Yeah, I've done my share over the years with no ill affects. You can use a wrap around or make one. This will give you an accurate square line to cut the tube....But I use a plumber/fitter pipe cutter to get a square accurate cut. You will have to file out the inside burr (careful it's sharp) so that the casting can slide back in. These things are "close" to being self centering. I use 2 long staight rods to eye ball the indexing between the front yoke and the rear U joint. It's worked for me. I wouldn't try to talk someone, who is nervous about it, into trying it but what is the worst that can happen (if you are a competent welder)???...You'll get a vibration. Really! That's it. If you screw it up, you'll get a vibration. It's not going to explode sending you off the road into that mini-van full of kids. If it vibrates take it out and see if it can be balanced. If it can't, find out what you did wrong. None of mine have had any vibrations and performed well for as long as I had the car. I sent the last one out due to time constraints. Shortened and balanced...100 bucks wholesale. Just don't ask me to take an automatic trans apart! 40 years ago a buddy of mine swapped a SBF into a 6cyl Comet one weekend. Sunday night he discovers the U joints don't interchange. He slid the 6cyl rear shaft inside the V8 front shaft, adjusted the length and then brazed the two together. Yes brazed. It got him to work and back on Monday until he could get it done right. Yes we called him an idiot.