Newer Excel Swingweight Calculator

[joostin]

2/12/23:  Updated version "Swingweight Calculator+" Excel file download in this thread:

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For latest version go to link above.

Previous version 3/24/21, Excel file download:

Swingweight_Calculator_20210324.xlsx

 

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Updated notes 4/29/22:

 

Swingweights come out the same as online calculators from Hireko and Okrasa.

 

My intents for the Excel version were:

 

- Accuracy.  A scale is only as good as its tolerances, calibration, and the person's accuracy.  A calculator is perfect, but only as good as the person's accuracy.

 

- Give SW instantly to 0.1 decimal (Leaderboard one fluctuates, rounds to whole numbers, and judging where the line fell on the hash marks it's not clear if say D1 or D1.5).  Again, a calculator in itself is perfect (person measuring is not), why not give a more precise number?  As a hobbyist I can take all the time I need to measure gram weight to 0.1g and balance point to 0.5mm, then just enter those 2 numbers and let the perfect calculator give a SW.

 

- Something to calculate and record all clubs in one place, and be able to tweak specs in the same place.  The Excel one posted years ago by dieselG was great, and I took that concept for my own version.

 

- Something to determine SW numbers if I were to modify with lead tape, or to hit a SW number on the nose without guessing. (Moreso the prior as I try to modify by feel)

 

- Something to see what happens to SW when I choke up on the club

 

More recent post:

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OP from 4/26/20 when I was dumber:

 

Hey guys, I made a new swingweight calculator spreadsheet - link at bottom. For years I've been using the one from @dieselG because it's great, but wanted to see a few things differently. I actually think a calculator can be better than using a scale because it doesn't deal with any manufacturing tolerances. If you’re off, it’s on you and your own measuring accuracy.  If you have time to be meticulous (like measure to within 1/32" and 0.1 gram), that's awesome.  The algorithm is basically what the scale is trying to reproduce, and a calculator can easily show to 0.1 swingweight unlike some scales.

 

This new calculator addresses a few things I wanted to see:

 

- Like @dieselG's, just type in a description of your club(s), the gram weight, and the balance point's distance from the butt end of the grip in inches.  If you're not too familiar with Excel, you can type in the fraction if it's easier for you. For example: 32 3/8 (32 space 3/8), then enter; or just type in 32.375.  To measure balance point I'm a fan of @Howard_Jones's method where you put a piece of tape on the shaft, balance the club on a blade edge, press a little to mark the tape, then measure to that mark.

 

- It seems the actual baseline standard for swingweight is a little up for debate. Dave Tutelman's research shows D0 at 213.5 oz-inch (or 6050 gram-inch.. rant below). Others I've seen online including by @Nessism show 213.25 oz-in. It doesn't really matter - just 0.14 difference in SW – but I’m picky, and unfortunately that can actually be rounded a whole SW either direction if caught somewhere in the middle.  So I'm showing both SW readouts in columns F & G, to 0.1 SW, but I default to column F because Tutelman is The Man.  You can hide a column if you choose sides.

 

- For you Excel people - and again probably no one notices or cares - the VLOOKUP formula in @dieselG's (or anyone else's) sheet will round down to the next lower number even if it matches a number.  That results in 0.1 SW too low sometimes, which drives me nuts!  I moved the lookup table to another sheet, switched the formula to INDEX/MATCH, and tricked it to round up or down correctly.  Also it goes from A0.0 to Z9.9!  I don't know nearly as much as real Excel nerds, so I'm gloating a little to have figured out the formulas esp. in column G, haha.

 

- I wanted to show the actual torque values for both a 14" fulcrum and a zero fulcrum - torque at the butt end - like what I showed in my "mad lead tape scientist" post.  And it's oz-inch, not gram-inch.  No physics or engineering class mixes metric with imperial units in an equation/result... come on boys and girls (even you Tutelman :)!  Inch-oz, oz-in, ft-lb, or lb-ft is cool.  I don’t know how useful it will be, but I like absolute values (to be within 1 oz-in for example), and think the torque at the butt end can be a powerful tool down the road rather than sticking to the old 14" SW scale numbering.

 

- Also wanted to show MOI at least in it's simplest form, I=mr^2.  It assumes the club is a point mass at the balance point from the butt end, because that's the best I can do without an MOI device or building a pendulum or disassembling all the components to find their individual balance points.  How close it is to reality?  I don’t know.. You real club builders and people with Auditors can let me know!  Again, I don’t know how useful it will be, but I think it can be.  *Disregard this OP MOI note!*

 

- Prints in one page if you don't mess with the columns and rows too much (print 100% or scale to fit on 1 page).

Best part of all this:  Like me, you don’t need any equipment for all this info – just the spreadsheet and ability to measure accurately. The calculator can be downloaded here:  *Edit: see above for latest version*

If it gets taken down or doesn’t work, you can PM me.  It can be messed around with and tweaked. That's it for this quarantine session.  I have some ideas around progressive swingweights / SW slope, but that'll have to wait for another post.  Thanks for reading and stay safe.

 

TLDR:

Get a SW scale.  If you don't want to get a scale use this or an online calculator, but be very meticulous with your measuring for the best accuracy!

Edited March 4, 2023 by joostin
Pointing to updated thread

[Howard_Jones]

Short input only....dont use imperial for BP, use metric, unless you have a ruler with a resolution down to 1/32" who is equal to 0.79 mm, (1/16" is not good enough).

To be able to measure BP as best as we can, use the "knife on the vise method" and when done, place the ruler and the butt end of the club against the same wall as point zero.

The right numbers of OZ is 213.5 so the first club in your example has a SW value of D 3.2

Your MOI calc is whats called #2 MOI or "area MOI" and it does not represent the dynamic MOI value, but is whats used for construction beams

I really dont know how far of we gets, but there is a few hundred points up to the return values the dynamic MOI value form a Auditor scale returns.

[Stuart_G]

@joostin said - Also wanted to show MOI at least in it's simplest form, I=mr^2. It assumes the club is a point mass at the balance point from the butt end, because that's the best I can do without an MOI device or building a pendulum or disassembling all the components to find their individual balance points. How close it is to reality? I don’t know.. You real club builders and people with Auditors can let me know! Again, I don’t know how useful it will be, but I think it can be. 
It's going to be very inaccurate (due to the fact that the head concentrates a lot of weight at the end of the club) so I wouldn't bother with MOI in that particular form. Without at least breaking the club down and looking at the individual component weights and distances from the axis, it's really just wasted effort at best. You'd be better off making assumptions (coming up with a best estimate) about the head weights and using the online specs for grip weight.

[joostin]

You heard him, 213.5 it is! I agree to measure in mm if you can. My 4 ft ruler has mm on one side so I use that mostly because the imperial side only has 1/8" hash marks. It's more accurate in mm and easier to tell if you're in between hash marks, and you can eyeball to about 0.5mm or 0.020". I'll convert to imperial because like most of us in the US it's hard to think in metric (we design in imperial at work but also have to work in metric at times). The MOI equation in the calculator is for a point mass rotating about an axis at a distance, r, and will have the same units as an Auditor will give (kg*cm^2). The 2nd moment of area is different and in units like in^4 or cm^4... took a couple civil engineering classes way back in college which were pretty cool.

[ChaosTheory]

Good work. Thanks.

[joostin]

Understood. However I'm interested to see the numbers play out with an actual set that's been "matched" - whether a flat SW set, a 1.33 SW progression set, or true MOI matched set. It may be a couple hundred points low to an Auditor's readings, but maybe it's proportionate or has relative implications... don't know until it's compared. It may prove to be completely useless, but until then the column will spit out some numbers to analyze.

[Stuart_G]

I do understand your purpose for including it - but it's not going to be accurate enough to tell you anything useful even in that limited context. It just doesn't have any real relationship to the actual MOI of the club so the progressions will not be an accurate representation of the real MOI progressions. So any conclusions or paterns you might obtain or think you see from the data will also not be accurate or any real validity. It's just not possible for anything useful to come from data that is that inaccurate. And more importantly, you'd really just be looking at two different representations of the same simple point mass system so it really is not going to show you anything new that the torque numbers aren't already able to show you.

 

[Howard_Jones]

Tom Wishon had a excel file he shared some years ago, i never had it, but as i understand it, it returned the same values the Auditor MOI scale does.

[joostin]

Thanks Stuart, all thoughts, feedback, and learnings are welcome.

[360flip]

Just wanted to say thanks to @joostin for the spreadsheet. Was using leaderboard.com and hireko entering single club values at a time which was annoying.

[joostin]

2 hours ago, 360flip said:

Just wanted to say thanks to @joostin for the spreadsheet. Was using leaderboard.com and hireko entering single club values at a time which was annoying.

👍 I put the updated version at the top of the original post and a more recent thread since this one came back from the dead!