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temp everything in place. Drill 1/2 through, using your eye to level and plumb the bit, perhaps against some light reference lines that are scribed through the starting point of the drill.
Square the starting point around to the other side of the column, set two more reference lines that are plumb and level through the starting point, and finish the bore. This works well with twist bits, less well with augers.
What you have done, is reduce the error of your free hand drilling by 1/2, made the entry and exit points exactly where you want them, and removed the error in alignment on the inside of the bore by reaming with the bit. For this reaming, you need a twist bit that is as long as the hole is deep, in order to make a passage that is consistent in its taper from one end to the other. This is indeed a long bore, and I wouldn’t be surprised if you ended the process by bending the bolts a little in the center, to help them get through without digging into the sides of the bore as you push them through.
Replies
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Jim:
I think scooter has it right in post #17. Use a jig, I know its ruffsawn stuff, you'll just have to keep a side marked for consistency. Also the block stock you use to guide your bit in should be drilled on a press and be of a harder(oak)species. Where is this project? I'm also a Coloradoan, I'd love to see this thing, 'sounds awesome.
The Machine
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John's method is the one that works for me. One guy does the drilling, while the other watches and maybe even holds up a speed square to help him eyeball the situation and then directs the drill operator.
*General makes a jig ........set your drill in it, set the angle ...you will be spot on.
*I would opt for clamping, temp spiking or somehow joining the pieces together. Also no one here has mentioned a pilot hole. I would do that first. Then you can drill from both directions to minimize tearout. I have a craftsman cordless drill with a level on it. It helps a bunch. I could at least drill i pilot hole with it. Im sure there are corded drills with levels. If you are joining several pieces then measure, square and center each hole to where they will align if you must pre drill prior to erection. Drill from front and back side of each member and it should work out especially if you drill a PILOT hole first....Oh yea....a 1/2 spade bit is slightly smaller than the extension pieces you buy to make it long. I have to wollow the hole a little when i drill 1/2" holes 8" or more. I usually put nut and washer on end i wallow and carriage head on other end.
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I've spent the last week setting rough sawn 6x12 beams supported by a post comprised of 4 6x6's that surround the 6x12 and are attached with 16" long carraige bolts. I've had quite a bit of a problem getting the holes drilled true. Does anyone have a suggestion or two to make next week a little more bearable for me.
jim at great white
*Go to hardwicks and get a drill bit long enough to go all the way through.
*b TVMDCUse a pocket square, even a piece of 2x4 to help guide the bit perdendicular to the surface of the wood. And as Luka says, get a long bit.By the way, how are the 6x6 posts positioned? 2 rows of 2 centered under the beam with rabbits cut to let-in the beam? That's only 11"?Regards, Bill
*We have to do that kind of drilling once in a while. A bit long enough to handle the depth is good. I also have a small round level glued to the top of an Milwaukee drill motor. It looks like the ones on an automatic builders level. The drill is a 500 rpm model which is slow but allows the user to keep his eye on the level. Not exactly high precision but helps keep the bit pretty straight.
*Jim, the easy way is make yourself some long bits. Drill rod is pretty cheap and you can easily weld bits on the end. How big a hole are you drilling? I've got a number of bits like this, they're good for all kinds of things if you've got 'em. Joe H
*Jim, Some of our hurricane tie-down we have to use in Florida not only have us attaching the lumber togeather but also alining it in between two 3/4 holes of the anchor itself. The inspectors don't like to see a lot of sloop. I use a $34.00 mini drill press on my 1/2 drill. It gets me going straight for the first 6 or so inches then a switch to a bit long enough to go the entire distance. Any way you do it, it's a pain.
*I have a 16" long x 1/2" bit, so I'm plenty long enough on the drill bit part of the problem.the posts are set two on each side of the beams in a square pattern with 5 1/2" between them everywhere. Sort of like filling the outside corners of a tic-tac-toe board with squares and the bolts need to run through one 6x6 then the 6x12 and finally through the other 6x6. This works out to 4 bolts at each column, and I have to do 18 of these columns.I have been trying to predrill the posts before standing them and then running the drill through each side after they are stood and can't seem to get the holes to line up.Some times I get the connection made in about 5- 10 minutes and other times it seems that I fight with one bolt for an hour trying to get it through and the nut and washer on.Shakey said it best "Any way you do it it is a pain."thanks and keep them coming jim
*Do you have to do bolts? If you ran long lag screws into the 6x6, through the beam and into the other 6x6 from one direction, and run lags as well from the other side, you wouldn't have to make the holes line up, even off-set them a little to be sure the screws wouldn't hit each other, or if strength requirements permit, let them just meet in the middle. No idea about what it does to your engineering, though, to exchange bolts for screws, and too late if you've started and have to match what you've done, but i'm just practicing thinking outside the box and it's really late here...seems like a lot of work for a rose arbor, though...
*Hey Jim,can you clamp some stops to the 6x6's to provide a rest for the 6x12- set the whole thing upright with a few braces and drill in place? one shot all the way through per bolt- shouldn't be a problem to align that way...
*Jim, you've got too many holes. Drill only ONE of the uprights before you stand it, then use that hole as the guide to drill the other post(s)?? Joe H
*temp everything in place. Drill 1/2 through, using your eye to level and plumb the bit, perhaps against some light reference lines that are scribed through the starting point of the drill.Square the starting point around to the other side of the column, set two more reference lines that are plumb and level through the starting point, and finish the bore. This works well with twist bits, less well with augers.What you have done, is reduce the error of your free hand drilling by 1/2, made the entry and exit points exactly where you want them, and removed the error in alignment on the inside of the bore by reaming with the bit. For this reaming, you need a twist bit that is as long as the hole is deep, in order to make a passage that is consistent in its taper from one end to the other. This is indeed a long bore, and I wouldn't be surprised if you ended the process by bending the bolts a little in the center, to help them get through without digging into the sides of the bore as you push them through.
*Joe H. is right, you're trying to pre-drill too many pieces. You're dealing with woodgrain and not machine steel, which means that the bits will tend to wander and misalign.Use a block on first pre-drilled post to hold the beam on, clamp the second post to the first post and beam with a pipe clamp on both sides while you drill out the remaining beam and post.Gabe
*I don't understand exactly what you're drilling but when I bolt a header to the top of a post for a pole barn (never did more than 3-2x's and a 6x post together), I nail everything up temporarily and then drill from one side.
*Ship auger might help .....self feed and for me, easier to keep straight.
*the reason that I'm trying to predrill both posts is that holes for head of bolt and also washer and nut end are both exposed.I think that just letting the drill run through the second two members, as some of you have suggested, may not leave me with a desirable end result. This is on a rather expensive home with a very caring builder, very good reputation for customer satisfaction.jim
*Jim, more junk to clamp together, but add a sacrificial 1x on the far side. That will keep the tear out to a minimum. Joe H
*Jim,You're thinking that tearout as the drill breaks thru will leave an unsightly, ragged hole instead of a Forstner bit smooth.Using a ship auger, with its full cutting sides, will keep the hole true and the threaded point will help pull thru quickly. Just clamp everything tightly together as you drill.With a little care as you reach the breakthru point you will see the point as it comes thru the other side of the post. STOP! If you can't control that last inch to be sure the auger stops before tearing thru, switch to a spade bit.Use that little hole as center and finish the hole from the opposite side. Should be only about 1/4 inch left and could be quickly done with a short spade bit chucked into another drill. No tearout. If you don't have an auger this looks like an excellent time to add to your tool collection.
*Use a template/jig. Set up some 3/4" MDF with "fences" on three sides (left, right and top). Measure for the hole, get it square, and drill them out one at a time knowing that no matter if it is 5 or 50 posts, they'll all the at the same height and centered.If the issue is one of the bit/drill wandering, set up a drill block on top of the jig. This would be a 6" piece of square stock with a STRAIGHT hole drilled through it. Align it to your jig, and you can't go wrong. The bit will always go in straight.
*As you might notice by my byline, I have put up trolley wire, which means playing "Wichita Lineman". You can buy ships augers up to 2 feet long, and I have had to drill holes fully that long. If you have somebody eyeball the drill bit as you go in, you can make an amazingly straight hole even cutting through a log (utility pole).Incidentally, using a rotary impact tool really works nicely when you are hanging from a pole without a lot of bracing. A big ol' rotary drill will twist you right off that pole. The rotary impacts its way through.