3 Nov
2007
3 Nov
'07
5:23 p.m.
On 3 Nov 2007 at 22:18, Tony Duell wrote:
As have I. One of the problems with small twist drills
is that they screw
themselves into the workpiece when cutting, so if you don't feed them
fast enough they strech and break. Had that happn a couple of times
I find it very annoying that most companies that sell small (<2mm) taps
only sell them in sets of many sizes, and not individually. I know for a
fact I am going to break them from time to time, and I don't want to have
to replace the cet each time.
Small Parts (http://www.smallparts.com) here sells metric taps and
dies in sets of the same size down to M1.0. I suspect that the same
can be gotten from McMaster-Carr in the US and from many places in
the UK. Strangely, I've found it easier to find oddball tools in the
UK than in the USA.
Much below 2mm, my hands and eyes just aren't steady enough to trust,
even with the aid of a loupe so I can see. For larger sizes, I use a
drill press or lathe to hold the tap or die when possible on the
securely-clamped workpiece. It's just too easy to apply side forces
or have the workpiece slip with a hand wrench.
Solid carbide drills are the things that snap on me. They cut small
holes very clean and fast, but they're very brittle. I've broken
them simply by inserting them into the drill chuck. Frame saw
blades I buy by the hundred--anything less is just silly.
Cheers,
Chuck