In my limited experience, I'd say that's true with the exception of the length of the mandrel. The bushings that I got with the slimline starter kit
were only about 1/4" long, where the replacement bushings that I ordered are about 1/2". Depending on the lengths of the tubes used (thus, the length of the blanks) it could be too long for the non-adjustable mandrel.
Also, if you turn things like the mini plumb bob kits
, or the short pieces of a teacher's pen kit
, you'll have to stack a bunch of bushings together to make the non-adjustable mandrel work.
Had I known all this when I started, I'd have bought the professional pen maker's mandrel
. The length is adjustable.
Now that I've looked up all these links, the different length bushings may just be a manufacturer thing.
BTW - I had some brass bushings in my garage that had the same inner diameter as the pen making bushings, so I chucked them up tight on my mandrel and turned them down with a file to make some spares. I noticed that my slimline bushings were getting really worn already. So, you could probably buy some at a home store and make your own for a fraction of the price.