On Wed, 20 Feb 2008 13:29:16 -0800 (PST),
wrote:
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I wonder what would be regarded as best all round material for a tap
and die set?
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I suggest that you consider if you need a *SET*.

Most hobby machinists have a type/size of work they tend to do
most of their work in, and there tends to be only a few thread
sizes in any given type/size of work. Thus with a set you will
wind up with a large number of taps/dies you won't use.

More helpful will be several styles of taps in the same sizes
that you use frequetly such as taper [to start] with plug to tap
to bottom of hole, and gun or chips-ahead for most through holes.
If possible, talk to some other home shop machinists that are
doing the types of work you are interested in and see what the
common threads are. Metric is becoming increasingly common.

Other useful additions are exact diameter screw machine length
[stubby] drills (for more tool part clearance and rigidity) for
both tap and body diameters and a 135 degree split point for more
accurate location (less tendency to walk). A spotting [not
center] drill will also help in accurate location. A larger
spotting drill with a 90 degree point or a chamfer tool will
break the edge of the hole for a better start and will also
insure the threads are below the surface when you need to parts
to fit flat.

A tap guide to accurately locate the tap when starting [both
location and perpendicularity] will greatly reduce your tap
breakage. At the very least make a tap block to hold tap
perpendicular to the surface for starting.

A proper tap wrench to apply only torque will also be a major
help in avoiding tap breakage.

Proper tap lubrication will also be critical.

I find that the plastic ammunition boxes that reloaders use [see
your sporting goods store or Harbor Freight] are perfect to store
the taps and screw machine length drills together for quick
selection while protecting the tools.

For home shop use I suggest any of the made in USA taps/dies on
sale, or *BRAND NAME* imports. The no-name imports are too
variable in quality. Plain HS steel [no surface treatment] for
taps, drills and dies, will be adequate for home shop use as the
speeds/usage is low.

Check the NG archives for threads on the "best" tap lube, etc.