Spaghetti Stringing (Part 3: Stringing an AMF Head Master 2)
Posted 5th July 2020
The spaghetti stringing system differs greatly between racket models, as each frame requires nuances in the design to tailor it to the specific string pattern and grommet configuration. The patents filed by Werner Fischer do not clarify some of the finer practicalities of stringing a racket with his system, nor do they contain solutions to racket-specific problems that may be encountered. There are various complications that can arise without first examining the system in closer detail.
Effective preparation can make the process far more straightforward and will help to avoid critical stumbling blocks, that could otherwise result in having to rip out the strings and completely start over. Some of the elements requiring planning are as follows:
- Number of crosses to use;
- Number of mains to be omitted (if required);
- Number of sheaths (tubes) required;
- Potential locations for blocked holes;
- Knot type, quantity and locations.
Spaghetti rackets are strung to the basic principles of the two-piece method, in which the mains and crosses are strung separately. Before attempting to string a racket with the spaghetti system, however, it is vital to accept that the system departs from conventional stringing practices, as the system involves many faux-pas that go against the advice of any stringing purist and even manufacturers’ warranties.
In this example, an AMF Head Master 2 tennis racket is converted with the spaghetti system. The Master 2, released in the mid-1970s, is from the same era and range of rackets as Mike Fishbach’s AMF Head Professional, which was used with a spaghetti system to surprising success at the 1977 US Open. Both rackets have an extruded aluminium frame with a plastic throat piece – the Master 2 throat piece is dark blue, while the Professional has a red throat piece, from which its namesake the Redhead originates. Although not as popular as the Professional, the Master 2 (and its predecessor, the Master) was still influential as one of the earliest examples of a metal racket to be fitted with a plastic grommet strip.
The Master 2 has 30 grommets on each side. To help explain the spaghetti pattern, the grommets are numbered 1 to 30, starting from the throat. The prefix L or R refers to the left or right side when mounted in the machine; grommet L8, for example, refers to the 8th grommet up on the left side. Grommets L1 to L6 and R1 to R6 are through the plastic throat piece.
Despite its rounder head shape, the Master 2 features a very similar (if not identical) stringing pattern to Mike Fishbach’s Redhead, with 18 mains and 18 crosses. Both rackets also have shared grommets on the three outermost main strings, at the throat (grommets 7, 8 and 9) and head (grommets 22, 23 and 24). The shared grommets are an obvious stumbling block for the spaghetti system, as they would require two mains and two crosses to pass through a single grommet. From photos of Fishbach’s spaghetti racket taken in 1977, it is clear that to avoid having four strings through a single hole, Fishbach omitted the outer two mains on each side, leaving just 14 pairs of main strings.
Omitting the outer two mains leaves 16 holes on each side completely vacant for the cross strings. Fishbach’s spaghetti system had 6 pairs of crosses – the top and bottom crosses utilise the shared grommets that would normally also be occupied by LM8 & RM8. The system works perfectly for six crosses and keeps a well distributed pattern, making use of the topmost and bottommost available grommets with a regular spacing of two empty grommets between each cross.
If the racket is to be used on court (and not just kept as a novelty showpiece), Kevlar strings are strongly recommended, particularly for the crosses. As the string pattern is so open, standard nylon synthetic strings are likely to break within the first few hits. There is nothing more disheartening than to see the result of several hours work disintegrate before your very eyes, so be warned! For the Master 2 racket used in this example, the intention was simply to trial the stringing method with no real plan to use it in play, so the racket was strung with Head Synthetic Gut PPS 16 (1.30mm).
The spaghetti stringing system puts a lot of stress on the frame in strange, unplanned for places. This is due to increased stress imparted from the double-strung mains and reduced stress from the omitted crosses. With old or well-used rackets, the lower tension the better if frame shape is to be preserved. The single-sided version of the spaghetti system is also slightly easier on the racket. However, because the strings are double-pulled, the reference tension should be increased slightly to compensate for pulling twice the amount of string. As the crosses maintain the frame shape, it is also recommended to use an additional 5-10 lb tension on the crosses to somewhat counter the effects of the spaghetti system and pull the frame sides back into place.
For the Master 2, the selected reference tensions were 50 lb for the mains and 60 lb for the crosses. An additional +10 lb on both the mains and crosses is suggested if you are confident the frame can withstand the load.
The main strings were relatively straightforward to install, although the double-stringing method introduced some minor complications. The most important thing to remember when stringing the mains is to keep them running parallel both inside and outside the frame. Each main of the pair should always run either top-to-top or bottom-to-bottom and should always occupy the same side of the grommets. This can be tricky to ensure and it is easy to inadvertently leave twists in the mains or crossovers on the outside of the frame. The best way to avoid this, before feeding the strings through a grommet, is to run a finger between the pair of strings from where they emerge from the previous grommet, separating top from bottom until the finger reaches the ends of the strings. Then insert the ends into the next grommet.
Standard tennis tubing with an inner diameter of 1.70mm and wall thickness of 0.20mm was used for the sheaths. The tubing was close enough to the gauge of the string that it slid on easily, but without leaving too much space. A closer fit would have been preferable, but smaller size badminton tubing with an internal diameter of 1.10mm was too narrow.
In retrospect, it is perhaps worth looking beyond racket stringing suppliers for suitable tubing to use. Flexible or semi-rigid tubing made for applications in the pneumatics industry offers a wider range of sizes and colours, in both PTFE (otherwise known as F4 or by its brand name Teflon) and nylon 12, which has similar properties to nylon 11 suggested in Fischer’s patent. Bowden tubing used in 3D printing (normally made from PTFE) is also a good alternative. Metric size tubing with an inner diameter of 1.50 mm or imperial size tubing with an inner diameter of 1/16” (1.59 mm) gives a closer fit to typical tennis string gauges than standard tennis tubing.
It is important to know in advance how many crosses the racket will use, as this determines the number of tubing sections required. For the Master 2, with six crosses, the total number of tubing pieces was 14 x 2 x 6 = 168. The four corner sheaths on each side were omitted as they were very close to frame, meaning the total was reduced to 160. The tubing was cut to lengths of 2cm, requiring 320cm of tubing in total. As tennis tubing typically comes in 3m coils, two packs were needed.
To create consistent lengths, the tubing was cut using a Stanley knife, with a steel ruler and cutting mat. The tubing cuts like butter, so it is easy to get a clean cut. As the tubing is supplied in coils, it helps to straighten out the tubing before cutting, by gripping the tubing firmly with one hand and running the other hand along it while lightly gripping it at the same time. It took roughly an hour to cut all the pieces.
It is easy to forget to slide on the tubing when stringing the mains, or miscount and have the wrong number. If this happens, there is no choice but to pull out the strings and re-install them with the correct quantity of tubes.
Mike Fishbach allegedly used triple-strung crosses for a stiffer string bed and better load balance over the frame. For the Master 2, however, the crosses were double-strung in accordance with Werner Fischer’s design and in much the same way as the mains.
There is a time-saving trick when stringing the crosses that requires only a single length of string and also reduces the number of knots required. When starting at the head, create a loop on the inside of the frame between two adjacent grommets, directly below the grommet of the first cross. Take the ends of the string through the grommets of the first cross and pull tension against the loop formed on the inside of the frame, before clamping and continuing to the next cross.
When pushing two strings together through a single grommet, it helps to first sharpen the ends of the strings with a Stanley knife. It may be necessary to repeat this every so often to get fresh, sharp points for lacing the strings, as they dull fairly quickly. Pliers were still necessary to grip the strings and push them through the grommets together.
With the Master 2, fortunately all grommets were wide enough to accommodate two strings fairly comfortably. The most constrictive grommets were those in the plastic throat piece, which were slightly narrower than the other grommets around the frame and required a bit of patience to get two strings through. A slow, steady insertion helps to prevent the strings twisting within the hole. Be sure to inspect each grommet hole for twists in the strings before proceeding to the next one.
For most rackets, however, the majority of grommet holes are not designed to accommodate two or more strings and fitting an extra string through a grommet can be a frustrating (but not impossible) task. Although enlarging or tampering with conventional grommets should not be necessary for the spaghetti method, an awl may be an essential tool for getting multiple strings through holes that are meant for only one string.
When using an awl, be very careful so as not to damage the string. The awl has to be gently inserted, then using a slow left/right steady rotation, push the awl through as far as possible before leaving it for a few seconds. This enlarges the hole and compresses the existing string. For particularly difficult holes, it may help to coat the tip of the awl with wax or chapstick. Alternatively, a pathfinder or guide awl can be used for literally guiding the second string through the blocked grommet hole. Of course, the process is easier to get two strings through the holes if using a thin gauge string.
There are inevitably places where two or even four strings lie side-by-side on the outer edge of the frame. With the double-stringing technique, any potential blocked holes that would normally cause only a minor nuisance are made significantly more difficult to overcome. It is important to identify these before they occur, as installing the crosses may otherwise be near impossible.
In planning the pattern for the AMF Head Master 2, there were likely blocked holes:
- L8 and R8, used for the cross strings and blocked by the main strings being tied off;
- L12 and L13, used for tying-off the cross strings (and also blocked by the cross strings).
One method to make blocked holes less of a problem is to insert a piece of scrap string between the outside rim and the length of string that, once tensioned, will block the hole. Then continue installing the strings normally. When you return to the blocked hole to feed string through it, grip the ends of the scrap string firmly with pliers and tug it gently to pull the blocking string aside. After feeding string through the hole, slide out the scrap string and discard.
Knots are tough. Getting a tie-off string through a grommet already containing two main strings is not an easy task, and while a tie-off hole may just about accommodate three strings, a standard hole certainly cannot. Tennis rackets generally only have larger grommets in six places to allow a two-piece stringing method (starting the crosses on either side), and the positions of these grommets along the frame are unlikely to match those required for a spaghetti pattern. Even if it is possible to tie off one string of a pair, tying off its partner string is going to be very difficult.
There is, however, an innovative way to tie off the outer mains and bottom cross that avoids this problem entirely. After clamping the last main or cross, take the ends of the strings through the next two vacant grommets along the frame. The ends are then joined on the inside of the frame using a double fisherman’s knot (nicknamed the impossible knot because it is nearly impossible to untie). The fisherman’s knot comprises two overhand knots, which can be made with more turns to create the double fisherman’s knot. The double fisherman’s knot has excellent holding strength, but the real beauty of this knot is that no anchor string is required. Instead, the tension of the two strings pulls the knot tight.
On the Master 2, the mains finish at L7 and R7. For tying off, skip grommets L8 and R8 (these are used for the bottom cross) and use the two vacant grommets on each side between the two bottom crosses. The crosses then finish at either L7 or R7 and are tied off on the same side between the 2nd and 3rd cross from the throat. Note that this does result in four strings lying side-by-side on the outside of the frame at one point.
Tying the double fisherman’s knots was, admittedly, a horrendously frustrating task and took numerous attempts to get a satisfactory knot. It is very tricky to tie the knot in such a restricted space and it is very easy to lose a lot of tension in the process. Some tension loss is inevitable and for this reason it is advisable to add at least +10% on the tension for the outer mains. To help reduce tension loss, with the two loose ends of string, pull one end through an adjacent vacant grommet. Attach a starting clamp on the loose string and let it hang down, using the weight of the clamp to gently pull the string taught. Tie the first overhand knot around the taught string and pull it as tight and as close to the frame as you can with a starting clamp before starting the second overhand knot.
Braided nylon chalk line was used for the holding strings. Braided rather than twisted line is preferable, as it has less stretch. String bed scissors were perfect for getting clean cuts of the line. With a total of 168 knots to tie, the process took time – three and a half hours to be exact. It also left some pretty sore fingers afterwards, so wearing protective gloves may be advisable. Parnell knots were used to start and finish on the outer main strings and were reinforced with epoxy glue before cutting off the excess string.
Standard off-the-shelf epoxy glue (resin & hardener) was used for the projecting means. Photos of original rackets strung by Fischer in the 1970s suggest the epoxy was only applied on the outer face of each string bed. However, to help prevent the glue from being dislodged during play, it is better to apply the epoxy on both sides such that the glue forms a whole 360° around the string. This is fiddly, but leaves a satisfying finish. When applying the glue, keep the racket in the machine but watch out for epoxy dripping on the clamps or tracks. A small piece of scrap string makes a good applicator. Leave the glue to harden on one side completely (minimum of half an hour) before flipping the racket and completing the other side.
Applying the projecting means was time consuming as it required continuously mixing small amounts of epoxy. As the epoxy hardens very quickly, only a few means could be applied at one time before it became too hard or too stringy to use effectively. Depending on the preferred finish, it is likely to take between 1-2 hours per side to apply the projecting means.
It almost goes without saying that spaghetti stringing is incredibly time consuming – even an experienced stringer will struggle to finish a single racket in an afternoon. The single-sided version is less work, but departs from the full characteristics of Werner Fischer’s invention.
Installing and tying-off the main strings took around two hours, while the cross strings took around one hour. But with all the additional steps, the Master 2 took a total of around 12 hours to string with the spaghetti system. This was undoubtedly slow due to being a first attempt, and does not include the time taken for a trial run, which was aborted due to excessive tension loss and miscounted sheaths. Allegedly, it took Mike Fishbach and his older brother Peter nearly 30 hours to string their spaghetti racket. Much of the process is trial and error and a lot of practice is needed to be able to string a spaghetti racket in the modest 2-3 hours required by Werner Fischer.