A Series 4 Glitch

We hit a glitch with a few short production Series 4 heads; here is what has happened:

The Short Production Run

A while ago, our R&D house in Sydney suggested to us a change of production facility from the one in Malaysia which produced the first shafts for us. This was for commercial, not technical reasons. After some research, they have suggested another facility, based in Taiwan but with a factory in Xiamen which currently makes golf shafts, ski poles etc, and they are keen to take over production of both heads and shafts. The tooling has been sent to them.

Whilst this change over was in progress, we asked the R&D house to produce a short production run of Series 4 heads for people who were anxious to get their hands on as Series 4 head without delay. The have been a few failures among those short production run units.

The Problem

The technical analysis of the problem has been as follows:

The tungsten weight is inserted in the form of shot- ie spherical balls - which is loaded into cones at either end of the head, and is then fixed in a composite material. The composite material composite material contained small round beads which fit between the tungsten balls, and resin. It was thought that this "tungsten in porridge" composite would be stronger than makes any difference, but the failures have involved a rupture within that mass.
This is surprising, but can be readily fixed for the future, by introducing microfilaments of glass fibre. These now hold the tungsten mass together in a way makes it hugely much stronger than the original recipe. Why was this not done in the first place? Apparently it is simply because composite manufacture typically involves looking for maximum strength with minimum weight, and the filament solution is fairly heavy, and thus not something that composite engineers usually do. But, at these extremities of the head, weight is what we are looking for anyway, and so the unusual step of using filament is good. The microfilaments also, it seems have, an added benefit, in that they increase the bond strength of the bond between the endplate and the rest of the mallet, by acting like little anchors into the bonding material (there has been no failure of this bond, but the greater the strength of every link in the chain, the better)
The original recipe seems to have been marginal; even slight differences in the mix can produce fairly wide differences in strength, it seems, and the failure looks like one that is likely to happen soon or not at all [see PS1]. Both the prototypes were fine, as are some of the short production run units.

The R& D guys in Sydney had 2 heads left from the 1st run. They took off the end plates, refilled them using the filament material, and sent one to me to test and the other to a player to test in the ACT.

The testing has been reassuring [see PS2]. We have been using the modified heads as hammers on concrete without ill effect. There is every reason to believe that the new configuration is fully durable.

If you have a short production run Series 4 head

If you have a short production run Series 4 head, the advice is: take your mallet out and whack some cannons as hard as you will ever play in a match. If there is no failure soon, there will probably never be a failure. If there is a weakness in your particular head, better to find out now than risk a failure during a match.

We will of course replace the head without charge as soon as we are able with one with the modified filament system, whether your one has failed or not.

In the meantime, some users have been taking the opportunity to check that their weight choice is right for them. If you want to change weight, feel free to say so.

Replacement Series 4 Heads – When?

We are now getting full production underway. The new production facility will first put out some samples, using the existing tooling. Ultimately, it seems that that they will want to recut the tool (mould) and I am going to get them to slightly reduce the width of the head from 65 mm to 58mm (the 3 weight choices will stay the same).

This production should be through rapidly - within a month we hope. But I have to repeat that the time estimates I have been given on previous development issues have all blown out to at least some degree, and the best I can do is to keep pushing.

Comment

Of course, this has been a set-back, albeit that we are confident that the bug has now been fixed. I guess that this sort of thing goes with the territory of innovation; if it was easy, someone would have done it all a while ago. The early users have been very understanding, and I hope that for these early users, the advantage of being first in the field with the Series 4 compensates for the short-term inconvenience.

Robert Fenwick Elliott

24th July 2006

Postscript

PS1

We spoke too soon. There has been a further failure of a short run in the UK a day or so ago. During a game of golf croquet, which is particularly worrying. And so it seems that, whilst a failure is likely to happen soon or not at all, a delayed failure is also possible.

PS2

The two remakes have both been working well, without mishap. Tim Murphy recently took one to victory in the NSE doubles; see news.

22nd August 2006