One question I am routinely asked is recommending the correct sized shaft extender for a particular shaft. While this may sound cut and dry, it is not always the case. Let us discuss the difference between extending steel and graphite shafts in selecting the correct size.
Determine Extension Size for Steel Shafts
There are two primary size shaft extensions for steel shafts. They are for 0.580” and 0.600” shafts or the two most common sizes in golf. That is referencing the outside diameter of the butt ends of the shafts. There have also been 0.560” and 0.620” steel extensions, but I do not believe there are current shafts with those diameters today.
Before you promise to extend a shaft for a customer, always measure it first with calipers or micrometers. If you do not have these tools, it is possible to look up the specs on the internet as manufacturers will publish the outside diameter of their shafts. There are steel-shafted golf clubs with shaft diameters different from these, such as 0.610” and 0.500”. The latter is for junior golf clubs. Commercially available extenders do not exist, and you will have to create your own extenders for those.
If you are curious, the butt end of steel shafts will typically have wall thicknesses of 0.020”. Therefore, a 0.600” outside diameter steel shaft has a 0.560” inside diameter, while a 0.580” outside diameter steel shaft has a 0.540” inside diameter.
Commercially available steel shaft extensions have been traditionally made of steel. However, there are shaft extender made of nylon that are strong enough. However, most clubmakers stick with extenders for steel shaft made from steel.
Determine Extension Size for Graphite Shafts
While determining the proper size extender to use for a steel shaft is fairly easy, graphite shaft extensions are more problematic. For starters, selecting the correct size graphite shaft extension requires measuring the inside diameter of the shaft, not the outside diameter. Graphite shaft wall thickness vary considerably. How much? Well, we offer 13 different sized extenders specially for graphite shafts and there are still certain sized shafts we cannot extend.
Manufacturers do not publish the inside diameter of the shafts, only outside diameters. Even if they did, the difference between the raw, uncut shaft and the shaft when cut to length can vary depending upon the length of the parallel butt section (if any) and how short the club is. Constant taper graphite shaft will vary in diameter along the length of their butt section.
If you do not have calipers to measure the inside diameter, we do offer a handy little color-coded shaft golf shaft measurement gauge to help make your selection.
If you are extending a whole set of woods or a set of irons, will that mean that you need the same size graphite shaft extender? Not in all cases. However, if you measure the inside diameter of each shaft and the difference is exceedingly small, you can get away with ordering the larger size and then hand sand the portion going into the butt end up to 0.020” to fit. Beyond that, you will need a mixture of sizes.
Summary
So to recap, commercially available steel shaft extensions are based on the outside diameter of the shaft and graphite shaft extenders are based on the inside diameter. Always physically measure the shaft. Even if you know the manufacturer used a 0.580” butt end steel putter shaft, the shaft could have been cut down for a shorter person or junior golfers where it removed the parallel but section. Steel shafts have relatively similar wall thicknesses in their butt ends, while the butt end graphite shaft can vary greatly. Lastly, it is best to match the extension material with that of the shaft.
Understanding the differences between extending steel and graphite golf shaft is important in any size clubmaking operation. By following these ideas, it will make this task easy to accomplish when the case arises.
