fancy steampunk blunderbuss rifle

Step 11 Adding threads (gah)

A threading machine would solve your problem here but I didn't have one.

I had an inch of threaded tube though which a wanted to glue on.

I tried with a stick inside (lazy right?)
That broke off when attaching the tubes

I used a proper dowel...it broke.

I used a large bolt, glued it inside. It held.

(Use steel not wood.)

I had never used gorilla glue before, it holds metal, wood, steel, but it is slow and you can't get it off of your hands. so wear gloves, or you will have BLACK HANDS LIKE A DIRTY PERSON, for several days.
It stains you.