Granite Post.

[Thomas]

What the best means of drill 1/4" hole threw granite post... post 6" x 6".

Thanks.

 

[Ed of all trades]

Carbide Hammer drill? Ed

 

[mjw357]

Diamond bit, water for coolant and lots of patience.

 

[EddieWalker]

I would think that it would be the same as drilling through concrete. I have a small SDS drill that I keep in my truck all the time and use it for anything half an inch and smaller, or minor chipping and removing of tile. For bigger, and faster, I has a 1 9/16 SDS Max that is a beast.

If this is only a one time thing, then you can rent one. When my Hitachi died on me during a job, I rented a Bosch for something like $40 for a day. I wasn't impressed with the Bosch, so I bought Makita at Home Depot.

 

[Egon]

SDS half in hammer drill with the carbide bit. Don't add water. Dry the dust blows out of the hole. If you do a search on this site you should find pictures of drilled granite.

[video]http://www.tractorbynet.com/forums/projects/159329-cutting-granite.html?highlight=Splitting+rock[/video]

Shows some holes drilled in granite.

 

[robstaples]

Granite is hard but can be brittle in small pieces. Depending on grain size. A hammer drill has a risk of cracking the post. I'd get a high grade hollow diamond drill bit and use water to cool the bit and wash away the waste. I use a wet bit adapter that feeds water into the drill bit. Will take about 30 minutes depending on muscle pressure.

 

[5030]

I would think that it would be the same as drilling through concrete. I have a small SDS drill that I keep in my truck all the time and use it for anything half an inch and smaller, or minor chipping and removing of tile. For bigger, and faster, I has a 1 9/16 SDS Max that is a beast.

If this is only a one time thing, then you can rent one. When my Hitachi died on me during a job, I rented a Bosch for something like $40 for a day. I wasn't impressed with the Bosch, so I bought Makita at Home Depot.

I'm kinda puzzled why you didn't like the Bosch. I have one and it's a beast. The only thing I don't like is the reverse paddle.

 

[oosik]

Around here the lava flows will form into columnar basaltic shelves. These "basaltic posts" can be from 6" in diameter to 6' in diameter and as tall as 100 feet. They are used for many & varied projects - gate posts, yard decoration, fountains etc, etc. I've seen one local company drill one for a fountain display in a yard.

They used an automated drilling machine - clamps on to the post, positions the drill, auto feeds water based lubricant etc. The drill they used was a diamond faced coring bit. It was similar to a wood hole-coring bit. The machine would drill 10-12 inches, stop, back out and the operator would insert a tool to break out and remove the center. The tool would reinsert, drill another 10-12 inches and the process would repeat. In the end, this process leaves a perfectly round, ultra smooth hole.

 

[EddieWalker]

I'm kinda puzzled why you didn't like the Bosch. I have one and it's a beast. The only thing I don't like is the reverse paddle.

I liked the Hitachi a lot better then the Bosch. It had more power, felt better in my hands and just seemed to work better. For a very long time, I was a huge fan of Bosch. They invented the SDS stuff, and I was going to buy a Bosch SDS Max when the Hitachi died. But when it came to spending the money, I went with Makita and feel it was a good decision. My Bosch tools are failing on me sooner then I would have expected. My big belt sander and 5 inch orbital sander where Bosch, but now I have Makita, which I like a lot better. I'm slowly replacing every other brand that I've bought over the years with Makita. I just don't know of a better brand out there.

 

[dadster4]

They make diamond bits that look like flat spade bits for drilling glass and tile. they are too short to go through your post, but will give you a good start from each side, then follow up with a carbide bit. I've used them for drilling through marble...cut like butter!

 

[5030]

I liked the Hitachi a lot better then the Bosch. It had more power, felt better in my hands and just seemed to work better. For a very long time, I was a huge fan of Bosch. They invented the SDS stuff, and I was going to buy a Bosch SDS Max when the Hitachi died. But when it came to spending the money, I went with Makita and feel it was a good decision. My Bosch tools are failing on me sooner then I would have expected. My big belt sander and 5 inch orbital sander where Bosch, but now I have Makita, which I like a lot better. I'm slowly replacing every other brand that I've bought over the years with Makita. I just don't know of a better brand out there.

The only Makita I have is one of their gas chainsaws and it's a dandy. My Bosch has all kinds of power...too much actually but I don't use it everyday either.

 

[bigtiller]

They make diamond bits that look like flat spade bits for drilling glass and tile. they are too short to go through your post, but will give you a good start from each side, then follow up with a carbide bit. I've used them for drilling through marble...cut like butter!

That's what I would do. Using a SDS rotary hammer will blow the back side of the post out.

 

[robstaples]

Thomas, examples mentioned above for hammer drills were used the split big stones. You haven't said anything about your column except 6 by 6. I've drilled dozens of holes on granite from 1/4"to 4". Diamond drills cut a smooth gentle hole in the material. But they are carbon and will burn up if they get too hot, IE water cooling and it cleans the grit away so the drill engages the granite instead of making friction heat. Hollow core allows the water to keep the bit cool as the hole gets deeper. I've burned up the diamonds not using a flush or submerged method. If you can water jet it with a garden hose and keep withdrawing the bit to cool and clean , it will last through your hole. Hammer drills fracture their way thru the material, which is fab for many jobs.