Lesson on taps please

Aukai

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The stash I got from Dave of Greenfield taps are 3 in a box, straight 4 flute, and the 3 are not the same, so I did hunt online, and got some new to me information. Each one has a different starting profile, I'm a little confused when they start talking terminology. Is this taper, plug, and bottoming?

I haven't heard how things are going, hope all is well there.
 
Yes taper plug and bottoming taps. Old school in my book. Taper is the easiest to start with something like 5-7threads of chamfer. Plug is about medium with some thing like 3-5 threads of chamfer and bottoming is as it sounds for tapping close to bottom of a hole. 1-3 threads of chamfer.

Now a days we are very far past those old days. But they still work for hand tapping.

Had to edit out some of my typos it’s 1am here and I can’t sleep
 
Yea sometimes I forgot which forum I’m on sorry. I spend a bit of time on more professional forums that cater a bit to the money making side of what I do.

Yea for me it’s form taps or spiral flute bottoming taps typically. Of course rigid tapping on a cnc.
 
For through holes you only need the taper tap (5-7 threads on the taper)

For bottoming holes, I use the taper tap until it reaches the bottom, then run the bottom tap.

For all tapping I use heavy sulfur cutting oil and clean the taps after use. {Aluminum, steels, brass, bronze, copper.}
I can get about 1,000 holes in aluminum 6061T6 from a 4-40 tap.

I mostly start the tap in the drill chuck that drilled the hole to start it straight, the switch to hand tapping for the rest of the hole.
For delicate tapping (like 4-40) I will use the spindle in the mill to start the tap straight, using my hand to turn the spindle from the belts up top. Two (2) turns and back to hand tapping.
I power tap only 1/4-20 NC and larger (3/8 NF and larger).
 
As Mitch said, but In stainless I use all three one after the other.
My favourite taps these days are the spiral flute taps or as Americans call them "Gun" taps
 
As Mitch said, but In stainless I use all three one after the other.
My favourite taps these days are the spiral flute taps or as Americans call them "Gun" taps

Just a small correction as gun taps are not spiral flute taps. What is commonly known as a gun tap is a spiral point tap. They direct the chips down for through holes while spiral flute taps pull the chips right out of the hole for closed holes.

Editing to add a photo for more clarity

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My bad, thats exactly what I meant. I find they also help or appear to help pull the tap straight when hand tapping.
 
The nice manual tap holders have a conical divot in the (non-tap) end of them. You can push the center of your tailstock into that divot, to ensure proper alignment as you hand feed the tap in (while turning the wheel on your tail stock). This way you get exceptional alignment with a tap, where you are using your lathe as a jig to keep alignment of your tap perfectly with your hole. This also prevents the "wallowing" effect you can get when you entirely hand-start a tap. This is a great option when you want to gently hand thread with delicate taps, or with gummy metals.
 
Here are some of the sets I have

9/16”-12, 5/8”-11, 5/8”-18 and 1”-8

each set has a taper, plug and bottom taps

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