Men’s Longline V-Neck Blazer Jacket with Double-Welt Flap Pockets
Introducing a men’s sewing pattern for a refined longline blazer with a deep V-neck opening, elongated proportions, and tailored structure — Modern Linearity with Architectural Elegance.
When To Wear
This longline blazer offers a contemporary alternative to classic suiting, making it suitable for:
- Business & Creative Workwear: a sharp yet modern silhouette for progressive office environments.
- Smart Casual Styling: Works seamlessly with tailored trousers or minimalist separates.
- Transitional Seasons: Designed for suiting fabrics that provide structure without excess bulk.
Key Design Features
Silhouette: Longline, straight-cut blazer of an elongated length and clean vertical lines.
Neckline: Deep V-neck front with clean-cut edges, replacing traditional lapels for a modern, streamlined appearance.
Closure: Single-breasted front with three-button closure.
Sleeves: Two-piece set-in sleeves with a tailored profile and buttoned cuffs.
Pockets: Flap pockets at the waist and a welt chest pocket.
Back: Side panels to refine the fit and shape through the torso and double vents for movement.
Level Of Difficulty
Advanced. This pattern requires confident tailoring skills, particularly for precision V-neck construction, pocket detailing, interfacing placement, and sleeve assembly.
Fabric Recommendations
Select suiting fabrics that emphasize clean lines and vertical structure:
- Wool suiting
- Wool-blend suiting fabrics
- High-quality synthetic or mixed-fiber suiting materials
Additional Supplies
- Lining fabric
- Fusible interfacing
- 3 buttons for front closure
- 6 smaller buttons for sleeves
Cutter’s Must
From Main Fabric:
- Back – 2 pieces
- Side – 2 pieces
- Flap – 4 pieces
- Pocket Bag – 2 pieces
- Pocket Facing – 4 pieces
- Chest Pocket Welt (marked on pattern as "Off-Set Welt") – 1 piece
- Upper Pocket Bag – 1 piece
- Lower Center Front Facing – 4 pieces
- Center Front Facing Insert – 2 pieces
- Front – 2 pieces
- Collar – 2 pieces
- Upper Sleeve – 2 pieces
- Lower Sleeve – 2 pieces
From Lining Fabric:
For drafting lining patterns use main patterns with the following modifications:
- Back – use Back pattern excluding vent extensions, cut 2.
- Side – use Side pattern excluding vent extensions, cut 2.
- Pocket Bag – use Pocket Bag pattern, cut 2.
- Upper Pocket Bag – use Upper Pocket Bag pattern, cut 1.
- Upper Sleeve – use Upper Sleeve pattern excluding vent extensions, cut 2.
- Lower Sleeve – use Lower Sleeve pattern excluding vent extensions, cut 2.
- Front Lining – use Front Lining pattern, cut 2.
From Fusible Interfacing:
All interfacing pieces are cut using the corresponding main pattern pieces.
- Front - cut 2.
- Flap - cut 2.
- Pocket Facings - cut 4.
- Chest Pocket Welt - cut 1.
- Collar - cut 2.
- Center Front Facing Insert - cut 2.
- Lower Center Front Facing – cut 4.
Important Information
Before cutting your fabric:
- Print and lay out pattern pieces to determine yardage.
- Check mirrored pieces, notches, and grainlines.
- For patterned fabrics, align carefully for symmetry.
Assembly Instructions
Preparation
Apply fusible interfacing to the Collars, Fronts, Chest Pocket Welt, Pocket Facings, Center Front Facing Inserts, Lower Center Front Facings, and Flaps - fuse from the wrong side using a hot iron, pressing firmly until fully bonded.
Darts & Front Shaping
- Sew waist darts on each front.
- Press darts toward the center front.
Chest Welt Pocket
On the left Front construct a single-welt chest pocket:
- Fold the Chest Pocket Welt lengthwise right sides together and stitch across the short ends. Turn right side out and press.
- Pin the Chest Pocket Welt (turned downward) to the garment front along the marked placement line.
- Place the Pocket Bag of lining fabric over the Chest Pocket Welt, then pin the Pocket Bag of main fabric turned upward above it. Stitch 5 mm on either side of the marked line.
- Slash the opening between the stitching lines, clipping diagonally into the corners. Turn the pocket bags to the inside.
- Secure the free edge of the Chest Pocket Welt to the Pocket Bag with zigzag stitches.
- Align both pocket bags and stitch around the contour.
- From the right side, secure the Chest Pocket Welt ends to the garment.
Body Shaping
Attach Sides to Fronts, press allowances open.
Pocket Flaps
Place the Flaps right sides together, stitch along the outer edges, turn right side out, and press.
Side Pockets
Construct Double-Welt Pockets with Flaps:
- Press Pocket Facings lengthwise, wrong sides together.
- Pin upper and lower pocket facings to Front along markings.
- Place lining Pocket Bag on lower pocket facing; place main Pocket Bag on upper pocket facing with Flap inserted between upper pocket facing and bag (flap turned upward).
- Stitch 5 mm from each side of marking.
- Cut opening through center, clip to corners.
- Turn pocket bags inside, roll pocket facings to form 1 cm lips, press.
- Press Flap down over opening.
- Zigzag pocket facing edges to pocket bags.
- Align and stitch pocket bags together.
- From wrong side, secure pocket facings ends to small fabric triangles.
Back Assembly & Vent
- Sew the center back seam.
- Sew the back panel seam down to the vent marking and press seam allowances toward the back.
- Fold the left vent extension to the right side of the garment, stitch along the hem foldline, turn right side out, and press.
- Topstitch along the folded edge of the left vent.
- Fold the hem allowance of the right vent to the right side, stitch along the edge of the vent extension, turn right side out, and press.
- Lay the vent toward the side panel and secure the top of the vent with a diagonal reinforcing stitch.
- Press the hem allowance to the wrong side.
Shoulders
Sew the shoulder seams.
Sleeves & Shoulder Structure
- Stitch the upper and lower sleeves together.
- Set the sleeves into the armholes.
- Press the hem allowances to the wrong side.
- Attach the shoulder pads.
Center Front & Collar Components
- Place the Lower Center Front Facings right sides together and stitch along the outer and lower edges.
Turn right side out and press. - Stitch together the Lower Center Front Facing, Center Front Facing Insert, and the Collar.
Lining Assembly & Hem Finish
- Stitch the lining pieces together.
- Place the lining and the jacket wrong sides together and baste along the edges.
- Turn under the hem allowances of the jacket body and sleeves and hand-stitch them to the outer garment.
Joining Center Front Facing, Collar & Neckline
Insert the front edge and neckline edges of the jacket between the assembled Center Front & Collar Components and stitch.
Buttonholes & Buttons
- Work buttonholes on the left front.
- Sew buttons onto the right front and sleeves.
