Taps

[ian45662]

I have to install a 1/4-28 touch hole liner that I need to drill and tap in the barrel. Do I use just a regular tap or do I need to use something called a bottom tap if there is such a thing.

 

[LRB]

In most cases a standard taper tap is what you will need. Bottom taps have no taper and are generally used to cut threads to the bottom of a blind hole. Most vent liners require threads all the way through the hole. Be sure to use the proper recommended drill size.

 

[paulvallandigham]

Follow wick's advice on this project. Most stores don't carry " bottoming taps", altho they are available. Many machine shops buy their taps by the dozen, and when they need a bottoming tap, they grind down one of the tapered taps to do the trick. Compared to machinery down time and labor costs, taps and dies cost pennies.

 

[bob243]

A standard taper is usually fine for this, but if you use a bottoming tap be very sure you start it out straight. For a 1/4-28 use a #3 drill. There is quite a few options out there for a tap, personally I like OSG or Greenfield, but unless you plan on using it alot, the extra cost might not be worth it to you. Hertel and Cleveland are good taps as well, I mostly use their drill bits. No offense to anyone here, but I try to avoid the imports, the majority of the things I tried ended up in the junk pile after the first time I used it.

 

[Zonie]

I must agree with bob243:
My wife once bought a set of black taps and dies for a present. They were made in China and while I'm sure the Chinese made some good taps and dies, these weren't them.
They are pure junk and are doing well to tap the correct threads into a block of maple.

Buy the best taps/dies you can afford.

 

[FPDoc]

A large percentage of tap and die sets sold to the general public are only needed or used to freshen up slightly dinged existing threads.
The expense of high quality tools is small when you really need clean/accurate threads.

 

[mudd turtle]

Thank you to all you folks who answered my post on taps and dies. I am persueing this further with all of your help. Thanks again. mudd turtle.

 

[flaming canvas]

I buy the 3 tap sets. The first one may not go in far enough to tap all the way through the wall of the barrel, especially in the small calibers.

 

[Zonie]

If a person needs to shorten a taper tap into a bottoming tap they may do as paulv said and grind the taper off but, when they do this they must keep in mind that they don't want to overheat the material.
Keep a bowl of water right next to the grinder, then grind for a second and cool for two or three seconds. Then grind for a second and cool...until the tapered area is removed.
zonie

 

[paulvallandigham]

Good point to remind folks about, Jim. Many years ago, my father had a small business going in our basement, and one night we were kept from getting to sleep because he was grinding something ( a tap) off to make a neede bottoming tap, because he ran out of the ones he had, and needed one to get some machines ready to be shipped the next day. The grinding wheel was on the end of his work bench, right next to the ductwork for the furnace, with one duct coming into my bedroom 2 floors up right at the foot of my bed. You would think the grinder was right in the bedroom for all the magnification of the sound that occurred. Years later, when Dad was teaching us how to use tools, he showed us that bottoming tap he had " made ". He always kept a can of water on the bench next to the grinder, and held the piece in his own fingers so he could feel instantly when it was getting too hot! :shocked2: :nono: :thumbsup:

 

[44-henry]

I tend to buy most of my taps from Enco. You can buy either import or American made taps there. If possible try to buy carbon steel taps rather than high speed steel. Carbon steel can be broken into pieces with a punch if you break one in the barrel, the high speed steel will require more creative measures and sometimes the use of a EDM to get them out.

 

[flashpanner]

Don't forget to use cutting fluid when tapping saves the grief of that unhappy sound of "TINK".
My favorite is TapMagik, others work well too.

 

[bob243]

Tapmagik is great stuff. Rigid Dark is quite a bit cheaper and works fine for taping or general milling. A gallon will last a long time.