Mantle Sawing Method

[cblewis]

New sawyer. 

Customer looking for a mantle from a red oak. Wants a 9"x5"x72"

Are mantels best sawn by boxing the pith in the center or taking the material from a face and eliminating as much sap wood as possible?

Thanks in advance. 

[Wlmedley]

There are plenty on here that have been sawing longer than I have but if it was me I would center the pith and use the center of the log. I believe you would have less movement doing it that way and if log is big enough no sapwood.

[doc henderson]

That is true.   If you take from the edge of a log, it may cup.  from the center, the pith may find its way to the surface on one of the flat sides (closest to the pith).  you can also pre saw to direct the crack.  best to saw and let it set and then trim it flat after some drying time.  selling a green plank for a mantle, they "get what they get and don't throw a fit".

[YellowHammer]

Also let him know the thicker you cut it, the more it's going to crack open like a rail road cross tie when it dries out.  

[doc henderson]

Rustic country charm!

[123maxbars]

I use to saw/build a lot of mantles. After years of frustration over thick mantles checking/cracking I went with a different method. I took 8/4 slabs that were kiln dried and ripped them down to the mantle thickness I wanted and laminated them together.  Resulted in a very stable piece with no cracks and you would only see the laminations if you walked over to the piece and looked on the face of it, which most people do not observe. 

[123maxbars]

Forgot to add the pic to my previous post. This was red oak that the customer wanted me to use some Cherry stain on, 

[WV Sawmiller]

   I went down to visit and stack wood for Poston one day a few years back and he had a customer come in to have a mantel sawed out of their log. I remember he also sawed a thin board off the log and gave to the customer and suggested they use it to test any stains they might want to try. I thought that was a simple thing to do but a very good idea.

[Ventryjr]

Also let him know the thicker you cut it, the more it's going to crack open like a rail road cross tie when it dries out. 

Do you think this could be avoided by sawing/drying a longer piece then cutting it to length after drying.  In hopes of cutting out the cracking or checking?   I cut a few thick "mantle" pieces 2 years ago and set them aside to dry.  White oak and maple.  They were arrpox 6' long and the splits only seemed to travel 1' in from either end.  Leaving ~4' of good un-cracked material. 

[doc henderson]

end checking is from rapid water loss via the end grain or open ends of the tubes.  the easiest route for water to leave.  bark really slows water loss from the sides of a log like our skin for the human.  Cut the log into a rectangle and now there are exposed side that loose water although slower than the ends.  you can slow the water loss form the ends with an end grain sealer.  you can slow it all down by using a kiln to minimize the water content difference of the outside of the mantle and the core.  It is counterintuitive, but you keep the RH humidity high, so the gradient is less.  Cracks occur due to a dry and shrinking outer layer vs a still swollen wet core.  A crack will follow the path of least resistance such as the shortest distance from outer wood to the core, or where there is already a fine crack or weakness.  The inner and outer circles of a log shrink the same by percentage.  the outer circle of a 1-foot diameter log is 3 feet in circumference.  A 1-inch circle in the core is 3 inches in circumference.  the outer is drying faster than the core.  at say a 10% the outer is shrinking 3.6 inches and the core only 0.3 inches.  It takes time for the inner moisture to move out of the log and the bigger the gradient, the more likely to crack.  However, some gradient must be present for the water to move.  This is where schedules come from for different species.   You can pick a side to pre-crack or cut.  this can control the location say to the bottom or top of a mantle. It can be later filled and everything squared back up.  The rustic fad has helped some in that many embrace the nature and imperfections of some projects.  "And that is all I have to say about that".  Forest Gump.

[doc henderson]

So, the cutting long and shortening later may just expose the next end grain that will later check.  the stress along the piece will still cup or crack.  Seal the ends, and stack with other wood near the top and bottom sides of the mantle.  stack other wood all around it so it slows the water loss, and you forget about it for two years.

[doc henderson]

These extremely short logs (cookies) were placed in a box face to face in the order you see.  the outer ones split.  You could also cover mantle in sawdust or shavings.  You need all surfaces to be exposed equal conditions of airflow and RH.

[doc henderson]

The center one also had the pith in the center and the others cracked where the pith is closest to the outside.

[doc henderson]

If you do woodworking, you can make 4 mantles from one cant.  yes, you can!   


@tule peak timber 

[VTwoodworker]

If you have a 24"+ log you could get the mantle on either side of the pith.  The result would be mostly a vertical grain piece that would be stable and minimize cracking.

[WV Sawmiller]

  I have had customers buy 2" thick mantels and I have had them want 6" thick mantels.

  I saw my stock mantels into 3" or 4" thick mantels and either leave one and sometimes 2 live edges. I make sure all my mantels have approximately 12" of clear wood showing after any edging. I have had customers want me to edge one side and others wanted both sides edged.

    Some customers want mantels 6" square and 5' long. Others want them wide.

    My stock mantels are normally 8-10 feet long. I tell the customers if they are too long they can use the excess length to make corbels.

[tule peak timber]

I always highlight the pith and the crack through it on the face of my mantles. Mostly I do hollow form when they are larger than 6 inches and plug the ends with a thin cookie from my "cookie library". That said I get 2 premium mantles from one boxed heart timber, and that includes the face with the heart crack and the top and bottom more thinly sliced from the same board. If you do it right, all the grains and the cracks match up and if they don't, a little carving and then they do.

[Larry]

That's cool. Highlighting the pith adds a lot of character and interest to the mantle. Never thought to do it that way. I have made hollow mantles and like that method but mind are sorta boring......

[tule peak timber]

Weighs about 12 pounds