Do you think the manufacturers can claim friction welded hex shank drill bits are one piece construction?!

[Altan]

Normally 1/4" E6.3 hex shank drill bits are made of one piece steel if the diameter is more than 7.1mm approximately. They just machine the round shank to hex shank. But when the diameter is smaller than that they follow different way of making it. Some American (USA made) bits are plugged in a special way, I have seen old stock Irwin bits using that style and also Insty bit, they are both made in USA, Also Milwaukee bits which are not USA made having the same style. Here you can see the Insty Bit one 

[Altan]

Here is the Irwin USA made drill bits

[Altan]

And here is the Milwaukee one, in all above you can see a round neck between the hex shank the body of the drill bit, kind of plugged drill bits, but this is not the only version of plugged drill bits. It seems that neck is to squeeze the drill bit into the hex shank, but Austrian brand Alpen makes plugged hex shank drill bits which do not have that neck.

[Altan]

Here is a photo of Alpen drill bits, It looks it is size 6mm and the same style is used for size 2mm as well. 

[Altan]

Some brands like Bosch and Makita have similar plugged drill bits into the hex shank plus a pin in the hex shank. 

[Altan]

Here you can see where the pin is.

[Altan]

You can see the same pin in Makita drill bits as well. 

[Altan]

Here is a photo of Bosch Multi Construction hex shank drill bits. You can see some lines on the neck of some (the ones with smaller dia) of them, that means most probably they have been friction welded to each other (the round bit and the hex shank) and imperfections have been machined, I have seen some other drill bits made the same way with better quality friction welding and not machined at all and you can see the neck is not even symmetric. There are a few brands using this style. My question is, should we accept these drill bits as one piece construction?! Or is it legal by definition to claim these bits are made of one piece of steel?! I will make a video on YouTube explaining it in depth.

[Altan]

It seems some DeWALT, Famag (German made) and Irwin drill bits are made this way as well. 

[Altan]

It seems another way of making hex shank drill bits is to produce plain hex shanks with a hole in and with a specific (unknown for me) type of welding (melting) weld the drill bit into it. If you look at this photo carefully you will notice a circle on the neck bigger than the diameter of the drill bit (5/64") and smaller than the diameter of the hex shank. This is a hex shank Irwin drill bit.

[Altan]

Here is a photo of a hex shank drill and tap from Champion Cutting Tools 

[Altan]

Alpen makes their hex shank Multi Purpose drill bits as forged one piece construction even with smaller size. Recently I saw their brad point drill bits to have a forged hex shank also.