Routering Concrete

[sdppm]

Yes I mean Concrete, Can I , with a carbide bit, router an oval in concrete, I poured a circular driveway with four large compass points poured in the circle. I want to put the four oval N S E W breaa letters I got for the compass. I think I probaby can as When I routered out the hole in my table saw extention table a few years ago I inadvertently routerd the 1/4 inch steel plate on the support legs with no apparent damage to the router bit. I am assuming that the steel was harder than the concrete

[RicodJour]

How's your insurance situation...?

Steel may be harder than concrete as a whole, but it's not nearly as abrasive. You won't get very far with a regular carbide router bit. It'll dull to crap in no time if it doesn't break first. Steel is also more uniform - you don't hit pieces of stone (read granite) in steel.

You really need diamond cutting tools with concrete and stone. Wet cutting keeps things cool, but it's messy as opposed to dusty.

I'd probably use a diamond blade in an angle grinder to hog out most of the recess and establish straight edge lines, then use a Dremel type tool or a rotary shaft like a Foredom to do the detail work.

R

[Robert Allison]

You can do it with a concrete router bit. I get mine at a local tool supplier. I use them with concrete countertops. They are diamond impregnated carbide bits. Plan to spend some money.

Here is one place that has them:

[Leon]

concrete driveways do?

[gfretwell]

I found out the hard way a carbide bit will cut concrete. I cut a perfect circle in my driveway, about 1/4" deep, when cutting a pierce of plywood. It didn't even slow me down much. :-( If you don't have a lot of material to remove it will work but the bit will be toast. Wear good PPE.

[Shopdog]

I want to see a picture of the driveway with the compass, sounds like it would be nice!

Searcher

[Doug Miller]

That is *not* a correct assumption.

[Robert Allison]

No.

[sdppm]

I plan on the bit being toast. I need to router 3/8 inch deep. Once I do the edge I can hog out the center with a diamond lade.

[Mike Marlow]

Rout Howard... rout. The router routs out material.

[Andy Dingley]

Doesn't matter - what's the aggregate?

Anyway, no. Use an angle grinder instead.

Some people like to pour lead in as an infill afterwards (this also hides variations in the groove depth). I find it weathers to a dull grey which is indistinct, unless you coloured the concrete first. Sulphur inlay is a more interesting colour, and easier to work with. I make sundials this way, using slate tiles or brickwork as well.