Easy DIY balance board and accurate SW measurement

bfroxen

Rookie
Here's my cheap, easy-to-build, and easy-to-store balance board. See further down for SW measurement.

Materials:
1. 18" ruler
2. 1/4" wooden dowel, cut into two 2" pieces and one 7" piece
3. Hot glue

Use hot glue to affix the two 2" dowels to the ruler with the dowels touching each other and the line of contact aligned with the zero point of the ruler (centimeter scale). Place the longer piece of dowel on the other two and align the racquet on top with the handle along the ruler. Twist the long dowel to find the balance point, and read the balance measurement from the ruler at the end of the handle.




For swingweight measurement, I found it difficult to accurately measure the distance to a hang string using the TWU method. I use a small rod attached to the butt of the racquet with three rubber bands as shown below. The rubber bands need to be tight enough to hold the rod against the butt when hanging, and the rod should be aligned with the face of the racquet.



Then, I pivot the racquet on the rod using pencils like in the TWU method. The hang distance is zero (or in this case, I used -0.1 cm to account for the height of the raised logo).

To measure the swing period, I use the 240 fps video recording of my iPhone. There is a free app called "CMV edu" that allows frame-by-frame analysis with timecode to the thousandths of a second and the ability to draw a reference line. I record ~25 swings, determine the time for 20 swings, and divide by 20 to get the period.

I created a spreadsheet (link) to do the calculations and simulate added weight. With a scale that measures to 0.1g and these methods, I was able to take a new racquet and add a bunch of weight to match it to my other racquets in just one attempt. Let's just say it was much more trial-and-error with less accurate measurements.

I hope this helps someone.
 

alidisperanza

Hall of Fame
Here's my cheap, easy-to-build, and easy-to-store balance board. See further down for SW measurement.

Materials:
1. 18" ruler
2. 1/4" wooden dowel, cut into two 2" pieces and one 7" piece
3. Hot glue

Use hot glue to affix the two 2" dowels to the ruler with the dowels touching each other and the line of contact aligned with the zero point of the ruler (centimeter scale). Place the longer piece of dowel on the other two and align the racquet on top with the handle along the ruler. Twist the long dowel to find the balance point, and read the balance measurement from the ruler at the end of the handle.




For swingweight measurement, I found it difficult to accurately measure the distance to a hang string using the TWU method. I use a small rod attached to the butt of the racquet with three rubber bands as shown below. The rubber bands need to be tight enough to hold the rod against the butt when hanging, and the rod should be aligned with the face of the racquet.



Then, I pivot the racquet on the rod using pencils like in the TWU method. The hang distance is zero (or in this case, I used -0.1 cm to account for the height of the raised logo).

To measure the swing period, I use the 240 fps video recording of my iPhone. There is a free app called "CMV edu" that allows frame-by-frame analysis with timecode to the thousandths of a second and the ability to draw a reference line. I record ~25 swings, determine the time for 20 swings, and divide by 20 to get the period.

I created a spreadsheet (link) to do the calculations and simulate added weight. With a scale that measures to 0.1g and these methods, I was able to take a new racquet and add a bunch of weight to match it to my other racquets in just one attempt. Let's just say it was much more trial-and-error with less accurate measurements.

I hope this helps someone.
Interesting gadget. Did you compare your measured SW to a machine?
 

bfroxen

Rookie
No, I have not compared the swingweight measurement to a machine. The physics are sound, so the accuracy of the result depends on the accuracy of the measurements (and lack of mistakes in calculation). The fact that I am able to make predictions and verify them by measurement indicates that the result is good enough for my needs.
 

10shoe

Professional
My first couple balance boards were homemade. The first one pre-dated extra long racquets. When the extra longs showed up I tried to make something reminiscent of a slide rule at the measuring end to accomodate various racquet lengths (pics below). The scales were printed with an inkjet printer and taped to the backs of 2 separate pieces of Lucite. They are now water damaged thanks to a small flood.

These days I have a Prince Tuning Center which gives readings as a balance point. I record that in my database and let the computer translate to points HL or HH for customer consumption.


 

Znak

Professional
NB: I need to adjust the mm side. Right now I only have 3 ticks between each 0.5cm instead of 4. Everything is sized correctly just need to make that mod will repost soon.

I wanted a board/beam for myself and I had a bit of time today so I whipped up a print-at-home template if anyone wants to use. I've made 2 versions, 1 if you have a printer that supports 11x17", and the other for your regular 8.5x11" paper (the latter you'll have to trim and tape together). I've factored in a safety margin of 0.25" so make sure you're printing them out at 100%.

I'm waiting for Amazon to ship my ink so I haven't printed them out yet, but I plan on laminating it since my wife has a small machine for her classes, will post follow up images. If you spot any errors let me know.

Link to 11x17 version: https://drive.google.com/file/d/1ynR9sWonrJy6iZl1penH232mdf6Rip07/view?usp=sharing
Link to 8.5x11 version: https://drive.google.com/file/d/164t1DYZRYP4NH2w4e8KSa2YuQ-z89Z6N/view?usp=sharing

**Edited versions to include all the mm:
Link to 11x17 version V2: https://drive.google.com/file/d/1A4AtWKzEkB2EcngcGeS1QLDdNNh7Znx7/view?usp=sharing
Link to 8.5x11 version V2: https://drive.google.com/file/d/1FkNn5FxKmE69TMal_dyaGfOWm_B0b27b/view?usp=sharing

 
Last edited:

Clash Ah ah

Rookie
I wanted a board/beam for myself and I had a bit of time today so I whipped up a print-at-home template if anyone wants to use. I've made 2 versions, 1 if you have a printer that supports 11x17", and the other for your regular 8.5x11" paper (the latter you'll have to trim and tape together). I've factored in a safety margin of 0.25" so make sure you're printing them out at 100%.

I'm waiting for Amazon to ship my ink so I haven't printed them out yet, but I plan on laminating it since my wife has a small machine for her classes, will post follow up images. If you spot any errors let me know.

Link to 11x17 version: https://drive.google.com/file/d/1ynR9sWonrJy6iZl1penH232mdf6Rip07/view?usp=sharing
Link to 8.5x11 version: https://drive.google.com/file/d/164t1DYZRYP4NH2w4e8KSa2YuQ-z89Z6N/view?usp=sharing

That’s great. It would be great to have all the mm’s between the cm’s. That’s all I can see is missing.
 

satchmo_d

New User
So using the dowels on the printout, would the two short ones that are glued together be centered on the “balance point“ line?
 

Znak

Professional
So using the dowels on the printout, would the two short ones that are glued together be centered on the “balance point“ line?
I believe so. If you'll be doing something like the method by the OP, as long as that main top dowel lines up with the balance point line you should be relatively accurate
 

Znak

Professional
Here's my cheap, easy-to-build, and easy-to-store balance board. See further down for SW measurement.

Materials:
1. 18" ruler
2. 1/4" wooden dowel, cut into two 2" pieces and one 7" piece
3. Hot glue

Use hot glue to affix the two 2" dowels to the ruler with the dowels touching each other and the line of contact aligned with the zero point of the ruler (centimeter scale). Place the longer piece of dowel on the other two and align the racquet on top with the handle along the ruler. Twist the long dowel to find the balance point, and read the balance measurement from the ruler at the end of the handle.




For swingweight measurement, I found it difficult to accurately measure the distance to a hang string using the TWU method. I use a small rod attached to the butt of the racquet with three rubber bands as shown below. The rubber bands need to be tight enough to hold the rod against the butt when hanging, and the rod should be aligned with the face of the racquet.



Then, I pivot the racquet on the rod using pencils like in the TWU method. The hang distance is zero (or in this case, I used -0.1 cm to account for the height of the raised logo).

To measure the swing period, I use the 240 fps video recording of my iPhone. There is a free app called "CMV edu" that allows frame-by-frame analysis with timecode to the thousandths of a second and the ability to draw a reference line. I record ~25 swings, determine the time for 20 swings, and divide by 20 to get the period.

I created a spreadsheet (link) to do the calculations and simulate added weight. With a scale that measures to 0.1g and these methods, I was able to take a new racquet and add a bunch of weight to match it to my other racquets in just one attempt. Let's just say it was much more trial-and-error with less accurate measurements.

I hope this helps someone.
Hey there, going through your excel doc, thanks for sharing! Under the constants tab, can you explain to me what the SW Axis is? Does this change per racquet? Cheers.
 

Ryebread

Semi-Pro
@Znak
thx for the file
VERY kind of you to look out for your family, here on the forum!
cheers

I've printed it out and not using anything on the balance point, I just taped the sheet to a spare wood shelf.
I moved the sheet of paper so that balance point line is right on the 'edge' of the shelf so that the racket can just fall off the shelf if it's pushed too far.
I find the balance point just before the stick is teetering. is this sufficient?
 

Znak

Professional
@Znak
thx for the file
VERY kind of you to look out for your family, here on the forum!
cheers

I've printed it out and not using anything on the balance point, I just taped the sheet to a spare wood shelf.
I moved the sheet of paper so that balance point line is right on the 'edge' of the shelf so that the racket can just fall off the shelf if it's pushed too far.
I find the balance point just before the stick is teetering. is this sufficient?
Hey of course np, sharing is caring!

I don't see why that wouldn't work — you might just have a trickier time reading the value, but I believe the concept is the same thing. Let me know how it goes!
 

Znak

Professional
With help from @bfroxen I finished my board and swingweight tool. I ended up using a cabinet door handle, I wish I spent the extra $2 and got a 6-inch handle, but it does the job! I also took bfroxens idea for calculating the swingweight and modded slightly. I found a zepp handle mount and tossed in a shaft rod as well used the app CoachNow since I'm on Android. Still testing out the spreadsheet, I think I got the hang of it, got SW 292.5 for a VCORE 95 (2018) unstrung, which sounds about right if you add around 30 for strings. In all I think I spent about $8 considering I had most things lying around. Not bad for a quarantine project!





 
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Znak

Professional
thank you very much for putting that together, made it so much easier.
Damn I was just working on measurements today and I think I made a bonehead move. I put 3 ticks instead of 4 between each 0.5mm groupings. The spacing and everything is correct just have to remeasure if it doesn't fall on a .0 or 0.5. I'll work on a v2 update later.
 

esm

Hall of Fame
With help from @bfroxen I finished my board and swingweight tool. I ended up using a cabinet door handle, I wish I spent the extra $2 and got a 6-inch handle, but it does the job! I also took bfroxens idea for calculating the swingweight and modded slightly. I found a zepp handle mount and tossed in a shaft rod as well used the app CoachNow since I'm on Android. Still testing out the spreadsheet, I think I got the hang of it, got SW 292.5 for a VCORE 95 (2018) unstrung, which sounds about right if you add around 30 for strings. In all I think I spent about $8 considering I had most things lying around. Not bad for a quarantine project!





Great idea on the SW setup. I was also thing about changing to similar setup, so unstrung SW can be easily measured.
can I ask if it is okay to see how you attach it to swing? I was thinking using the other side of my home made balance board to hang it for swinging. (Currently using the other side of the home made balance bird to hand the racquet on the top second cross to measure the string SW).
thanks.
 

Znak

Professional
Great idea on the SW setup. I was also thing about changing to similar setup, so unstrung SW can be easily measured.
can I ask if it is okay to see how you attach it to swing? I was thinking using the other side of my home made balance board to hang it for swinging. (Currently using the other side of the home made balance bird to hand the racquet on the top second cross to measure the string SW).
thanks.
Sure I'll send you a photo next time I test a racquet
 
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anarosevoli

Rookie
For swingweight measurement, I found it difficult to accurately measure the distance to a hang string using the TWU method. I use a small rod attached to the butt of the racquet with three rubber bands as shown below. The rubber bands need to be tight enough to hold the rod against the butt when hanging, and the rod should be aligned with the face of the racquet.



Then, I pivot the racquet on the rod using pencils like in the TWU method. The hang distance is zero (or in this case, I used -0.1 cm to account for the height of the raised logo).

To measure the swing period, I use the 240 fps video recording of my iPhone. There is a free app called "CMV edu" that allows frame-by-frame analysis with timecode to the thousandths of a second and the ability to draw a reference line. I record ~25 swings, determine the time for 20 swings, and divide by 20 to get the period.

I created a spreadsheet (link) to do the calculations and simulate added weight. With a scale that measures to 0.1g and these methods, I was able to take a new racquet and add a bunch of weight to match it to my other racquets in just one attempt. Let's just say it was much more trial-and-error with less accurate measurements.

I hope this helps someone.
Great idea, i also want to do this because I want to match unstrung racquets. Do I have to weigh the racquet and measure the balance point with that construction installed? Or is it irrelevant and the calculation will be correct when I only use the weight and balance point of the racquet? I know that SW is about the same with or without the construction but I'm not sure if it will be calculated correctly.
 

bfroxen

Rookie
It is not necessary to weigh and balance the racquet with the pivot rod installed. You could, but you'd end up getting the same result (within the limits of measurement capability).
 

tlm

G.O.A.T.
Here is my answer:
Yep I use a 3 sided ruler to balance the racket on and then find the center of the racket which with normal length rackets will be around 13 1/2”. So find the center point at 13 1/2” then measure from edge of ruler to center point and you have your balance. Every 1/8” is 1 point it’s simple and very accurate, no need to make a board up and have to store it.
 
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