Conical Transitions...or any for that matter.

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Well-Known Member
Apr 8, 2004
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Ok so for those of you who have seen this post (
You know that Im making a somewhat tall three transition roc.
I started out by trying the paper method as suggested. I liked it alot as its a very good method...but man do i suck at it, when trying to smooth everything out all i do is screw everything up. I try to keep work like that to a minimum.....It doesn't give me as many chances to screw something up.
So now im looking into buying transitions either from Balsa Mac. or if i can find the right plastic ones Id even go for those.

So heres my main question.
When using conical transitions (the ones that taper off to a point) how do you make the aft tube perfect plumb to the one below it?
I have a bad time with this and often end up with a roc the looks like some sort of squiggley line. (real crappy)

OR if possible and even better yet...where can i get the right plastic transitions for this.

**NOTE: all tube are standard size. from BT-55 BT-50 BT-20 BT-5

thnx for all and any help.

If you have spare parts, dry assemble some centering rings and BT onto the smaller tube so that it now has the same OD as the larger tube. Then use the same techniques as for coupling like-sized tubes.

I've got something like this in use at the moment; wrap masking tape around the BT to keep the CRs in the right spots (one wrap on each side of the CR).
If you buy your transitions from Balsa Machining, you should only have your "squiggly line" problem is the tubes don't fit snugly enough on the shoulders of the transitions. If the tubes are indeed too loose of a fit, just do the ol' wrap of masking tape to get a good fit and everything *should* line up just fine.

Good luck!
any manufactured transition wether it is plastic or balsa should give good alignment, provided your body tubes are cut strait (I cut mine on a mitre saw)
For good alignment with paper transitions cut all smaller size body tubes long enough to put several inches into larger tubes with centering rings then put your transition over that.
I think Apogee has a good selection of plastic transitions?
Check out other vendors on Mikes link list at the coffee shop section of this forum.