Half inch drill bit for quarter inch drill?

In My Humble Opinion
41

This whole thing started because you want to attach a lamp to the desk, right? So you do have a clamp. It’s the thing that you were going to feed through the desk. But if you really have no way to clamp the 2x4 in place, don’t even do the test, as it might spin round and cause injury.

(That said, my brother has a portable workbench like this one from Black & Decker in his basement that he’d use for this sort of thing. So you might consider buying one if these sorts of projects occur from time to time.)

42

I have a work bench in the basement with a large clamp, but the bench is too light, and the whole thing shakes if i try to saw a piece of wood. So I never use it. It might be good enough for this.

I don’t yet have the monitor arm, and even if i did, the clamp it comes with wouldn’t be suitable for this.

I do have some little c-clamps that i mostly use when I’m gluing up wood. That’s what i might use to affix a piece of scrap wood to something solid. But what something solid…

43

@puzzlegal
Particle board is not known for strongly holding screws to support something heavy in torque situations.

Are you putting in screws to hold the arm, or bolts? Is the weight of the monitor going to be at the end of a long arm screwed into particle board?

If so, consider decorative bolts and nuts.

44

Neither. These things come with large clamps.

45

What size is your drill chuck? Is it a 1/4", or a 3/8"? Most drill chucks are 3/8" nowadays, but 1/4" was the standard for a drill for many years.

I would just use a 1/2" twist drill, but just about every one I’ve seen has a 3/8" shaft.

46

There are lots of 1/4" shaft bits around, like this one – though the titanium bit is surely overkill for the OP’s requirement:

I will say that personally, in my limited experience, I’d much prefer a twist drill bit to a spade bit. And I wouldn’t use a hole-saw type bit except for drilling a hole bigger than 1/2". A cheap 1/2" twist bit with a 1/4" shaft is likely the best bet for this application.

47

1/4"

It’s old.

48

I don’t know if you can get a 1/2" twist drill with a 1/4" shaft. Maybe a spade bit is the way to go.

49

Please don’t leave us in suspense. What are you doing?

50

Well, right now I’m waiting for the monitor arm to arrive.
So I’m in suspense, too :wink: But i decided to buy a half inch regular drill bit with a quarter inch chuck, and see if that works.

51

Just a random thought, but earlier you’d mentioned needing to drill this hole because clamping wasn’t an option. Does the part of the new monitor arm the goes through the desk have a nut and a washer that holds the arm in place? If so, have you checked that where you drill this much-anticipated hole will leave ample room for the nut and washer?

I almost did something like this once with a desk that had a horizontal stiffening board on the underside and where I’d first planned to drill my hole would have meant I’d then have to cut away a section of the board to fit the washer.

52

I was going to correct your terminology, then I remembered how the last hundred times I asked a glorified stock shelver for a specific item went.

53

It comes with two different options for attaching it to a desk. You have to attach one if them to the base. The option that involves a bolt has a large flange to attach to the bottom of the bolt, not just a “nut and washer”. (That’s why a hole as large as 2" in diameter will work.)

Yes, I’ll have to leave room for that. I asked the technical sales help a lot of questions about the clamp option, but when that wasn’t going to work, i did not ask as many questions about the specifications of the bolt option. The surface of the desk is large, and i have a lot of places i can drill. I’m sure i can find a suitable place. But I’m waiting for the monitor arm to arrive to pick a place because i want to be looking at the parts when i decide where to drill.

54

Gosh, this thread is still going, and the holes is still not drilled!

I own just about every one of the drills suggested above, and each has their own pros and cons.

A conventional twist drill of half an inch is likely the easiest idea. It is the drill that will be most useful after you buy it. Just get one with a reduced shank. When drilling it will be worthwhile pre-drilling the hole with about a 1/4 inch drill. The point on the 1/2 inch is not a point, and pre-drilling will stop it wandering. Particle board is prone to bad behaviour, and whilst pre-drilling in ordinary lumber is not needed, pre-drilling the particle board may help the drill staying on course. Not that it really matters in this use.

A conventional drill will however almost certainly split out the backside of the hole in particle board. This probably doesn’t matter but is unsightly. Drill from both sides using the pre-drilled hole will help mitigate this.

A hole-saw is another possibility, with care. A 1/2 inch hole is small for one of these. They are bad at clearing chips, and need constant removal to clear chips. However if you drill a smaller hole on the circumference of the desired hole that the hole-saw can clear chips into it works vastly better. You can start the hole with the hole-saw to just touch the surface and mark it. Then drill a say 1/4 inch hole inside and intersecting the saw marked cut, then start with the hole-saw again. The chips will be driven into the hole and fall out of the work rather than gumming everything up.

A spade bit will work, but in particle board they have a terrible habit of trying to cut a triangle once the pilot point is no longer well anchored in the wood. The particle board is likely to start to disintegrate before the hole is done. and the drill may start to go nuts. Again, drill far enough through so that the pilot just exits the other side, and then swap to drilling from the other side, and go slow.

The hole saw will usually give a good edge, as will a carefully used spade bit. A conventional bit will risk tearing the edge.

But just marking out a hole, drilling a heap of small holes with the drills you have and if you have a suitable file, cleaning it up with that, is a perfectly acceptable answer and a time honoured one at that. A technique that is hard to beat if you need anything other than a perfectly round hole.

The best drill is often the one you already own.

55

But this thread convinced me to buy the arm! I was afraid it might not work at all, or if have to do something difficult. After reading the first several posts, i plopped down a lot of money. So fine feel your comments aren’t appreciated.

56

It helps to drill a pilot hole in the particle board for the wood screw. Then fill the hole with wood glue and drive in your screw. This makes for a much stronger anchor point. (They are a bit harder to get out.)

57

No screw. I need to run a bolt through the desk, and effectively, that will be part of a large clamp, with the base of the arm above the desk and a large disk below the desk. The bolt is expected to be loose within its hole.

58

I was once tasked with securing a small safe to an office floor. The room below was an unfinished utility room, so I was able to drill a 0.75" hole centered between the floor joists and run a 3/4" bolt to the bottom of the safe, using an old 7.25" circular saw blade as the washer on the underside. Worked a treat and looked interesting from below.

59

Okay, the deed is done.

I measured carefully, drilled a pilot hole, and realized I’d made a mistake in measuring. :slight_smile: So I drilled a second pilot hole in the right place.

I had trouble with the pilot hole – particle board is harder to drill than I expected, and the first bit I tried was rather dull. I swapped it for another bit and that went fine, although I did need to drill the hole in 3 steps, as the drill bit got jammed with sawdust and I had to clear it out.

I had covered both the top and bottom of the desk with masking tape, and that’s also a little hard to drill. :slight_smile:

After I completed the correct pilot hole, I used the enormous 1/2" drill bit, starting from the bottom. I just drilled up enough that I wouldn’t make a mess when the bit came through.

Then I drilled the rest of the way from the top. The 1/2" bit froze in the hole a couple of times, and I had to pull out the bit and start over. Once I even had to “unscrew” it from the hole. I think that was from not holding the drill at exactly the same angle consistently. But anyway, I ended up with a nice clean hole, large enough for the bolt and small enough that the base on the top and the plate at the bottom covered any mess. (Including the wrong pilot hole.) And I am typing this now while looking at my browse in my new external monitor.

Thanks for all the help, everyone.

60

Picture?