The subject of frequency matching golf clubs comes up frequently (pun intended) across many golf forums. It is a rather simple process, but requires a consistent method. I assume that your frequency meter (now called freq meter or FM) is bolted steadfastly to your workbench and that you are familiar with the operations of measuring club length and clamping clubs into your meter. I would suggest that anyone here would first read the resource EQUALIZING GRAPHITE SHAFT TIPS by Patrick Blair in the leading edge resources folder. This is a very good methodology for producing varying sloped clubs that will adjust the actual feel of the club to a desired level. (Pat wanted his wedges to be softer.) I am presenting a way that the clubs will all feel the same way. I guess you could call my treatise a precursor to Pat’s. This method is used for either graphite or steel shafts. The equalizing shaft section is taken in part by a process used by Keith Chatham. I am unsure if it is of his own doing or someone else’s doing.

Make sure your FM is bolted down very well to the bench and make sure you can get duplicate readings on the same shaft before you start. You should be able to get acceptable readings. For instance a range of acceptable readings would be: 245, 246, 244, 244, 245, and 246. These would all be for the same shaft. If you can not achieve these types of results, your FM is not bolted down well enough or you are not twanging the shaft consistently enough. I use a cable tie that is mounted to the bench. Some use a piece of wood with a notch or just their finger but they keep their hand in a predetermined position on top of a block of metal or wood.

1. EQUALIZE THE SHAFTS

If you are making eight irons, pull them out of the bin and identify each one by a number. You must have on hand an iron tip weight or any club head. Measure your raw shaft length. If there is any shaft that is longer or shorter, make sure to mark all of the longer shafts to the shorter shafts length at the butt. Here we will measure the raw shaft CPM.

Insert shaft #1 into the clamp. The butt end of the club will be at the outside end of the shaft clamp. Install your tip weight or club head via rubber band, plastic wrap, or bubble wrap. As long as the fit is snug, it doesn’t matter what you use. Measure the frequency of the “club” at least three times. Write down your results and if any result varies by more than 1 CPM high or low, throw out the reading and ensure the “club” is properly clamped, your shaft to head fit is snug, and your FM clamp is still bolted stoutly to the bench. Repeat this process for the other shafts in the set. Use the SAME tip weight or club head when measuring the raw shaft CPM. At this time, your raw shafts should be re arranged into playing order. For the most part, the shaft with the lowest reading will go in the 3 iron and the shaft with the highest raw shaft CPM will go in the PW. The other wedge shafts might be a totally different design, weight, or flex based on the needs of the player. Indeed, they might just be an extension of the set or much softer or much stiffer than the others. Again all based on the needs of the player. Rename the shafts as 3 iron, 4 iron and so forth.

Some club builders will also use shaft weight to sort their shafts. It is a similar process to that above, but they will first grab their shafts and weigh them on a gram scale. Then they will equalize to raw shaft CPM as above. I find this just adds an extra step in that usually the heavier shafts will have higher raw shaft CPM readings anyway.

2. TIP TRIMMING SENSITIVITY (TTS)

You will need to know how the tip responds to trimming. If using a new shaft, you can use an old bore thru iron. One without a hosel is best. Make sure that the hosel hole has been reamed out to .370 before you start to speed things up. Insert the shaft tip into the bore thru. Make sure the shaft tip is flush with the bottom of the club sole. Use a piece of rubber band or plastic wrap to wedge between the head and the tip of the shaft. Some shafts will be slightly over .370. You will either have to enlarge your hosel hole or sand/scrape the paint or chrome off the shaft tip.

Now, in investigating a shaft (I do a similar technique with an Apache Multimatch machine) you are just trying to find out how much the frequency will change for cutting an 1/8th of an inch because you are looking for your tip trimming sensitivity. An 1/8th inch is a reasonable expectation of repeatable measurement. At this point, you want the measurement to be as small as possible, but not so small that you can't hit it consistently.

You need to measure the length of the "club" you will be building. Say you believe your 6 iron standard length to be 37". You will want to create a "beam length" of 37". You will put the "club” (the one with the shaft inserted into the sole line in the bore thru) on your chosen measurement device. Measure the sole to butt length of 37". (I will now call this the beam length. ) Use a highly visible Sharpie or marker to draw a straight perpendicular line on the shaft. Take the "club" out of the measuring devices and put it into your freq machine. Match the line you made on the shaft to the outside end of the freq meter clamp. Tighten down. This setup has a beam length of 37 inches. Now twang the shaft. Repeat at least three times. Write down your readings. If there is one that is way off, make sure you are bolted down well and the clamp or rubber band hasn't loosened up. Repeat that reading. It should be within 1 CPM of the other readings. If not, you are still not bolted or clamped down properly.

Ok, now, remove the shaft from bore thru head. Get another piece of rubber band (plastic) and insert the head on the tip. Expose 1/8th inch past the sole line of the club. You must again measure the club. You can simply take a rule and measure 1/8th HIGHER on the butt to make your new shaft line. (1/8" is exposed through the bore thru bottom. You can't use the same line on the shaft butt because that club would 1/8th" shorter....therefore move the line up 1/8th" closer to the butt to get your standard iron reading.) Repeat as before. Write down your readings. The beam length is still 37 inches, you are just measuring it 1/8th of an inch further up the shaft. Continue and repeat this process until you have measured all of the parallel tip of the shaft.

Each shaft will have a certain amount of parallel .370 tip (except of tapered .355 shafts.) If parallel tip section (PTS) is two inches let's say, you will continue as above until there is no parallel tip left at the top of the hosel of the test club head If you are writing your measurements down, there might be some consistencies in the reading or there might be some inconsistencies. For instance, I have one iron shaft that takes 1/4" to move 4 CPMs. I have another one that moves only 2CPMs. You might have an inconsistent shaft reading or you might have an inconsistent shaft. Try another shaft just to be sure.

If you need to cut 1/4" off the tip (in our test above) to have a 2CPM movement, and it is consistent for the entire parallel section, the shaft will have a 8CPM tip trimming sensitivity (TTS). That is if you cut 1", you will raise the frequency 8 CPMs. If a shaft has a 6CPM tip sensitivity per inch, then the frequency will change 6cmp for every inch you cut off. You will find some shafts will change one amount for the first inch, then some other amount for the second inch and either stabilize or not for the rest of the parallel tip. It is up to you to keep a record. If the first inch changes the reading by 6 CPMs and the second inch changes the reading by 8 CPMs, you will have a variable tip trimming sensitivity. You will of course keep a record of how the trimming changes throughout the entire parallel tip section if the amount is variable. If you notice a consistent TTS except for the last inch or two on a shaft with a lot of parallel tip section, you have probably run into an issue the shaft designer did not anticipate. Especially if the TTS is greatly reduced, I wouldn’t cut the shaft that much. It is very likely that you’ll get a club at that point that loses its feel relative to the other clubs in the set. If you get a shaft from a different lot, they might change just a little bit (rare), but you will soon find shafts that are the most consistent and (hopefully) you will use those. Watch out for shafts that are butt trim only they will fool ya!

I personally identify the spine location for this measurement process and put it in the "twang line" of the shaft.....that is, I put the spine in the same direction as the shaft moves up and down when I check the frequency. I feel this adds consistency to my process. Explanation of spine identification and location is available in the Resource area of ICG website.

3. WEIGHT MATCH THE HEADS

Gather together the iron heads you are looking to match. Weigh each one on a reliable gram scale. There should be an increase of 7 grams per head as you go up in the set. For example, the 3 iron weighs 240 grams, the 4 iron weighs 247, and so forth. Don’t worry about any wedge heads besides the PW at this point. This process is called weight sorting the heads.

If the weights are inconsistent, you will need to add some lead tape. Here is an example:

Because the 5 iron, 9 iron, and PW were all one gram heavier than spec weight, we will have to add weight to the other iron heads to be sure to achieve a 7 gram weight progression between the iron heads. We arrive at our final weight after adding lead tape or by adding weight into a weight port designed by the club head manufacturer. Weight sorting the heads will allow us to achieve an easier frequency match of the heads and a much more consistent feel in the final product.

4. STARTING THE FREQUENCY MATCHING

With your fitting process or the spec sheet you have obtained from the club fitter, you will have a certain frequency in mind to start out with. We need our 3 iron to be 240 CPMs. You will take your 3 iron head and install it to the 3 iron shaft as above by using plastic wrap, bubble wrap, or a rubber band. I also make sure the spine is at 12 0’clock. Make sure you are using the exact 3 iron head you want in the set with any tip weights, port weights, or lead tape installed on the head from the onset. We will also know the length the 3 iron should be, it’s swing weight, and the type, weight, and size of grip to be used.

We want the 3 iron to be 38.5 inches long. Take the shaft and head that is wedged together from the above paragraph and measure it to 38.5 inches. Make a perpendicular mark on the butt end of the shaft to indicate this length. Install your shaft/head combination (now called THE CLUB) into the FM clamp. Measure the frequency at least three times as outlined above. Your reading should be within 1 CPM of each other, say 231, 230, and 232. We will average the reading to get 231. We determined before that our shaft has an 8 CPM tip trimming sensitivity. We will pull the head from the shaft while clamped in the FM (this saves time.) Then we pull the shaft from the FM clamp. As we need to get to 240 CPMs, cutting an inch will get us to 239 CPMs. I would suggest cutting an exact inch from the shaft. (As our reading was an average, we might really have a shaft that starts @ 232. Cutting an inch will get us right to 240 CPM. It is always better to have to go back and “cut a little more” than to have to start over with another shaft!) We go ahead and do so. Reassemble the head on the shaft; measure again to ensure a beam length of 38.5 inches (the new mark will be an inch closer to the butt of the shaft because we cut an inch from the tip, remember?) Install the shaft into the FM clamp at our new mark and test again at least three times. Our measurements are 239 CPM, 240 CPM, and 240 CPM. As our average reading here is 240 CPMs, we will put the 239 reading down to the repeatability of the equipment. You can always test another couple of times and make sure the readings are still 239 CPM, 240 CPM, or 241 CPMs. For the purposes of our example, however, we will consider that this reading is 240 CPMs. Move onto the next step, still using the 3 iron.

5. SWING WEIGHT MATCHING

It will be necessary for the club maker to obtain a number of left over butt cut offs from previous club builds. Try to use steel shaft butts for steel shafts and graphite shafts for graphite shafted clubs. The best scenario would be to have the same type of butt cut offs as you the shaft you are assembling, but that is indeed too much to ask. Try to make sure the cut offs are from the same type of shaft. For example, use all dynamic gold regular steel. You will want a range of sizes from _ inch to at least 4 inches in half inch increments. These cut offs will approximate the weight of the shaft that will eventually be cut off. We can’t cut off the butt of our 3 iron yet, as if we do, and our swing weight is incorrect, then when we add or subtract the weight necessary to achieve a certain swing weight, then we change the frequency of the overall club and have to start over! Indeed, this is a balancing act (pun intended!)

We must measure how much shaft butt is left beyond the sharpie mark at 38.5 inches. There is 3.5 inches of exposed butt beyond the line. (In future measurements, just measure the amount of butt that extends beyond your frequency meter clamp.) As we are using a regular steel shaft (i.e. dynamic gold,) we should get a 3.5 inch butt cut of a similar shaft. We need to also look at the weight of the grip we need to install. According our pretend specs, our grip is an XYZ model that weighs 50 grams. Fortunately, we have another similar grip available that has a slit down the side and has the butt hole enlarged that weighs exactly the same amount as our target grip. (Think balanced certified please.) The grip is slit down the side so we can slip it on our 3 iron without having to cut the extra butt section off. If there is minimal or no build up tape required, then use as is. The weight of the double sided tape we will eventually use to mount the actual grip is minimal so we don’t have to specifically account for it here. See below.

Slip the slit grip on THE CLUB, making sure that the Sharpie mark 3.5 inches from the butt is equal to the butt end of the slit grip. Put the club as you normally would on your swing weight scale, making sure the butt of the club hangs past the end line of your swing weight scale. This can be achieved by specially machining a hole at that point of the swing weight scale or by using a cable tie to hold the club on the swing scales beam. The cable tie adds minimal weight. We are trying to achieve a maximum of 1 swing point variation. I have found that as long as I use the same cable tie for all the clubs in the set, we get to within _ swing weight point at the end. Again, we are trying to pull the swing weight and the frequency to within acceptable and measurable limits.

To review, we have our 3 iron in the swing weight scale with the butt hanging off the back or through a hole in the back of the scale. The proxy slit grip is installed ending at 38.5 inches and the rest of the club is on the swing weight scale. Take the 3.5 inch butt cut off and attach it to the sole point of the club (where the shaft would poke out on the head) with a piece of masking tape. This piece of butt is a proxy for the weight that is hanging off the back of the swing weight scale. Balance the scale. We have a reading of D0. We are a little light of our target measurement. We will have to add an additional two grams of weight to our hosel port or tip weight. Just to verify the balance, add two grams of lead tape to the bottom of the club…either where the tip weight would be on the inside of the club or just add lead tape to the sole if that is your methodology. Re balance the swing weight scale. We should now have D1 swing weight. But wait a second, our frequency will now be off right? (Because we added some weight to the head area to balance the swing weight scale.) It’s back to the frequency meter! Take off the extra shaft butt you added to the head to counter balance the shaft remaining attached to the shaft we are working on. Also, remove the slit grip and keep it handy.

Re-clamp THE CLUB into the frequency meter clamp (shaft spine in twanging direction.) If you are using the weight port or tip weight, pull the head and use whatever type weight you will need in the final presentation of the club. Don’t forget to remove the 2 grams of lead tape we used as a quick balance on the swing weight scale. Keep that handy though, you might be able to reuse it down the road on the other clubs. Twang your newly re weighted 3 iron. You get readings of 237 CPM, 238 CPMs, and 239 CPMs for an average of 238 CPMs. We are 2 CPMs softer than our target. We need to pull the head from the shaft, use our TTS and figure out how much more tip we need to cut to get back to 240 CPMs. Our shaft has an 8 CPM TTS an so we need to cut an additional _ inch from the tip. Do so, but make sure your cut is very exact. Many club makers will cut to the left of their line, the right of their line, and so forth each time. It is personal preference. It doesn’t really matter as long as you remain consistent in your building practices. Re-assemble your 3 iron using rubber bands, mount in the FM clamp and test your club. We got readings of 239 CPM, 240 CPM, and 240 CPM this time with the added weight. Looks like we are very close to what we need to achieve.

At this point, if I personally would be very sure of myself as I have assembled thousands of clubs in this manner. I would cut the butt of the shaft at this time, making sure I re measured the beam length to be 38.5 inches. I would use the slit grip and mount THE CLUB into the swing weight scale. We should achieve the D1 reading (to within ?? swing weight point.) If not, we missed something like the beam length is incorrect, or our original swing weight reading was incorrect.

It could also be that the balance point of the shaft has changed tremendously compared to what we predicted by using the butt cut off at the head end of the swing weight scale. If you are cutting off more that 3 inches or so from the butt area, make a preliminary cut that is just 3 inches (or even closer like _ an inch if you have a TTS of 8 CPMs or higher and have plenty of parallel tip section left.) If making a preliminary cut and leaving some extra length on the butt, re check the swing weight with the butt cut off on the head. If you are still close, the chances are the additional extra change in butt length will not affect the over all swing weight of the shaft by more than _ swing weight point. Shafts like the True Temper TX-90 or any other steel shaft that is sub 100 gram cut weight will almost always result in a change in swing weight if you are cutting quite a bit from the over hanging butt section. Double check these types of shafts with a preliminary butt cut of at least an inch..

6. ACHIEVING FREQUENCY SLOPE

We will now assemble the other clubs in the set as we did before. However, each target frequency will change based on its length. For the most part, clubs will tend to get a higher frequency reading in CPMs as they get shorter in a set.

The slope part of what we are trying to achieve is if the length of the clubs are plotted along with the frequency. The consistent slope will have a similar amount of frequency change for a certain amount of overall length change. Defining SLOPE is beyond the nature of this article. However, be aware that there are all kinds of slopes. Some feel a certain type of slope fits a certain type of golfer (hitter, swinger, etc.) There are certain types we might want all of the frequencies to be the same (FLAT LINE SLOPE or SINGLE FRQUENCY SET.) There are also REVERSE SLOPES where the clubs get softer as you move to the shorter irons in the set. And there is the MODIFIED FLAT LINE SLOPE that increases 1 CPM for every club in the set. Many club makers will stop increasing the frequency of the clubs at the 8 iron because they feel that many players will not make the same swing with their 9 irons and up as they do with the 8 iron and down. Indeed, this is somewhat the basis for the Rifle spinner shafts that are out there right now. My present irons are all sloped normally from 4 iron to 8 iron. The 9 iron is the same as the 8 iron and the PW and other wedges are progressively softer as they go up in loft.

Making these different slope types to the golfer is what we mean when we say that golf club fitting is part art and part science. There is no right or wrong answer because each golfer will feel them differently. The only slopes that are correct is the one in which the golfer achieves an ability to hit the ball consistently or more consistently than his present set. For our example, the 4 iron will be 241 CPM, the 5 iron 242 CPM, and so forth. The is the MODIFIED FLAT LINE SLOPE from above. The PW will be 247 CPM. Continue using the same techniques above and you will achieve frequency matched irons.

7. ACTUAL PRACTICE VARIATIONS

If you are getting to a point where are your raw tip readings will get you close to the maximum parallel tip section of a particular shaft, you should probably use a flex stiffer that you currently have. I have found that shafts that are kind of dead when you remove the majority of the parallel tip section. This will result in less tipping for you and more feel for the golfer. You should work this out ahead of time based on the set layout. Don’t change a flex in the middle of building the set. The idea is to make the choices before hand to ensure that the clubs feel similarly club to club.

To experiment with this concept, purchase some shaft blanks that you would use in your own set. However, make one the flex you would normally use and purchase one a flex softer and one a flex stiffer. Assemble the clubs on the same type of club head (i.e. Ben’s 6 iron cavity backs…..make sure they are all Ben’s and they are all cavity back 6 irons.) Make sure your head weights, lengths, grips, etc are all the same. Keep track of which is which. Try to see if there are performance differences in the clubs. Look at shot height, feel, and balance point. Does one particular type make the club feel more solid? For most shafts, there is a noticeable change in feel and/or performance.

Sometimes I will simply sand down the length of a shaft on a sandpaper belt if I need to shorten the length by 1/16th of an inch. This is totally acceptable.

The preliminary results of the swing weighting process above are usually very good as long as you are using regular weight shafts (Raw weights of 115 grams and above.) As mentioned above, any shafts that weigh less than that will change their swing weight balance points by quite a bit when you have a bunch of shaft butt hanging off the back end of the swing weight scale. Even when counter balanced by shaft butt cutoff sections attached to the head for swing weight measurements. Be careful to ensure that you don’t have to throw that shaft away. I have gotten swing weight changes of over 3 swing points when using the lighter shafts. I use that process because I find that the rules of thumbs listed in technical areas on club making sites are sometimes taken too literally. That is, it is simply a rule of thumb, not a physical law. Preliminary cutting is especially useful when using a new type of shaft in which you are unfamiliar. It is possible that if you know a certain shaft and you realize you have a lot of butt cut that is going to happen to build to a swing weight measurement that is in reference to the actual swing weight you are going to achieve. That is maybe your target is D3 lets say. You might have to build to D5 for your numbers to really hit D3 when you are using more than two inches of butt extending out of the swing weight scale.

If you find you really like the results of manufacturers tipping instructions, you can plot their slope to see what they are trying to achieve with those instructions. For instance, say that you really like Dynalight Gold shafts from True Temper. Equalize the shafts as in step one above. Then just follow the manufacturer’s trim charts. You will waste one shaft (or be able to use it down the road in your pitching wedge,) but you will gain a hell of a lot of shaft knowledge. Make sure the heads you are using are all weight matched with 7 gram progress. The 3 iron will need to be cut one inch, the 4 iron, 1.5 inches, and so forth as outlined on the True Temper website. You will actually cut the tips off the shaft and change out the club heads for each tip trim set. You will also need to measure the swing weight of the clubs as well. (You will not change the swing weight by counter balancing with the cut off shaft butts, however. You are trying to see if the swing weight will change based on the True Temper trimming instructions only.)

By doing this set and plotting the frequency versus length (slope) you will find out the slope that True Temper is trying to achieve with the supplied trimming instructions. What happens if you just trim up to the eight iron (3.5 inches) and just switch out the head for the 9 iron and PW? (Remember to change the beam length to that of the 9 iron and the PW. These of course will be shorter than the 8 iron in a standard set.) You could try the same earlier in the experiment with different irons heads. Here’s a hint, but this is how to achieve different types of feels by short shafting tapered irons. The same idea can be used for graphite shafts and anything else. Good luck with your frequency matching. Hopefully this article will teach you the real truth about club making and club fitting. As soon as you think you have it figured out or have made a step towards understanding everything, a portal opens and you realize that there are many, many more things to learn. The only way to achieve ENLIGHTENMENT is to continue to learn and change as change occurs to you. BE GOOD!