WS Trimmer, paraglider trimming bench

Warning: a first unit of this bench has been printed, tried and validated by its author; these trials are neither a certification nor a validation by a workshop. The bench is provided free of charge, without warranty to the extent permitted by law, and used at your own risk; this does not exclude liability for personal injury, liability for defective products, or liability for fraud or gross negligence. Trimming a wing must follow its manufacturer's values and procedures, and a measuring error can change how the wing behaves in flight: have any re-trim checked by a qualified workshop.

Risk of falling: the bench stays on the table only because the line pulls on it. If the line goes slack, or pulls too far upwards, the 5 kg water bag tips the bench over and it falls with the bag. Set the cord so that the bag rests on the floor as soon as the line slackens, and keep everyone out from under the bag.

Download the STL files

One STL file per part, already oriented for printing, in millimetres. Recommended materials are further down.

• bobine_ecrou.stl248 kB
• bobine_tete.stl312 kB
• cible.stl222 kB
• coulisseau.stl846 kB
• entretoises_grappe.stl1166 kB
• poulie.stl515 kB
• socle.stl259 kB

The laser holder, in the version for your distance meter

Leica DISTO and Bosch models under €500, at the manufacturer's dimensions (length × width × thickness) plus 0.5 mm of clearance. Other distance meter: see further down.

• Leica DISTO D1115 × 43.5 × 23.5 mm · 129 kBimage
• Leica DISTO D110 / E7100i120 × 37 × 23 mm · 130 kBimage
• Leica DISTO D2 (v1, 100 m)116 × 44 × 26 mm · 130 kBimage
• Leica DISTO D2 (2025, 150 m) / D2G127 × 50.5 × 24.5 mm · 130 kBimage
• Leica DISTO X1125 × 53.5 × 25.5 mm · 129 kBimage
• Leica DISTO X3 / X4132 × 56 × 29 mm · 127 kBimage
• Bosch GLM 40 / GLM 30105 × 41 × 24 mm · 130 kBimage
• Bosch GLM 50-22 / 50-25 G / 50-27 C / 50-27 CG / 40-31119 × 53 × 29 mm · 126 kBimage
• Bosch GLM 80111 × 51 × 30 mm · 130 kBimage
• Bosch GLM 100-25 C / 150-27 C / 120 C142 × 64 × 28 mm · 129 kBimage
• Bosch Zamo (IV, 2025)104 × 38 × 23 mm · 127 kBimage
• Bosch PLM30-21 / EasyDistance 2094 × 36 × 23 mm · 126 kBimage
• Bosch PLM40-23 / 50-23 / 60-23C / 70-23C, UniversalDistance 30 / 40C / 50 / 50C, PLR 30 C / 40 C100 × 42 × 22 mm · 130 kBimage
• Bosch PLM70-27 / AdvancedDistance 50C / PLR 50 C115 × 50 × 23 mm · 130 kBimage

To check the trim of your wing, every line has to be measured under the same tension. Here, two 3D-printed parts do the job with a laser distance meter and a 5 L water bag: a bench that sits on the edge of a table and tensions the line to 5 kg, and a laser holder that catches the line's attachment tab at the wing end. Hardware: ≈ €15, plus shipping.

How it works

• The bench hooks onto the edge of the table. The two risers lie flat on it, each on a spool; you simply pass the maillon loop over the top.
• A carriage on wheels links the risers, through a cord and a pulley, to the water bag hanging under the table. As long as the carriage floats between its end stops, the line is tensioned to ≈ 5 kg.
• In front of the risers, a white target flips up and locks square.
• At the wing end, you slide the line into the notch of the holder, the tab comes up against the stop, and the laser lying in the holder aims at the target. The online trim tool works out the differences, with the offset given below.
• For travel: target folded down, a hook-and-loop strap around it.

Files to print

Seven files for the bench, one per part, already oriented for printing, no supports needed; then the laser holder, in the version for your distance meter.

The laser holder, sized for your distance meter

Same part (the notch, seen from below), one version per distance meter: the Leica DISTO and Bosch models under €500, at the manufacturer's dimensions plus 0.5 mm of clearance. The holder is 3 mm lower than the distance meter, so that you can grip it and reach its buttons. Some distance meters only measure from their rear face: their reading is longer by their own length, and the table says how much to subtract. GLM 100, 120 and 150: rear pin folded in.

Other distance meter: measure it (width, length, thickness), enter the three dimensions in scad/support_laser.scad and regenerate the STL; btn_cote opens a wall facing side buttons.

Which material

PETG, 4 perimeters, 25 % infill, target in matt white. No PLA if the bench travels by car: it warps in the sun.

If you have it printed by JLC3DP: everything in SLS 3201PA-F nylon, except the target in white SLA 9000HE resin. Allow ≈ €70 for printing the bench. The parts clamped by screws or pulled by a line (base, carriage, laser holder) must not be in resin: it breaks instead of bending.

Cheaper, for a bench that stays at home: at JLC3DP, base, carriage and laser holder in PLA (FDM), the small parts in nylon, the target in 9000HE resin. PLA is stiff and holds the screws well at room temperature. Allow ≈ €50 to €55 instead of €70 (an estimate, to be confirmed by the quote). One rule: never leave the bench in a car, PLA softens at around 60 °C. Rare use does not make resin acceptable either: it breaks when the screws are tightened or when dropped, not from wear.

What to buy

Nothing but screws, lock nuts and wheels, in two orders from France: all the fasteners sold singly by visseriefixations.fr; none of the European shops checked also stocks the wheels, they come from a 3D-printing shop. Prices read on 8 October 2026, shipping not included (it is only shown in the basket).

Fasteners: €1.46; wheels: €12.90; plus shipping for the two orders. The cord is any 2 mm cord (leftover line, halyard, paracord). The pulley bearing is taken from the fifth wheel, the weight is your water bag, and there is no glue and no threadlocker: everything is screwed through clearance holes, with a lock nut at the end. The laser is not counted: a 30 m Bluetooth distance meter (HOTO QWCJY001 or equivalent) costs €30 to €40.

Assembly

The full diagram, with the hardware (labels in French): schema_montage.png.

1. Pulley: take a bearing out of a spare wheel and press it into the pulley. Place the pulley in its slot with a spacer on each side. Slide an M5 lock nut into its pocket, on one side of the base, pass the M5 × 40 screw through from the other side and screw it in (4 mm hex key) until the head seats, without forcing. Head and nut stay below the sides.
2. Wheels: a lock nut in each of the 4 pockets of the carriage, then for each wheel an M5 × 25 screw from underneath, through the wheel and a spacer.
3. Play: tighten the fixed side, push the two other wheels to the bottom of their groove (slotted holes), tighten. The carriage must roll by itself when you tilt the base.
4. Spools: on the M5 × 80 screw, one spool, the rib of the carriage, the other spool, the lock nut in the cap. Leave it alone from then on.
5. Target: slide an M3 lock nut into the pocket of each lug of the carriage, on the inner side, then place the target between the lugs: it keeps the nuts in. On each side, screw an M3 × 12 screw through the lug (2 mm hex key) until its head seats. The end of the screw is the axle of the target.
6. Cord: figure-eight knot in the well behind the target; the cord runs in the channel of the base, goes over the pulley and is tied to the handle of the bag. Weigh the full bag at 5.00 kg.

Adjust the cord so that the bag rests on the floor when the line is slack, and lifts off as soon as you pull.

Setting the offset in the trim tool

The tool asks for the distance between the attachment point of the riser and the target. On the bench, the whole riser is held on the spool: the axis of its screw is 21 mm from the face of the target, on the laser side.

Offset to enter: 21 mm.

Set the distance meter to measure from its front face: it sits flush with the nose of the holder.

Going further

• NOTES.md (in French): design choices, dimensions, prices recorded, variants set aside and what has been checked.
• The OpenSCAD models are in scad/, the scripts that regenerate the STL files, the images and this site in outils/. Repository: https://github.com/alexandre-pereira/ws-trimmer, site: https://trimmer.wesoar.fr.
• A first unit has been printed, tried and validated by its author; these trials are neither a certification nor a validation by a workshop. Follow the wing manufacturer's values and procedures, and have any re-trim checked by a qualified workshop.

Licence

© 2026 WeSoar SASU. The bench is designed by Alexandre Pereira; WeSoar SASU owns the rights and distributes it.

Any copy credits "WS Trimmer, paraglider trimming bench, designed by Alexandre Pereira, © 2026 WeSoar SASU", the file's licence and the repository link. Whoever modifies a file says so: the CERN-OHL-S requires a dated notice briefly describing the change, CC BY-SA requires changes to be indicated; a modified version of these files is shared under the same licence.

The licence allows you to make and sell benches. Whoever sells them becomes their manufacturer and is responsible for their safety: general product safety (Regulation (EU) 2023/988), liability for defective products, statutory warranties. Share-alike applies to the adapted files, not to the printed object: as far as the licence goes, it is enough to tell the buyer where to find the source files (the seller's own, if modified). A modified version or a bench built from these files must not bear the WeSoar name or logo.

Details are in LICENSE (the French version is authoritative), the legal notice at the foot of the bench page.