Double-Breasted Blazer with Double Welt Pockets with Flaps and Double Back Vents
A men's hip-length double-breasted jacket with peak lapels, a four-button front, a chest welt pocket and flapped double-welt hip pockets. Side panels, two back vents and a full lining.
When To Wear
- As a suit jacket with matching trousers for business and formal occasions.
- As a separate jacket with flannel trousers or chinos and a shirt or a fine knit.
Key Design Features
Silhouette: Shaped by front darts that run into the hip pockets and by side panels between front and back; padded shoulders.
Length: Hip length, covering the seat.
Collar: Peak lapels. The collar is cut in two pieces, upper and under collar, both interfaced; the under collar is hand-stitched at the neckline. Buttonhole in the left lapel.
Sleeves: Two-piece set-in sleeves with eased caps; mitred vents closed with four buttons through worked but uncut buttonholes.
Front: Double-breasted, four buttons in two pairs, buttonholes on the left front; separate front facings.
Pockets: Single-welt chest pocket on the left front; double-welt hip pockets with flaps on both fronts, welts 1 cm wide.
Back: Centre back seam; two vents in the seams between the back and the side panels.
Finishing: Fusible interfacing on the fronts, facings, collar, flaps, chest welt and all hem and vent allowances; vents and hems slipstitched by hand; shoulder pads.
Lining: Full lining, 2 cm shorter than the jacket and sleeves, with a pleat at the centre back and a jump pleat at the hem, sewn around both vents; the jacket is turned through an opening in a sleeve seam.
Level Of Difficulty
Advanced. Flapped double-welt pockets, a chest welt pocket, double vents, mitred sleeve vents, a hand-finished collar and a bagged lining.
Fabric Recommendations
Wool or wool-blend suiting and jacket fabrics of medium weight, such as worsted, flannel or tweed.
Additional Supplies
- Lining fabric
- Fusible interfacing
- 4 buttons for the front
- 8 smaller buttons for the sleeves
- Shoulder pads
- Sleeve heads (optional)
Cutter’s Must
From Main Fabric:
- Back – 2 pieces
- Front – 2 pieces
- Side – 2 pieces
- Upper Sleeve – 2 pieces
- Lower Sleeve – 2 pieces
- Collar – 2 pieces
- Center Front Facing – 2 pieces
- Flap – 2 pieces
- Chest Welt (marked on pattern as “Off-set Welt”)– 1 piece
- Pocket Facing (lower pockets’ welts) – 4 pieces
- Pocket Underlay – rectangle 14 × 6 cm – 1 piece (chest pocket; trim to the width of the pocket bag)
From Lining Fabric:
Use main pattern pieces with the following modifications:
- Back Lining – use Back pattern, add 2 cm pleat at center back, exclude vent extensions; cut 2.
- Front Lining – use Front pattern excluding central front facing area; cut 2.
- Side Lining – use Side pattern without changes; cut 2.
- Upper Sleeve – use pattern excluding vent extension; cut 2.
- Lower Sleeve – use pattern excluding vent extension; cut 2.
- Flap – use pattern, cut 2.
- Upper Pocket Bag – use pattern, cut 2.
- Lower Pocket Bag – use pattern, cut 4.
- Shorten both jacket and sleeve linings by 2 cm at hem.
From Fusible Interfacing:
- Front – 2 pieces
- Center Front Facing – 2 pieces
- Collar - 2 pieces
- Flap – 2 pieces
- Chest Welt - 1 piece
- Hem allowances of Fronts, Back, Sleeves and Vents.
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
1. Preparation
Apply fusible interfacing to the wrong side of Fronts, Center Front Facings, both collars, Chest Welt, Flaps, hem allowances of body and sleeves, and vent extensions.
Body Shaping
- Slash pocket opening on the front, stitch dart, cut along fold, and press open.
- Baste along pocket opening edges.
Pocket Flaps
- With right sides together, stitch each Flap to its lining.
- Turn right side out and press.
Chest Welt Pocket
On the Left Front, construct a single-welt breast pocket:
- Fold welt lengthwise, right sides together. Stitch short ends, trim corners, turn, and press.
- Place the pocket underlay wrong side down on the right side of one lining pocket bag, aligning the upper raw edges; turn under its lower edge and edgestitch; baste the remaining edges.
- Place welt face down along pocket marking.
- Layer one lining pocket bag over welt, and the second lining pocket bag (with the pocket underlay) above, facing upward.
- Stitch 5 mm on each side of marking.
- Slash between stitching, clip diagonally to corners, turn to inside.
- Zigzag or hand-stitch welt’s free edge to lining pocket bag.
- Align pocket bags, stitch around contour.
- From right side, secure welt ends to garment.
Front Panel Seams
Stitch front panel seam; press allowances open.
Double-Welt Pockets with Flaps
Construct double-welt pockets with flaps:
- Press welts lengthwise, wrong sides together.
- Pin upper and lower welts to Front along markings.
- Place lining pocket bag on lower welt; place the second lining pocket bag on upper welt with flap inserted between upper welt 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 welts to form 1 cm lips, press.
- Press flap down over opening.
- Zigzag welt edges to pocket bags.
- Align and stitch pocket bags together.
- From wrong side, secure welt ends to small fabric triangles.
Body Assembly
- Stitch Backs together at center seam. Press open.
- Join shoulder seams.
- Attach Sides to Backs up to vents; press allowances open.
Collar & Facings
Attach lower collar to jacket:
- With right sides together, pin lower collar to neckline.
- Stitch neckline, clip curves, press seam allowances down.
Attach upper collar to facings:
- Stitch upper collar to center front facings along neckline; press seams open.
Join Facings to Jacket:
- Place center front facings + upper collar right sides together with jacket.
- Stitch continuously: hem → lapel → collar → opposite side.
- Trim, grade, and notch where needed.
- Turn right side out and press collar/lapels flat.
Sleeves – Two-Piece with Vent
- Stitch Upper and Lower Sleeve together to vent notch, easing as necessary; press open.
- Turn sleeve right side out.
- Fold vent and hem allowances to right side, stitch diagonal across vent corner for clean miter, trim to 1 cm, press open.
- Turn allowances inside, secure with cross-stitch, form vent overlap.
Sleeve Cap
- Ease-stitch between notches, pull threads to fit armhole.
- Steam-shrink fullness.
- Stitch sleeve seam, press open.
- Set sleeves into armholes, sewing from sleeve side.
- Fold padding (if used) and hand-stitch to sleeve caps.
Vents & Hems
- Fold back vent facing to right side; stitch along hem foldline.
- Turn right side out, slipstitch invisibly along edge.
- Fold hem allowance of side panel to right side; stitch along vent facing edge.
- Turn right side out, slipstitch invisibly.
- Lay vents toward back; secure at top with a short diagonal tack.
Shoulder Pads
Sew in shoulder pads.
Lining
- Form movement pleat at center back; secure below neckline and a few centimeters above hem.
- Assemble lining same as main garment, leaving 20 cm opening in one sleeve seam.
- Insert lining into garment, right sides together, aligning center back and shoulders.
- Stitch lining to facings and neckline edges.
- Turn upper collar edge under; press.
- Place upper and lower collars wrong sides together; hand-stitch lower collar to upper collar and back neckline with loose zigzag.
- Form jump pleat along hem; attach lining to hem allowance, stitching to right vent fold and left vent facing edge (make a small horizontal snip at base of left back vent in lining before attaching).
- Turn right side out through sleeve opening; close opening neatly.
Finishing
- Work buttonholes on left front and lapel as marked; attach buttons.
- Work non-cut decorative buttonholes on sleeves; secure vents with buttons.
