How to thread a strap through a buckle and slider

A buckle and a slider turn a plain strap into a dress belt, a bag strap or a shoe strap. Here is what a buckle is made of, which kinds of buckles and sliders exist, how to match the strap width and length, how to attach the buckle and tuck the end into the slider so it does not stick out.

Parts of a buckle

• Frame: the outer part the strap passes through.
• Bar: the cross axis the strap is attached to.
• Prong: the pin on the bar that goes into a hole in the strap and holds it.

A slider (keeper, strap loop) is a separate frame without a prong: it slides along the strap and holds its free end in place.

Kinds of buckles

• With a prong. The classic for belts, bags and shoes: the prong goes into a hole, and the length is easy to change by moving it to the next hole. Our antique rhinestone buckle is this kind.
• Frame buckles without a prong. The strap is held by friction: the end goes through the frame and over the bar. They are common on fabric belts, where holes are awkward.
• Double rings. Two rings the strap passes through in a loop. They adjust smoothly without holes and are popular on fabric and woven belts.
• Adjusters. A frame with a bar in the middle: a bag strap is threaded through it so its length can be changed smoothly.
• Decorative. Buckles that work as ornaments: with rhinestones, engraving, an unusual shape. They often sit on dress, shoe and bag straps, where looks come first.

Kinds of sliders

A slider holds the free end of the strap so it does not curl up or flap. It can be fixed, sewn or fastened right behind the buckle, or moving, sliding along the strap so it can be placed nearer the end. Long belts often have both: a fixed one by the buckle and a moving one further on. Sliders are made of leather, fabric or metal; metal ones with rhinestones, like our graphite slider, add decoration to the strap.

Matching the strap width

Measure the inner opening of the frame, not the outer size of the buckle: the strap should pass freely with 1-2 mm to spare, but not wobble. The same goes for the slider: our graphite slider is 21×15 mm and fits a strap up to 9 mm wide. Allow for thickness too: firm leather or doubled webbing takes more room than it seems.

Why exactly 1-2 mm? If the strap fits tight, it rubs the frame, its edge wears, and in time it starts to jam. If the gap is large, the strap skews in the buckle and the prong pulls the hole sideways, stretching it.

Working out the strap length

Measure around where you will wear the belt: the waist, the hips or over a coat. Add 15-20 cm to this measurement: part of it goes into fastening the buckle, part into the free end tucked into the slider. For a bag strap, measure the length you want from fixing to fixing and add 10-15 cm for adjustment and fastening the ends.

Strap material and finishing the ends

What you need

• a hole punch, or an awl and a hammer;
• rivets, or strong thread and a leather needle;
• a sharp knife and a ruler;
• for a fabric belt, interfacing or a firm stiffener.

Step 1. Attach the buckle to the strap

1. At one end of the strap, cut a small lengthwise slot for the prong, 3-4 cm from the edge.
2. Pass the strap end around the bar so the prong comes out through the slot.
3. Fold the end to the back and sew it or fix it with rivets. A fixed keeper loop can go between the buckle and the seam.

Step 2. Punch the holes

Try the strap on and mark the comfortable position. From that point, punch 2-4 more holes 2-2.5 cm apart in each direction so the strap can be adjusted.

Punch the holes exactly on the centre line of the strap: off-centre holes make the belt sit crooked. Match the hole diameter to the thickness of the prong: it should go in freely but without play.

Step 3. Fasten and tuck in the end

1. Pass the free end of the strap through the buckle frame from below.
2. Put the prong into the right hole.
3. Tuck the free end into the slider as the arrow shows: it lies flat along the strap and does not flap.

A fabric belt with a buckle

Dresses and coats often get a belt of the same fabric. Cut a strip twice the finished width plus seam allowances, back it with interfacing, fold it in half right sides together, stitch and turn it out. Wrap the end that goes to the buckle around the bar and sew it by hand with tight stitches. If the buckle has a prong, the holes in a fabric belt get eyelets or are oversewn with buttonhole stitch, otherwise the fabric soon frays. We explain how to finish a hole by hand in «How to make a buttonhole by hand».

Other uses

• Bags: an adjustable strap with a buckle and a decorative slider.
• Shoes: sandal and shoe straps, where a rhinestone buckle doubles as decoration.
• Clothes: a dress or coat belt, half-belts, cuffs.

The antique rhinestone buckle is oval, 57×37 mm, with a prong: it suits belts, bags and shoes.

Caring for rhinestone buckles

Rhinestones on decorative hardware are glued, so keep them away from water, perfume and detergents. Wipe the buckle with a dry soft cloth, and hand-wash garments with such hardware or take the belt off before washing. The metal finish dislikes abrasives: do not clean it with powders or rough sponges.

Common mistakes

• Strap tight against the frame. It rubs the metal and wears along the edge. Leave 1-2 mm to spare.
• Off-centre holes. The belt sits crooked and the prong stretches the hole.
• A short free end. It slips out of the slider. Leave at least 8-10 cm after the buckle.
• A fabric belt without stiffener. It creases and twists in the buckle, so interfacing is a must.

Frequently asked questions

What if the strap is slightly wider than the buckle?

Thin tape or fabric can be gathered a little at the end that wraps the bar, but for leather take a larger buckle: a squeezed strap rubs the frame and wears quickly.

How do I replace a buckle on a finished belt?

Unpick the seam or remove the rivets at the bar, take out the old buckle, put in the new one and fasten the end the same way. If the prong slot does not line up, cut a new one.

Can a prong buckle go on a fabric belt?

Yes, if the holes are reinforced with eyelets or oversewn. Otherwise the prong stretches the fabric within a few uses.

Where to buy

Buckles are in the Buckles section, sliders in the Sliders section, by the piece, with a wholesale price from 10 pieces.