Tips for drilling Large Holes

[Glowbug]

Yeah, I meant chassis punch, what Steerpike was talking about

I bought a Greenlee one for 3/4" holes because it's a commonly-used size in antenna mounts, but it was around $50 new. Should have looked on Ebay first, I know.

[toufu]

The hole punch idea sounds nice. What kind of tools do I need? Anyone wanna point me to a tutorial? Thanks.

[cliffforrest]

Clamp the metal plate to a 1" piece of wood before drilling.

First drill a 1mm pilot hole.

I bought a "good-enough" Chinese made drill press for <US$100 which has make all this so much easier!

[toufu]

Hey guys, will this thing work? Is this a standalone or do I need other stuff to make it work?

http://shop.vetcosurplus.com/catalog...oducts_id=1214

[Juergen Knoop]

Originally Posted by toufu

I am trying to drill large holes (1/2 inch) on smaller, light panels.

Those http://en.wikipedia.org/wiki/Counterbore will produce the best holes in aluminium sheets or panels.
Me normally uses this http://www2.westfalia.de/lexika/werk.../Stufenbohrer/ or this http://www2.westfalia.de/shops/werkz...m_16_30_mm.htm kind of drill.
Don't know the english expression.
regards

[Steerpike]

Originally Posted by toufu

The hole punch idea sounds nice. What kind of tools do I need? Anyone wanna point me to a tutorial? Thanks.

You need about a 1/4 - 1/2 inch drill bit - depending on final hole size, and a shifting spanner.
The punch comes in three parts: a sharp cutter, a cup, and the bolt.
You bolt the cutter to the cup - each on opposite sides of the sheet - with the bolt, which goes through the pilot hole you drilled.
Then you tighten the bolt until the cutter is forced into the cup, cutting a perfect hole in the sheet as it goes. When you are done, you disassemble the punch and take out a washer-like disc of metal that it has cut out.

http://za.rs-online.com/web/search/s...duct&R=0543557

These are not expensive - this one is around $12. Bigger ones obviously more expensive.

[Buckapound]

I find chassis punches at the local flea market all the time. Since they are used by electricians, they are fairly common, although small ones (1/2", etc) are somewhat rarer. I won't bore you all with what great deals I've gotten, but they're out there--so start looking.

--Buckapound

[pchw]

Look for a Harbor Freight store nearby, there are a few in BA. When on sale with coupon, the chassis puncher set cost around $15. I use them to punch holes for tube socket and ruined only one puncher so far.

[T in AZ]

Tapered Reamer, for light stuff

[Bonsai]

Originally Posted by Jaac

For large hole drilling i use a drill like this:

I sharp the edges on the spinning stone to make them sharp. It works fine. I did my XLR (26 mm ??) in 6mm of aluminum. You should use some coolant to cool the metal. Also with large drill use the lowest RPM's on you drilling machine.

And other methode is to use point-welding drills like:

But i don't know if the are there in your size. But also here is you have a drill bit that's large enough you can grind it to the point welding shape like in the picture above.

Wow. I dont think this is very safe advice for drilling metal of any kind.

I really would suggest you follow the advice further up this thread. To summarize:-

1. use a drill press and make sure your work is clamped well clamped to the drill press work surface or
2. make sure your work is well clamped if using a hand drill
3. start with a small drill diameter and work upwards with bigger drill bits to your final hole diameter
4. Use slowest drill speed - especially for aluminium
5. Use some cutting fluid - it works and makes a big difference (some 3-in -1 oil also works well)
6. Best solution: Drill press and a stepped cutter. Second best solution: hand drill and a stepped cutter.