How much variance in bat weight should you expect?

[MsDinosaur2]

Something else got me to thinking about bat weights so I rounded up a few bats and checked their actual weight versus their listed weight. Of 9 bats, only one (a -9 drop) was underweight, by .3 oz. The rest were all over their listed weights. The overage for the 9 bats came out to 9.2 ounces or an average of slightly over one ounce overweight.

My 11 yr old DD's 30-20 was one of the worst offenders at an actual weight of 22.5 ounces. I guess I can kind of understand now why her swing seems to slow down so much when she's tired.

How much variance in weight should you expect and how much variance does it take to become an issue?

 

[FPMark]

In my experiance, every manufacture is different. Anderson is probably the worst, because I believe they weigh them before installing the knob. They are usually about 3 ozs. heavier than listed. I don't remember ever seeing one that was under weight, but I haven't wieghed all of them. Most that I did weigh were usually about .3 to 1oz. heavy. The place I buy from has a scale for anyone to use so I have weighed a lot of them. Thats also why it is recomended that you have you dd swing before you buy.

What kind of bat was the 30-20 that weighed 22.5?

 

[MsDinosaur2]

DD's 30-20 is a Rip-It Force. The blue and white one from 2009, I think? Maybe Rip-It does the same as Anderson and weighs pre-knob.

It's a pretty bat and she loves it, but... She used an old sc777 30-18 last weekend for a friendly competition her batting instructor was having (x many points for back of the net, y many for deep on the side, etc...) and she just killed the ball with that ugly old thang. Turned in the high round score of the day (beat the next highest girl by 30 and the high woman by 10) :-D Naturally, I'm now wondering if I can persuade her to set the Rip-It aside till she's a little bigger and go with something in the range of that sc777 for U10 ball this spring.

 

[Amy in AZ.]

Here is an article concerning the swing weights of bats. http://paws.kettering.edu/~drussell/Publications/TPT-SwingWeight.pdf

I like the part that explains about how the balance point of various bats is different, although they both may be marked the same weight.

 

[MsDinosaur2]

Thanks, Amy. That was fascinating.

I went to estimate the balance points of the two 30" bats and found that the Easton was about 18" and the Rip-It about 18.5". They're pretty close considering that the Rip-It actually weighs 4.2 oz. more.

I don't have equipment to measure MOI, but with both a lower balance point and lower weight, it's certain that the Easton does have a markedly lower swing weight than the Rip-It. Extrapolating from the 30" baseball bat measurements, I'd guess its MOI is somewhere around 1,000 less.

 

[Carty]

In Ted Williams book The Science of Hitting he mentioned how he specified a bat certain weight and could tell when a bat was even 1 ounce off. He said he changed his specification to say "not more than" a certain weight because of the variance. Amy - that is one of my favorite web sites.

 

[Greenmonsters]

In my experiance, every manufacture is different. Anderson is probably the worst, because I believe they weigh them before installing the knob. They are usually about 3 ozs. heavier than listed. I don't remember ever seeing one that was under weight, but I haven't wieghed all of them. Most that I did weigh were usually about .3 to 1oz. heavy. The place I buy from has a scale for anyone to use so I have weighed a lot of them. Thats also why it is recomended that you have you dd swing before you buy.

What kind of bat was the 30-20 that weighed 22.5?

The bats are NOT weighed w/out the knobs! Anderson's listed bat weights are swing weights, not actual scale weights. The knob on the Anderson bats is solid aluminum and weighs approx. 1.4 oz but has little bearing on the force imparted to the ball at bat-ball collision. The Rocketechs (RT) are considered -9 (9 oz drop v. length) the Techzillas (TZ) are considered -10s (10 oz drop v. length), but the same length in each bat will actually weigh about the same because the RTs are end weighted and the TZs are more balanced/handle weighted. The Nanotek is a true -10 drop i.e. swing wt = scale weight. A 34/24 Nano swings similar to a 33/23 TZ and a 32/23 RT. A change from a balanced to an endloaded bat can require a significant adjustment period. Going from endloaded to balanced isn't as big a deal. Bottom line with Anderson or any other bat manufacturer is that you should try to swing one before you buy.

 

[absdad]

All companies will have different allowable tolerances. What may be acceptable for ABC corp., may get rejected at XYZ inc. Generally the more expensive the bat, the higher the level of QC, and less allowable variance. The company that makes your $300 bat may not allow more that +-.5oz, wheres your cheaper bats that you might find at Wallyworld, they may not care that a worker accidentally squeezed an extra 1.5oz of glue in the barrel putting on the end cap.

 

[FPMark]

The bats are NOT weighed w/out the knobs! Anderson's listed bat weights are swing weights, not actual scale weights. The knob on the Anderson bats is solid aluminum and weighs approx. 1.4 oz but has little bearing on the force imparted to the ball at bat-ball collision. The Rocketechs (RT) are considered -9 (9 oz drop v. length) the Techzillas (TZ) are considered -10s (10 oz drop v. length), but the same length in each bat will actually weigh about the same because the RTs are end weighted and the TZs are more balanced/handle weighted. The Nanotek is a true -10 drop i.e. swing wt = scale weight. A 34/24 Nano swings similar to a 33/23 TZ and a 32/23 RT. A change from a balanced to an endloaded bat can require a significant adjustment period. Going from endloaded to balanced isn't as big a deal. Bottom line with Anderson or any other bat manufacturer is that you should try to swing one before you buy.

Weather they are weighed with or without the knob is irrelevant, they weigh much more than any other -9 bat of equal length. My understanding of the way Anderson scaled the Rocketech was to end load it and then use the knob to counter balance it so it would swing the same as a -9. If you consider the -9 to mean 9ozs less than length in actual weight, the Rocketech is more like -6. Weigh it and see. And while your at it, weigh a techzilla too. They don't weigh the same.

Don't get me wrong, I like Anderson bats, especially the Rocketech. The OP was just asking about weight variance. I assume they meant scale weight.

 

[Justanotherdad]

I just bought my daughter a popular 32/23 -9 bat and weighed it as soon as I got it with a scale I use for Pine Wood Derby cars. It actually weighed 22 5/8 ounces. I weighed her 32/22 bat from last year and it weighs slightly more than 22 1/4 ounces.