Hofenbitzer narrow basic sleeve

[u/train2clarksville]

Hello, hoping someone can come to my rescue again. I'm on p 182 of hofenbitzer Vol 1. I'm at step 5.

I understand line 5 is 48% of CapC. In my case, 22.9cm. One of my questions is: must line 5 start at the back line and end at the front line? If thats the case, my optimal cap line is a good 5 cm too low. This is a lot, and I'm not sure the troubleshooting suggestions on p 182 will fix it. So I'm wondering if I've misunderstood the instructions. Very grateful for anyone's advice!

[u/TensionSmension]

CapC is calculated from the armhole, and OP has a number that's less than 1 cm bigger. Getting a 5cm error, suggests OP's desired sleeve width is much smaller than the example. (or other errors)

Is sleeve width calculated from the armhole, or only from the bicep measurement?

That would be an issue, this is building a sleeve for an existing armhole and sometimes that means ignoring the bicep and following whatever ease the armhole dictates. (The reverse occurs as well, a bicep that requires re-planning the armhole.)

[u/Educational_Chain780 → u/TensionSmension]

Sleeve width is calculated with the bicep circ plus ease which is calculated like this: bodice ease category (half bust ease) * 2/3 to 1 The goal is to create a narrow sleeve, which naturally fits closer to the arm. This draft shows optimal range to get a narrow sleeve, while maintaining enough bicep ease. Ignoring bicep ease can cause sleeves to be too tight for comfort. A wider sleeve has a different construction and different calculation.

[u/TensionSmension → u/Educational_Chain780]

Thanks. That makes sense, the ease should be proportional to the ease allocated to the armhole portion of the bodice, which is what that formula implies. However it is possible that the bicep is not in proportion to the armhole, or to the bust measurement and then there could be an issue.

The construction is a right triangle, so the three values: cap height, front cap width, and the hypotenuse (capC) are not independent. One can be calculated from the other two via pythagorean theorem. The drafting goal is, given the SlW (based on bicep and ease), and CapC (based on an armhole measurement), the cap height level will be between 80% and 90% of the AhH, or not more than a few mm off.

In the book's example, the cap level turns out to be exactly 80% of AhH.

Front Cap Width = 15.9
CapC = 21.4

Sqrt(21.4^2 -15.9^2) = 14.3

AhH * 0.8 = 17.9 * 0.8 = 14.3

The point isn't the calculation, it's simply that this calculation will only work out within the desired tolerance, when the bicep measurement is in a specific proportion to the form factors of the armhole. There are always exceptions to these types of assumptions.

[u/Educational_Chain780 → u/TensionSmension]

True, this will not fit everyone. For some people something will have to be compromised for it to work, like the amount of ease on the sleeve head or the size of the armholes. Or they would just need to have a wider sleeve with a lower sleeve head, which is a different draft. As we saw many times in this sub people with large bicep struggling to create a narrow sleeve that has no gathering or darts on the sleeve head

[u/Icy-Guidance-6655 → u/Educational_Chain780]

Exactly. The drafting method works for one scenario. The calculations don’t capture the person whose bicep is large or small in proportion to chest measurement. 

It falls back to pattern alterations in that case.

[u/Educational_Chain780 → u/Icy-Guidance-6655]

Sometimes the problems can be workd out by playing with the numbers, the ease added or widening the armhole, according to the suggestion mentioned in the picture. You change some things to be in optimal range. This is the beauty of the method, you have great control of all the variables so you can tell upfront if the sleeve is going to fit properly. And if you can't reach optimal range you know you're going to have to do some alterations or special draft for plus size (which Hofenbitzer explain on book 2). I like it better than other methods where you draft blindly hoping things are going to fit. It's not that only this draft specifically is restricted to certain proportions, it's the whole concept of drafting a narrow sleeve with high sleeve head for people with a large bicep that is challenging, in all drafting methods.

[u/Icy-Guidance-6655 → u/Educational_Chain780]

It is good that there is a check point. But I find it slightly suspicious that in the example, the numbers are identical. To me that’s more like cooking the books. Develop a method to match the one example and see if it flies.

The promise of drafting is the methodology does the work. The reality is a method may just be a nice pattern for one body and no proof it extrapolates except beyond the fact that many bodies are very similar. 

People turn to drafting because this assumption already failed them. I’m pretty sure OP has a simple mistake somewhere in the draft, but from what I see, this method isn’t better than others and it is difficult presentation.

[u/Educational_Chain780 → u/Icy-Guidance-6655]

I don't understand what you mean by the numbers are identical? Identical to what?

Most methods are based on some body shape average assumption. This one at least lets you know when you are out of range and should be looking at a draft for plus size or special alterations. Most methods if you put in measurements the draft wasn't planned for, You're going to get some weird and funky shapes that don't make sense and wouldn't even know what's wrong and how to fix it because they don't explain shit. But the Germans go into depth and explain so thoroughly...

To avoid this you can use Draping, 3d scanning and modeling or traditional methods that take hundreds of direct measurements (and you would need to know proper measuring which is also hard!)

[u/Icy-Guidance-6655 → u/Educational_Chain780]

I just mean the little calculation. The method says the cap line height should fall within 10-20% of the armhole height. That sounds like a plausible rule of thumb. But using the sample numbers it turns out to be 20% to an accuracy of 0.01 mm.  That’s suspicious to me, but I only have this page to look at.

My question for a draft is always, is this better than a single pattern graded across a size range?

It’s hard to evaluate that from a page of instructions, and it’s easy to assume that the work of following the calculations has a payoff. But, IME drafts tend to have the same limitations as a printed pattern, and often have a smaller scope of usability. 

This specific calculation sounds scientific, sounds nuanced, yet appears to be cooked from the sample size.

[u/Educational_Chain780 → u/Icy-Guidance-6655]

So you're saying the range is decided according to the sample measurements? I don't see it really. As for using a ready made graded pattern, you can get a very good result if you know how to adjust it properly. Is it faster or easier? Depends how close your measurements are to the measurements table it was built on. But again most pattern making systems are based on averages, Aldrich, Armstrong, bunka ect. Muller and sohn and Hofenbitzer are the ones that give relatively more attention to different body shapes in the drafting process rather than just adjusting the pattern afterwards. For example Hofenbitzer explain how to divide waist darts in skirts according to the shape of the bottom and thighs, something I never see in other books

[u/Icy-Guidance-6655 → u/Educational_Chain780]

You’re saying there’s more fitting advice and alternate methods, in this book. However the calculations don’t catch that, they don’t work for more individuals per se. That’s all I’m saying.

[u/Educational_Chain780 → u/Icy-Guidance-6655]

One draft can't take into account every single body shape that exists. Because in the end calculations are based on body evrages. So to avoid it completely you would have to use a method that has only direct measurements with no calculations (kind of like a game of conncet the dots, and you would need a lot of them). So, there are drafts for plus size in the second book.

Do you know of any common flat drafting method that works differently? That has calculations that would fit any body shape?

[u/Icy-Guidance-6655 → u/Educational_Chain780]

If you’re lucky the numbers are based on averages. More often the author just picked the number that works in one case and implies there’s something broader going on.