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I would like to drill or whatever a 6mm hole through the centre of a piece of bright steel 10 inches long. Any ideas how I can do this.

turn down the shank, silver solder it into a bar or tube

Dormer do a 315mm long 6mm HSS drill bit

Part number A1256.0X315

Good luck in keeping it in the middle of the rod.

Doable if you're not too concerned about run out. If you are then find a company near you that does spark drilling. I had a 2 off 2mm x 50mm hole sparked last year for not a lot on money and in a very difficult location. Multispark was the name of that company, they are in Poole if that's anywhere near you? If not just google Spark erosion and you will find lots of companies doing it.

Or do a search for companies that do gun drilling. That's the industry term for drilling deep, straight holes through things like crank shafts and gun barrels.

somebody might even think one is manufacturing a barrel ? ;-)

I was informed that if I drilled long blind hole & then when I added a side porthole... technically I have created a muzzle loading firearm .... or a pipe!

If it has to be accurate? then the first thing is an accurate external round profile so turn the material in a lathe to achieve that..... then find its centre (4 jaw chuck & run out clock gauge) then centre & drill in a lathe using collets etc & slowly with plenty of lube/coolant.
Support to prevent run out is essential -so 25% of the length inside the chuck & a support at 25% from the other end. Also dont reset the work piece or try to drill from the other end, but increase the drill diameter or length.

For a nice smoothbore ;-) finishing via a boring bar might be better, then a sized reamer.

Its not a barrel. Thanks for your input. I have a few options to think about.

We use Hammond gun drills however not as small as 6,0mm If finish is not important then a decent long series such as a Dormer or Guhring will do the job, just take your time and peck drill.

I have an assortment of diameters to 380,0mm here if you are stuck.

Ovenpaa wrote: ↑Fri Dec 17, 2021 12:16 pm We use Hammond gun drills however not as small as 6,0mm If finish is not important then a decent long series such as a Dormer or Guhring will do the job, just take your time and peck drill.

I have an assortment of diameters to 380,0mm here if you are stuck.

I looked at Hammond gun drills but they don,t have any prices on the Web site. I am guessing it would be expensive to set up to use gun drills on the lathe. They recommend you use through coolant to flush out the chips and keep the gun drill cool.
Ovenpaa a question for you do you think you could get away with drilling a 6mm hole 150mm deep using a gun drill using hand applied coolant. In bright steel or stainless. As a first shot I will do as you suggest and try a long Guhring drill held in the tool post and not the headstock. I can afford to ruin a few to get to a suitable end result.

Alpha, how about starting with a length of 6mm stainless steel barrel - it would be simple to just drill out the rifling.........