Drilling Stone for Fireplace Mantle

[Maknwine]

I have a large piece of red oak I cut on an alaskan mill with the intentions of putting up a mantle. It's massive now and will still be massive by the time it's cut down to about 7 1/2 ft by about 16 in wide. It's 3" thick. The idea is to drill the stones to mount some anchors or do large threaded rod with high heat epoxy just to hold the back edge to the stone. My design plans has 3" thick sides to work as legs to do the main weight bearing of the mantle. The sides will have a curve cut into it from bottom to top. The face edge of mantle piece will retain the live edge. It will be rustic in nature with a little bit of a timber frame type of construction as well.

Anyway, my question is that I'm looking for a used hammer drill or rotary hammer drill off craigslist to get the holes drilled in the stone and I wondered if anyone had some experience drilling the type of stone listed in the url below. Any advice on type of drill is better or to stay away from, drill bits for this stone, hammer drill vs. rotary hammer, or better ideas than what I thought of as to mounting to the stone.
Tks
Tom


http://www.arboristsite.com/attachm.../139618d1275771736-freebay-insert-1-small-jpg

 

[forgeblast]

your url doesnt link because you need to be a member of arborsmith to see the image.
I would imagine if you use a masonary bit it would work, I have used them on everything from fieldstone (sandstone, mudstone) cement, to carving stones like alabaster.
http://www.tractorbynet.com/forums/projects/252940-mantle.html is our mantle, but we went into wood studs.
My buddys mantle that i have drying in our lean to off the barn will be going into stone, I think we are going to be doing it the same way, drill and epoxy, hang.
Fireplace Mantel Installation Instructions and Tips - How To

 

[BeezFun]

Hammer drills can be rough on masonry, as long as the fireplace has been there for awhile it's probably ok. You might want to hire someone who does core drilling, they could use a diamond bit that just cuts, won't shake the mortar out of your stone joints. Pullout strength is one issue, make sure you put the pins in at an angle so they are working against the edge of the stone if they try to pull out. The other issue is fracturing the stone, that's a lot of weight. If you could put some kind of support down at a 45deg angle on each edge that would really help.

 

[MrPete]

You can rent a hammer drill at most any tool rental place. Would hate to see you buy one and only use it one time. They will also help you out with what type of drill bit to use.

 

[SPIKER]

Not sure of what type of Masonry you have on the fireplace. STONE is very unpredictable and most are simply faced with stone and have block/brick or even wood/metal in behind. Core Saw is best way for this application but have be difficult in horizontal applications. Renting is way to go for this one time use jobs.

that all said I think you have a couple issues to attend to first is getting your mantle dry so it won't MOVE after it has been put up. This could take up to a year maybe more at that thickness of WO then you need several good measurements as most mantles are removable (slid onto pins and or supported on side brackets.)
I would look into who built your place to see if you can find the mason who put up the FP and request their help costs usually would be worth it for their professional help in this type of application where a couple hundred pound mantle could come crashing down on someone stoking the FP...

M

 

[cqaigy2]

Nice picture of you potential mantel. Do you happen to have one of the fireplace? SPIKER has a good point. Most of the fireplaces made today just have stone facade that won't take much weight. As mentioned before, it maybe better to mount the mantel to a wall stud possibly put a supporting member under each end as well. Another thing to be aware of is the minimum distance your from the top of the opening of the fireplace.

Had a friend that put in a fireplace for looks mostly, it was gas but they had the installer put the wood components, mantel etc. too close to the opening and it didn't pass as a functional fireplace. Kind of makes sense because wood/paper will change chemically when heated and the ignition temperature drops.

Sounds like a real cool project, can't wait to see how it turns out! Good Luck.

 

[bigtiller]

FYI - I used my rotary hammer to drill holes in rocks just for the fun of it this summer. Rocks the size of a baseball cracked into pieces with a 3/16 SDS bit trying drill through them. Softball size rocks held together by using increasingly larger bits up to 3/8 but the front and back sides of the through hole blew out, deforming the rock. I never tried drilling any bigger rocks but I assume they would blow out the same.

 

[Egon]

Rotary hammer drill with the concrete bit. Don' put to much pressure on bit when drilling.

Also try and stay away from edges.

I've drilled a few holes in granite when splitting rock? Goes quite fast and easy.

There should be a thread or two on splitting rocks which would include the drilling.

 

[Maknwine]

Sorry about the link not working. I tried the link after posting without being logged in and thought since it worked for me.....I'm an idiot.

Well, I think these older pics should show the stonework. I dont think it's feaux stonework, these stones are pretty large. Of course we bought the house used so no idea who built it or method used for what's behind the stonework. Luckily, my dad's my go to man for making sure I dont do stupid stuff or at least keep it to an acceptable amount. He's a licensed general contractor with many houses under his belt. But I can't say that he has had to drill through these large types of stones before. I know he doesn't have a hammer or rotary hammer drill.

Pics attached and thanks for the cool links and good advice. Maybe these pics will bring on some more. The one link for the mantel install guide I did google up a few days ago. The piece of red oak I'm using (first post pic) has been drying under lean to shed for over a year. Have planed the top and bottom and moved into garage. I plan to start smoothing front live edge up, cutting butterflies out of walnut for the large cracks, then trimming excess weight off to move it into the house for more drying.

 

[Maknwine]

another pic that maybe gives a little more depth