Wintertime Posted February 29, 2008 Share Posted February 29, 2008 I have an old benchmark that I want to put into a piece of granite. I have the disk, and a friend has a house in the Sierra foothills that has plenty of small granite rocks lying around, so I thought we were in business--until I realized that I had nothing with which to drill a 1.25" hole in granite... I've read the threads here from "WFlover" and "Spoo," and have talked with my friend who has the granite. He has a hammer drill, but his largest bit is 5/8". I've been calling local hardware stores, and have not found anything over 1". We're thinking that might actually do the trick, because most of the shank of the disk is only 3/4"; it's just the flared bottom part that's wider. Maybe we could drill a 1" hole, then widen the bottom part with a star drill? Which brings me to issue #2: no one around here carries star drills. I can't even find them on the big stores' websites (e.g. Lowe's or Home Depot). Ace's website has some, but only up to 3/4". I think I actually did run across some specialty bits that were over 1", but they were close to--or in excess of--$100. Not an amount I'm willing to pay for a one-time use! Those of you who've done this on an amateur basis (i.e., not buying expensive professional-quality tools), do you have any suggestions on which tool (or what combination of tools) would best suit my needs for this project, and where I might find it/them? I'm willing to order online if it's a reliable, trustworthy company--preferably a site associated with brick-and-mortar stores. Thanks! Patty Quote Link to comment
+89SC Posted March 1, 2008 Share Posted March 1, 2008 Tool rental. I rented a monster hammer drill with a 1.5" diamond bit for $30 for half a day. It drilled through a 6" concrete floor like it was nothing. Rental is the way to go. The bit alone costs $100 to buy. Quote Link to comment
+Kewaneh & Shark Posted March 1, 2008 Share Posted March 1, 2008 Harbor Freight 6 PC. SDS MASONRY BIT SET $9.99 - 6" long by 1/4", 5/16", 3/8", 1/2", 5/8", and 3/4" 5 PC. SDS MASONRY BIT SET $15.99 - 16" long by 5/16", 3/8", 1/2", 3/4", 1" 5 PC. 3/16" TO 1/2" MASONRY BIT SET $3.99 - 3/16", 1/4", 5/16", 3/18" and 1/2" Quote Link to comment
+Renegade Knight Posted March 1, 2008 Share Posted March 1, 2008 (edited) Tool rental. I rented a monster hammer drill with a 1.5" diamond bit for $30 for half a day. It drilled through a 6" concrete floor like it was nothing. Rental is the way to go. The bit alone costs $100 to buy. I'll second this. Our surveyors have access to bigger budgets to buy the right equipment. Having tried masonry bits on tile...which may be about as hard as granite I think Diamond is the way to go. Edited March 1, 2008 by Renegade Knight Quote Link to comment
+Kewaneh & Shark Posted March 1, 2008 Share Posted March 1, 2008 Our surveyors have access to bigger budgets... I've never met a surveyor with a big budget. ... or worked for one. ... or been one for that matter. - Kewaneh Quote Link to comment
Wintertime Posted March 1, 2008 Author Share Posted March 1, 2008 Thanks for the rental suggestion; I'll check into that. Kewaneh, that's interesting about Harbor Freight product #46754. My friend has ordered stuff from them before, and I had found #46755--which appears to be exactly the same set, only $5 more! Any idea what the difference is? And since the largest bit in that set is 1", what would you recommend for drilling out the other 1/4"? Patty Quote Link to comment
+Kewaneh & Shark Posted March 1, 2008 Share Posted March 1, 2008 Thanks for the rental suggestion; I'll check into that. Kewaneh, that's interesting about Harbor Freight product #46754. My friend has ordered stuff from them before, and I had found #46755--which appears to be exactly the same set, only $5 more! Any idea what the difference is? And since the largest bit in that set is 1", what would you recommend for drilling out the other 1/4"? Patty Product #46754 & product #46755 are identical except for the bit length - 12" long vs 16" long. Bits 4" longer cost $5 bucks more. If you only plan on using them once, just auger the bits after the hole is the depth you want. Twist the drill side to side in the hole and force it larger. You'll most likely destroy the bits in the process. Or you could start with some smaller pilot holes around the perimeter of a 1-1/4" hole, then drill out the center with the 1" bit. - Kewaneh Quote Link to comment
+GEO*Trailblazer 1 Posted March 1, 2008 Share Posted March 1, 2008 If you are not going to submit it for inclusion in a data base you could take a hammer and unflair it. Just make it mostly round. The flare is for making it not easy to get out of the setting. If you use the industrial benchmark setting stuff(glue)from Berntsen or other company I do not see that to be any problem. Quote Link to comment
Papa-Bear-NYC Posted March 1, 2008 Share Posted March 1, 2008 (edited) And since the largest bit in that set is 1", what would you recommend for drilling out the other 1/4"? Patty Patty I have seen pictures of unused disks - in fact I have one given to me by a surveyor right here on my desk - and the stem does not flare out. The have a notch or a gap at the end, which is pushed out by being forced into, the drill hole on top of a small wedge. In other words the flaring doesn't happen until the disk is set. That's what keeps it from coming out of the hole. If you have an old disk, and it flares out 1/4 inch, I would hazard a guess that originally the stem was 1" all the way down and that extra 1/4" got there as part of the mounting priocess. What to do? Use a vice or something similar and squeeze the disk slowly back to it's original shape. Disclaimer: if you break the disk, I will not replace it. There may be some disks that were flared to begin with, but I don't see how they would work. There's a good picture of a couple of disks before being set which shows this (with the little wedge also showing). It's in the report of the Triangulation of Massachusetts (1922) on page 194 (this is page 200 in the PDF file). Click on this link Special Publication 76, and go to page 200 in the PDF (Just put "200" in the page entry space at the top of your Adobe reader )and you'll see what I'm talking about. Pb Edited March 1, 2008 by Papa-Bear-NYC Quote Link to comment
Papa-Bear-NYC Posted March 1, 2008 Share Posted March 1, 2008 (edited) (error) Edited March 1, 2008 by Papa-Bear-NYC Quote Link to comment
+GEO*Trailblazer 1 Posted March 1, 2008 Share Posted March 1, 2008 The New GEOCAC benchmark I just got from Berntsen is already flared and it is brand new. Quote Link to comment
+t8r Posted March 1, 2008 Share Posted March 1, 2008 Has anyone here actually drilled a hole in granite with a star drill and hammer. That takes the patience of job. If your rental outfit offers a carbide bit with the power unit, that should be good enough. Look out for worn out bits; the cutting edge should be the largest diameter on the bit. If the bit is worn so that it is tapered slightly smaller toward the cutting edge it may stick in the hole. They can be real difficult to pull out. Quote Link to comment
Wintertime Posted March 1, 2008 Author Share Posted March 1, 2008 Yeah, maybe we should try pounding or squeezing the flared part back together, at least partway. As I mentioned initially, most of the shank is only 3/4" wide, so if we could get the flared part down to 1" or less, I could buy a 1" bit and we should be good! Patty Quote Link to comment
+Renegade Knight Posted March 1, 2008 Share Posted March 1, 2008 (edited) Our surveyors have access to bigger budgets... I've never met a surveyor with a big budget. ... or worked for one. ... or been one for that matter. - Kewaneh I never met one that didn't have a rig full of gear that would make a benchmarker cry, who didn't also complaine about a lack of budget. It's all relative. Back OT. Why not contact a company who carves granite for a living? A headstone maker for example. Take the guesswork out. They could probably do the job for you for less mess and fuss. Assuming you can get the granite to them or they can come to the granite. Edited March 1, 2008 by Renegade Knight Quote Link to comment
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