Star drill?

[willshak]

X-posted to other relevant group.

Before there were concrete drill bits, or electric drills for that matter, small round holes in concrete or rock were made by a round chisel type tool that was pounded into the stone with a small sledge hammer while turning the tool. It might have been 8" or 10" long. The face of this chisel had a star-like pattern, only with 4 points, like a plus sign " + ". I believe it was called a star drill. A Google search brings up a lot of sports drills (training regimen). Anyone know if they still make them, or if so, where to get one on-line? I'm trying to drill some 40 - 3/4" holes in concrete and my 1/2" corded electric drill with a concrete bit stalls on the stone aggregate in the concrete requiring me to stop and try to crack the aggregate with a large punch. I figured a star drill would work better.

[George]

Thats what hammer drills are for and also the reason why star drills are not so popular.

[Glenn]

Obviously you have never used a star drill.

Forget it. You will use the electric drill only, after about 15 min of pounding on the star drill. Maybe you are pushing it too hard. I usually drilled a 1/4" hole and then drilled it out bigger with the 1/2" or whatever.

[PeterD]

I'm 100% sure they are available, but I really don't think many 1/2" corded drills will do much for you.

These are impact, so you need an impact tool.

I use an IR tool that uses star bits, works nicely (but is air powered!) I know you can rent electric ones (or buy, but they are expensive).

But using a star drill in a standard drill won't do you any good, you'll never really make a hole--you have to have impact. BTW, with my IR tool, I provide the rotating force, the tool only provides the impact. And if I don't provide rotational force, things get very strange after a short while! (I usualy do a continous 90 degree rotation back and forth as I'm drilling...)

And, yes, the star drill will work better. I punch 3/4" holes about three inches deep in about a minute or so per hole.

Try a tool rental place. Tell them what you need, they will have something to do it.

[Reed]

Try Google

get you about 10 to choose from, about $10

[RBM]

We pretty much stopped using them in the early 70' but I would expect an electrical supply to have them. For 40 holes, you'd be better off using a rental hammer drill. Without the hammer, that blue stone aggregate just burns up bits

[willshak]

on 10/6/2007 5:54 PM Glenn said the following:

Obviously, you don't know anything about me.

[willshak]

Thank you for the direct answer to my question.

[willshak]

on 10/6/2007 6:05 PM PeterD said the following:

I have the small sledge hammer. I just want the hand tool star drill. I'm not going to try to put it in the electric drill. When the electric drill with the concrete bit just spins on a bit of aggregate I can use the star drill to break up the aggregate.

[Uncle Monster]

Bill, the classic hand held star drills are still available. Unless you're a masochist, the best thing to do would be to rent a big SDS hammer drill if you don't own one. I have a Bosch hammer drill that would make short work out of 40 holes.

[8~{} Uncle Monster

[Harry K]

Yep, 'star drill' is the correct term.

The hammers used on them even have their own names...wel it is really the name of how they are used vice the hamer itsself..

'Single Jack' - one operator who both holds the drill and hammers on it. 'Double Jack" - one person holds the drill and another uses a much bigger sledge hammer. That is one place where the old joke "when I nod my head, hit it" comes from.

I even have a 3/4" one. I have tried using it a few times but gave up. If my piddly littlel 3/8" 'hammer drill' won't cut it, it is off to the rental to rent a big electric. The speed those things go through holes is more than worth the rental cost.

Harry K

[Steve Barker LT]

You need to rent or purchase a good hammer drill. You also may be encountering rebar.

s

[willshak]

on 10/6/2007 10:55 PM Steve Barker LT said the following:

No rebar. I'm drilling 3/4" diameter holes 2" deep in a poured concrete sidewalk around my pool. The holes are to attach a mesh winter cover on my inground pool. The holes are to hold the cover's 40 spring loaded straps. Previously, I had been using the solid winter cover with water bags. I just got tired of cleaning the water and debris that accumulated on top of the cover when I went to open the pool in summer. I looked enviously at my neighbor's mesh cover all winter and it was clean except for a couple of twigs laying on top. Then I looked at mine and there was a foot of dirty, leafy water after the rain and melting snow had pushed the cover deeper into the clean pool water.

When I first start the drill, I can see the crushed concrete powder coming out and forming a ridge around the hole. All of a sudden the powder stops building and I can hear the drill bit kinda bouncing over something. The bit never stops turning, it just stops cutting. I wash out the hole and look in. The aggregate filler in this concrete is small roundish pebbles, about the size of a green pea up to a lima bean size with colors of yellow, orange, grey, or whitish. I may see parts of one, or two, or maybe three pebbles intruding in the hole, the tops of which look sanded from the drill rather than cut. At this time I take the small sledge and a 12" long steel tapered flat nosed punch with a 1/4" wide tip and try to crack the pebbles into smaller pieces that the drill bit can handle. I think that the 3/4" hand tool star drill can do a better job of cracking the pebbles with fewer blows since the star drill will completely fill the hole and may crack two or more pebbles with one blow.

[RicodJour]

The hammer drill (or better yet, rotary hammer) is one of the more indispensable tools - there's nothing that works even remotely as well. Your question is vaguely akin to someone asking which is the best brand of screwdriver to use as a chisel, 'cepting a screwdriver is a lot closer to a chisel substitute. Yes, I know they used star drills for ages, and yes I know you could do it that way, but I'd borrow or rent one, or buy/sell on eBay to get the proper tool for the job. You'll find all sorts of projects for it.

R

[willshak]

I don't see the analogy about using a screwdriver as a chisel when the hand tool I was asking about is used for the purpose for which it was made.

[RicodJour]

{snip}

Hence the 'vaguely akin'. I was going to go with the 'asking for help selecting a horse drawn buggy' analogy, but I thought I'd stick to tools.

Not sure why your Google search turned up dead ends. When I Googled "star drill" it came up with a bunch of hits - Ace Hardware has them and eBay as well.

You'll be spending $10 or $20 on something you'll probably never use again and it's going to take you far more time to do the drilling. Your time, your money.

R

[BobK207]

You didn't say (or I missed) how deep the holes needed to be.

But even shallow 3/4" holes will take some time to drill 40 with a start drill (basically a hand operated masonry drilling system)

Rent (or borrow) Hilti or Milwaukee rotary hammer....either will make short work of 40 3/4" holes.

A regular drill motor & a concrete bit will take FOREVER (BTDT) use a rotary hammer, fast & easy.

Don't bear down on the tool, let it do the drilling & you'll be done in a few hours depending on hole depth.

cheers Bob

[RBM]

You are also going to have difficulty making any where near as clean and straight hole as with a rotary hammer

[hallerb]

harbor freight sells a hammer drill for 60 bucks bits a little more. a great price for a occasional need tool.

star drills work but can take hours, hammer drill can do the same job better in 5 minutes...

plus you have the tool for the next time you need a hole, or have other jobs. the chisel bit is wonderful, used it once to hrak up a big rock in my yard when planting some stuff.

[The Other Funk]

Finding the keyboard operational willshak entered:

After reading some of the responses I think there may be a misunderstanding. Are you saying that you want to use your 1/2" electric until you hit a piece of aggregate and then use the star drill and sledge to break that up? Then returning to the drill. If that's the plan then I believe that Home Depot has star drill's or any decent sized hardware store should have one. If you have a stone and tile dealer near by I'ld give them a call. Of course renting or buying a hammer drill is another answer. Good luck. Bob

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