Got grist?  If not, this podcast will help you understand just what this spinning term means, how it is figured and why it's an important part of spinning a specific yarn.
This episode continues the discussion of spinning a certain type of yarn, regardless of the fiber you choose.  This time we are not going to just copy a commercial yarn, but start from nothing but the idea of spinning yarn for socks.
A very important link on the web was mentioned in the podcast and it can be found here.  It is the work of Llyn Payne, and is a listing the the characteristics such as YPP and WPI of commercial yarns using the standard numeric system available on ball bands. From this information we can find the target range of these figures to use in our calculations for creating similiar yarns.
I would like to take a moment to explain a calculation that I mention in the podcast that did not get enough explanation.  The discussion was covering how to determine the amount of fiber needed to spin a project (in our example we were saying socks)  The formula uses grist, weight length and the number 16 (oz to lbs conversion).  It looks like this:
G=(M/W)L
where G=grist  M=16 for US weight or 1000 for metric  W=weight and L=length
Normally this calculation is used to figure grist (because we have the weight and length already) If we want to find out how much fiber to buy to make a certain yards of yarn at a certain grist we can do some algebraic magic and solve for W.  I did this in the podcast without really explaining how I got the amount.  Here's the actual calculation:
If I want to spin 450 yards of 2 ply sock yarn and look up in the above chart to see that sock yarn has a range of 1675 to 2100 YPP (which is the grist and I will take an arbitrary middle of the range figure 1800) it would be solved like this:
1800=16/W(450)
16/W=1800/450
16/W=4
Multiply both sides by W
16=4W
4=W
This means W (your weight of fiber needed) is 4 oz  I very conveniently choose a number that worked out evenly, it will not always do that, and the spinner should always round up to be sure to have enough.
A big thank you to my daughter who was in college more recently than myself and so could remember how to solve algebra equations.
Music today is from Mevio a podsafe music network.  The interlude music was by Kumpania Algazarra and is called Skabicine.  The closing song is Hardly Enough by WAZ 
As always a big thank you to Clare Dowling for the spinning song.