accurately drilling vertical/perpendicular holes
Discussion
I've got a wall, a drill, minimal experience and surplus enthusiasm
I want to drill a bunch of deep-ish holes - wells, perhaps - in the top surface of a wall (to install and bond some threaded rods into them). (it's a brick-on-edge type arrangement along the top of the wall).
what tool or piece of equipment do I need to buy or get to make sure that I drill my hole completely plumb, or at least perfectly parallel with the edges of the wall / perfectly orthogonal to the top of the wall?
cheers
I want to drill a bunch of deep-ish holes - wells, perhaps - in the top surface of a wall (to install and bond some threaded rods into them). (it's a brick-on-edge type arrangement along the top of the wall).
what tool or piece of equipment do I need to buy or get to make sure that I drill my hole completely plumb, or at least perfectly parallel with the edges of the wall / perfectly orthogonal to the top of the wall?
cheers
Edited by PlywoodPascal on Thursday 24th July 20:49
For the job you describe, perfection isn't necessary.
It's actually quite easy to eyeball it to accurate enough, a long bit makes it easier to do, and there's plenty margin to adjust early in the drilling. From the sounds of it you'll need some clearance to inject resin or similar to fix the rods in place, so overall any minor variation won't matter at all.
If you insist that you absolutely must have a way, small spirit level on the drill bit to get the feel for where the drill is aimed right. 2-3 holes in and you'll probably find you stop bothering.
It's actually quite easy to eyeball it to accurate enough, a long bit makes it easier to do, and there's plenty margin to adjust early in the drilling. From the sounds of it you'll need some clearance to inject resin or similar to fix the rods in place, so overall any minor variation won't matter at all.
If you insist that you absolutely must have a way, small spirit level on the drill bit to get the feel for where the drill is aimed right. 2-3 holes in and you'll probably find you stop bothering.
Moulder said:
That's a great looking device, but is it on sale yet?You can get drills with a spirit level built in, but expensive option if you don't need a new drill.
You can also get pillar drill stands that you clamp a normal drill in to, they're intended to work with whatever you're drilling clamped in to the base but it must be possible to modify one to drill below it's base, or drill guides which are like a length of pipe with stand. You need a flat surface for these options though.
PlywoodPascal said:
I want to drill a bunch of deep-ish holes - wells, perhaps - in the top surface of a wall (to install and bond some threaded rods into them). (it's a brick-on-edge type arrangement along the top of the wall).
If you're going to glue the studding in then the holes will need to be oversize - which gives you some wiggle room when gluing. I find that I can get the left/right axis by eye, then if it's important get a helper to sight forwards/backwards. That's usually where errors are made.Simpo Two said:
PlywoodPascal said:
I want to drill a bunch of deep-ish holes - wells, perhaps - in the top surface of a wall (to install and bond some threaded rods into them). (it's a brick-on-edge type arrangement along the top of the wall).
If you're going to glue the studding in then the holes will need to be oversize - which gives you some wiggle room when gluing. I find that I can get the left/right axis by eye, then if it's important get a helper to sight forwards/backwards. That's usually where errors are made.all for 20cm long rods/holes
12mm rod, 14mm hole - 0.57º tolerance
12mm rod, 16mm hole - 1.15º
12mm rod, 18mm hole - 1.72º
Moulder said:
Bargain at £166 
PlywoodPascal said:
I did a calculation to see how much wiggle room there is for the hole to be out of plumb before the rod would hit the side, though, and it didn't seem like much...
all for 20cm long rods/holes
12mm rod, 14mm hole - 0.57º tolerance
12mm rod, 16mm hole - 1.15º
12mm rod, 18mm hole - 1.72º
Your trigonometry is impressive - but do you really need to go in 20cm?all for 20cm long rods/holes
12mm rod, 14mm hole - 0.57º tolerance
12mm rod, 16mm hole - 1.15º
12mm rod, 18mm hole - 1.72º
What happens once the studding is fixed? Presumably something goes on top. Can you take up any errors with that?
Simpo Two said:
PlywoodPascal said:
I did a calculation to see how much wiggle room there is for the hole to be out of plumb before the rod would hit the side, though, and it didn't seem like much...
all for 20cm long rods/holes
12mm rod, 14mm hole - 0.57º tolerance
12mm rod, 16mm hole - 1.15º
12mm rod, 18mm hole - 1.72º
Your trigonometry is impressive - but do you really need to go in 20cm?all for 20cm long rods/holes
12mm rod, 14mm hole - 0.57º tolerance
12mm rod, 16mm hole - 1.15º
12mm rod, 18mm hole - 1.72º
What happens once the studding is fixed? Presumably something goes on top. Can you take up any errors with that?
https://www.slattedscreenfencing.co.uk/posts-and-t...
Hmm. How about a different plan? Skip the studding and go with https://www.wickes.co.uk/Wickes-Pergola-Down-Post-...
Bluevanman said:
Moulder said:
Bargain at £166 https://ebay.us/m/xAjIR0
Moulder said:
Too expensive for casual use. Good idea though. A small try square and a long series drill bit can help. It's common practice when using hand held thread taps to ensure the axis is perpendicular.WelshRich said:
I've ordered one - I have low expectations 
Chris Type R said:
WelshRich said:
I've ordered one - I have low expectations Sorry Uyghurs but it's a really good price!
motco said:
Moulder said:
Too expensive for casual use. Good idea though. A small try square and a long series drill bit can help. It's common practice when using hand held thread taps to ensure the axis is perpendicular.Moulder said:
How do you know it's too expensive? Plywood asked for ideas, and that is an idea. Nobody said it was a for a five pound secret Santa. For all we know Plywood could be the head of Tesco's.
Just Morrisons i m afraid But I suspect the other posters comments about the cost was in the context of value for money rather than an assessment of my (relatively meagre as it turns out) spending power
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