How to Match Shafts

Dave Tutelman -- November 25, 2005

I'd like to thank Dan Neubecker and Bernie Baymiller, who took the first cut at these instructions. I had their framework to start with, which was a big help.  --   DaveT

The primary use of the NF4 in most shops is in building clubs so the shaft flexes are matched -- to each other and/or to a specification -- just as it is with a frequency meter. Here are the instructions for several different kinds of shaft-matching projects:
  1. Matching a set of irons.
  2. Other use of the spreadsheet, including matching a set of woods.
  3. Matching an existing club.
Before you go to the instructions for the specific job you need to do, be sure to review how to set up the NF4 for any matching job. Those settings are described next.

NF4 Settings for Matching

Here are the settings you should use to do shaft matching:

1. Use the lower position of the toggle board, as shown in the photo. A consequence is that you will use the L-shaped toggle stop to set the pre-load.
2. Generally, you should use the bearing side of the middle bearing assembly.

Most shaft matching is done with the shaft in its most stable position. This will certainly be the case if:
  • You are using shafts that have rather small spines -- as many recent models do.
  • You are matching shafts in the direction of the traditional Natural Bending Plane (NBP), as found by a bearing-based spine finder.
However, there are other possible approaches. For instance, suppose you want to match the shafts in the direction of their stiffest plane. (That's my preferred matching strategy with spiny shafts, though not many clubmakers subscribe to it. Also happens to be the one that Dick Weiss' SST PURE recommends.) In that case, use the V-notch side of the middle bearing assembly, and measure the shaft in its stiffest plane -- which you will have determined before you start matching.

3. Set the beam length at 32" for irons or 38" for woods. This is short enough that it allows measurement of clubs at the short end of the range. But it might not work for all sets. Consider:

A short club with a very stiff shaft might "peg the scale" -- load it to more than its maximum capacity. If you are working with an exceptionally stiff shaft, you might want to test for this condition early in the process, and go an inch longer for the entire matching process if you discover the scale pegged. The matching will be as good, for all practical purposes.

4. Take your readings using a precision of 0.03Kg.


Last modified by DaveT - 12/4/2005