I agree - my yarns are much more consistent when I do this - but it's just not practical at the demos I do. It's easier to just slap an empty bobbin on and spend the first few minutes training my hands to produce the same (or similar) yarns with the new ratios. NTIF was pretty much a madhouse the whole time...we weren't *swamped*, by any means, but there was pretty much always someone around asking questions. The fair? Pretty much the same, only I got many more specific questions.
When I had filled 2 bobbins, put the empty one on, and started to ply, I was innundated with such gems as: "Oh, YOU'RE not spinning - them's already spun.!" and "That's Cheating!" and the like. I don't know *how* many times I stopped to explain the whole plying thing - the whys, the hows, and the reasons I prefer working with plied yarns to working with singles. (Honestly - consistancy and balanced twist are my 2 biggies. Strength - not so much, except in yarns I'll be weaving with.)
I figure, if I have 4 bobbins with the same whorl size, I won't have to spend those few minutes retraining myself. As AA explained, I *know* the bobbins won't be identical, and won't spin *exactly* the same, but I feel that they'll be close enough. I'm hoping, anyway - while my demo-yarn from the fair isn't too inconsistent, I see lots of areas I can improve on them. I can't prove it's the bobbins...but what the hey.
Bobbins are cheaper than a whole new wheel...*eg*
It's just nerve-wracking knowing that my lovely Norwegian lady is useless right now, and knowing that the fate of my flyer rests in UPS's hands. :shudder: I over-insured it, so hopefully they'll be extra-careful.
Guess I'll be spending time with the Scottish lassie now....I've got 2 bobbins of singles to ply up, and I guess I can start on something else on her. I've got silk on the Balkan spindle.....hmmmmmmmm. I've got all weekend to think it over - Herself and I will be on retreat (and me with just a spindle (OK...*2* spindles. I left the tahkli and cotton at home) and my sock to keep me occupied during "free time".)
AA promised he'd get right on it...but I'm not going to rush him. Steph said he's got a lot of wheels to get out, and I don't want to be the reason someone else has to wait for thier piece of spinning nirvana. *g*