"Swingweight Calculator+" Updated Excel + Normalized Swingweight Option. DIY Precision Measuring

[joostin]

Update to the Excel sheet I'm now calling Swingweight Calculator+ (kind of a Disney+ homage):

 

Swingweight_Calculator_Plus_Rev.0.xlsx

 

The previous one is here:  https://forums.golfwrx.com/topic/1713548-newer-excel-swingweight-calculator/ which had quite a few downloads.  Btw the title "newer swingweight calculator" was homage to diselG's "new sw calculator" from a post in 2011 (link), which was pretty much an extension of Tutelman's swingweight table (link), and same for mine.

 

Main Update:

 

There are posts that pop up all the time regarding grip weight and swingweight.  It's a popular practice and recommendation on WRX to measure swingweight using a standard 50 gram grip, rather than measuring with a midsize or jumbo grip on.  And of course StuartG has explained to stop using grip weight to adjust swingweight just about a million times!  To add to that, here are Mr. Tutelman's own words:

 

 

To address that I added the option to enter your grip's weight and balance point (normally about 4" from the butt) - whatever size grip you have.  The calculator will spit out an equivalent or "normalized swingweight" as if you had a 50g grip installed instead.  It will be more accurate than the approximation that you do in your head (5 grams = 1 SW point, lose 2-3 SW points going to midsize,...).  I could a add a column for a gripless swingweight, which should be heavier by 9-10 SWP, but I felt the sheet is already a bit busy.  Tape wraps can be included in your numbers.

 

Also I adjusted formatting and protected cells to help prevent errors, so it's a little friendlier especially if the user isn't the most Excel savvy.  It should also be a little better if you use it on cell phone like I do with the Excel app.  Swingweight was moved next to the club description for this purpose.

 

As mentioned in the orange textbox to the right of the calculator:

 

***Please Don't use Cut/Paste or drag any of the number input cells as it will mess up cell references.  Copy/Paste, Clear, Delete are all OK***

 

The following are examples of the flexibility of this Excel calculator.

 

Example 1.  For the simplest use, just enter the total weight and balance point, same as online calculators:

My driver above is D3.9.   However this is with a midsize grip...

 

Example 2.  Same driver as above but I entered the midsize grip weight and balance point to see the "normalized swingweight" as if the club had a standard 50g grip instead:

That comes out to D5.6 - almost 2 points higher as you might've guessed.

 

Example 3.  Adding 3 grams to the head, enter 3 and the distance of the weight to the butt of the club (keep ruler parallel to the shaft, like the diagram shows in the sheet):

Regular SW D5.8, normalized D7.4

 

Example 4.  If you were to use a 3 gram lighter weight screw, enter -3 and the distance of the weight to the butt of the club:

Regular SW D2.0, normalized D3.7

 

Example 5.  To see the effective swingweight when choking down the grip 1 inch, enter 1, then see the swingweight number on the right:

Effective SW C7.3 (no normalization for grip size as this is probably the least important or cared for calculation).

-------

 

There are some recommendations in cell comments.  E.g. Balance the club on a blade with tape protecting the shaft; preferably measure in mm; weight scale precision to 0.1g; etc.

 

There are disclaimers and notes in the orange textbox.  E.g. Get a real scale for ease of use and less chance of user error... Don't be a slave to a specific swingweight number on different builds! 

 

Free DIY calculators like this are fine for the hobbyist.  Assembled measurements are much better than calculators deriving SW from general component lengths/weights.  Just take your time to be as accurate and precise as you can.  Then it will be very close, if not spot-on, to an actual calibrated scale.  Again the calcs are straight from Tutelman's table (D0.0 = 213.5 oz-in, 1 point = 1.75 oz-in).  As mentioned in the past, the SW numbers you get here will be identical to those in the online calculators of Hireko (link) and Okrasa (link), and a little different than Leaderboard (my least favorite haha, link).  If you're like me, spreadsheet form is much more useful for recording, and you're able to test various scenarios like shown above.  This spreadsheet goes to 500 lines, so it can be an ongoing log if you like, but just be careful if you print, to not print all 28 pages 😄.

 

At the end of the day you want to be consistent with your own measuring methods and application.  Use swingweight as you wish, but be informed of its origins, limitations, and people's interpretations / misinterpretations.  Btw my own swingweight numbers are definitely not as even or evenly progressed as you might think due to going mostly by feel, and not really caring to hit exact SW numbers because the clubs work and feel good.  Hope it's as useful for some others as it is for me to record and play around with numbers.

Edited August 18, 2023 by joostin

[WasatchBogey]

Good work, thanks! Tried out the grip weight normalizer, works 👍 great

[BREWMASTER95060]

23 hours ago, joostin said:

And of course StuartG has explained to stop using grip weight to adjust swingweight just about a million times!  To add to that, here are Mr. Tutelman's own words:

Club MOI changes via grip and shaft weight VS head weight.
Varying component weights changes club Balance point.

Edited February 13, 2023 by BREWMASTER95060

[BREWMASTER95060]

There was a group on Yahoo called spinetalk.

he and I actually exchanged a few emails about 20 years ago

very smart guy.

If a grip weighed 10 pounds it would be hard to ignore. 🙂

Edited February 13, 2023 by BREWMASTER95060
Fix

[joostin]

9 hours ago, BREWMASTER95060 said:

Club MOI changes via grip and shaft weight VS head weight.
Varying component weights changes club Balance point.

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Yes.

For club MOI, the equation would be I = Σ(m*x²) for every single point of the club (as if the club was broken into a million tiny pieces), with m as the mass of each tiny piece and x being the distance from each piece to the butt end.  That's done on computer model, or it can be derived physically with a pendulum period like Tutelman shows, or an MOI machine of course.

[MFBach]

16 hours ago, BREWMASTER95060 said:

Club MOI changes via grip and shaft weight VS head weight.
Varying component weights changes club Balance point.

 

6 hours ago, joostin said:

For club MOI, the equation would be I = Σ(m*x²) for every single point of the club (as if the club was broken into a million tiny pieces), with m as the mass of each tiny piece and x being the distance from each piece to the butt end.  That's done on computer model, or it can be derived physically with a pendulum period like Tutelman shows, or an MOI machine of course.

I always like to proceed comments like this by clearly stating that I’m absolutely not a physicist… but isn’t the idea the same?
 

Grip weight is distributed so closely to the “fulcrum” that, while mathematically recordable/significant, it’s not as distinguishable during play as a similar amount of weight distributed at the end of the club?
 

At the end of the day, we swing a club with the handle/butt, not the balance point or 14” from the end? I’m still not fully confident in MOI build changes and their affects, so the change in total weight may be more significant compared to standard SW measurements? 

[AlohaPineapple]

thank you! the prev version was super useful, looking forward to playing around with this one

Edited February 14, 2023 by AlohaPineapple

[Skrimpdelite]

Thank you for this. Looking forward to utilizing it

[joostin]

11 hours ago, MFBach said:

 

I always like to proceed comments like this by clearly stating that I’m absolutely not a physicist… but isn’t the idea the same?
 

Grip weight is distributed so closely to the “fulcrum” that, while mathematically recordable/significant, it’s not as distinguishable during play as a similar amount of weight distributed at the end of the club?
 

At the end of the day, we swing a club with the handle/butt, not the balance point or 14” from the end? I’m still not fully confident in MOI build changes and their affects, so the change in total weight may be more significant compared to standard SW measurements? 

You're correct.  We have:

- mass/weight

- torque (in the swingweight case, weight times the balance point's distance to a fulcrum)

- MOI (above post)

 

If weight is added right on the fulcrum of an MOI machine (end of the grip), the MOI doesn't change... but total weight still does.  Then the farther that weight gets from the fulcrum the higher the MOI.  Likewise with a swingweight scale (14" fulcrum).

 

The swingweight scale is basically a torque measuring device that was a "good enough" practical way to get close to an MOI match.  But yeah, even a perfect MOI match doesn't necessarily translate to a swing feel match because of the swing not being on a fixed fulcrum, and there are differences in club weights and torques.  Then you have differences in swing planes, ball position, swing effort, ...

[joostin]

Quick note for anyone that uses the spreadsheet:  If you need to adjust column width, row height, or other formatting that is locked, you have to unprotect the sheet.  Find the Unprotect button circled below under Review.  There's no password to unprotect, and that will allow you full access to play with the sheet however you want.

 

 

Excel on my phone doesn't have that option, so I would do it on desktop/laptop.

[joostin]

I'll do a comparison to see what happens when measurements are off, but first an example of measuring with tight precision.

 

Finding balance point

Best is to balance on a blade edge, with tape that protects the shaft and gives some friction to balance on.  Also get the club as horizontal as you can:

 

Mark a little score on the tape with the blade and a fine marker or pen.  Butt a ruler and the butt of the club against the same flat surface like a wall.  Tape measure is fine, just push the clip in if pushing against a wall, or make sure it's pulled out if pulling against the butt of the club.

 

This measures at 718.5mm (convert to 28.287").  Even if your ruler or tape measure only has 1/8" hash marks, try to break that down by half (1/16") or by quarter (1/32") as best as you can.

 

Weighing

Best to have a scale that measures to 0.1 gram.  If not +/- 1 gram is not bad and still better than if the scale is +/- 1 oz.

Make sure the scale is calibrated if you can.  Weigh; take it off to bring back to 0 or tare to 0; weigh again.

 

Enter both numbers in Calculator+

This club comes out to D2.6

 

Correct vs Off Measurements

Here's the iron above, correctly at D2.6, vs what happens if a measurement is off by the amounts shown in the descriptions:

 

A balance point measurement that is off by 1/16" is off by half a swingweight point (but that rounds to D2 instead of D3).  1/8" is off by 1.1 SWP.  Half a gram is only off by 0.1 SWP.  1 gram is off by 0.2 SWP.  1 oz is off by 1.1 SWP.

 

Again if you're not able or inclined to measure precisely, or you need something quicker or less error-prone, by all means get a real scale!  Otherwise if you can measure as precise and consistent as you see necessary, no worries if you don't have a scale.

 

Plus... as in Swingweight Calculator+ 🙂... with this you can calculate things pretty easily without having to physically try them on a real scale, and as shown in the 1st post, calculate things that online calculators can't without physically altering and redoing balance point and weight measurements.

Edited February 18, 2023 by joostin