[atferrari]

Yesterday I went too far: while drilling a small plate (40x40 mm) held with my left hand I failed to keep it steady on the table of my drill press. As a result, my tumb's tip was deeply cut with the consequent bleeding and pain.

(Have to admit that it happened many times before but never with this result!)

To avoid this what should I use? I mostly work with small aluminium plates 200x200 mm or smaller.

The drill press is a quite small/cheap from Black & Decker and I cannot justify buying something better / bigger.

My game is electronics and many projects in the past were postponed because of my lack of skill and the lack of good tools. Many many years of frustration, to tell the truth.

A friend, suggested a flat vise sitting on the table. My questions:

Is a common vise big enough?

Is it to be left loose on the table while drilling?

In another forum I was suggested to use C clamps but I find hard to center the piece under the bit and adjust the clamp to find that it moved in the process.

Additional question: what is the best technique to ensure precise drilling? Heard of a tool quite appropriate for marking the points but I do not know the name so I cannot google for it.

Help appreciated. Gracias.

[Geof]

To answer your last question first: You would use a 'center punch' to make a small depression at the mark where you want to drill. Here is a link showing one http://en.wikipedia.org/wiki/Punch_(tool)

To hold small pieces of sheet aluminum use a piece of plywood in the shape of a paddle. Hold the aluminum down using countersunk wood screws with the edge of the head just overlapping the aluminum to act as a clamp. This way your finger are well away from the aluminum and you have a good grip on the handle of the paddle. The drill will center itself up in a good center punch mark.

[packrat]

One of these or another brand like it is better than a piece of plywood; G8079 Quick Release Drill Press Clamp - 10"

cary

[miniz98]

There are 2 tricks that we use. 1St is when drilling something by hand dull up the tip of the drill. 2Nd put a bolt in the table when drilling the part so that the piece is resting against it. When you do this the part will want to rotate clockwise. With the bolt trapping it from rotating you will be just fine. Basically your hand was in place of the bolt. Use this method for Aluminum or softer material. Also remember to run at low rpm, (300rpm).









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[packrat]

The bolt trick works sometime. Until the drill point breaks through and the part spirals up the drill flute.

On thin sheet stock, under 1/8" to 3/16" some type of clamp or a vise is the safe way to do it.

cary

[Mcgyver]

its the most dangerous tool in the shop...as you found out. How you proceed depends on the material, how thick it is, what you're drilling (hole, counterbore etc) and the diameter. Basically you've got to assess the likelihood of something getting away and from there determine how to or if it needs clamping/vise - until you learn through experience and hopefully some reading, err on the side of caution. How thick is the 40x40? Use a vise if its thick enough....if a small hole hold in the vise and let the vise float. If its thin, sheet metal is the most dangerous to drill.....I've used brad points with success for larger sizes in sheet metal but drilling sheet always makes me nervous.

Absolutely you have to centre punch your work like Geof says and learn how to centre it with a wiggler when you the job demands clamping, either in the vise or directly on the table....with the wiggler you can align the dp's spindle perfectly with the centre punch....clamp or at least use a stop

I almost always have a large heavy piece of angle iron clamped to the table as a stop in case something gets away - my safety device. Oh and, since you say you're not metalworker, please don't let the cut thumb lead you to wear gloves - that's really dangerous!

It doesn't and shouldn't be frustrating .....the key to eliminating that is knowledge so read all you can and ask away. What part of Argentina? I was there a few years ago in BA, really liked it.

[atferrari]

I've used brad points with success for larger sizes .

Absolutely you have to centre punch your work like Geof says and learn how to centre it with a wiggler

Hola Mcgyver,

Thanks for your reply.

Could you explain the expressions in bold?

I live also in BA. The very downtown, much to my regret.

What were you doing around here? Tourism?

Gracias for your help.

[Shane1234]

Hola Mcgyver,

Thanks for your reply.

Could you explain the expressions in bold?

I live also in BA. The very downtown, much to my regret.

What were you doing around here? Tourism?

Gracias for your help.

here is a video of how a wiggler is used.....
The Machinist Wiggler How To

here is a wiggler for sale.....
General Wiggler/Center Finder Set << Machinist and Toolmaker << Online Catalog << Penn Tool Co.

here are brad points.....
Brad Point Drills

notice the little tit on the end, good for finding your center from using a punch, and then drilling without changing out tooling (can drill right when you find center).

[Mcgyver]

Shane I think nailed it on all accounts, thanks. My thoughts on brad points is that they work very well thin stuff - they actually cut out a disk, but it would not used them for 'plate' which is typically taken, Was there for um, a school trip. BA and Santiago....BA is a very beautiful city but left the solid impression you want to be of the monied group. For those who haven't been, probably most North Americans, its called the Paris of the west and with good reason, contrasting that there are also massive slums and poverty. Anyway, we had a blast, lots of warnings about street violence but we were ok, best place in the world for red wine and red meat I think....lots of Malbec and the worlds best steaks