What is the difference between Carbon Steel Taps vs High Speed Steel Taps?

HSS display abrasion resistance and can withstand higher temperature without losing its hardness. 

Since heat build-up will not reduce the hardness of high-speed steel, it is ideal for continuous use.  

HSS cuts faster and last a long time.

Therefore for machining operations, Carbon Steel, is not suitable.

HSS taps will stay sharp a -lot- longer than carbon and do not break as easily.

Carbon-steel taps are soft by comparison, they dull quickly.

Note: If you are hand tapping, there is very little difference between High Speed Steel and Carbon Steel.

These days it may be easier to get high-quality HSS taps, just because industry tends to favor them for production work, but if you can get high-quality carbon steel taps  they would work  just as well for hand tapping.

The bottom line is:

HSS cost more, cut faster, stay sharper longer and last a long time.

Carbon Steel Taps cost less, great for repairing, cleaning, and hand tapping.

It all depends what you want to do with your taps.

If you are not creating new threads, why not use Carbon Steel Taps?

They are great for cleaning and repairing threads by hand.