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[Chompy9760]

This sort of thing is right up my alley!

The "calculate" button doesn't seem to be doing anything at the moment (using firefox), but I guess you may be tweaking it!

If you are making a calculator, it's probably best to not to ask the user to calculate and input "Balance point = (total bat length x w1) / total bat mass", when you have already asked them to measure and input all the data required and the calculator could be doing this automatically.

I'm used to physically balancing the bat and measuring that distance from the toe, while your calculated balance point appears to be measured from the handle, to within 3-8mm of what I've physically measured, so it's pretty close, allowing for scale weight issues.

Again, it helps to label what your figures actually mean.  It took me a while to work out that your "balance point" is actually "balance point in mm when measured from the end of the handle".  In the green input section, you could label "Bat mass Kg", "Handle Length M" etc to make it idiot proof.
Looking forward to playing around with it some more

[hewmanity]

When I'm weighing the bat with the toe on the scale I've  noticed that I can get a fair bit of variation in weight depending on how high I've raised the handle. For my measurements I got my scales and a pile of magazines at the same height of scales. However in the image shown, it appears that the book that the handle is resting on is quite a different height to the scales.

[Chompy9760]

When I'm weighing the bat with the ton the scale I've  noticed that I can get a fair bit of variation in weight depending on how high I've raised the handle. Fory measurements I got my scales and a pile of magazines at the same height of scales. However in the image shown, it appears that the book that the handle is resting on is quite a different height to the scales.

Agreed.  I've had problems getting toe and handle scale weights before, and it can be inconsistent, so my preferred method of getting POB is to physically balance the bat and measure that exact point.  When I tested 4 bats with the 'calculated POB' versus the physical measurement, the differences were -3.94, -8.95, -5.15 and +2.82mm

Yes,  I have all this sort of stuff on spreadsheets, and tend to overthink all these details.  When I hear people go on about 'pickup' and 'feel' my eyes roll to the back of my head.  Quantifying this sort of thing with facts and numbers is something I've tried to do before, but few people actually get it.  Many prefer to say "this bat weighs 2 lb 10oz but feels like 2 lb 7" , so I applaud your work on this David!  Interesting to read your blog and paper, although a lot of the paper goes over my head!  I'll did a bit deeper another time.

[jonny77]

From a batmakers perspective, I can appreciate some benefits and many drawbacks personally.

Obviously for people buying online, it may give a measurement for then to work from. But would they have this initially and what determines if that measurement they're working from is their 'optimum'?

Just not sure if it's a little confusing for consumers. Most people who come into my workshop are already confused over balance points, dead weights, middle position, Grade, pick up etc etc. There's already a lot going on and just not sure this, although intended to simplify, may just confuse matters more. Especially for people coming into the sport.

I'd certainly need to understand it more to advertise it with my bats, as I'd need to be confident in explaining it to customers. Who personally, I think in the main, would still go on scale weight and feel. As In said, this could benefit people buying blind. But they'd still have to know what their optimum was, not something I'm sure many would take time or have the ability to find out.

I think in order for it to be adopted to the masses, you'd have to clearly sell the performance benefits. (If I'm at my optimum MOI, what does that mean in terms of performance gains?) As there are so many variables determining a bats performance (not least the batter), would this measurement be overall that useful? It's fine having the right MOI, but if it's a plank with a poor handle, is that measurement worthwhile? Appreciate that these things should be a given, but they're not always.

No doubt I'll be called old fashioned by many, but I kind of like that some sport isn't over engineered. I don't like that it's sometimes sanitised somewhat, but then I'm not adverse to technology either. I've got wrapped up in it at times in golf, but at no point did in improve my game more than practice, education and playing more.

If you were in Leeds anytime, I'd gladly welcome you into the workshop to explain it further and test some bats out though.

[frankspop]

I think the numbers I put in are wrong

Phantom TK

31cm handle
52cm blade
0.665 kg W1
1.065 kg Total weight

The MOI = 0.453 Kg-M²

Burns TK

29.5cm handle
53.8cm balde
0.685 kg W1
1.240g Total weight

The MOI = 0.528 Kg-M<sup>2

I double-checked the weights too but no better. I think I may be weighing incorrectly</sup>

Looks like you might be inputting W1 into the form instead of balance point.
The way it is set you have to do a manual calculation of BP, and the instructions are there under the last bat image before the form.

Balance Point = ((total bat length) x W1) / Total bat mass

where total bat length is simply the sum of handle and blade lengths that you measured already.

I'll think about whether to change the form to do the BP calculation for the user.  The way it is currently set out was meant to show the importance of those 4 parameters for MOI

[Cpatel93]

@frankspop Perfect, thank you 


When I'm multiplying the total bat length, is that in cm or meters?

[Cpatel93]

Ignore that, I found the answer ahah 

[Cpatel93]

Updated and likely correct numbers


Bat MOI

Phantom

31cm handle
52cm blade
83cm Total bat length
0.665 kg W1
1.065 kg Total weight
Balance point = (0.88 x 0.67) / 1.07 (length measurements need to be in units of metres, and mass in units of Kg)

The MOI = 0.355 Kg-M²

Burns

29.5cm handle
53.8cm blade
83.3cm total bat length
0.685 kg W1
1.240g Total weight
Balance point = (0.833m x 0.685) / 1.24 (length measurements need to be in units of metres, and mass in units of Kg)

The MOI = 0.327 Kg-M<sup>2

The Burns bat is 2 lb 8 oz 'natural' (with stickers, toe guard, and grip) but I didn't like the pick up so I added lead tape to the knobby bit at the top of the handle it's now 2 lb 11.5 oz. I used the 2 lb 11.5 oz for these calculations as its how I'll be using the bat.

Thank you all!</sup>

[Chompy9760]

Some feedback for your friend who did the site - I had another go today and the "calculate" button still did nothing - the page didn't change at all!  Was confused seeing that others were obviously getting it to work. 

Finally worked out that I had the display size too large on my PC(poor eyes here!), and CTRL mouse zoom out gave me a smaller size, and presto - found the result under the calculate button, where previously there was a white background where the "about" section started.   

Now to play around with it!

[Chompy9760]

I'm having some trouble entering the formulas from your paper into a spreadsheet - seem to get all the wrong numbers.
Forgive my ignorance, but what's the significance of the physical size of the digits, e.g.
Ix′=MBL2B3. (copy/paste loses the formatting) You've explained what MB and LB are, but, what does L(small2)B(large3) mean?

Same thing with Ix′=MhL2h3+(MbL2b12+Mb(Lh+(Lb2))2).  You've explained Lh and Lb but what's L(small2)h(big3) and L(small2)b(big12) etc?

I've been using POBmm from handle x MB as a measure of 'pickup' for years, but didn't know how accurate it worked out as a measure of inertia.  Your calculated MOI seems to have a more pronounced difference between weights and POB, and it's good to see some proof that it's an accurate measure of what you feel through your hands.

[hewmanity]

I've had a great time measuring every bat I could get my hands on. Generally the calculated balance point matched well with what I estimated while balancing bats.
I did the MOI for 17 bats and had a few interesting findings. I always found the claim that longer handle and shorter blade bats picking up better a little dubious as it pushes the mass lower. My data supported my scepticism.
The most difficult to interpret finding was between my two bats that weigh exactly. 1169 grams, a Blank Bats B1 and a Kook Ghost. The former feels beautiful to bat with, the latter completely awkward and heavy. They both returned almost exactly the same MOI. There are a few differences between the bats, the BB is a completely full profile while the Kook has a couple mm of concaving, the BB is far more bowed, the BB is a slightly longer handle and shorter blade option (this is my only example where I had matching bats and the subjective "pick up" was better in the long handle and short blade combo). The thing I suspect may make the difference in feel is that the ghost is about 8mm longer overall, and I'm only average height, so it may just be that the bat is too long for me.
The other thing that stood out is that I have a GM Haze and Noir of the same weight, and subjectively ifeel the Noir picks up way better even though it had a much lower swell, and the MOI measure confirmed this with the Noir having the clearly lower measure. I hcan only speculate as to the reason, but maybe it's due to willow density varying throughout the blades.

[Kai]

Really interesting, need to get my bats out to try this today.

[Tailendfielder]

Does the website save the data? We need a scatter plot! Maybe needs to be filterable by brand as well

[frankspop]

From a batmakers perspective, I can appreciate some benefits and many drawbacks personally.

Obviously for people buying online, it may give a measurement for then to work from. But would they have this initially and what determines if that measurement they're working from is their 'optimum'?

Just not sure if it's a little confusing for consumers. Most people who come into my workshop are already confused over balance points, dead weights, middle position, Grade, pick up etc etc. There's already a lot going on and just not sure this, although intended to simplify, may just confuse matters more. Especially for people coming into the sport.

I'd certainly need to understand it more to advertise it with my bats, as I'd need to be confident in explaining it to customers. Who personally, I think in the main, would still go on scale weight and feel. As In said, this could benefit people buying blind. But they'd still have to know what their optimum was, not something I'm sure many would take time or have the ability to find out.

I think in order for it to be adopted to the masses, you'd have to clearly sell the performance benefits. (If I'm at my optimum MOI, what does that mean in terms of performance gains?) As there are so many variables determining a bats performance (not least the batter), would this measurement be overall that useful? It's fine having the right MOI, but if it's a plank with a poor handle, is that measurement worthwhile? Appreciate that these things should be a given, but they're not always.

No doubt I'll be called old fashioned by many, but I kind of like that some sport isn't over engineered. I don't like that it's sometimes sanitised somewhat, but then I'm not adverse to technology either. I've got wrapped up in it at times in golf, but at no point did in improve my game more than practice, education and playing more.

If you were in Leeds anytime, I'd gladly welcome you into the workshop to explain it further and test some bats out though.

All good points.

Firstly, your true optimum is still objectively unacheivable until a player can do a test session with a range of bat MOIs where swing performance could be measured i.e. from one of the bat sensors now on the market.  A player would need to get data on the main shots in the vertical plane (driving), and horizontal plane (cut/pull/sweep), and build a swing profile.    This is unlikely a level the masses would be interested in, but could be possible for Pros and those with the interest and money to pay for it.   Technically straightforward to do, but would be epensive at the moment.  Until that is possible then MOI knowledge complements your probable 'preferred' bat that is based on feel and performance in nets and in matches.  So that when you come to buy another, you know what to look for or specifiy if able to through custom bat makers.

MOI as you say may be marginal in terms of what it might give a customer, given all the other factors at play, but for some marginal is still valuable.

Transition to using MOI with customers is like anything new.  If we believe this is a valuable parameter to base bat selection on, it is then a matter of education/explanation to shift to a new paradigm.

I'd be happy to pop up to Leeds for a chat on this.  DM me and we can arrange something.

[frankspop]

I'm having some trouble entering the formulas from your paper into a spreadsheet - seem to get all the wrong numbers.
Forgive my ignorance, but what's the significance of the physical size of the digits, e.g.
Ix′=MBL2B3. (copy/paste loses the formatting) You've explained what MB and LB are, but, what does L(small2)B(large3) mean?

Same thing with Ix′=MhL2h3+(MbL2b12+Mb(Lh+(Lb2))2).  You've explained Lh and Lb but what's L(small2)h(big3) and L(small2)b(big12) etc?

I've been using POBmm from handle x MB as a measure of 'pickup' for years, but didn't know how accurate it worked out as a measure of inertia.  Your calculated MOI seems to have a more pronounced difference between weights and POB, and it's good to see some proof that it's an accurate measure of what you feel through your hands.

Your question on the equations seems to relate to the fact that through the copy/paste it is losing the division operator.  L(small2)h(big3) is Lh squared divided by 3, and same for the other one bu 12 is the denominator.

If it would help you can DM me I can send you a spreadsheet with all the equations in.  One I prepared a while ago.  I'm happy to share it to anyone who would like it.