Comments on: Drilling perfectly centered holes

By: komradebob

komradebob — Mon, 01 Mar 2010 19:55:29 +0000

Also note, this trick only works if the piece being drilled is smaller than the feed depth the drill press is capable of, otherwise, you have to move the drill but/vise to get the work in the chuck and it will not return to the same location.

But it is a good alternative if you do not have a small lathe available. Even when using this method, I’d think about starting off with a center drill bit. They are cheap and very handy.

By: ktm

ktm — Mon, 01 Mar 2010 19:21:10 +0000

if you use the right feeds and speeds you dont need these little “tricks” you can drill a 3/16 inch hole through 12 inches of steel with the right feeds and speeds.

what do you do when you have a bigger, or irregular work piece?

Use a center drill first, then drill your hole. works every time.

By: The Ideanator

The Ideanator — Mon, 01 Mar 2010 03:55:40 +0000

I second that a lathe would be the best way to do something like this, but when you’re short on time, a lathe, or both, this would be the way to go. As someone who isn’t a machinist by trade or any standard for that matter, this is a hack.

By: lulz

lulz — Sun, 28 Feb 2010 12:20:44 +0000

Not a bad trick if ever you were considering making sound supressors/silencers for weapons. They need precision drilling. Lathe is a better alternative though.

By: Whatnot

Whatnot — Sat, 27 Feb 2010 19:40:58 +0000

Jesus what’s with those twats who go “Oh everybody that has years of experience or read one specific book knows this, this is boring”
Guess what’s REALLY boring? You idiots and your pratty comments, you types have been ‘helping’ for thousands of years too, and it’s enough already thanks.
And they forbid parents smacking kids…

By: medix

medix — Sat, 27 Feb 2010 15:29:29 +0000

For anyone who’s interested in other oddities of machining, check out the ‘Watts Drill’ – this is an age-old hack all to its own for drilling square holes. ;)

http://upper.us.edu/faculty/smith/reuleaux.htm

http://en.wikipedia.org/wiki/Reuleaux_triangle

By: Robert

Robert — Sat, 27 Feb 2010 08:35:25 +0000

I work for a company that makes office screens http://www.ecomfg.com/
And have spent some time working in all the departments of the factory (including metalwork). The way I’ve always done centred drill holes is to take the piece of metal (in my case it was with flat bar 25mm/2mm) and measure halfway across the flat bar (12.5mm) and ‘centre punch’ (I don’t know if that’s the real name but that’s what we called it in the factory) and punch a start dent on the metal then we would use a premade jig and clamp it all together in a vice. Once in the vice we place under a pillar drill and drill the hole! It sounds quite long winded but it worked every time!

By: cath0de

cath0de — Sat, 27 Feb 2010 08:14:59 +0000

good post and even better comments. thanks hAd and thanks guys.

By: medix

medix — Sat, 27 Feb 2010 03:35:50 +0000

Correction: I do know what they look like. ;)

http://en.wikipedia.org/wiki/Gun_drill

By: medix

medix — Sat, 27 Feb 2010 03:33:55 +0000

@smellsofbikes: This is what ‘gun drills’ are for. Never really seen what the actually look like, but from what I gather there is only one flute and the end of the bit is nearly flat.

By: smellsofbikes

smellsofbikes — Sat, 27 Feb 2010 02:55:16 +0000

By the way, in case anyone reading this needs to drill deep holes, by which I mean more than 10x as deep as they are wide, here are a couple of suggestions. Rotate the work, not the drill, as we’ve already said. Amazon.com will sell you really long thin drills, like 1/8″ drills 12 inches long, but I’ve found they don’t really work well because the flutes make the drill squirm and cut poorly. Use aircraft drills, that have long unfluted shanks with only a short fluted section at the very end. Peck: drill in maybe twice the diameter of the drill, then pull it all the way out to empty the chips. And if you can manage it, double-drill using one drill about 1/8″ or so smaller than the final size, and the second drill the final size, drilling an inch in with the smaller drill then following up with the larger, alternating as you drill through. (Similar to cutting a long thin rod on a lathe.)

By: therian

therian — Sat, 27 Feb 2010 02:13:44 +0000

“If you’ve ever been caught in the situation of needing to drill a clean straight hole down the center of a bolt”
Yep, when making home made gun :)

By: smellsofbikes

smellsofbikes — Sat, 27 Feb 2010 02:00:53 +0000

Spinning the work instead of the tool is a great technique for a lot of projects. It’s how people drill gun barrels, for instance, since the drill is self-centering when used this way so it’ll run right down the middle of the stock. It is also a good technique if you need to put a centered point on the end of a rod: chuck it in the drill and spin it against a bench grinder. You’ll get a nice sharp well-centered point. Ditto putting a centered cup on a nailset, if you have a small-diameter grinding wheel on your Dremel.
This is the reason lathes are the most versatile tool.

By: IM

IM — Fri, 26 Feb 2010 22:55:57 +0000

Drills don’t drill round holes btw. For small parts make a fixture to hold them in the vice (soft jaws, collet etc.) and center drill, drill then ream.

By: blizzarddemon

blizzarddemon — Fri, 26 Feb 2010 22:26:08 +0000

On the physics comment, while true the chuck has its place, it becomes much more center because it is the object instead of the bit in the drill. The centripetal motion forces any objects to it’s center. This phenomena can be broken, but it’s something a craftsman (relative to this case; a person with a lathe or a ceramicist using a wheel) takes into consideration while working.

Centering the chuck can be done wrong as well, but its more obvious then if the position of the bit lodged between the clamp was off.