UDS chimneys?

[Kiska95]

Just ordered these http://uk.rs-online.com/web/p/malleable ... s/2434196/ will let you know how i get on!

You will need 2 check nuts as they don't have a shoulder

[Teknik]

Nah, drilled the hole .5mm too small and threaded it into the actual barrel!
Did the same with all my nipples, got them threaded into metal of the barrel itself, worked really well!

[Kiska95]

good shot mate!!! well worth knowing

[essexsmoker]

I do that make a good tight fit. I have backnuts too though.

[Teknik]

After a lot of research online i found that a 3/4" BSP threaded pipe will go into a 24.5/24.75mm hole (switching between metric and imperial i know!) so i've got a step drill that goes up to 32mm... drill in till you hit the 24mm hole then let the 26mm on graze the barrel to just smooth off the hole and give the thread a chance to purchase.
Worked perfectly on all 9 of my holes

[Kiska95]

Nice! Good advice Teknik as I have a similar step drill

[essexsmoker]

You can get cone drill bits too which are stepless.

[Teknik]

You can get cone drill bits too which are stepless.

I used a cone drill, its got steps in it so you know which one you've drilled up too

[essexsmoker]

I call those step drills and stepless ones cone drills. Same difference.

[Teknik]

Ahh, they are all on ebay as cone drills