drilling a 14" hole with a 10" drill

Frank Fusco

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I got myself into a bit of a bind with a lamp project I am working on. (pics later, I have a reason to hold back for now)
The upright part is 14" tall. My longest 3/8" bit is 10". I hand held and eyeball sighted for the first part feeling pretty good about myself going (I thought) right down the center. Then I attacked from the other end, planning (hoping :rolleyes: ) the two would meet dead-on. No way, not even close. :huh: Now I know from all my foolings around with old style guns that drills, especially twist bits, like I was using, like to follow grain instead of going straight. That's what happened here.
So, I ended up buying a set of 14" spade bit. (much better for this type work, BTW) I then attacked the hole from the deep end and 'voila' drilled all the way through.
Problem solved. Not. :(
This bit found the 4" deep hole, flexed and continued on through.
Now I have a curved hole, first goes one way then goes the other.
Question is: how do I shove a rigid lamp rod through a curved hole? :dunno:
Right now, I'm thinking I won't. I might just use short sections at both ends and Gorilla glue them in place. But other suggestions are welcome.
BTW, for further lamps, I plan to keep length (height) to drill length available and drill before turning then use end holes for my centers. This might not be a 100% method but sure should be better.
 
I'd be tempted to use the spade bit to "straighten" the hole. Of course in the curved sections will be larger than the rod diameter, but I don't think that matters.

Maybe a forstner bit on a bit extender would work too?
 
I'd be tempted to use the spade bit to "straighten" the hole. Of course in the curved sections will be larger than the rod diameter, but I don't think that matters.

Maybe a forstner bit on a bit extender would work too?


I am considering using the 3/8" spade to just kinda chew away at the interior to enlarge and straighten the hole. Dunno if that would work.
Problem with extender is that the extender is too big to fit inside a 3/8" hole.
 
Boy, are YOU hosed! :) :) :)

That one's gonna' be difficult to fix. Did you get it to meet in the middle, somewhere? If you did... pick up the smallest hole saw you can find, and a piece of 1/4" cold-rolled steel rod long enough to fit (get forced) through. Take the pilot drill out of the hole saw & attach it to the 1/4" steel rod.

Now... I never said this would be EASY... in fact it'll be nearly heartbreaking to do... but it can be made to work. The hole saw WILL try to follow center as much as possible, but you'll have to stop at least every hole-saw-depth to clear out the "doughnut hole" with a spade bit.

It may take two runs, the second one to straighten the bore more than the first did, if your meeting point is a long way off center.
 
..... I might just use short sections at both ends and Gorilla glue them in place.

Seems the easiest option to me, gorilla or epoxy, through tubes are not the norm in the UK, just a 5/16" hole right through and bulb holder fixing in the top.

I use a homemade drill but that's just because I'm too tight to buy commercial.

__________
__________Made up the Auger to go with the hollow centre.
__________8MM drill brazed to a length of 5/16" mild steel rod.

__________click on images for larger view
_________ ___
 
Epoxy a short section of threaded rod at the top to mount the socket and harp. If you need a metallic part at the bottom, do the same thing.
 
Tim: That is essentially one plan. I could sharpen the sides of the spade bit and chew away. Or do like I did with a gun one time. I just took a section of steel rod and whacked on it with a chisel until it was a non-directional burr then chewed away with a drill.

Charles: I do wonder why the tube is the norm. A cord inside a solid lamp is not in danger. Having the right too, like yours, to start with is the wisest approach. And, I have never been accused of being in that category. ;)

Bill: Right now, that looks like the most expedient solution.
 
Frank I sent you a PM with a link. Wasn't sure I could post it here. I buy a lot of my parts for lamps from CSUSA, the big borgs, etc. CSUSA has instructions and also got some from a place a friend of mine gets his parts from. I don't use a brass tube all the way thru. I just use a piece at the top and will use a little epoxy if it is slightly loose. I do all my lamps that way. See what you think Frank.
 
One technique I've read for doing long holes is to rip the blank in half, then use a dado or router table to cut a channel right down the middle and then glue the two pieces back together. If you do it on a band saw, or a think kerf blad on the table saw, you should be able to get a nearly invisible glue line when you glue it back together, since the grain will match pretty closely.

Not saying I've done it, but I've read about it, fwiw...:dunno:
 
A couple of other thoughts:
1. Use a V-shaped cradle to guide the drill bit the first 3-4 inches into the lamp pole.
2. Make a solid drill guide block to aid in starting the hole for the first 3-4 inches.

I agree with what others have said about using a solid tube. I've never seen a lamp design that called for one.
 
Frank

They always used a hand held gouge to do lamp holes on a lathe back when I was in school.

Garry

The old method of drilling ramrod holes in guns or flute makers, including bagpiple flutes, used a spoon bit. Those do not follow grain as much as other bits. I think they are still available, some searching might find them.
Like others, I wonder about the necessity of a tube in the center of a big chunk of wood.
 
The old method of drilling ramrod holes in guns or flute makers, including bagpiple flutes, used a spoon bit. Those do not follow grain as much as other bits. I think they are still available, some searching might find them.
Like others, I wonder about the necessity of a tube in the center of a big chunk of wood.

Today they call them a shell auger. In my day they didn't have the twist section. Easily made. And spoon bit may well be what we called them..

http://woodworker.com then search for "shell auger" Garry
 
Frank, my grandpa turned some lamps out of walnut burl for my parents over 30 yrs ago and there is only a short tube piece epoxied into the top. They still use them and have had no problems.

BTW, the holes in these lamps don't meet up very well either, but no one notices. ;)
 
Frank I tried something today that worked really pretty darn well. I bought a 3/8" bit with a MT 2 taper from CSUSA. I put a tenon on both ends of my lamp blank. I drilled as deep as the drill would go (about 4 1/2") from both ends which were dead center. I then took my 14" long 3/8" twist bit and finished drilling thru. It actually worked pretty slick and the holes on both ends are dead center. Did 4 lamps this afternoon in about 4 1/2 hrs. I do make mine in two pieces with a based turned first with a 3/4" hole all the way thru. The when I turn the lamp body after being drilled, turned to shape I will cut a tenon on the end that will fit tight into the base. I use Titebond II on the tenon and then insert in the base. Let dry and finish. I use shellac on the lathe and then finish with rattle can lacquer.
 
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Frank I tried something today that worked really pretty darn well. I bought a 3/8" bit with a MT 2 taper from CSUSA. I put a tenon on both ends of my lamp blank. I drilled as deep as the drill would go (about 4 1/2") from both ends which were dead center. I then took my 14" long 3/8" twist bit and finished drilling thru. It actually worked pretty slick and the holes on both ends are dead center. Did 4 lamps this afternoon in about 4 1/2 hrs. I do make mine in two pieces with a based turned first with a 3/4" hole all the way thru. The when I turn the lamp body after being drilled, turned to shape I will cut a tenon on the end that will fit tight into the base. I use Titebond II on the tenon and then insert in the base. Let dry and finish. I use shellac on the lathe and then finish with rattle can lacquer.

Sounds like a good technique, I'll print out your instructions and save. I don't know how many lamps I will be making and hesitate to invest more $$$ into more drills. The MT bit is an excellent idea even though I could chuck up a bit on my lathe.
 
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