H-level on Taps - Help Please

[machine_punk]

Good afternoon. I'm getting ready to buy some nicer taps and need some help figuring out which "H-level" I need.

So far, I've only ever picked up the inexpensive sets from the box store and you don't have the option of deciding which class of fit you get...you just get what you get.

Here is the info I think you need to help with selection:
- planning to buy the taps from Enco:
- thinking about the set with the taper, plug and bottoming tap for the given size.
- planning to get Hertel
- they sell them in H1 to H5.
- I plan to get 8-32, 10-32, 1/4-20, 1/4-28, 3/8-16...those are the common sizes I use in my shop.
- I work in aluminum and mild steel mostly.
- I mostly seem to cut threads in through-holes, but would like to be able to tap blind holes too.

Which H-level do I want? I don't do particularly fine or details projects...just need to add a thread to mate with common hardware from the hardware store.

Is there some other style of tap I should be considering (easier, clears chips better, etc?)

Any plating or coating you particularly like on your taps?

Any other brand you particularly like?

I appreciate any input. Thanks!
Kev

 

[Strouty]

Curious as well.

 

[Ign]

The truth? It doesn't matter.

 

[Wamsutta]

H2 is the most widely used. H3 would be used for threads that are going to be plated. For most applications, H2 is the best choice because you can also use the tap for chasing threads without increasing the clearance.

 

[ss454]

http://www.cutting-tool-supply.com/TechTips/Tapping/HLimitsClass/HLimitsClass.htm

 

[machine_punk]

The truth? It doesn't matter.

While I suspect there is a lot of truth in this statement, I STILL have to pick one to order them from Enco.

H2 is the most widely used. H3 would be used for threads that are going to be plated. For most applications, H2 is the best choice because you can also use the tap for chasing threads without increasing the clearance.

Thanks...most-helpful answer so far.

http://www.cutting-tool-supply.com/TechTips/Tapping/HLimitsClass/HLimitsClass.htm

Thanks, interesting background material, which is very similar to the information in the Enco catalog, under the taps section.

It looks like "H2" is probably adequate for my needs...anybody else have preferences for style of tap (spiral, etc.) or tap coating?

I appreciate the feedback, everyone.
Kev

 

[ss454]

i prefer 3 or 4 flute taps for hand work. if you bust a spiral down in the hole its even more of a pain to get out. unless you are doing a lot of holes in tough materials **** as stainless, i don't think any of the ti coatings or such will be much of a noticeable benefit. just get regular hss taps.

 

[Finky198]

As far a taps goes a good 3-4 flute taper hss tap is the way to go. There no need for any special coatings. using tap oil is very important though as well as the proper drill bit sizes... Here is a good chart relative to tolerances.

 

[leg17]

Most general purpose in a machine shop use H-3.
Each number equals .0005 inch diameter, a half of a thousanth.
High numbers, such as H-7 to H-13 are useful for parts getting heat treated or heavily plated. Low numbers, such as L-5, are sometimes used for tight fits on threaded studs.
You will be fine with H-3.