PDA

View Full Version : Black Locust



Dave Lehnert
06-09-2016, 4:42 PM
Hello,

I have a friend at work who is new at running a sawmill. Woodmizer LT15.
He has a Black Locust tree he is going to mill.
He was wondering if Black Locust makes for good lumber. Any tips on milling, How well it does air dried etc...........

Cody Colston
06-09-2016, 6:31 PM
How the log is milled depends a lot on the size, any sweep and mostly, intended use of the lumber. I like to saw a combination of 4/4 and 8/4 stock 8 1/2 ft. long. I ususally saw everything to 8" width as that's the width of my jointer but lots of folks like wide boards/planks. They can always be ripped narrower and glued back for a seamless look.

Black Locust saws ok if green. It is highly resistant to decay and dries well. I've seen some amazing figure/grain in Black Locust.

Curt Harms
06-10-2016, 6:58 AM
How the log is milled depends a lot on the size, any sweep and mostly, intended use of the lumber. I like to saw a combination of 4/4 and 8/4 stock 8 1/2 ft. long. I ususally saw everything to 8" width as that's the width of my jointer but lots of folks like wide boards/planks. They can always be ripped narrower and glued back for a seamless look.

Black Locust saws ok if green. It is highly resistant to decay and dries well. I've seen some amazing figure/grain in Black Locust.

You've been able to get it to stay flat as it dries? I've wondered about black locust rather than pressure treated for outdoor furniture and structures but it's not readily available around here (SE. PA.) One reason I've heard is that it's difficult to dry flat & straight.

Cody Colston
06-10-2016, 9:14 AM
You've been able to get it to stay flat as it dries? I've wondered about black locust rather than pressure treated for outdoor furniture and structures but it's not readily available around here (SE. PA.) One reason I've heard is that it's difficult to dry flat & straight.

I've had no problems drying it flat. Seal the ends, sticker and air dry a couple of months before going to the kiln. The big problem with Locust is that once dried, it's almost impossible to drive a nail into without pre-drilling first. The stuff is harder than a woodpecker's lips.

Malcolm Schweizer
06-10-2016, 10:08 AM
This is yet another thread where I'm tempted to say, "It's terrible wood and you should send it to me right away to dispose of it for you." haha! Actually it's very good wood and I have even seen people use it to replace teak for boat decks. It is very rot resistant, and highly prized for boatbuilding.

Curt Harms
06-11-2016, 8:33 AM
Well, this might be why Black Locust lumber isn't readily available:


Damaging Agents- Black locust is severely damaged by insects and disease, probably more than any other eastern hardwood species. Ubiquitous attacks by the locust borer (Megcallene robiniae) and by the heart rot fungi Phellinus rimosus or Polyporus robiniophilus make growing black locust for timber production impractical. Locust borer larvae construct feeding tunnels throughout the wood, and the holes serve as entry points for heart rot fungi that cause extensive wood decay.

Locust borer attacks can begin at a young age and damage can be so extensive that trees are not suitable for fence posts. Many plantations planted in reclamation projects were seriously damaged, but more trees could be used if cut as soon as they reach post or mine-prop size. Slow-growing trees on poor sites are most susceptible to borer attack. On sites where tree vigor is low, repeated attacks often reduce black locust to sprout clumps. Damage to the sprouts is often as severe as in the original stem (37).


Outbreaks of the locust leafminer (Odontota dorsalis) occur almost yearly. Black locust trees throughout an entire region are often defoliated, and during years of low rainfall many are killed. Attacks by the locust twig borer (Ecdytolopha insiticiana) occur over a wide area and in heavily infested areas seedling mortality may be high. Black locust is attacked by a wide variety of other insects that cause some degree of damage (3).
Common diseases are heart rot and witches' broom disease, caused by a virus, Chlorogenus robiniae. In the southern Appalachians most large trees are infected with heart rot and decay of trunk wood is extensive. In the Texas root-rot belt, black locust is extremely susceptible to Phymatotrichum omnivorum (21). In New Brunswick, plantings of black locust are not recommended because of high mortality and dieback of branches caused by Nectria cinnabarina and because of superior performance by conifer species (40).



More: http://www.na.fs.fed.us/pubs/silvics_manual/volume_2/robinia/pseudoacacia.htm

Bud Millis
06-13-2016, 1:12 PM
Hello,

I have a friend at work who is new at running a sawmill. Woodmizer LT15.
He has a Black Locust tree he is going to mill.
He was wondering if Black Locust makes for good lumber. Any tips on milling, How well it does air dried etc...........


It is TERRIBLE wood!

Your friend should send it to me!

HAHA, just kidding - its great wood for outdoors, beats pressure treated. For some real fun, mill it at night under a black light or several black lights. You'll be impressed.

Bud

John TenEyck
06-13-2016, 10:41 PM
I milled some with my chainsaw mill several years ago and had no trouble drying it. There were some ends checks, but no worse than white oak. I milled some 4/4 all the way up to 10/4. I let it air dry 2 years, maybe a little more, then made this garden bench from some of it. It's not nearly as hard to work as some people claim. White oak seems harder to me.

339044

John

Cody Colston
06-14-2016, 5:26 PM
John, I've seen that bench before, either here or on another forum. Have I commented that it is nice? Really nice!

Kevin Beitz
08-22-2018, 7:22 PM
Spruce and Locust trees is the hardest logs to make lumber out
of on my mill...

Pete Staehling
08-24-2018, 6:50 AM
When i was in Maryland and shopped the SE PA sawmills I was told that the Amish used up most of what was available for fence posts, but I was usually able to buy some from Groff and Groff. It was always a delightful wood to work with. I have never been able to find any here in Tallahassee and wish I could.

I never did the rough milling myself, but the rough planks were always straight and true and the pieces i broke them down in to remain so. Yes it is hard, but when you want hard and weather/rot resistant it is hard to beat.

John K Jordan
08-24-2018, 9:04 AM
I have never been able to find any here in Tallahassee and wish I could.



Black locust grows everywhere around here, the next best thing to osage orange which I can't find. I've sawn and dried some but mostly for woodturning.

Dave Zellers
08-25-2018, 8:30 PM
I'm happy to see this thread come alive. I have a question about gluing black locust for outdoor use.

Something more than TB III I presume?

Curt Harms
08-26-2018, 6:03 AM
I'm happy to see this thread come alive. I have a question about gluing black locust for outdoor use.

Something more than TB III I presume?

I don't know that Black Locust is oily like some tropicals so I'd think gluing is not that much of an issue. I don't know, though.

Perry Hilbert Jr
08-26-2018, 6:22 PM
When black locust gets to any size here, it has rotten and hollow spots in side. For a wood that holds up as fence posts, there isn't much large enough for lumber. My local Lion's park has some very tall 18 to 20 inch black locust trees that need to go, perhaps a dozen or more. No body has been interested in them, even just to have for free. We are afraid they may fall and take out our pavilion. Even one tree service said they were too dangerous to climb for topping. At least two of them have large dead branches (widow makers) Such a job is not for the faint of heart or the foolhardy. This predicament seems to be common for any black locust over 40 ft high.

Dave Zellers
08-27-2018, 1:20 AM
Around here, Black Locust grows like a weed. Literally. The roots of a young established tree will send up sprouts relentlessly. But the roots are shallow and the trees topple in a big blow, especially when a lot of rain is involved. Then it becomes amazing firewood.

I'm encouraging the saplings to grow on my tiny plot specifically to use as fence posts. Doesn't take long- 6-7 years or so.

Malcolm Schweizer
08-27-2018, 1:11 PM
Spruce and Locust trees is the hardest logs to make lumber out
of on my mill...

Might I ask why spruce is so difficult? I thought it was a fairly stable and straightforward wood. Does this explain the high price? I'm buying quite a bit of it this week for my latest boatbuilding project.

John K Jordan
08-27-2018, 6:01 PM
Might I ask why spruce is so difficult? I thought it was a fairly stable and straightforward wood. Does this explain the high price? I'm buying quite a bit of it this week for my latest boatbuilding project.

I'm interested in hearing about that too, although I've never sawn spruce.

I do know that Virginia Pine give me grief. Not in the drying - it dries nicely and stays straight. But in the sawing! (Woodmizer) I think the problem is the sap usually builds up on one side of the blade and creates more friction on that side. If I'm not careful the blade will take a "dive" and the board will get thicker until I catch it. Then I have a badly cut board.

I have to spend some time cleaning off the sap. I stand behind the running saw and stick a long screwdriver on top the blade and scrape off the sap buildup, staying away, of course, from the gullets and teeth.

JKJ

Rob Luter
08-27-2018, 7:39 PM
Black locust is much like concrete, but harder and tougher on tools. It’s great firewood, with more BTU per cord than almost anything. I’ve never had the guts to mill it up for a project. I respect my tools too much.

Jim Andrew
10-02-2018, 10:31 PM
That black locust would make some great trailer decking.

david privett
10-04-2018, 9:08 AM
from what I understand black locust has to be felled and sawn the same day to minimize wear on tooling. but I have never done anything with the stuff. So it might be a tale.

John K Jordan
10-05-2018, 12:53 AM
from what I understand black locust has to be felled and sawn the same day to minimize wear on tooling. but I have never done anything with the stuff. So it might be a tale.

I havent heard or experienced that, but maybe it depends on where it grew. I've sawn it from a few days cut to on the ground for over a year. I mostly made turning blanks and boards to use outdoors around the farm.

Never thought it particularly difficult to work, softer and easier to turn than some woods I've had like Lyptus. I usually use Thompson 10V tools, maybe that helps, shaving-sharp.

The absolute worst wood I've ever had for dulling tools was a 3" thick plank of old walnut, said to be in a house as a fireplace mantel for 100 years. A new Starrett bi-metal saw was dulled in just a few cuts. If you want to play with it I still have the rest - we're not far up the road!

JKJ

JKJ

david privett
10-05-2018, 8:42 AM
are we talking about the same wood that is used for fence posts? There again no experience with it. I was told that once the sap sets up it will dull a chain in one cut, another tale?

William Adams
10-05-2018, 9:12 AM
IME, mostly it's tough stuff (my father and I felled one stand which was notable for _not_ dulling the saw incredibly quickly, usually we spent more time sharpening when cutting it than other woods) --- it's a bow wood, so if you can get straight lengths, a bowyer would want it.

Tom Hogard
10-05-2018, 9:33 AM
Had a mobile job where a black locust had gone down during a storm, finished off by a tree service. Total job was over 900 bf/ including 650 bf of black locust. The black locust logs had been down up to a month. Used three blades, two because of nail hits. Didn't seem to offer any difficulties. I also mill hedge (Osage orange, bois 'arc, bodark) fairly often and it, too, mills fine.

John K Jordan
10-05-2018, 12:43 PM
are we talking about the same wood that is used for fence posts? There again no experience with it. I was told that once the sap sets up it will dull a chain in one cut, another tale?

Yes, it's black locust, almost as good in the ground as osage orange. Mine is ositively IDed from the leaves, bark, flowers, end grain, and most reliably - from the distinctive yellow-green fluorescence from 365nm UV light. I've cut it fresh, old, by chainsaw, woodmizer, shop bandsaw. Like some other woods, it does dull tools but I never thought it excessive.

I have some turning stock air drying now for over 10 years. It might be fun to do a test and compare it with osage, persimmon, lignum vitae or another hard wood. Perhaps sharpen two skews to equivalent edges. (I have a SharpCkeck edge sharpness device) Check the sharpness before and after making some equivalant cuts. I also have a tree in the yard I let get too big and needs to be removed. Maybe I'll try some fresh vs aged cuts with the chain saw, a subjective test but who knows.

Again, maybe where it grows makes a difference, for example what minerals are in high proportions in the soil. I have no idea about this but maybe a wood expert would know about the conditions and chemistry that turns minerals in the soil into abrasive extractives in the heartwood.

I've never done and "woodworking" with black locust - I use it for things like garden stakes. I've used it for turning mostly when I wanted a heavy, utility piece such as a non-tippable pencil holder for a handicapped friend without good motor control. The wood, at least what I have, is bland and boring. It's cousin, honey locust, is far more interesting!

JKJ

david privett
10-06-2018, 8:11 AM
well now I know , I guess there are other exaggeration's besides fishing stories. go figure, where have we seen that before? District of Colombia maybe?

John K Jordan
10-06-2018, 12:22 PM
well now I know , I guess there are other exaggeration's besides fishing stories. go figure, where have we seen that before? District of Colombia maybe?

Maybe next time I drive by Cleveland I throw out a chunk of well dried black locust from my farm and you can try it yourself! I still don't know if the same species from elsewhere is different.

david privett
10-07-2018, 8:11 AM
please do, I will look forward to it.

John Lifer
10-09-2018, 3:44 PM
You HAVE to mill and use this stuff (locust and BoDock (Bois d'arc ) green or it is really tough to cut afterwards. But makes some nice stuff.

John K Jordan
10-09-2018, 6:01 PM
You HAVE to mill and use this stuff (locust and BoDock (Bois d'arc ) green or it is really tough to cut afterwards. But makes some nice stuff.

I think it's helpful to remember that like many things, what one is doing can make a huge difference! If I were sawing and planing by hand, cutting dovetails with a chisel, smoothing with a spokeshave, I think I would agree with working it green as much as possible.

In general, I've found the harder and tougher the wood the cleaner it cuts and the better it takes fine detail. Almost every thing I turn (including the locusts, osage orange, dogwood, persimmon, ebony, and lignum vitae) is air dried.

Good friend Richard Casey brought me some wood he harvested in the Australian tropics and warned me of the hardness of some, in particular, Gidgee. It was in fact hard but oh, how nice it was to work! I've turned "medium-sized" things from both locust and osage, and while slower to work than soft wood like cherry, oak, or sugar maple, I didn't consider it particularly challenging. What frustrates me is soft wood prone to tearout.

Just for fun and perspective I looked up the Janka hardness (Wood Database) of some of the harder species I've enjoyed turning. I realize the Janka numbers don't tell the whole story on workability, but look how far black locust is down the list:

4,390 lbf lignum vitae (true)
4,270 lbf gidgee
3,710 lbf argentine lignum vitae
3,080 lbf gaboon ebony
2,960 lbf cocobolo
2,620 lbf osage orange *
2,300 lbf persimmon *
2,150 lbf dogwood *
2,140 lbf pignut hickory *
1,700 lbf black locust *
1,580 lbf honey locust *
1,450 lbf hard maple *
1,350 lbf white oak *
1,220 lbf red oak *
(* wood local to me)

Maybe it's just that after turning lignum vitae, everything else seems soft.

394711

JKJ

Jason Mikits
10-19-2018, 10:23 AM
I've milled black locust to make Adirondack chairs and for the decking on my raised porch. Some I milled quickly and some I had for a couple years before milling. I love black locust and wish I could get more. My helical head planer had no issues planing it all, and it's a great outdoor wood. It does get hard when it's dry, but it's still just wood.

I think the reason Kevin had difficulties with spruce is because it can be knotty. Spruce knots play havoc if your blade isn't sharp or doesn't have enough set. These conditions can cause the blade to do a lot of waving. I had some issues with wavy spruce boards until I started using Woodmizers 4 degree blades, and changing them often.