Black locust/Osage Orange comparson via wood-database.com

[huisme]

So I've assumed that I'm stuck up here in the northwest peninsula working with woods that won't measure up to Osage, but then I checked out that database that was posted here a few days ago and I found some interesting stats.

It seems that while Osage has a much higher specific gravity and Janka hardness, Locust's modules of rupture, elasticity, and crushing strength are higher. If what I'm understanding is correct, this indicates that Osage would be more dense and more resistant to abrasion and therefore a longer lasting bow, while Locust would be just as fast at lower mass ad more able to take extreme bends.

I know these stats are no replacement for having worked with the woods in question, and I've only made two Osage bows while I've got six BL in the garage ready to tiller. I'm ^editnot looking to start a war of woods, just a little back and forth so I/we might better understand what we've got here.

Higher/lower comparative stats marked with +/-

Osage: http://www.wood-database.com/lumber-identification/hardwoods/osage-orange/

Specific Gravity (Basic, 12% MC): .76, .86 +

Janka Hardness: 2,760 lbf (12,280 N)+

Modulus of Rupture: 18,650 lbf/in2 (128.6 MPa) -

Elastic Modulus: 1,689,000 lbf/in2 (11.64 GPa) -

Crushing Strength: 9,380 lbf/in2 (64.7 MPa) -

Locust: http://www.wood-database.com/lumber-identification/hardwoods/black-locust/

Specific Gravity (Basic, 12% MC): .66, .82 -

Janka Hardness: 1,700 lbf (7,560 N) -

Modulus of Rupture: 19,400 lbf/in2 (133.8 MPa) +

Elastic Modulus: 2,050,000 lbf/in2 (14.14 GPa) +

Crushing Strength: 10,200 lbf/in2 (70.3 MPa) +

[Weylin]

Clearly BL can make great bows. There are plenty of examples to prove that. My understanding of BL is that it has a very high compression strength but that it is relatively brittle (i.e. not elastic) thus the ease of creating chrysals when design and tillering aren't done well. Osage on the other hand has a good compression strength and is highly elastic so it can therefor be abused quite a bit further and still not chrysal. I'm not an expert on BL or wood properties, this is just the information that I have gleaned through listening to people. I'm interested to hear what other people have to say about it.

[twisted hickory]

Intresting,
I have only made 4 Bl bows and all are great shooters. They are not as affected by humidity as hickory. I really like the wood myself. I have two premium stave's drying that I will make into my two favorite designs...It's good stuff. None of the stave's I have worked on developed compression cracks and some of the wood needed lots of heat correction and the stave's were tough to tiller due to the character they have. I have one about half done and the tiller has me stumped for now. I will finish it after hunting season.
Some of the guys here that like Osage say they like bl just as much if it's a good piece. Blackhawk may chime in with his experience.
Greg

[StickMan47]

Huisme, I posted that wood database link and have been going back to it and noticed the same thing. I have yet to locate any Osage growing here in Southeast Texas (I've had to buy all mine so far) but i have found some locust growing wild just waitin for my saw    According to what I have read on here and in TBB Black Locust makes a great bow, it's just finicky on tillering.

I know that a lot of research went into making that database but i believe it was made with woodworkers in mind; which technically is what we are doing when building bows, but I think hands on "bow" knowledge speaks for itself. The Bowyer's Bibles list the SG of a lot of woods which is what caught my eye on the database. I came across a Catalpa tree on the jobsite and was needing info about it. found out it prolly just gonna be firewood. But I brought it home before finding the database.

I hope I didn't open a can of worms with that link, but I'm sure some of the experts on here can give us some of their hands on opinions. 

[huisme]

Black locust has made my favorite bows, while I was able to make the two Osage bows from dried staves just as heavy as I like at lower volume per pound of pull with less sweat over compression fractures. I really like the wood, I was just surprised the database (which does look like it was made by people who know their stuff) showed these kinds of numbers for the stuff compared to black locust.

Of course, the people who made the database obviously weren't going through each wood with bows in mind, but they did put them through stress tests that would be useful to a bowyer.

Even if you did, it seems like pleasant fishing to me 

[Capt]

Can anyone check out a wood named Tzalam on the wood database you use and see how it fairs as a bow wood... I just made my first bow and being in Mexico it was hard to find popular US woods... I just came by this half trunk of Tzalam in a lumber yard by chance.. It's seems super dense... And it's dark....?.

Any analysis much appreciated?

[huisme]

Along with the bow you posted, it looks like a beautiful bow wood- but structurally it's about what some people consider all woods to be next to Osage Orange

It looks like besides its medium-high bow-making qualities, it naturally takes an excellent finish.

I'd love me a piece of that stuff, first to make a bow and then to do some finishing work with other woods.

Like black locust. Because it's the best I have.

 

http://www.wood-database.com/lumber-identification/hardwoods/tzalam/

Specific Gravity (Basic, 12% MC): .63, .78

Janka Hardness: 1,400 lbf (6,230 N)

Modulus of Rupture: 12,800 lbf/in2 (88.3 MPa)

Elastic Modulus: 1,900,000 lbf/in2 ( 13.10 GPa)

Crushing Strength: No data available

[DLH]

Does it list how they test these different values? The reason I ask is because bow builders chase rings and choose straight grained boards which can handle the stress of the bow. I piddle in furniture building and straight grain isn't needed or wanted because of the plain look unless its quartersawn white oak or sycamore. A lot of osage is twisted snakey and down right naughty they would saw through all of this to produce lumber and violating a lot of its strength whereas they may have a relatively clean piece for another species. Wood also varies a lot from tree to tree I hope you see where I'm going with this PA is almost like a wood database I have found a lot of info on different woods searching the forum through google. I could be wrong about their methods of testing and sawing they may not use dimensional lumber to do tests. Just wanted to throw that out there. That database is very useful I think they may even list SG?

[huisme]

If you click the hyperlinks for each stat on the site they list their methods, and yes there is SG. Not sure about whether they take grain into account and/or compensate in any way, but I'm open to the idea that they did, and could have just found something through standardized testing most of us wouldn't have thought was true.

[DLH]

Yeah it's definitely something to consider I was just speculating and have no idea what they do haven't looked into it but may dig around there sometime. I would really like to see how they do their tests.

[mikekeswick]

Osage - makes a great bow however it is very easy to make the bow overbuilt. Osage bows should be very narrow and often aren't.
Black Locust  - makes great bows. The fact that chyrsal's show up when you mess something up is, in my book, just great 


If I had to use one one wood for ever more then it would likely be locust. It's premium bow wood.

[lostarrow]

All of the figures have to be taken into consideration together and in ways we've not been able to put down on paper as to why a certain kind of wood is better than others for any given task . The numbers can be helpful but don't tell the whole picture. There is a lot to consider when looking into the mechanics of "working wood"   .   Would you say a car would be faster , if it had better tires  than it's competitor , without considering anything else?  Just something more to think about.

[blackhawk]

This isn't the first,second,or third time+ the "wood database thread" and its numbers pops up...

Its useless to me as a bowyer IMO...

Black locust is excellent bow wood...but its not as "rubber band like" as osage..in general and on average it doesn't stretch as far.....but there's always the exception to the rule because within the same species you can have great variety and difference in wood properties...and the wood database numbers can kiss my @$$....because its more important in being able to read the certain piece of wood in your hands...I've had some very exceptional pieces of locust that were as dense as osage and had great tension,compression,and elastic modulus,and even better than some osage I've used...and on the other end some very poor quality stuff...it takes lots of time in the saddle to be able to know a certain piece of woods "limits" disregarding what species it is or who puts "numbers" on them...just because it says it has such n such numbers doesn't mean the piece you have in your hand is the same....and that's where firsthand knowledge is waaaaaaay more important whether your a novice or master bowyer....when it comes to bows those who have many bows under there belts are going to be waaaaaay more valuable than some non bowyers tests...

[twisted hickory]

This isn't the first,second,or third time+ the "wood database thread" and its numbers pops up...

Its useless to me as a bowyer IMO...

Black locust is excellent bow wood...but its not as "rubber band like" as osage..in general and on average it doesn't stretch as far.....but there's always the exception to the rule because within the same species you can have great variety and difference in wood properties...and the wood database numbers can kiss my @$$....because its more important in being able to read the certain piece of wood in your hands...I've had some very exceptional pieces of locust that were as dense as osage and had great tension,compression,and elastic modulus,and even better than some osage I've used...and on the other end some very poor quality stuff...it takes lots of time in the saddle to be able to know a certain piece of woods "limits" disregarding what species it is or who puts "numbers" on them...just because it says it has such n such numbers doesn't mean the piece you have in your hand is the same....and that's where firsthand knowledge is waaaaaaay more important whether your a novice or master bowyer....when it comes to bows those who have many bows under there belts are going to be waaaaaay more valuable than some non bowyers tests...

Blackhawk,
I am glad to see your 2 cents worth. I am new to this bow making thing. What do you look for when selecting a piece of Black Locust and wheather or not it is a good piece of wood? I have a tree located that is almost phone pole straight in one section and could get 5 or 6 really nice staves out of it. I am debating as to cut it down or not. It's in kinda tough place and if it's going to be so so wood I would not be inclined to bother. I have seen your short molly Bl bow
Just trying to get some insight,
Thanks,
Greg

[DavidV]

The wood database gets information straight from FPL tests which were very thorough. But take these at face value, not all the info is there (ie: tensile strength, etc.) Also the only numbers we have for osage are predicted based on the green numbers.....

If you really want to get confused compare Black Locust with Pignut Hickory...

Pignut hickory
Average Dried Weight: 52 lbs/ft3 (835 kg/m3)
Specific Gravity (Basic, 12% MC): .66, .83
Janka Hardness: 2,140 lbf (9,520 N)
Modulus of Rupture: 20,100 lbf/in2 (138.6 MPa)
Elastic Modulus: 2,260,000 lbf/in2 (15.59 GPa)
Crushing Strength: 9,190 lbf/in2 (63.4 MPa)

Black Locust
Average Dried Weight: 51 lbs/ft3 (825 kg/m3)
Specific Gravity (Basic, 12% MC): .66, .82
Janka Hardness: 1,700 lbf (7,560 N)
Modulus of Rupture: 19,400 lbf/in2 (133.8 MPa)
Elastic Modulus: 2,050,000 lbf/in2 (14.14 GPa)
Crushing Strength: 10,200 lbf/in2 (70.3 MPa)

The hickory still has extremely high crushing strength but it's belly is sometimes overpowered.... maybe locust is the same? But hey, I don't have enough experience.