A few questions regarding drafting and construction of trousers

[DOG SALT]

Hello everyone, i have been working on some trousers, and a few questions have came up. Looking at various drafting systems, the amount added to the backs above the waist line (how far the center back seam is extended over the waist line) seems to be somewhat random, or at least there may be room for improvement on some methods. I have seen instructions to take the waist, seams and dart measure, and square from the center back to the waist line. I have also seen just a given measure for the extension such as 1" for a lower back, or 2.5" for a higher one. I have also seen some such as in the rundschau where they sweep to find the measure there. In my mind, wouldn't a proportionate measure to be added there make more sense? Such as 1/12th scale, or maybe 1/8th? I havent been able to use the rundschau since I use imperial measurements, but maybe that method is very good?
      The seat angle is something I have been thinking about. Most methods I have seen for finding this just use a proportional method. Often I have seen they rule a line from 1/2 the distance of the front fork extension (1/12 scale from the center front) to a point 1/6 scale + 1 inch or so up the center front line from the crotch line. I have read that taking a direct measure is a better method, and I was wondering how one would take that and apply it. How would this measure be applied to these points? Do we use the point 1/6 scale + 1" up, and pivot there, or pivot from the point 1/12 scale from the CF? Or do we use completely different points for this?
     Finding the knee measure is also something I have had trouble with. Ideally the knee measure would be found by ruling from the inseams and outseams to the hem, as this would give the most natural taper, right? There are a few issues with this method though. If ruling from both seams to the hem, the distance on ether side of the knee will not be the same. They will vary maybe 1/2" at most, meaning the center line wouldnt actually be in the center. So to solve this, Taking one of these measures, and then using it for both sides would work. For example, rule from the hip line to the hem, find the distance from CF at knee to outseam, then apply to the inseam knee. Does this suffice? Or maybe using the inseam is better for this method?
     One final question I have regards construction. I have looked at a few guides such as poulin, cabrera, rineheart, on constructing wasitbands. When making  a trouser with slant pockets, they all say to bring down the pocketing when sewing the waistband on, it wont be caught by the stitches, and can be layed over the pressed open waistband seam. This seems impossible to me, as with the seam of the slanted portion of the pocket, all layers are connected. You cannot just fold down the seam allowance of the slant pocket. I believe you could do this with inseam pockets, but not slant pockets. Am I missing something though? Or is the solution to this to simply not press the seam allowance open, but let both go upwards into the waistband area, as it cannot be done with these types of pockets? This is how I have seen it done with my ralph lauren pants that I took apart, but maybe that is just a cheaper, simpler way of doing things.
     I know I have written a lot here, and I thank anyone that has read this, and anyone that gives any help. Let me know If I need to clarify anything. Thanks so much!

[peterle]

I only can speak about the rundschau system:

For me it´s quite logical to sweep the center back point of the waistline when you´r supposed to create a level waistline. (besides I never got the advantages of the "scale"method in imperial systems. seems quite complicated and intransparent to me).

Wich seat angle you install on an individual pattern depends on several things: slimmer trousers, "Sitting trousers"and voluminous bubble bums need a more slanted seat, "standing trousers" , wider trousers or flat bums need a straighter seat. You get to develope a feeling for the average seat angle in your pattern system so you can adapt it for the individual. For me  the rundschau pattern provides a simple and effectiv method to influence the seat angle. I can not imagine how a seat angle could be measured directly and I never heard of it, I would be highly interested in how this works.

The knee width of a trouser is also mostly a matter of style and as you wrote yourself, it should be distributed evenly on both sides of the center line. So you ´ve to establish the foot width, the knee width and then you create the seam lines by connecting. When you aim for an evenly tapered leg, you connect the crotch line/ outseam point with the hem point . The crossing point with the knee line gives you half the knee amount you have to apply to the other sides of the centerline. Hollowing this lines in knee height for 1-1,5cm will give a more pleasant look.

Concerning the constuction question I can´t help you. Maybe the books were referring to slanted piped pockets? The slashes wouldn´t reach the waistband line and the pocketing could be folded out of the way. I also don´t see a way (or even purpose) to do this in a cut out slanted pocket.

[TTailor]

Regarding the height of the cb point above the horizontal construction line, there are many methods. I find some methods give too short a line, and the cb intersection is often not at 90 degrees which produces a dip at the cb waist. I think it becomes a matter of getting used to a draft and how it performs on the body.

Seat angle again is one of thise things that changes with the body as Peterle mentions. Most drafts have a controlling factor to developing the seat angle and you can make changes once you know what the average angle is and what it produces consistently on the body.

As for slant pockets, No, it is impossible to just plain irritating to read about that type of construction. You would have to make a slash in order to do that or only sew the facing and pocketing on up to the waistline, not into it, and even then it would be awkward at best to sew the waistband on without catching the top of the slant pocket facing and pocketing.
Sometimes those instructions ask you to open the waist seam allowance. Again, it is a technique that I have seen done, but with a slant pocket even more complicated/ not worth it.
A side seam pocket might be easier to not catch in the waistline seaming as long as you plan ahead, but complicated to separate the pocketing/facing when sewing the side seams together, so you can then sew the waistband without involving the pocket elements.

Sewing techniques evolve, fabrics evolve and needs change, so there is not one way only to sew, and the older methodologies are interesting but dont need to be followed slavishly.

[Gerry]

I'm only a neophyte when it comes to garment construction, but I've spent a lot of time learning how to cut trousers. Anyway, buyer beware (in terms of my input).

Re rise at back. As a rule of thumb, the lower the garment's waistline sits towards the hips, the more rise you need.

When learning, I went through my wardrobe and measured everything I had, then used my findings as a guide. All my off-the-peg trousers sit on my high-hip, or just above it. They all have a rise of between 2 - 2.5 inches. I like the cut of low-rise trousers, and for my needs I require a couple of inches, otherwise the top of my backside is in danger of being exposed (builder's bum).

When a waistband is around waist height (which is more traditional with tailormade stuff) then the rise isn't as critical in terms of exposure of the behind. It's more about balance between back and front. Hence the lower rise used by many tailors.

If you take a rise measurement from the small of the back to the waistline at the front, this can be used to check your draft to see if you have the correct/enough rise. After drafting, turn your tape measure on its edge and inch along each crotch curve, front and back, measuring up to the waistband in both both cases. If you used a French curve, use its measurements to determine the lengths. Add the two results together together plus two widths of the waistband (minus any seam allowance). Hopefully the two lengths tally, or at the very least the rise will be slightly higher at the back (which can then be cut down after fitting, if necessary).

I don't use a pivot method anymore for underside/back, so can't help you there.

I also don't understand your comments about the knee. You measure a quarter of your chosen knee circumference each side of the crease line of the leg, at knee level. Usually, there's no allowance on the top so everything is symmetrical. Or do you mean something else?

Have you checked out Rory Duffy's trouser making course?

https://vimeo.com/ondemand/thehtatrousermaking

[Gerry]

Dog salt, I've reread your comments about 'knee placement' and I think I understand what you're trying to say.

In most cases, if you took a straight-line taper from crotch-line to hem (trouser bottoms), you'd most likely end up with a ridiculous amount of ease/material around the top of the leg. It would look anything other than 'natural'.

Aside from unwanted, additional material, this approach would also result in a straight line to/from the fork on the inside leg. There's a bridge between the legs, and the forks are pulled a little into the centre of this bridge. Unless you have some curvature there, the trousers will be v-shaped in that gap. If someone has spindly legs in particular, and therefore a wide bridge, it will look ill-fitting.

[DOG SALT]

Gerry, yes I forgot to mention that after finding the knee measure, I would hollow the inseam 3/8" so it would have a nice curve to the knee. With my attempt at doing this, the inseam thigh region became too curved inwards. I have used a 3/8" hollow before, and it hasn't brought that region inwards too much. This was when I used a 20" knee or so. So i believe using just ruling the crotch to the hem and then hollowing may not suffice. It may always bring the crotch-knee curve inwards too much. I was using a very large cuff opening though when trying this, 21", and so maybe it was just that using such a great cuff opening would lead to that, and maybe a shallower curve should be used. I think though that a smaller knee measure may be a better solution. So maybe rule the crotch to knee, find the knee measure, and subtract 1/4" or so, then hollow? Or Maybe just rule the hip to hem, and then use that knee measure on both sides, as when I tried this, I believe it was a smaller measurement ruling the other side and using that measure. I cannot think of a good reason why one would be better than the other though. Maybe the outseam would be best for this, as it would give a long, unbroken line. In poulins book and the rundschau method I have look,ed at, they (basically) rule from crotch and hip to the hem. This means using these methods, the knee does not measure the same on both sides of CF. I will be looking at duffy's series once I get the funds. Im certain it will be really good.

Terri, for the waist I meant that with drafts I have seen they take the 1/4 waist, add allowance for seams and darts, and then square that measure from the CB to the waist line. The point of the top of the CB would be 90 degrees. This would give a large back rise, maybe 3" for my measurements. This would give a dip in the back? Using this method, the back rise would be dependent on the waist measure, which doesn't really make sense to me. If you wanted two 3/4" darts instead of one, your rear rise would be higher. This seems a little arbitrary. Most other measures on the draft are proportionate, so why shouldn't this one be? Maybe I'm reading those drafts wrong, or misunderstood what you wrote, though? With the construction, would it be safe to say that most, if not all trousers made with slant pockets do not press the waistband seam open? It seems that with all the guides I have read, they instruct to press that seam allowance open. I guess this is to say that back in the day, inseam pockets were much more common, so they just failed to mention the instructions for slant pocket waistband construction?

Peterle, the direct measure method for seat angle was mentioned by jcsprowls on the old forum. I dont think he mentioned how he does it. I looked his username up on this forum, and couldnt find it. I wonder if he is still here. So ruling to the hem, and then bringing this measure in at the knee a bit will give a better finished product? Do you mean like what poulin does in his draft? Do you know why this gives a better look? I would think that this wouldnt be as graceful, as the lines arent straight then, but I guess I am wrong?

There must be other ways of finding the seat angle. I saw that duffy uses the drop as a way to calculate. I dont have the actual details of calculation for that though. What if I have a very flat seat, and want walking trousers? I see it mentioned that the seat angle will have to be changed for this, but the amounts are never given. Or what if I have a very large seat, and want sitting or riding trousers? Most drafts fail to give a way to find the seat angle for this. Any resources would be greatly appreciated.

Thanks for the help so far!

[TTailor]

Terri, for the waist I meant that with drafts I have seen they take the 1/4 waist, add allowance for seams and darts, and then square that measure from the CB to the waist line. The point of the top of the CB would be 90 degrees. This would give a large back rise, maybe 3" for my measurements. This would give a dip in the back? Using this method, the back rise would be dependent on the waist measure, which doesn't really make sense to me. If you wanted two 3/4" darts instead of one, your rear rise would be higher. This seems a little arbitrary.

Darts are determined by how much you need, and if the pattern was for someone with a full seat then you need more darting and it makes sense that you gain in length by using your example. A full seat would also require more of a slant to the cb line so it all works together.

If you square from the back of course that gives tou the correct angle , but some draft dont square from the cb, they have an arbitrary amount above the line and then they join it to the side seam and the angle at cb is not correct as drawn. Maybe they figure you know how to make it correct?

[Gerry]

Dog Salt, with respect to the crotch-knee curve, how are you evaluating your findings? Are you making toiles and things are too tight when your line is "too curved inwards". Or is it simply that things don't look right to your eyes?

I just had a look at Poulins book and you're right, he does (initially) rule "from crotch and hip to the hem", then (crucially) measures in each side at the knee-line to create shape. That's a new one on me. Yes, I can see that you're going to get a tiny amount of asymmetry.

Ruling down from the crotch line would avoid this, however he appears to have taken the line from the seat, on the outside seam, in order to come in a little at the crotch line. I do this myself, even though I use a 1/4 seat measurement at the crotch line. I find it results in a straighter/smoother curve into the leg from the hip, which fits me better.

Frankly, I'd just rule out 1/4 of your chosen knee circumference each side of the crease at the knee line. Shape as mentioned above, by cutting into the crotchline if necessary. In reality a 'double thigh'/full-lap circumference is often a tiny bit smaller than the seat circumference, so it doesn't matter. Though it varies with stance, increasing as the legs are widened; which is why 1/4 seat is mostly used for this measurement (one size fits all). At the end of the day, it's not critical: we're talking about a tiny 'transgression' of the line and ease on the underside/back more than compensates for a slither of material 'stolen' from the top.

That aside, I wouldn't lose too much sleep over exact symmetry of the crease line. It's always going to be a bit of a fiction at some point(s) and any deviances are usually minor.

Re rise, it's often easier to draw in a 'rise line' that you've estimated. Then, using a ruler or tape measure, swing up your 1/4 waist + allowances + dart(s) measurement, like a compass, from a pivot point at/near (depending on cutting system) the topside's outer waist point. Then your rise isn't at the mercy of obscure calculations.

[posaune]

I erased the letter  - don't want to violate the law. 
sorry
Posaune

[DOG SALT]

Im doing my best to learn everything I can about drafts, and I hope asking more questions is not a bother to those in this forum.

Duffy actually put his trouser draft on his website a few days ago, and looking at his draft answers, or at least gives me some good info on the questions I had. He has an interesting way of calculating the seat angle based on the drop. I wonder where that method originated. He finds the knee by adding 1.5" to 2" to the finished hem width.

For his draft, he adds the seam allowances to the inside leg on the backpart. Does this have an advantage over evenly distributing them to both sides of the backpart, like in modern drafts? Another detail I have seen is that the center line of his draft is actually 1/24 scale towards the outseam. His front crotch line measurement (horizontal measurement at crotch line) is 2/3 scale, like in many drafts, but other drafts often use the 1/3 scale as the crease line, which is further inwards than Duffy's draft. Why would Duffy bring this line outwards, when according to many old drafts, a line further inwards will give a cleaner look? Maybe he prefers a little more comfort in his trousers? He also uses 3" of ease at hip, compared to the 2" I have seen on many before, so maybe he really prioritizes comfort? As a note, he uses 3/8" for seam allowances rather than the standard 1/4", so that may change things a small bit.

Here is a link to the drafts on Duffy's website: https://www.handcrafttailor.com/notes-for-video-series

[Gerry]

I rented Rory's video series last week and really enjoyed it. Definitely learned lots of new tricks to try.

As with many UK tailors, he uses the divisions of scale method. Which is another word for estimates. Estimates compiled (no doubt through empirical observation) in the late Victorian and Edwardian ages. That's where these methods come from: scale is a convenient yardstick to guess other measurements; and in all fairness, the body is often predictably proportioned. However, men were shorter and slimmer a hundred years ago (that much is evident from the example measurements given in arcane books). Times have moved on, so this over-reliance on divisions of scale is a puzzle to me. Especially when we can measure.

I always measure the height of seat to floor. Likewise the knee. The methods for 'calculating' (estimating) these positions can vary from book-to-book (though not so much in the case of the knee). This alone should set alarm bells ringing. None of these methods give a correct seat or knee placement in my case. The seat is always too high and the knee too low. Consequently, none of the trousers I constructed using estimates have ever worked. Lesson learned.

His knee measurement is half inside leg plus 2 inches in the direction of the crotch. You can take it the other way too, in the direction of the hem (half inside leg minus 2 inches). It's a standard calculation. One that displaces my knee by 1 inch. Not such a big deal with looser fit trousers, but with a narrow leg the taper to the knee is more prominent and any wrong positioning looks odd.  So I measure.

For knee measurement, I find it's easiest to do when seated, with the lower leg at 90 degrees to the upper. Feel the inside joint for the nobly bit (ask someone if they have joint pain before doing this on someone else!). Just above that point is the centre of the knee - you'll see that this is the case when you straighten your leg while remaining seated. Simply measure to floor from the side of the knee.

Four seams on the back leg from knee to hem is fairly common. I've seen many tailors use it; and I do too. The material works its way round to the other side, so it all works out. Take a look at this guy's cutting method:

https://www.youtube.com/watch?v=JDE5V0KLsZ4
https://www.youtube.com/watch?v=XgwOrZo9vLA

From what I understand, you get a copy of Rory's new book when you sign up to his course. I'm sure that most of the detail will be in there. I inferred from his drafting video (which wasn't explicit in this particular instance) that he uses different leg positionings depending on leg figuration/stance. And he marks the three positions. 1, 1a and 1b, the middle one being for a straight leg. But this is conjecture on my part.

I know from my own experience that with my body type (straight and angular), positioning the leg towards the fork results in a more prominent curve on the outside seam. I end up looking like I'm wearing women's pants. Conversely, positioning the leg slightly towards the side-seam straightens things out. Though I don't need to do that. Moving the waistline over towards the hip straightens things out enough for this problem to disappear (for me).

Regarding ease, I measure, which takes out all/most of the guess work. Take your normal seat measurement standing up in front of a chair. Holding the zero end of the measure firmly in one hand, to the side of the hip, gently lower yourself into the chair allowing the measure to expand as you do so. The 'free' hand keeps the measure taught enough to stop it slipping. Once seated, allow the measure to slacken slightly (don't hold it rigidly taught) and take the measurement.

It can be tricky; and you'll need to do it a few times at first to get the hang of it - to make sure your measurement is correct (best of three sort of thing). For yourself, it's advisable to do it in front of a full length mirror, to check that the measure is correctly positioned at the seat. Better still, get someone else to do it for you. With practice, it's an easy enough measurement to take.

The expanded seat measurement, minus your original seat is the bare amount of ease you need across the back of the trousers. In my case my seat is 38" and it expands to 41" when seated; so a difference of 3" in total. I would use that measurement for 'skinny fit' jeans and reinforce the CB seam. In reality, for trousers, I add another one inch for comfort. So two inches per panel (two inches on the draft). Whether this is necessary depends upon the cutting method, though (some inadvertently add the extra ease you need).

[peterle]

I just can guess the purpose to add all the SA´s to the inner underside. When you lay down the cut out top sides to start the drafting of the undersides in checkerd or striped fabrics, the matching outseam lines of top and undersides will care for a perfect pattern matching at the outseam. The result is a perfect chevron at the outseam from knee downwards.

[Gerry]

I just can guess the purpose to add all the SA´s to the inner underside. When you lay down the cut out top sides to start the drafting of the undersides in checkerd or striped fabrics, the matching outseam lines of top and undersides will care for a perfect pattern matching at the outseam. The result is a perfect chevron at the outseam from knee downwards.

That's true.

It also saves the bother of marking out seam allowance on the topside and/or on both sides of the underside.

Having said that, I do add allowance from waist to crotch on the topside and underside. Though not on the legs of the top. This tapers the seams down to the knee, bringing them forward at the knee by the amount of seam allowance used.

Commercial manufacturers typically do this (the waist is equally divided by all four panels). There's a natural bend in the knee, pushing the cap forward into the front of the trousers. If the trousers have a particularly narrow leg, the seams hang on the back of the knee. By bringing them forward slightly, it looks more natural and drapes better.

Historically, the early Victorians continued this seam tapering effect to the foot, flaring the underside legs from knee downwards in order to compensate for the narrowing of the topsides. The only explanation I found for this, was that it stopped the trousers from "flapping around". Early pantaloons were more of a narrow leg fit, so perhaps the extra weight of the backs pulled the leg into the fronts, giving better definition of the leg? Or created the illusion of this? I've never made vintage trousers, so would be interested to hear.

Neither the gentleman I linked to above, nor Rory, add any seam allowance on the topside. So the whole seam is brought forward. His explanation for this was that it makes the pockets easier to access. Though a shallower angle on the pocket does just the same, so I don't know.

What I've found, is that doing this with a larger allowance can have the effect of drawing attention to the backside, even if it's not large. Also, if the seams are too far forward (which can happen with a larger seam allowance, say half an inch) it makes the front pieces look tight, as if they're being pulled into the back.

[peterle]

I think the flaring of Victoran topsides have to do with it´s tightness: A tight hem has to be brought forward on the foot very much by ironwork, otherwise the leg would cling hardly to the shin and the back hem would swing away from the heel. Thus the leg gets a bit of an shallow S shape (or at least J shape) by ironwork. So does the seamline, it would curve forward at the hem. So to compensate and make the seamline look perfectly straight when worn, you have to flare the lower topsides. This would be especially true for trousers with foot straps (stirrup trousers?) to keep them taught.

Someone with costume history background will know better.

[TTailor]

Yes Peterle i think you are correct, but, I think it also has to do with the footwear worn. Dress boots were very popular styles, and the trousers were narrow, bur the hems were not shortened as they are worn today.