26 replies to this topic

[tom1]

Hi, if you have got to drill body work or sheet metal, what is the best way to get a good round hole. Not one that has got an elliptical look ? hole size, say 13mm sort of size

[100ev8]

dont use a battery drill !

[sonikk4]

A brand new drill bit and high speed. 13mm is quite large so what is going into that? an ariel by chance??

[TehMarchant]

If you're drilling a large hole use smaller pilot drill holes.

[MiniGrin]

Id use a cord powered drill that has a quick spin speed, use a smaller drill bit first (slower speed so as to be more precise) and then move up to the larger drill bit. (So basics what's said above )

[sonikk4]

There is another option if you do not have a drill bit that size. Use a high speed grinder and carbide burr. Mark your hole on some masking tape, drill a small hole to start with say around 7mm then use a barrel carbide burr open the hole up.

[roughneckin]

Easiest way to do this.  Pick your spot, use a punch to make your initial starting point, drill pilot hole, drill main hole.  Drill bit won't shift after the punch so no oval hole.

 

Good luck!

[sonikk4]

Easiest way to do this.  Pick your spot, use a punch to make your initial starting point, drill pilot hole, drill main hole.  Drill bit won't shift after the punch so no oval hole.

 

Good luck!

 

You need to be really careful punching thin metal unless you can get a block behind, you may end up deforming the steel.

[Fast Ivan]

 drill.gif   57.33K   1 downloadsgrind the end of the drill so that it looks like this (or get someone to do it for you)

 

 

Or use a step drill

 

 

[roughneckin]

 

Easiest way to do this.  Pick your spot, use a punch to make your initial starting point, drill pilot hole, drill main hole.  Drill bit won't shift after the punch so no oval hole.

 

Good luck!

 

You need to be really careful punching thin metal unless you can get a block behind, you may end up deforming the steel.

 

You bet.  Nice and easy, just need a small starting point.  I find that if I don't have anything to hold the bit to where I want it, it likes to wander.

[sonikk4]

 

 

Easiest way to do this.  Pick your spot, use a punch to make your initial starting point, drill pilot hole, drill main hole.  Drill bit won't shift after the punch so no oval hole.

 

Good luck!

 

You need to be really careful punching thin metal unless you can get a block behind, you may end up deforming the steel.

 

You bet.  Nice and easy, just need a small starting point.  I find that if I don't have anything to hold the bit to where I want it, it likes to wander.

 

 

I have had to repair many a wayward punch mark on aircraft caused by the careless and uninitiated. Pain in the backside. 

[tom1]

Some nice points, this was on a piece of flat sheet steel, that was clamped to the pillar drill table and I drilled a pilot hole first, about 5mm and it still went out of round.

[Fast Ivan]

for jobs like this I have made a tool that basically sandwiches the sheet beween two blocks of steel that have been dowled together, its got various sized holes in it for all the different holes I've had to do. its easy to make and works well, unless you need to put a hole in the middle of a 1m square sheet or something big

[tom1]

I like this. just spoke to a ex sheet metal worker and he said to drill the hole under size and then use a cone cutter.

[tom1]

I like this. just spoke to a ex sheet metal worker and he said to drill the hole under size and then use a cone cutter.