How to string a tennis racquet: the four-knot method, step by step
A string job is judged by the ball, not by the eye. An under-tensioned string, a string crushed by a clamp, a frame that went oval during the job: none of it shows on the finished string bed, and all of it shows in a ball that comes off a little higher, a little shorter, from one shot to the next.
The method below is the one the Matcheur workshop teaches: a four-knot job with a monofilament, on a 16 × 19 pattern. It works for every machine, electronic, crank or drop-weight, fixed or flying clamps, 2, 4 or 6-point mounting. Each step also exists as an interactive assistant, in French, to open on your phone next to the machine.
The equipment before you start
The machine. It pulls the string to a set value and holds the racquet during the job. Three families: electronic (constant pull, set to a tenth), lockout crank (tension is reached at the click), drop-weight (a weight on a bar; tension is right when the bar is level). They are compared in the stringing machine guide.
The clamps. Fixed, mounted on a base that slides on the turntable, or flying, clamping two neighbouring strings together.
The starting clamp. A small independent clamp that holds one end tight against the frame. It is used to start the mains and the crosses, and as an extension when the string is too short.
The tools. Multi-purpose pliers, awl, string guide, cutters, ruler.
The string, chosen beforehand. Material, gauge and tension are decided first: how to choose a tennis string and what tension to string at.
How much string to cut
The racquet is the ruler. You measure in lengths of the centre string, running the string along the string bed from one grommet to the other:
Mains: number of mains + 1. On a 16 × 19, seventeen lengths of the centre main. Folded in two, this string gives two ends of 8.5 lengths: eight mains on each side, plus the margin for the knot.
Crosses: number of crosses − 1. On a 16 × 19, eighteen lengths of the centre cross.
It is a starting point. The offcut depends on how each person draws the string to the tensioner: note what is left after each job, and take off half a length if the offcut is generous. For a 16 × 19, a 12 m set is enough. If you string often, a 200 m reel covers sixteen jobs from a single production batch.
Before cutting the new string, remove the old one working from the centre of the string bed outwards, mains and crosses alternately: the frame relaxes symmetrically. Then run a finger over every grommet. A split grommet cuts the string within a few hours of play; it is replaced before the job, never after.
Mounting the racquet without distorting it
First count the throat holes: the holes running through the bridge, on the inside. Six holes, three passes: the mains start at the throat. Eight holes, four passes: they start at the head.
Lay the racquet flat, handle in line with the cradle, and tighten the supports in a set order: first those that hold it on the axis, at the head and the throat, then the side supports, in symmetrical pairs. On a 6-point mounting, the two centre posts go inside the frame. On a 2-point mounting, only the head and the throat are held: alternating the mains becomes the frame's only protection across its width.
The rule fits in three words: contact, no force. The supports stop the frame from moving; they must not shape it. Measure the outside width of the head once the racquet is mounted: you will check it again at the end.
Setting the clamps and the tension
A clamp is set on an offcut of the day's string, not on the racquet. Close it on the offcut and pull hard along its axis: it must not slip. Open it and look: a light mark, no flat spot. Too tight, it nicks the monofilament; too loose, it lets tension escape.
The clamp goes tight against the frame, in line with the string. A few millimetres too far, and the string relaxes between the clamp and the grommet. A flying clamp is placed the same way, on the string you have just pulled and its already tensioned neighbour.
You clamp when the tension is reached and stable. Depending on the machine:
Electronic: the pull is constant; wait one or two seconds for it to settle before clamping.
Lockout crank: turn smoothly until the click, and clamp straight away. The same rhythm on every string is what makes it accurate.
Drop-weight: tension is only right with the bar level. If it drops, take up the slack and start again.
Which value to set? It depends on the string as much as on the player: that is what the range's elongation curves show.
Starting the mains
The two centre mains are strung with a single string folded in two. The middle of the string sits on the bridge (three passes) or at the head (four passes), and each end runs up its centre main.
Starting clamp on the right end, flat against the frame, on the outside.
Left end on the tensioner, slack removed, then pull.
Clamp the first main tight against the frame once tension is reached.
Without the starting clamp, pulling the left end would drag the string through the bridge, and the clamp would hold a main with no real tension. The starting clamp gives the fixed point. It stays in place until the first right main is pulled and clamped.
Filling the throat, then alternating
The mains running through the throat bridge are pulled first, one side then the other, before stringing the rest one string at a time:
Phase 1, throat, left side: second and third mains (and fourth with four passes).
Phase 2, throat, right side: first right main, then remove the starting clamp; second and third.
Phase 3, one string each side, alternately, up to the last two mains.
The frame is never more than three or four mains ahead on one side. Each new string is pulled while the clamp still holds the previous one; the clamp is moved once tension is stable. Before the last mains, check the manufacturer's pattern for a skipped hole.
The four knots
A four-knot job has two for the mains and two for the crosses. All follow the same geometry: the last string comes out of its grommet, runs along the bumper to the neighbouring tie-off hole, goes back in, and the knot tightens around the anchor string, the already tensioned string running through that hole. Tension pulls the knot against the grommet: the grommet is what stops it.
The string that takes the knot is pulled 10 % higher than the others, to make up for what the knot takes back. The clamp stays on until the knot is tight.
The Parnell, the reference knot
Make a half hitch around the anchor string: over, under, through the loop.
Pull it tight against the grommet, free end drawn towards the frame.
Make a second half hitch, in the same direction of turn.
Tighten in an arc towards the grommet, then cut at 2 or 3 mm.
Because the first half hitch is tightened before the second, the Parnell does not choke the anchor string. It is compact, sits clean against the grommet, and does not come undone.
The other knots
Double half hitch: the same two half hitches, tightened together at the end. Easier to learn, bulkier.
Pro knot: a half hitch, then a single return through the loop. The most compact, for a crowded tie-off hole; in a wide grommet, the Parnell holds better.
Starting knot: two turns around the anchor string, end passed back through. It starts the crosses without a starting clamp and must be clearly bigger than the grommet.
Two rules apply to all of them: tighten by hand, never with the machine, and always towards the frame. Pulling the free end outwards loosens the knot.
Starting and weaving the crosses
The crosses always start at the head and work down to the throat, from the side the manufacturer specifies. Three ways to start the first one:
With the starting clamp, the safest. Leave a tail of about forty centimetres, held tight against the frame. After a few crosses, the tail goes back to the tensioner; it is pulled and tied off with a Parnell. All four knots are then identical, and the first cross gets real tension.
With a starting knot. Simple, no accessory. The knot takes the pull directly: it must be bulky, especially with a slick monofilament.
Starting knot and clamp. The clamp takes the first pull instead of the knot. For a wide or damaged grommet.
Then each cross weaves the opposite way to the one before: if it went under a main, the next one goes over. Weave one cross ahead, before pulling the previous one: the mains are still free, the string rubs less, and a weaving mistake shows straight away. Pull the string in a wide arc, square to the string bed, without sawing the mains. The last cross is pulled at +10 % and tied off in the throat-side tie-off hole.
Checking the job
Four knots tight against their grommets, cut at 2 or 3 mm.
An alternating cross pattern from end to end.
Straight strings, aligned with the awl without forcing.
The head width, compared with the one measured before the job. A gap of several millimetres signals over-tight mounting or an unbalanced stringing order.
Take the racquet off only after the last knot, side supports first. A monofilament loses part of its tension in the first few days: that is normal, and it is why jobs are compared after the same delay. What comes next: when to restring. And if something went wrong along the way: common stringing mistakes, and how to fix them.
Frequently asked questions
Two knots or four?
A two-knot job uses a single string for the whole string bed; a four-knot job uses two pieces, one for the mains and one for the crosses. The second is the easiest to learn, the easiest to measure, and the only one that allows a hybrid, with two different strings. Some manufacturers require it for their frames.
Why pull 10 % higher before a knot?
The knot takes back a little string as it tightens, and the last string, held by a knot rather than by the next string, loses more than the others. The 10 % make up for that loss. They are only applied to the string that takes the knot.
How long does it take to string a racquet?
Count one to two hours for the first jobs. With practice, twenty to forty-five minutes depending on the machine. Speed comes from consistency: you save time by removing do-overs, not by rushing the moves.
Which machine to start with?
All three families string correctly. An electronic machine holds a constant pull and sets to a tenth; a drop-weight also pulls continuously, more slowly, and asks you to watch the bar; a lockout crank is fast but needs a steady hand. More than the tensioning type, look at how the racquet is mounted and at the quality of the clamps: they are what protect the frame and the string. More in the stringing machine guide.
Where can I learn with an instructor?
The Matcheur workshop runs a stringing course: about three hours to string a racquet from start to finish with this method, on a professional machine. And if you would rather hand it over, a string job at the workshop costs 12 €, with your string or one from the range, in Aube, near L'Aigle in Normandy (the workshop).
The string itself is chosen before the job: the range runs from N°1 to N°7, from the softest to the stiffest.
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