typical slab thickness, and practical slab lengths?

[forrestM]

Hello & Merry Christmas,

I have a customer wanting to slab a large pine tree (white pine, I believe). It is 30 inches dia. and 17ft long, and straight the whole way. They want to do it on site which will require me to use my chainsaw mill. I was wondering what thickness do people typically cut slabs? is it 2 1/2" or 3"   --- what would be most useful? What's your standard SLAB?   Also, it seems impractical to me to cut a 17 foot long slab just because I can. What is most practical when you have to choose a length for your slabs, or when you have to choose lengths in general? Would you do 2 8' sections or a 12' and a 4' ? or just cut it 17ft and size it later?

Just looking for some pointers on the matter.


Thanks,
Forrest

[Den-Den]

If you are just cutting and they are doing the handling, then 3" + thick and full length.  If you have to move the thing and dry it, size according your equipment and storage space.

[Brad_bb]

Yeah, who cares about the length.  You're being paid to saw it and one set up- cutting as one log, is easiest/most efficient for you.  Thickness should be dictated by customer.  Keep in mind  how much will need to be removed to get it flat.  I typically mill 2.75 and 3.25" thick.  They'll could end up at 2" and 2.5 respectively.  It just depends on how thick they want to end up.  With pine, they won't be that heavy when dry compared to the hardwood I'm cutting.  So let them dictate the final thickness they want to end up at and add at least 1/2 to 3/4".  Don't forget the width of your kerf.  Take that into account.

[BenTN]

What brad said, let the customer dictate thickness. Keep in mind the amount of material removed from a piece to flatten increases with length. The same amount of twist in an 8' slab will flatten easier than a 17' slab. We adjust our thickness according to width of slab, length of slab and species. Some species move more that others. It is all dependent on the finished thickness desired.

[WV Sawmiller]

   Remember also that you can always make them smaller later. I'd suggest making them as long as your equipment and storage will reasonably accommodate.

  What does the customer plan to do with the finished wood? That should govern the thickness. Good luck.

[YellowHammer]

If it was me, and somebody asked me to slab a 17 foot, 30 inch diameter hunk of wood with a chainsaw mill, I'd cut it as thick as possible so I could make as few as cuts as possible, turn the saw off, get the money and drive away in a cloud of dust. :D :D

The thicker the slab the more prone it will be to crack when drying.  We cut some white pine, not a lot, which is very forgiving when drying, up to 4 inches thick, full width, with minimal drying cracks, and I bet it would do pretty good thicker, too.  I've done some pretty thick white pine cants and they seemed to dry OK.

Generally though, the thinner the cut, the less prone to drying defects.  As long as the customer knows the risks, make sawdust.

Hardwood is a whole different matter.

One very illustrative talking point I have with people who want me to  
mill thick hardwood slabs for them, (because I won't do it for myself due to the high defect rate), is to make sure they understand it will crack.  I tell them the more I cut thick to where it looks like a crosstie, the more it will dry like a crosstie.  Then if they ask what do I mean, I tell them to get on a set of railroad tracks and walk a mile and count how many hardwood crossties aren't cracked, and that's their chances of success sawing thick hardwood. After that, it's their wood, their cracks.  

[moodnacreek]

2 1/2" has always been an easy thickness to sell.  People will ask for 4 and 6" thick and turn around and buy 2 1/2" all the time.

[GAB]

If it was me, and somebody asked me to slab a 17 foot, 30 inch diameter hunk of wood with a chainsaw mill, I'd cut it as thick as possible so I could make as few as cuts as possible, turn the saw off, get the money and drive away in a cloud of dust. :D :D

The thicker the slab the more prone it will be to crack when drying.  We cut some white pine, not a lot, which is very forgiving when drying, up to 4 inches thick, full width, with minimal drying cracks, and I bet it would do pretty good thicker, too.  I've done some pretty thick white pine cants and they seemed to dry OK.

Generally though, the thinner the cut, the less prone to drying defects.  As long as the customer knows the risks, make sawdust.

Hardwood is a whole different matter.

One very illustrative talking point I have with people who want me to  
mill thick hardwood slabs for them, (because I won't do it for myself due to the high defect rate), is to make sure they understand it will crack.  I tell them the more I cut thick to where it looks like a crosstie, the more it will dry like a crosstie.  Then if they ask what do I mean, I tell them to get on a set of railroad tracks and walk a mile and count how many hardwood crossties aren't cracked, and that's their chances of success sawing thick hardwood. After that, it's their wood, their cracks.  

Cracks are an opportunity to use butterflies in your finished product.  Some might say it adds character.
Gerald

[woodworker9]

I saw most of my slabs 10/4.  Occasionally 3", but not very often.

Every table I build with them sells, so it hasn't been an issue at all.

[WDH]

I saw mine 9/4.  In hardwood, that is 2 3/8" thick rough.  They normally plane out flat at a finished 2". 

[Magicman]

I saw whatever thickness that WDH tells me to saw.  8)

[scsmith42]

We always start with a clear understanding of what thickness that the customer wants the installed slab to be, and then add for shrinkage and drying related movement.

The amount added depends upon log width (wider gets more fudge room), log quality (defects, amount of taper plus spiral grain all factor into the equation), and log length.  

It requires less material removal in order to clean up a 30" wide 8' long slab milled from a straight, clear log, than what is required in order to clean up a 60" wide, 14' long slab milled from a gnarly log with a lot of twist.

Crotch or forked logs also will have a bit extra added.  Narrow crotches don't move much, but in the case of a massive log with a branch almost perpendicular to the pith will frequently distort more where the grain changes direction.

Typically we start at at least 2.5" for narrower, clear slabs with the understanding that they will S2S at around 1.5" - 1.75".  If we're milling a 72" wide, 16' long slab from a gnarly trunk, most likely it will be milled around 4" thick - also with the same goal of cleaning up around 1.75" - 2" thick.

Lots of customer want really thick slabs until we educate them about the weight.  

Also keep in mind that slabs milled across the center of the log will shrink in thickness about 2X more than slabs milled closer to the bark.

[WDH]

All I have to do is hold up some fingers ;D. 

[OffGrid973]

Go 3" as the chainsaw has a little more take than a sawmill...easy to work down to 2.5" or even 2" after final drying.  I have people who love to make floating shelves out of 2.5" pine, makes a statement and easy to get a bolt into for hidden floating mechanism.

[DPatton]

I saw whatever thickness that WDH tells me to saw.  8)

MM, 😁😆😅I know it's never gonna happen but What If WDH was wrong just this one time? In all seriousness WDH as many of us know there's no fail safe right answer to this question. It all depends on the log at hand and the final product desired. Some logs will produce 1 1/2" planed smooth both face lumber when rough sawn 1 3/4" thick. Others take 2 3/4" or 3" to make a dried, and planed smooth 1 1/2" slab. However if I was a betting man I would cut it what ever thickness Danny say's if I need it to plane out smooth at full thickness. Yellowhammer also has a great response to this post on thickness depending on how you are drying and what your final product needs to be.

[WDH]

I have sawn and dried many hundreds of slabs.  I have found that there are several keys:

1).  Saw the slab out of the log properly.  I like to center the pith and rotate the log 180 degrees as you saw it.  Some logs require more rotation than others because of stress.

2).  Slabs that are air dried before kiln drying have already been through the period above fiber saturation point where the bad things happen in drying.  The day/night conditioning that air drying slabs undergo helps dry them more gently.  Now they can be kiln dried to final moisture content without going at a snails pace.

3).  Critical that the air drying stack foundation be perfectly level.  Also, I put green green stickered slabs on a pallet and this pallet goes on the base of the foundation (I have poured concrete air drying pads).  Then, stack other pallets of wood that have been air drying for a while or is already air dried to use the weight of these drier pallets of wood to help keep the slabs flat.  I also sticker on 16" centers.  Trying to skimp on stickering is paying a dollar to make a nickel (old saying).

4).  Once kiln dried to below 10%, examine each slab for flatness before planing.  Some pallets of slabs have every piece flat so that they can be immediately planed.  On some others, the top two layers may have some twist, warp, or bow.  These can be put back on the sawmill, shimmed, and have the top skimmed with the blade to get one side flat.  Takes some time, but it is worth the effort on slabs worth hundreds of dollars. 

5).  Store the slabs in a climate controlled space.  I stack mine vertically against the wall in the slab building.  This helps in allowing customers easier access to viewing the slabs.  Yellowhammer's slab rack where the slabs are stacked in a circle so that each can be seen is a good way to display the high value ones.  I keep the humidity in the building at 40% or less with two large room dehumidifiers and an air conditioner.



 



  

[Magicman]

You need more Walnut.....much more Walnut.  ;D

[Bruno of NH]

Very nice WDH