drilling concrete precasts steps

[bjr23]

I got the 1" rotary hammer drill from Harbor Freight and am drilling 5/8" holes and am installing railing around some precast steps using 3/8 lead bolt anchors and every hole I drill blows out the concrete on the back side of the holes. I have to drill clear thru because the steps are only 2-1/2" thick in most spots. Is there a diamond hole drill less aggressive or a different method. I won't have much steps left as they'll be all busted up by the time I get the railing mounted. Help. Thanks bjr23

 

[Thistle]

Possibly a smaller hammer drill with more speed & less impact such as a Bosch 1/2" 2 speed model.I've had mine for 21 yrs,gets used quite a lot still.Nice thing it works on masonry,wood or metals just by flipping the switch from hammer/drill to drill only mode.Can drill holes & drive screws into material that my 1/2" Dewalt cordless wont even budge. Use 1/4" hexhead Tapcons with a 3/16" bit.They should have enough strength to hold up against any abuse or shock with the railing.

 

[rustynut]

bjr23,
I'm thinking that i'd drill a small pilot hole maybe without using the hammer drill
and go at it from both sides a little at a time with the correct size.
May take a bit more work but should keep from blowing it out.
good luck
rn

 

[semipro]

Is there any way to back up the work area with a piece of scrap wood. Something like that attached to the backside of the step may prevent the blowout.

 

[maverick06]

Is there any way to back up the work area with a piece of scrap wood. Something like that attached to the backside of the step may prevent the blowout.

+1 thats what you want to do.

You could try to drill a hole top and bottom and get them to meet in the middle... but good luck getting that to line up.