Drilling a lot of 1/2" holes, best method

lockhaven · Aug 27, 2011

depending on the thickness of the material a sheet metal drill bit would be better. If you cannot clamp it securely use a reverse helix end mill it will push the work down instead of pulling it. I program CNC machines and using them is not cheap. Make a good set up on any drill press aligning the center of the 1" dimension use two pointers to get the spacing and put a bar over the top so that the work will not climb up the drill but so you can move it along. If you use a piece of the stock as a heal block then the "clamp" will be the correct height.
I am a mold builder and designer so you being a fellow TBNer if my crude description is not clear PM me and I will draw the setup for you, free of course

bearhawk · Aug 27, 2011

Paddy said:
...There are 450 holes to drill so I need to get it right....

Get about a foot long piece of 1-1/4" square tube and layout 3 holes with the right spacing.

Clamp this to your drill press aligning the center hole.

you will have to pilot the first hole on each piece, but once the first one is drilled you just slide it along and pin the tube on the hole to the right or left with a spare drill bit.

RobertBrown · Aug 27, 2011

I had to drill about 60 holes to recieve 1/2" steel pipe. The material to be drilled was 2"sch.10 black steel pipe. It was a gate. it turned out a lot better than expected......
I can tell how not to do it

. I used a 3/4"drill in a 1/2" 120 vac milwaukee. It was tough, tedious, unforgiving work as the holes had to line up and your starting on a piece of 2" pipe so all the holes had to pre drilled with pilot holes. So I effectively drilled each one twice.
Do not do it this way!

LD1 · Aug 27, 2011

I tend to agree with turnkey4099 here

You are making this more difficult than it sounds.

First thing I would do woudl be the lay-out. You dont need to wory about centering on the 1" tube yet, just lengthwise along the tube, and mark where the holes need to be.

Since you are doing 450 holes, I would assume many of the peices are going to be identical. You can mark them all at once to save time and ensure accuracy.

ONCE everything is marked, use a drillpress. If you dont have one, or know someone that does, buy one. You should be able to get a decient one for well under the machine shop quote.

Assuming the press has a vice, get it set up and centered for the first hole. This is where you worry about centering it up widthwise on the tube. Drill the hole. DONT move the vice or any of the settings. Simply unclamp the vice, slide the tube down the vice to the next mark, reclamp and drill. Everything is clamped tight and it is square (not round) tube, so I wouldnt mess with a pilot hole.

Use lube (as mentioned) to prolong too life. It's only a 1/2" hole in 1/8" tubing. Even a small homeowner drillpress should be able tp punch through in under 5 seconds. And without constant lube flow, and just a HSS bit, I'd probabally run it in the 200-300 RPM range.

But this should take no more than 1/2 a day to set up and drill ALL the holes.

And I would advise AGAINST getting the BEST bit money can buy. Because most places will interpret that as carbide. And you DONT need or WANT carbide for a job like this unless you are a well experienced machinest. carbide bits are brittle and very pricy. Only use them if you have to (hardened material). Just get a good brand HSS bit. And I am not fond of the coatings. Because once you sharpen them...coating is gone anyway. So save your money. A 1/2" good bit shouldnt be more than $8-$10 anyway.

And if you dont have a drillpress, or dont know anyone that does, or are unwilling to buy one, I guess you only have two options....the machine shop, or 3 days with a hand drill and less than optimal results and burning up a ton of bits, because hand drills spin TOOO fast IMO.