In past I've used my Insta-Cure glue, which is a cyanoacrylate brand, and held the pieces together until it set. Which could take 10 to 15 minutes. Usually it would take several tries, as I would slip or sneeze and it would come apart. Once I tried to drill out the axel and insert a small piece of metal to adhere to but found I couldn't hold the drill steady enough to drill straight. I also lacked a press and vice to hold anything.
So last night while trying to put the below models together it clicked that I should try blue tack to hold the wheels close enough together so the glue could set.
Well it worked! I fumbled a little getting the gun carriage into place the first time but then it fell into place. The pictures below tell the story.
If you have any other suggestions I would love to hear about them.