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ROCKBATS - Discussions regarding Wood Baseball Bats


ROCKBATS - Discussions regarding Wood Baseball Bats

Founded by a wood scientist from the USDA Forest Service, Forest Products Laboratory. RockBats has developed this forum for discussing wood science, and the physics of baseball bats.

Location: Wisconsin
Members: 89
Latest Activity: Sep 11, 2015

Our Video that discusses the importance of straight-grain wood, and also our "engineered" laminated bat that improves the performance of hitting a baseball.

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Discussion Forum

Moment of Inertia

Started by John MacDougall. Last reply by John MacDougall Oct 13, 2010. 3 Replies

I would like to make a proposal to all wood bat makers that would, essentially, bring us into the 21st century with regard to the "Swing Weights" of bats, using Moment of Inertia.  MOI has been used…Continue

Broken Bat that speared Tyler Colvin... analysis

Started by Roland Hernandez. Last reply by Chris Corso Sep 24, 2010. 7 Replies

 .We've all probably already have seen the video of a broken bat spearing Tyler Colvin...…Continue

Bottom-of-the-9th, Game-Winning, Walk-Off Homerun !!!!

Started by Roland Hernandez. Last reply by Roland Hernandez May 29, 2010. 2 Replies

.I just finished catching my breath. The Milwaukee Brewer's right fielder - Corey Hart - just hit a game-winning, Walk-off Homerun in a 0-0 game in the 9th inning vs. the Mets. Corey was using his…Continue

Broken Wood Bats - Tell Us Your Story

Started by Roland Hernandez. Last reply by Roland Hernandez May 13, 2010. 8 Replies

.When a solid-wood bat with good straight-grained wood breaks - it should crack - like when you break a "green" branch over your knee - and stay intact.     When a bat breaks into 2 pieces, quite…Continue

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Comment by Walter Ambrosch Master Turner on May 11, 2010 at 11:39pm
In reply to the question on Oak and on today's wood being weaker.

Thereare many types of Oak, generally Red and White. Red Oak has similar weight and properties to Ash and White Oak is more like Hickory... but they both have the similar Ray structure like Maple. So they would have to be treated more like Maple or Birch then Ash or Hickory.

Hickory is Hard and heavy... good thing for tool handles but not good if you want a -3 drop game bat.

Hickory also has a grain that does not split as easy as Oak. So while I have made some test bats out of Oak, the cost and problems associates with it take it off the table for bats.

In regards to new wood being of a less quality than wood 10 / 20 / 30 years ago or more?

This is not necessarily true for every specie.

Ash trees which which are perfect for Bats are about 50-60 years old and have an even yet fairly quick growth rate of about 2" in dia every 8 years.

Maple is actually stronger if it grows a little slower making the trees older.

These rules have not changed for hundreds of years.

What has changes is Bat Design, Bat Weights and the way the wood is dried to make it suitable for wood turning.

As roland has pointed out all about the need for straiight grain, let me talk a little about moisture.

Customers... do not buy a bat that was hanging in an over dry store for weeks, months or years unless it was wrapped in plastic. It can over dry just hanging there.

Bat makers... too many of us are using wood that is too dry.

Besides doing a moisture test on wood, I can tell if the wood is too dry the first few seconds it is turning on the lathe. Dry wood turns hard and dusty and good bat wood turns easier with BIG shavings coming off.

As a customer you cannot tell what moisture your bat is except if you weigh it and see if it gets heavier or lighter during the season.

To get more -3 drop weight bats some Maple bat makers will dry their wood down to 4% - 5%. That just make the wood Brittle. I know Slugger understands this because I have toured the inner workings of their operation and walked into their dry kilns. Their first choice is NOT to over dry their wood.

In fact until the 60's many of Sluggers Bat wood was only Air dried on terrace hills over the hill from my shop. Air dried ash around here is about 12-14% moisture. They then took it to Louisville where they place the lumber in storage and then 1 month before using it they would "equalize it" in a warm room so that they all ended up at the same moisture of about 10%.

Ash is dried to about 10% and Maple to around 8% in general but this varies from load to load slightly and if the lumber is stored in a dry environment it will continue to loos moisture.

So.. To all bat makers... order your Maple at 8-9% moisture and your Ash at 9-11% moisture and we can eliminate over dried wood as part of the problem.

I still suspect the LS Bat that Mike Goodman has fail could have just been a bad bat with bad slope of grain.
Comment by Roland Hernandez on December 9, 2009 at 1:43pm
I've done quite a bit of work on bat shape analysis, relating to performance and durability. Basically, when you test a bat in a machine - you can tell alot about how one bat shape might outperform another... or how one bat shape might be more prone to breaking, compared to another.

However, something that I want to study more is...


All things being equal in a test machine (bat velocity, ball velocity)... big-barrel bats will outperform smaller-barrel bats. However, when swung by a human... players cannot swing a big-barrel bat as fast as a smaller-barrel bat....

FACT: Bat Speed is the #1 most influential factor that increases Ball Velocity.

So, a player may actually find that they get lower performance with a big-barrel bat.

I like to tell players that it's not JUST about how fast the bat is swinging thru the strike zone (bat velocity), it's ALSO about how fast you can accelerate your bat from the ready position - to the strike zone.

If you are using a bat that is too large, then you won't accelerate fast enough... and you'll be behind on those fastballs.

btw: the measurable bat property that is used to define "big-barrel", "small-barrel", etc. is moment of inertia. Studies show that, IN A MACHINE, higher moment of inertia increases ball velocity... but studies also show that human players cannot swing a bat as fast with higher moment of inertia, compared to a bat with lower moment of inertia >>

MY QUESTION: Are there any ingenious methods out there to select the proper bat shape?

Most charts and recommendations ONLY refer to length and weight, and "holding the bat out at arms length for 30 seconds", etc.

I'm talking about... fractional tweaks, high-speed video analysis, etc... to make sure you are optimizing your bat velocity and control.
Comment by Roland Hernandez on December 6, 2009 at 3:19pm
Each league has it's own rules... however, they often state that they follow "NFHS rules", or "NCAA rules", or even "MLB rules".

Other leagues have to approve the bat (by inspection) before allowing it.

It's safe to say that ALL leagues allow wood bats that are made from a single, solid piece of wood.

For the NFHS and NCAA... if a bat is made from anything other than a single, solid piece of wood - then they have to be submitted to the Baseball Research Center at UMass-Lowell for testing... BESR, BBCOR, or ABI.

The BESR is the Ball Exit Speed Ratio - this will soon be phased out - and replaced by the BBCOR (Batted Ball Coefficient of Restitution). These 2 tests are primarily to assure that a bat does not perform higher than a bat made from a single piece of wood.

The ABI test (Accelerated Break-In)... is intended for those kevlar and carbon-type composite bats... that perform higher with repeated use.

Other leagues... such as the International Baseball Federation (IBAF.ORG) or the Confederation of European Baseball (CEB) - require a manufacturer to submit a bat for approval... even the solid-wood bats.

Once a manufacturer is on their list of "approved bats", only those manufacturers can supply bats to teams in that league.

RockBats is approved for IBAF (international baseball) and for CEB - European Baseball.

Then there is Major and Minor League Baseball. Each year, manufacturers have to re-apply to get on the list of approved manufacturers. Only manufacturers on that list can supply bats to Major and Minor League players.

I've never seen this list PUBLICLY advertised... it is the list that is sent to all equipment managers of Major and Minor League teams.

Some professional leagues - like the Independent Professional Baseball Federation follow the MLB rules... which only allows soild-wood bats.

YES, you are correct - many of these leagues don't have an easily accessible list of approved bats - or approved bat suppliers.

For the leagues I mentioned above, current requirements for using a wood composite bat is to have it approved... by whatever method they require (testing or inspection).

I believe, that with the shrinking supply of BIG trees to make bats... and with the unknown future of Ash resources due to the Emerald Ash Borer, many of those leagues that currently ONLY allow solid-wood bats will NEED to begin considering some sort of allowance for wood composite bats.

What we at RockBats advocate is that if a league is going to call itself a "wood bat league", they should only allow ALL-WOOD bats.

I hope that this info was useful.
Comment by Michael Thomas Weber on December 6, 2009 at 2:30pm
I was unsure of what the requirements for leagues higher than high school. I am a IHSAA umpire and the books do not say much concerning the requirements for wood bats. Do you see the composites or a bat like yours more broadly used in the professional leagues? The maple bat has cast many doubts on the use bats other than the traditional ash, though I seen a company that is using some unusual woods, like elm and birch.
Comment by Roland Hernandez on December 4, 2009 at 9:03am
The only league under MLB that allows wood composite bats is the Rookie Leagues - lower than Class A. However, to get certified to supply composite bats to this league, a bat manufacturer has to submit their bats through a series of tests, which are expensive - to show that the composite bat performs the same as an ordinary stick of Ash.

Not only are these bats tested for ball velocity, but they are then cut-up to view the internal construction - the manufacturer is charged for all of these tests.

By the time a bat manufacturer has gone thru all of this expense, THEN are they allowed to sell to the Rookie Leagues... and in most cases, those are the leagues where 18-20 year old players still have to buy their own bats.

This makes it really difficult for a manufacturer to justify getting a composite bat approved for Rookie League baseball.
Comment by Michael Thomas Weber on December 4, 2009 at 7:47am
That does cover many leagues, so I am assuming that the MLB allows composites as well.
Comment by Roland Hernandez on December 3, 2009 at 1:42pm
Good question.

Corked bats are illegal in leagues that allow ONLY solid-wood bats - i.e. bats made with one-piece of wood.

In leagues that allow composites (like those with the plastic handles and wood barrels), this laminated construction is perfectly OK. In fact, we are trying to promote to those "wood bat" leagues that if they are going to call themselves a "wood bat league" - that they should only consider bats that are made with ALL-WOOD.

Our solid-wood bats are approved by the International Baseball Federation (IBAF)... which mostly covers solid-wood bats.

And BOTH our solid-wood RockBats and our laminated-wood RockBats are approved in the Confederation of European Baseball (CEB). We have teams in Europe using this laminated design.

When buying a composite wood bat, it is important to inquire with your league if this bat is allowed. If you are in a league that allows bamboo, and those plastic handle bats... then this laminated design is typically allowed also.

I hope that this info helps.
Comment by Michael Thomas Weber on December 3, 2009 at 1:31pm
I have a question for you about having basswood in the barrel of the bat. I have seen this idea a couple of times recently, using various woods that are lighter than the regular hardwoods. My concern is that the bats would be considered illegal because it is illegal to "cork" a bat. Does that rule apply to the methods that you use to construct a bat?
Comment by Roland Hernandez on November 21, 2009 at 12:51pm
Sorry it took so long to reply... I'm been out-of-town, and away from CheckSwing for awhile.
There was another blog posted awhile back on CheckSwing that asked about Bamboo Bats, and below is what I posted. I mainly commented about BAMBOO (the material). Note that bamboo is a good/great material for use in baseball bats, but just like wood, you have to make sure that you have "good-quality" material.
The following is what I posted...

When I was a research engineer for the Forest Service, USDA Forest Products Laboratory - I explored the use of bamboo for use in structural products (beams, joists, etc). A guy from Mexico wanted to use it to make glued-laminated beams out of this. This is a fabulous material - it grows fast, has great strength, and can be machined like wood. It is no surprise that it has been used to make baseball bats - in Asia, they even use this to make scaffolding (workers walk around on this framework 100 ft up in the air!)

You hear a wide variety of reviews on bamboo bats - "they never break", "they have no pop", "they have great pop", "they warp", etc., etc. This is no surprise. That's because the properties of bamboo (the material) vary GREATLY.

The properties that affect baseball bat performance... density, stiffness, strength, hardness... vary greatly in bamboo depending on how old the stem was when it was harvested. Here are just a few tidbits about bamboo to keep in mind. When I list these - I'm talking about the pure material properties (when it is still in the form of a round tube or stem)...

- Bamboo grows like a grass, because it IS a grass.
- bamboo that is cut down after 1 year can be as soft as pine or basswood
- bamboo that is left to grow for 7 to 15 years (approximately) can be as tough as Hickory
- there are also differences between the outer shell and the inner shell
(it can be as soft as basswood in the inner shell, and as tough as Hickory in the outer shell)

- the strength can be as strong as Hickory (or stronger).. DEPENDING ON AGE.
- but the stiffness is only average


So, what does this all mean?
- bamboo is a great material for baseball bats.
- however, it has highly variable properties, so that's why you see the whole range of reviews.
- if you run into one bad bamboo bat, you shouldn't dismiss that manufacturer forever
- the best thing to do is to inspect your bat before purchasing (tap it on the ground and listen to the sound)

The story about the warped bat makes sense... my guess is that whoever made that bat blank - glued up several densities of bamboo strips together to try to achieve a target weight of billet. Unfortunately, they glued up the strips in an un-balanced manner. Higher-density bamboo expands faster than lower-density bamboo... so the outside curve of your bat (likely) has the higher-density bamboo.

I often joke with players that come across warped bats - that this is their "OPPOSITE-FIELD HITTING BAT".

I hope that this info helps.


Roland Hernandez, Founder
Comment by Anthony Fruhling on November 7, 2009 at 11:09am
I have a question about Bamboo bats. I have a friend that bought a bamboo bat this past summer and after reading your articles here I decided to check his bat for the straightness of grain. On his particular bat you can't even see the grain until you get up on the barrell. I was just wondering if this was natural or how else could I tell?

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