an existing hole that is not centered on teh spot the new one needs to go..... so centering is kinda "iffy" even if I pound in a wood plug....

[Kdahm]

Yellow pages

Look under "Concrete - Breaking, Cutting, and Sawing"

For a 14" long core, 4" diameter, I would expect a charge of between $50 and $100, but it might be less. There may be a minimum charge, though.

Hypothetically speaking, if I were to hypotherically need a hole cut in some alleged concrete or rock, I might consider grabbing the company's core rig out of the cabinet on a friday and making sure it was back by monday morning. Since I'm the one who makes sure it doesn't walk out on its own, that wouldn't be a problem. That would be the wrong thing to do, though, so I'll have to figure out something else the next time I need a hypothetical hole.

Masonry and cocnrete bits up to 1" don't cost that much, though.

Karl



------------------
At a certain point in the course of any project, it comes time to shoot the engineers and build the damn thing.

[chkz]

can't ya rent the damn things??

just wondering....

Chris

[thistle]

NORMAN ATKINSON
Member posted 08-24-2005 03:26 PM
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Couldn't buy one at Wall-mart?

My goodness Sir, Gentlemen never BUY consumable tooling.

Rent ? in the time taken to drag my sorry posterior around the various rental establishments ,the subsequent interaction with the inevitable 16 year old genius behind the counter and subsequant recooperative visit to the local purveyor of ales and beers....
well that is why i welded it up
-cost electricity,materials all scrap.

I AM A HOME SHOP MACHINIST HEAR ME ...burp fart and and my wallet sqeak

should imagine that you could make a 4 inch
bit easily
scrounge up a piece of pipe,or tube about 18 inches long,a piece of plate or even a bit of bar ,weld across one end .
I would heat the masonry bits with a torch and see if the brazing would
let go and then braze them into slots cut into the end of the pipe.
I would use 3 carbide tips .
weld a piece of 1/2 inch steel rod through the center protruding both ends to act as a pilot and at the other end a drive
file 3 flats for the chuck jaws .

drill a 1/2 inch pilot where you want to go
and see what happens.