Basic block for jersey and knit fabrics.

I have drafted the basic easy fitting block for jersey and knitted fabrics since it looks like the closest to hand-knit fabric in the amount of ease required for the standard fit sweater.

The instructions say: A block with 2 cm ease allowance for easy fitting tee shirts, tops and dresses (first bracket). Here it is:

This block is simplified as compared to the basic block for woven fabric. The front and back are the same except for the neckline; no bust darts; no shoulder darts; the armholes are the same for front and back; and the sleeve is symmetrical, so only one half of the sleeve is drafted.

In the table I summarized the measurements for sleeves and armholes:

	Close fitting block (bust measurement+10 cm/4" overall ease)	Jersey basic block (bust measurement+8 cm /3⅛" overall ease)
back armhole height	18 cm (7 ")	19.4 cm (7 ⅝")
armhole depth	11.3 cm (4 ½")	10 cm (4")
sleeve cap height	14 cm (5 ½")	11.5 cm (4 ½")
sleeve width	33.8 cm (13 ½")	37.2 cm (14 ⅝")
bicep measurement	28.4 cm (11 ⅝")	28.4 cm (11 ⅝")
sleeve ease (sleeve width measurement minus bicep  measurement)	5.4 cm (2⅛")	8.8 cm (3 ½")

Here is what we have for jersey basic easy fitting block compared to the fitted block for woven fabric:

•  the overall ease allowance is less;
• armhole is higher;
• sleeve cap is lower; 
• sleeve itself is wider in the bicep area;
• significantly more ease in the sleeve;

So, easy fitting jersey block has less overall ease, but significantly more ease for the sleeve. Let’s do some calculations. 

For the close fitting sleeve we have ease allowance that is 54% of the overall ease; for the jersey we have sleeve ease allowance  that is more than overall ease, 110% to be exact. It is huge amount of ease.  Armhole is also noticeably higher. Sleeve cap is significantly lower. If you make the sleeve cap so much lower than the armhole height, you have to do your sleeve wider to achieve the same sleeve cap perimeter as armhole has.

Then there is one more interesting difference:

Sleeve length for woven fabric block is 58.6 cm (23 ¹/₁₆").

Sleeve length for jersey block is 56.4 cm (22 ⅜").

Do we really need shorter sleeves for jersey garments?  I don’t think so. In the basic block I would expect sleeves to be the same length.

But for the sleeve to reach the same point on the arm the length of the sleeve is not the only factor – we need to consider the total distance from the center of the neck on the back, over the shoulder and down the arm. Let’s see:

·         for the woven fabric basic block we have: 7.2+13.3+58.6=79.1 cm (31 ⅛")

·         for the jersey basic block: 7.6+11.2+56.4=75.2 cm (29 ⅝")

·         the difference is 3.9 cm (1 ⅝")

This is a serious difference in the suggested length of the sleeve. Why?

I feel like I’m 5 years old. I’m asking ‘Why?’ all the time, non-stop.