How to Prevent Twisting, Bowing and Cracking of Wood on Seacoast Chassis

[seacoastartillery]

     The need for straight white oak is paramount when we construct our Chassis for our seacoast carriages.  Long 3" X 3" x 34" long timbers don't stay straight very long if they are subjected to varying humidity conditions.  We are faced with ensuring that our Chassis rails stay straight after building them in the very dry Colorado air and then delivering them to much more humid conditions in Georgia or Iowa.  By deep hole drilling these beams with a shop made 1.500" Dia. Gundrill to within 1" of the bottom of a 34" long beam, and filling the hole with a strong, straight aluminum extrusion surrounded with epoxy casting resin, we can be sure that the chance of the wood going "wild" on us is very small indeed.

     The captions for each photo contain the description or instruction you might find helpful if you want to use our methods of wood control.  We will be happy to answer any questions you might have.

Mike & Tracy


The wood holding lathe fixture is constructed of alumium tooling plates so no machining was necessary beyond edge trimming after bandsawing and drilling and tapping a few 1/2-13 holes.





Aluminum tooling plates were used to construct this simple wood holding fixture.  It has never failed yet.





We use a 1.50" Forstner bit to drill an accurate pilot hole for our shop-made 1.498" dia. gundrill. 





Cooled by shop air, the special wood bit drills an accurate 1.500"  hole in the white oak timber end grain to 2.00" depth.





Mike shaped our big 1.500" dia. gundrill by making a free hand sketch of our professionally made metal cutting gundrill bit. The shaft is a hollow DOM mechanical tube .625 I.D. and  .875" O.D.  braised on to the gundrill bit and held by the 3-jaw lathe chuck with about one foot sticking out past the lathe headstock.





This pic shows how we get the shop air into the tube for cooling and blowing woods chips out of the deep hole.  A 4" long delrin bearing fits loosely over the end of the DOM tube.  It has a center drilled into it 1/8" deep for a 1/4" ball bearing which is about .010" from a faced off steel rod of 1.25" dia. held in the mill's Kurt Ang-Loc vise.  This rod is merely a stop for the air bearing so it doesn't shoot off the gundrill tube when an air fitting is attached to the nipple screwed into the side of the delrin air-bearing tube.





A close-up for the air flow parts with the stop not yet brought up to the .010" gap position.





The masking tape is 33" from the tip of the gundrill.





The gundrill is placed into the pilot hole with just .002" clearance almost until it touches the hole's end.  The rotation is slow for wood, between 400 and 600 RPM, depending on the type of wood.






Next we make an air plenum to collect the compressed air and most of the wood chips which are blown out of the drilled hole.  just split a plastic milk jug in half and place over the end of the beam and cut a hole in the side for a shop vac nozzle, wrap with some duct tape and you have it.





Mike operates the lathe and I vacuum chips.





Luna, the shop cat loves sitting on various perches at a safe distance for the machinery, watching every move we make.





This is the casting resin we use.  It pours like water after 30 seconds of mixing which helps it flow around all those fins that the aluminum extrusion has.  Oops forgot to take a pic of that, but you can see it's shape in a later pic. It starts to set up in about an hour which is fine; you have plenty of time to mix and pour.  In 5 hours it is hard as a rock and plenty strong.





On their website they have a volume calculator which makes it easy to order enough, but not too much.  We bought three 1,9 pound kits to do 4 rails, 33" of 1.5" dia. each to fill. About $23.00 per kit is what the stuff costs.





We made a funnel out of a bit of a tea jug.





We poured to within about 1/4" of the end.  Should have stopped at 1/2".





It changes color and expands slightly as it starts to cure.





We have about 125 pounds of Upper Carriage and Tube which has to recoil on the chassis rails.  That's why we are so particular about them staying straight and flat.  These are the 1.6 scale,  7 Inch Treble-Banded Brooke Seacoast and Navy Rifles  that we made recently.





This photo shows the shape of the epoxy enclosed extrusion which is 33" long.  The Chassis is 10.5" wide and the 4 transoms that join the rails are milled precisely to fit the rails and held together with lots of hand made bolts.





These are enough bolts for two Chassis.





Final assembly before testing and delivery.  That's right, we deliver to anywhere in the U.S. except Hawaii.  We will crate and ship to Hawaii.





These two went to the mid-west and to the east coast for delivery in September of 2012.  We delivered another to Iowa last month and we are now finishing the last one of these for sale via an internet auction.  Have not decided which site yet.  This last one is due to be complete by June 2013.

[MKlein]

M & T that is very interesting method. The quality of your work is impressive.
I have been experimenting with different ways to dry 1-3 inch thick pieces of oak that a local saw mill saves for me when they are cutting logs.
Any pics or ideas/ methods that people have that work might be helpful. Or homemade dring ovens. I have found that red oak splits pretty bad.

[Zulu]

M&T,
This is great!
I'm not clear on one point.  The casting resin is poured around what?  An aluminum rod?  What diameter?
This procedure goes far and above anything I could attempt.
I really appreciate the things that go into projects that involve a lot of thought and labor.  Especially when the end product will never be seen or even known about by the end user.
It speaks volumes about your characters.
Thanks for the explanation.
Zulu

[rampa room artillery]

I would buy a working set of prints and part specs for that carriage.  Please let me know if you are interested?


   Rick Bryan

[seacoastartillery]

 

 M & T that is very interesting method. The quality of your work is impressive.
 I have been experimenting with different ways to dry 1-3 inch thick pieces of oak that a local saw mill saves for me when they are cutting logs.
 Any pics or ideas/ methods that people have that work might be helpful. Or homemade dring ovens. I have found that red oak splits pretty bad. 

       Mark,    Thanks for the compliment.  We began a two year research project on finding white oak which had been air dried or kiln dried properly.  This exercise cost us over $900.00 in junk wood.  We went through 3 lumber mills with various types of kilns and discovered that most of these people just wanted your money, and any old quick method was good enough for them.  We had two piles of wood in Mike's basement which snapped, crackled and popped for at least six months until every piece in the stack was destroyed.  We tried all the suppliers recommendations, but nothing could stop the relentless forces of destruction.  We covered the ends with parafin wax.  We covered them with latex paint.  And with autobody paint, etc., etc.  Nothing worked. 
 
      You see the wood was forced to dry too quickly, so the money could be sent more quickly.  No real thought of quality or even complete drying was on their minds.  Finally we contacted our gunsmith friend who is an absolute perfectionist and he had a source, just one of two in the United States per him and his guild, that could Reliably dry, using a one year process of air and kiln, white oak in thicknesses up to 3.5 inches.  That was four years ago.  This outfit has always delivered properly dried, stable wood which can be sawed, routed and worked without any fear of finding pockets of collapsed cells or hidden checks.  We don't actually know the name of the mill and kiln doing the work and nobody will tell us, but we pay a regular hardwood lumber yard plenty for good solid white oak and that is what they deliver.  The order has to be placed one year in advance which forces us to plan ahead and we are getting better at that.  Red Oak is much easier that White to process, but I think 8/4 is as thick as you can regularly find for sale.
 
 
 

 M&T,
 This is great!
 I'm not clear on one point.  The casting resin is poured around what?  An aluminum rod?  What diameter?
 This procedure goes far and above anything I could attempt.
 I really appreciate the things that go into projects that involve a lot of thought and labor.  Especially when the end product will never be seen or even known about by the end user.
 It speaks volumes about your characters.
 Thanks for the explanation.
 Zulu   

       
 
      Thanks for your kind words, Michael,  the resin is poured around and through an X-shaped aluminum extrusion, although extrusions can be just about any shape, even a rod.  This changes the total weight of the beam very little, but it removes lots of wood which we both know likes to move and warp whenever it gets a chance.  The aluminum extrusion is stiff and acts like rebar in concrete.  We buy these from MSC in 12 foot lengths.  We needed 24 feet for the current batch of beams we had to make.  They are about 50 cents per foot plus $15 shipping per 12 foot piece.  You are right, they are totally hidden, because all the ends are capped with hardware that the original carriage had.  The two outer rails had radiused flanges bent 90 degrees from the forward ends of the iron plates which protected the wood rails from the sliding carriage.  The center one had a separate cap with an iron loop or handle which assisted the gunners in rotating the Chassis about the center-pintle, on the traverse tracks, for pointing.
 
 Tracy
 
 The extrusion before it is hacksawed to length.
 
 


     Sorry Rick, other than a few working sketches of problem areas or features, we don't have drawings.  We make a prototype until it looks right and everything is to the scale we are using and then we make the few production models by using the proto as a master.  That is a very old method, but it works well for us.

 

[Frank46]

Mike and Tracey, I'm truly amazed at the skills in both woodworking and metalworking that you have. This is coming from a guy that has to setup some sort of fence so I can trim a few inches off a door. Forget about using a tablesaw even though I have one. Wood butchery at its worst thats me. Thanks for sharing.Frank

[Ranger99]

great photos and
great work.

[MKlein]

There wasn't one split in this pile of wood a month ago. Now it is looking like some good firewood. If anybody has methods that work for drying wood on a small scale, like a homemade kiln or other methods please share. 200 years ago this was common knowledge but as you can see that modern times has uneducated us on simple tasks. I was trying to make a coehorn mortar bed and Brooke Carriage from scratch.
 

[Double D]

Paint the ends with a a think oil based paint and put it under the house for a couple of years and let it season slowly.   I cut  750 bf of white oak about 10 years ago in 2"x 8"x 8" and 2"x14"x8' and one 1"x10"x8' planks.  Made stack under the house in  Virginia on the dirt.  I stickered it and left  it for two years.  Every few months I turned the boards.  Then it was moved it to a storage warehouse for two years, then hauled to to Montana where it has been sitting for the past 5 years in th attic and rafters.  I have some bowing and some minor splits but very little to no check.  I have made a number K.I.S.S. Golf ball mortars bases and the SAMCC carriage from it.,   

[Ranger99]

i'm no expert, but i can say that
if you're cutting green wood to that
size, i can't think of a way to keep
it from cracking and checking.
it'll have to cut to size after curing.

[rampa room artillery]

Is the air out there in the Midwest that dry?   I am use to my east coast humidity.

[GGaskill]

It takes a lot of paint and a lot of patience.  You have to slow the drying process so that it happens to the whole board at more or less the same time; otherwise one part is trying to be long while another is trying to be short. 

Put at least a couple of coats on the end grain and one on the rest of it.  In the beginning, try to store in a cooler, more humid area so the drying rate is not too fast.  After a year or so, you can move it to a warmer, dryer area.  But patience is a great virtue while doing this.  You can't rush it.

[seacoastartillery]

     Thanks,  Frank,  but don't sell yourself short like that.  I remember when we had the last white oak-red oak discussion almost 4 years ago that you were the one who was the expert on Live Oak and you told us how it was so important for the old time sailing ships, especially big Navy ships like the Constitution, because they needed very strong, tough wood that grew in large diameter sweeping curves that the naval constructors used for Knees that supported the gun decks and very tough wood for the decks, themselves.

     White oak, being waterproof, was used for grog barrels and ship's planking used below water level, scupper rails, etc., listed in order of importance!

Oh, it's egg coloring time; be back later.

Tracy

[seacoastartillery]

     I have never dried our own wood,  so we can't really give advice on that, but we researched the subject thoroughly and we can offer one strong "Do This" to balance our list of "Don't Do This" items.  First of all mentally prepare yourself to proceed slowly.  Whether air dry only or a combination of air and kiln drying also provide cover for your air drying stack of stickered wood.  Provide plenty of weight to hold the stack in contact with the sticker pieces.  Use only dry stickers, never uncured.  Place stickers at regular intervals of 2 to 3 feet apart.  Places stickers so they are exactly opposite each other.  The total time for air dry only on white oak is seven years.  Combo drying time is on year for experts who know all the tricks with 1/2 air dry and 1/2 kiln dry time.  For all others, two years air dry and 6 months of low heat kiln drying.  All wood should be sealed on the end grain immediately after felling (logs) and again immediately after rough sawing, allowing 1/2" loss per 2" of finished wood desired.  Use a sealer designed for the purpose or latex paint on the end grain.  Rotate the entire pile of wood every 4 months.  Use logs harvested only in the late autumn or winter months in the U.S..  Do not let steel or tin covering sheets touch the boards which are drying (oak).  Tannic acid can cause a reaction which stains the wood.  Do not wrap wood in plastic sheets as mold can occur due to excess moisture.  Never fan dry wood during the air dry time.

That's it.  All of our notes boil down to this.  Good luck.  If you are like most people and have no patience, then forget this effort. There is no quick way which produces stable wood, there just isn't.

Tracy & Mike

[MKlein]

Cut me a new stack of project wood out of an oak tree that must have died when the septic tank guys dug through the roots. Noticed leaves turned brown last July and didn't turn green this spring. So to protect the kids from falling huge limbs it was cut down with the handy 18" Pullin chain saw. Cut the logs about 3 ft then stood up on end and cut with chainsaw down the middle. Then sliced with bandsaw many different sizes. Put a thick layer of ruberized undercoating on the ends. Then stacked in a shop that I have been letting the outdoor humidity get in. Been rotating 180 degrees every 2 days so far so good. I will know in a few weeks if it is going to crack bad or not. Hoping that some of the process took place while it was dying out in the yard.

[Frank46]

Mike and Tracey, I'm far from an expert on live oak. The only experience I have with it is picking it up and chucking it on the burn pile. But living here in Louisiana you get to see a lot of live oaks. My experience limited at the least is that I love to read. Sometimes scares the heck out of my daughters when they watched "life of Pi". Big deal I said, there was a Chinese man who spent quite some time after his ship was torpedoed during WWII, think his name was Poon Lim or something similar. And yes wood runs away when I start marking it up to be cut. Frank

[rivercat]

Hi All,
I have been reading this post with interest with regards to curing timber etc.
As I need to sometimes turn up tampions for cannons on a lathe and these can be of various sizes I have used in the past Poly ethinal glycol, General rule of thumb for every 1" thickness of wood you leave it fully covered for one week hence 6" thick timber=6 weeks etc.
The basic principal being that through capillary attraction the wood will soak up the glycol pushing the moisture out of the wood then left one week to dry and away you go. When turning these up you tend to have a silky finish as the glycol basically turns to a form of wax. I have not had any splitting, shakes etc.
I am not sure if you can get this in the USA or if you can weather you guys have tried this method.
Rivercat

[Double D]

Poly ethanol glycol in the US.  PEG....also poly ethylene glycol.

The MSDS is pretty innocuous http://www.sciencelab.com/msds.php?msdsId=9926620

[GGaskill]

Antifreeze?

[Double D]

Is ethylene glycol the same as poly ethanol glycol?

The msds for  antifreeze is different than for PEG.   https://safety.as.arizona.edu/msds/Antifreeze.pdf

 

[MKlein]

Does this mean that it needs to be submerged in it or  just sprayed on? I would need a large tank.

[megajoules]

readers might like to know tha PEG has been continiouly sprayed onto the Mary Rose for circa 30 years ~ the following is from their website,
During passive conservation, the ship structure itself couldn’t be completely sealed for obvious reasons. Instead it was regularly sprayed with filtered, recycled water kept at a low temperature, which stopped it drying out, and prevented microbial activity. Without spraying, the wood would have shrunk by anything up to 50%, warping and cracking as the water evaporated from its cellular structure.
The conservation team then sprayed the hull with polyethylene glycol (PEG) to replace the water in the cellular structure of the wood. There were three distinct phases, with a low molecular weight PEG to begin with, then a higher weight to strengthen the outer layer of wood. Finally the hull will be carefully air dried.
Source: http://www.maryrose.org/archaeology-and-conservation/mary-rose-conservation/#The use of PEG-link
 
However I dont think some of us are prepared to wait that long~ FYI its well worth the effort to make a visit to Victory & Fort Nelson, whilst waiting! 
 

[seacoastartillery]

     Those considering use of PEG for preservation and dimensional stabilization of green wood would be well advised to do plenty of study before actually taking action.  Think about the implications of this story of what happened to the chassis and gun carriage holding up the 8" Armstrong 150 Pdr. Rifled Muzzle Loader mounted at Trophy Point on the grounds of the United States Military Academy at West Point, New York. 
 
      Captured from Col. Lamb's Confederate Army and Navy defenders of Fort Fisher during the second Battle of Ft. Fisher in Jan. of 1865, it was located in Battery Purdie, about half way down the Seaface of the fort.  Despite a total expenditure of approximately 40,000 shot and shell during the Dec. 1864 and Jan. 1865 battles by the Federal fleet, the gun survived with nary a scratch, only to be hauled north shortly after the battles. 
 
       We have studied this gun quite a bit, and found several historical accounts of it's carriage and chassis construction.  The accounts we have read agree that the Chassis wood was mahogany and the gun carriage wood was rosewood.  It's appearance must have been truly a jewel among the long line of seacoast guns at Fort Fisher.  No paint dulled the startling beauty of this carriage as received from  Sir W. G. ARMSTRONG & Co.  Some simple transparent wood finish, like boiled linseed oil provided a modicum of moisture protection. 
 
       The following timeline of carriage and chassis replacements came from several senior museum staff members we talked to.   The original carriage lasted approximately 35 years.  The first replacement around the year 1899 was grey painted white oak and it lasted approximately 75 years!  The second replacement was done by the Champlain Cannon Works of Glens Falls, NY.  It built a nice, authentic oak carriage and chassis, then, for some unknown reason, decided to treat it with an experimental,  polymer preservative. This carriage collapsed into a pile of mush about 15 years later, so in the late 1980s or early 1990s Paulson Bros. Ordnance built a really nice looking metal carriage and chassis for the almost 16,000 pound tube which, with proper painting, will most likely be good for 200 years plus.   
 
 Mike & Tracy


This is the most recent wood carriage and chassis built by John Braxton, a seacoast carriage builder from Snow Camp, North Carolina.  It is located at Fort Fisher in Kure Beach, NC.  Last we heard a replica tube was built for it by a company unknown.  Mounted on The Fort Fisher wood carriage, is the original tube on loan from the US Army at West Point in 2005 and 2006.




It was bitter cold along the North Carolina coast in Dec. of 2005 when we visited Fort Fisher to finish our field drawing of the tube that we started at West Point in 2004.  We worked 8 hours a day for 3 days to finish 8 pages of field drawings and notes.  To find the fort just follow the   SKI FORT FISHER  signs along the road leading south from Wilmington, North Carolina!