Lesson 2—Making the Boys Pajama Pants


Welcome back to the Christmas Morning Serge-Along, featuring the BERNINA L 850! Be sure to enter our giveaway for a chance to win The Big Book of Serging and a Gold-Plated Presser Foot #1 from BERNINA. During this five-week serge-along, we’ll be making adorable Christmas Morning Pajamas in sizes 3–8. The lessons will present the free downloadable patterns and instructions in easy-to-digest sections. New lessons will be released each Tuesday. You can also order (optional) special-priced kits with premium fabrics and trims in two size options, and two different colorways, for boys or girls.

Previous lessons are available here: Lesson 1

Downloadable PDFs for Lesson 2:

On our BERNINA L 850, we love using the knee-lift to raise and lower the presser foot as needed throughout the construction process. This serger always stops with the needles up, which is a great feature. Sometimes the fabric needs to be adjusted under the presser foot, therefore the needles need to be in the fabric to hold it in place while the adjustment is being made – with a heel-tap of the foot control, the needles sink into the fabric. Another great feature of our BERNINA L 850 is that our most-used tools are stored in their own slots in the threader cover of the serger. The whole time we were making our garments, we never lost a tool! We love features that help to keep us organized!


• The additional serger foot required for this project is the piping foot. There are other feet that are useful but not required.

• There are notions that you REALLY NEED, like a glue pen and Wonder Tape and others that will be extremely helpful.

• You know where the following part and markings are on your serger: stitch finger, the knife and the markings on the toe of the all-purpose foot.

• How to serge off before you reach the end of the fabric.

• What serger tails are and why you DO NOT cut them off against the fabric edge.

• You must know your seam allowances and what to use a guide for the fabric edge.

You Have:

• Cut out the boy’s pants and shirt, including the facing strips and bias strips to the lengths required. The bias strips are labeled as to where they go in the garments.

• Fused interfacing to one collar piece and to both 2″ facing strips.

• Set your serger for 4-thread overlock. The settings will be given in the construction directions.


We need to talk about a few more things before we get started with the pants construction. Serging tips and learning different techniques will make your serger sewing more successful. We would suggest that you try each of the tips and techniques. Decide which ones you like the best and are useful to you and add those to your serging repertoire.

Tips and Techniques for WEEK 2

• Using pins, glue and clips to hold pieces together while serging.

• Using glue or Wonder Tape to hold seam allowances in place to keep them from flipping in the wrong directions when serging across them.

• Using Wonder Tape to match seams.

• What to do with the serger tails.

• How to take out a misplaced seam.

• Creating piping.

• Removing bulk from a piped seam.

• Tips on serging an inside curve.

• How to serge a circle.


Using Water-Soluble Fabric Glue

Fabric glue holds the pieces together without using pins. The Sewline glue pen, our favorite, is a refillable glue stick, made for fabric. The glue is colored but dries clear and is totally gone after the first washing. We use this glue ALL of the time, since it temporarily holds things together under the serger foot until the seam is serged to make it permanent. When gluing pieces together for a seam, place the glue within the seam allowance (photo 1), align the edges and stick the pieces together. Let dry for several seconds. Serge. This method is very helpful when matching plaids (photo 2). We also glue the seam allowances down to the fabric to hold the seam allowance in a specific direction before a second seam is serged. For example, if you want the shoulder seams in a shirt to lie toward the back—glue them to back. When the neck is serged, the seam allowances will remain toward the back, since they have been glued (photos 3 & 4).

TIP: If you are gluing serger-made piping to another piece, place the glue along the serged seam. The threads of the seam create a raised surface making the glue application very easy.

• Using Straight Pins

Glass-head pins are one of our favorite types of pins. They are fine and have glass heads so they can be ironed on and heads will not melt. These are used in heirloom sewing and all types of sewing and serging. We have two different pinning methods that we prefer. These methods are used because the pins are easily seen and do not get buried or hidden in the fabric. A buried pin that you cannot see and do not remove before it hits the knife can wreak havoc on your knife. Pins can certainly be used to hold pieces together when serging but you must be careful to pull the pins out before they get close to the knife.

Method 1 – Place the pins into the fabrics perpendicular to the edge of the fabric with the heads of the pins in the air, not against the fabric. The pins are clearly seen to be pulled out before they get close to the knife (photo 1).

Method 2 – Pins can also be placed along the seamline with the points of the pins toward the serger and the heads of the pins toward you. The pins can easily be pulled out of the fabric as the point of the pin gets close to the front of the foot (photo 2).

• Quilt Clips

Quilt clips are great to use with your serger. They have a rounded side and a flat side. The clips hold fabric layers together with a firm grip and should be used with the flat side on the bottom (photo 1).


Wonder Tape is a paper-backed, wash-away, double-sided, sticky tape that is 1/4″ wide. This tape will stick two fabric ends together that need to match, like the end of a sleeve or hem edge. It can also be used to match intersecting seams, like at the underarm/sleeve seam in a shirt or in pants where the center front and center back come together in the crotch area. Typically, for joining seams, you would tear a 2″ piece of tape from the roll. Tearing the tape from the roll makes it easier to remove the paper after the tape is applied to one side of the fabric. Place the tape on the right side of one of the fabrics, aligned with the fabric edge and centered over the seam or as shown in the photo, centered over the piping (photo 1). Remove the paper and stick the right side of the other piece in place, matching the seams or trim and the edges (photo 2). Look at the seams from the right side (photo 3). Do the seams match? If not, separate and try again, matching and sticking the seams together again. Once seams match perfectly, you are ready to serge (photo 4).


1. After serging a seam in the interior of the garment, you might want to cut off the serger tail close to the fabric at the beginning and end of the seam to neaten, BUT DON’T! Always leave 3/8″ to 1/2″ or longer serger tail extending from the seam on each end (photo 1a). If you cut the serger tails against the edge of the fabric, the serger stitch will start to unravel and the seam will open (photo 1b, top of seam-serger tail cut too close to fabric). The tails help to keep the seams together at the ends (photo 1b, bottom of seam). When this seam is crossed with another seam the tail will be removed by the knife of the serger (photo 1c).

2. If one end of the serged seam is not going to be crossed with another seam, like at the end of pants leg or the end of the sleeves, those tails need to be “tied-off.” Tying off a serger tail can be accomplished using several methods. Methods 1 and 2 are our favorites since we try not to use a seam sealant unless absolutely necessary.

Method 1: Straighten the loops in the tail by sliding the tail between your fingers, beginning at the fabric edge and sliding to the end of the tail. Repeat several times. Fold the tail to the inside, against the stitches of the seam. Using the sewing machine and a straight stitch (L=1.5), take one stitch on the serger seam allowance and swing the tail in front of the needle and take another stitch, swing the tail in front of the needle. Repeat, weaving the tail back and forth as you stitch. Trim the excess serger tail and machine thread close to the machine stitching (photo 2, left seam). You can also stitch the serger tail to the serger seam allowance using a tiny zigzag.

Method 2: Leave the serger tail 4″- 6″ long. Thread the end of the tail into a tapestry needle or large eyed blunt-tipped needle (photo 2, right seam). Weave tail into the seam allowance (photo 3, right seam). Trim off the excess tail (photo 4). TIP: If the tail is too short, insert the eye end of the needle under the stitches in a weaving pattern starting about 1″ from the end of the seam so that the needle’s eye extends out the end of the seam, close to the short serger tail. Thread the tail into the needle’s eye and pull the needle back through the seam, weaving the tail through the seam.

Method 3: You can also tie a knot in the serger tail close to fabric. Dot the end of the seam/knot with a seam sealant within the seam allowance and let it dry. Once dry, trim the thread tail close to the knot.


The easiest way to take out an overlock seam is to remove the needle thread (3-thread overlock) or threads (4-thread overlock) from the seam. Once the needle thread(s) are removed, the seam falls apart. Using a 4-thread overlock as the example (photo 1a) and looking at the right side of the serger stitch, the two threads interlocked at the upper edge are the upper looper and the left needle. The looper thread is the more curved, outermost thread. The left needle thread is the straighter thread that sits on top of the upper looper thread. If you only clipped and remove the left needle thread (figs 1b & 1c), the loops would catch on the right needle thread, so the right needle thread must be removed as well in order for the stitch to be removed. The right needle thread is the easiest to spot since it is the straight thread in the middle of the stitch. Clipping the needle threads in several places and removing those threads will remove the stitch (photo 1d).

When you look at a serger tail, you will see two threads that are very loopy and two threads that are straight. The two straight threads are the needle threads and the loopy threads are the looper threads. Using a straight pin, pick out the two straight needle threads from the serger tail close the fabric (photo 2). Once the needle threads are pulled from the serger tail, all four threads separate. There will be two needle threads (the shorter ones) and two longer threads (the looper threads) (photo 3). Pull the needle threads (the shorter ones). The seam will gather (photo 4). The needle threads will break, or they can be clipped every 6 or 7 inches along the seam on the right side. Continue to pull these threads to remove. Once the needle threads are pulled from the stitch, the stitch will fall apart (photo 5). This seam removal method keeps all the threads in long pieces, which is much cleaner than using a seam ripper along the back or front of the seam, which creates LOTS of tiny threads. But seam rippers certainly work in removing the seam too.

When re-serging the seam correctly, either use the clean finish technique for replacing the seam, bumping the edge of the fabric against the knife OR turn the knife off so that no additional fabric is cut when it is re-serged.


1. Serger Settings

4-thread overlock



Foot: Piping

2. Cut the piping cord 2″ longer than the bias strip.

3. Raise the presser foot and place the cord under the foot and into the groove. Lower the presser foot (photo 1).

4. Center the bias strip under the cord (photo 2).

5. Fold the bias strip in half with the cord in the fold and the cut edges to the right (see photo 3).

6. Slide the fabric under the toe of the foot and start to serge. Once the fabric is caught under the needle it will be easier to adjust the fabric or cord. Continue to serge, adjusting fabric or cord as needed. Make sure the fold of the fabric remains taut against the cord and the cord remains in the groove of the foot (photo 3).

7. If you are making several pieces of piping, which is the case with the boy’s pants and shirt, have all of your bias strips cut to piping lengths required. Using one long piece of piping cord, start the first piece as described. Once the end of the first strip goes under the toe of the foot, place the second strip under the cord. Serge the second strip and once the end of the second strip goes under the toe of the foot, add the third strip in the same manner. Continue until all piping strips are made. Cut strips apart. Measure the piping strips and label each piece indicating where they go in the garment.


The seam can be a bit bulky in areas where a piped collar is sewn to a neckline or when the ends of a piped cuff are sewn together having two pieces of piping meeting in the seam. Eliminating the bulk of the cord in a seam is optional. Some sewists prefer to leave the cord in place, others prefer to remove the cord from the seam allowance. Use the following method to remove the cord from the piping in the seams allowance.

1. Place a pin through the cord/piping in the center of the piped area or several inches from the cut edge of the piping. This pin is important as it will hold the cord (photo 1).

2. For a 1/4″ seam, pull 1/2″ of the cord out of the piping (see photo 1). You can use the your serger tweezers, if necessary. On our BERNINA L 850, the tweezers are inside the front door… love that! Cut away a scant more than the given seam allowance from the end of the cord, in this case about 5/16″.

3. Slide piping fabric toward the cut ends. The newly cut cord end will disappear into the fabric tube, leaving a bit more than 1/4″ of the piping without cord (photo 2).

4. Repeat steps 2 and 3 to remove the cord form the other end of the piped piece.

5. Remove the center pin.


• To serge an inside curve (photos 1 & 2) you must manipulate the curve of the fabric into a straight edge (see photo 4). The tighter the curve, the harder that is to do.

• Don’t try to straighten the whole curve in one step. Straighten the fabric about 1″ or so in front of the foot, serge, straighten another inch or so, serge. Continue in this manner until the entire curve is serged.

• The seam allowances for this pattern are 1/4″. You can place tiny, 1/16″ to 1/8″ long, perpendicular clips along the edge of the curve (photo 3). The tiny clips will allow the curved edge to straighten more easily (photo 4). If your seam allowance was 5/8″, the clips could be 1/2″ long, perpendicular to the curved edge. The clips can never be longer than your seam allowance. The end of the clip should end no less than 1/8″ from the seam allowance.


There are several methods to serge a circle. Here is one of our favorites.

Note: If your serger has a freearm this is a great place to use it. With our BERNINA L 850, remove the slide-on table to use the freearm (photo 1).

1. Raise the needles and the presser foot, slide the fabric under the foot with the edge of the fabric against the knife, as you would for a clean finished edge (photo 2).

2. Lower the foot and start to serge, keeping the edge of the fabric against the knife to clean finish the edge. Continue to serge, stopping when the beginning serger tail is about 1″ in front of the foot. Stop and pull the beginning serger tail to the right, perpendicular to the beginning stitches (photo 3). Serge slowly and as soon as the knife cuts off the beginning tail (photo 4), stop.

3. Turn the knife off. On our BERNINA L 850, the switch is easily found on the lower left side of the serger (photos 5a & 5b).

4. Serge, overlapping the beginning stitches about 1/2″ to 1″ without fear of cutting into any previous stitches since the knife is no longer working (refer to photo 7).

5. Raise the foot. Pivot the fabric away from the needles (photo 6). Lower the foot and serge off (photo 7).


• If you are just beginning to use your serger, you are welcome to use the sewing machine to baste seams in place before serging the seam. Once you build your confidence, you will omit the basting step and just serge the seam.

• Before seams are serged, match the plaids by pining or gluing within the seam allowance.

• Use glue or Wonder Tape to adhere seams allowances in the correct direction. This will keep the feed teeth from pushing the seam allowances in the opposite direction.

• Use glue or Wonder Tape to match crossing seams so that they match perfectly.

• Read through all directions before starting for a more successful serging experience.

I. Main Construction

1. Set the serger as follows:

4-thread overlock

Stitch length = 2.5-3.0

Blade cutting width = 6 (default setting)

Foot: All Purpose

2. Press the waistline casing to the wrong side 1-3/8″ on each pants piece (fig. 1a). Unfold (fig. 1b). It’s easier to press the fold for the waistline casing before the center fronts and center backs are serged together.

3. Place pants right sides together aligning the edges.

4. There are two methods to serge center front, center back and waist of pants. Read through both methods and choose your favorite.

Method 1 – Clean Finish the Waist

a. Pin or quilt clip the center fronts together.

b. Refer to Tips for Serging an Inside Curve and serge the center fronts together (fig. 2), matching the plaids if you can.

c. Separate the front from the back and clean finish the top of the pants (fig. 3).

d. Pin or quilt clip the center backs together.

e. Refer to Tips for Serging an Inside Curve. Glue the serged seams together at the waist within the seam allowance since you want these seams to match. Serge the center backs together (fig. 4), matching the plaids if you can.

f. Hold the center front and center back seams together at the top edge. Glue the center back seam allowance to the pants in the opposite direction from the center front seam allowance. Glue for about 3″ through the casing area (fig. 5). Gluing the seam down to the fabric will help the elastic run through the casing more easily since it will not get stuck on the seam allowance.

Method 2 – Circular Waist

a. Pin or quilt clip the center fronts together and the center back together.

b. Refer to Tips for Serging an Inside Curve and serge the center fronts together (see fig. 2), matching the plaids if you can. Repeat for the center back (fig. 6).

c. Hold the center front and center back seams together at the top edge. Glue each seam allowance to the pants in opposite directions. Glue for about 3″ through the casing area. Gluing the seam down will help when you get ready to run the elastic through the casing (see fig. 5).

d. Refer to Serging in a Circle and clean finish the top edge of the waist (fig. 7).

5. Change to the piping foot. Find the piping bias strips for the pants cuff. Refer to Creating Piping and make two pieces of piping, one for each leg.

6. Center and glue the piping to the right side of each lower leg, matching the edge of the leg with the edge of the piping seam allowance. Serge the piping in place with the piping in the groove of the foot (fig. 8). Trim the piping even with the outer edge of the pants legs.

7. Fold each cuff piece in half, wrong sides together, and press well. To keep the layers from shifting as they are serged, glue the long edges together (fig. 9).

8. Center and glue the cuff edges to the piping/pants. The piping will be sandwiched between the pants and the cuff. Serge the cuffs in place with the pants on top and the piping in the groove of the foot (fig. 10). NOTE: Since the cuff has two layers of fabric on top of the piping and the pants only have one layer, it is easier for the foot to “read” the piping through one layer than two layers.

9. Change to the standard foot.

10. Press the cuff away from the pants. Glue each cuff/pants seam allowance to the pants (fig. 11).

11. Trim the sides of the cuffs to align with the side of the pants legs by laying a ruler against the cut edge of the pants and drawing a line through the cuff.

12. Remove the cord from the seam allowance at each end of the cuffs, if desired.

13. Follow the center front seam allowance from casing area down to the crotch and glue crotch area seam allowance in the same direction. Repeat for the center back seam allowance.

14. Place the front to the back of the legs, right sides together matching the center front and center back seam, the lower edges and the piping. Optional: Use Wonder Tape or glue to help in matching the seams.

15. Serge inner legs, starting at the end of one leg, serge up the leg, through the crotch and down the other leg (fig. 12).

II. Finishing

1. Measure the child’s waist. Cut the elastic to that measurement or 1/2″ to 1″ less for a more snug fit. The elastic will end up 1″ less than the cut measurement, since the ends are overlapped 1″ when inserted into the casing. If you don’t have the child to measure, use these standard measurements to cut the elastic.

3-4     21″

5-6     22″

7-8     23″

2. Fold the casing to the wrong side of the pants and pin (fig. 13a).

3. Optional: Fold a 2″ length of ribbon in half and press. Glue the ribbon layers together. Slide the raw edges of the ribbon under the serged seam of the casing at the center back. Glue in place (fig. 13b). This tab indicates the pants back and will differentiate the front from the back, being very useful when little ones dress themselves.

4. Using the sewing machine, straight stitch (L=2.5) the casing in place along the serged seam, leaving 3-4″ unstitched between the side and center back. The center back ribbon tab will be stitched in place when the casing is sewn in place (fig. 14). Insert the elastic into the casing. Overlap the elastic ends 1″. Zigzag (L=2.5, W=2.5) in a square around the overlapped elastic (fig. 15). Expand the waistline of the pants to distribute the elastic in the casing. Stitch the opening in the casing closed. Make sure the elastic is distributed evenly in the casing and straight stitch, back and forth, through the casing/elastic at the center front (fig. 16). Repeat for the center back (see fig. 16).

5. Tie-off the serger tails at the end hem edge. Refer to What To Do With Serger Tails, #2.

All Done!



• Shirt Construction

• Finishing the End of Piping

• Piping a Curve

• Attaching the Collar with Your Serger

• And more serger tips!

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