Results 1 to 15 of 15
  1. #1
    Join Date
    Apr 2008
    Location
    Canberra
    Posts
    816

    Default how thick should I make my slabs?

    Hi All,

    I have always been keen to give chainsaw milling a go and we have recently had a large gumtree go heels up on our urban property. Its approx 14 meters tall and has an uninterrupted sawlog on it of about 5 meters from the base to where the first branches start. Its approximately 600mm diameter for this length and as straight as a pole.

    I would like to slab this, and use the resulting lumber to make an outdoor setting. Stainless frame, timber top set in frame, bench seats. Something like the attached image.

    I was wondering how thick one would need to cut the slabs to allow for cupping, finishing etc? I was thinking nominally that the finished slab might be 30 to 40mm thick? the job will be done in situ and i wasnt envisaging manipulating the log for back sawing etc...I was going to just slab the lot from top to bottom but will be grateful for advice on all aspects of this project...I havent done wood work in years!

    Cheers in advance.

    Brendan
    Attached Images Attached Images

  2. # ADS
    Google Adsense Advertisement
    Join Date
    Always
    Location
    Advertising world
    Posts
    Many





     
  3. #2
    Join Date
    Apr 2005
    Location
    Nerang Queensland
    Age
    65
    Posts
    10,763

    Default

    I chainsaw mill to 50mm to achieve a min 30mm final product.
    Neil
    ____________________________________________
    Every day presents an opportunity to learn something new

  4. #3
    Join Date
    Jun 2003
    Location
    Gatton, Qld
    Age
    47
    Posts
    3,067

    Default

    On the Lucas I do 65mm slabs to give a finished dressed, dried product of 50mm.

    And yeah, don't do anything silly like rolling the log around, just slice it from top to bottom
    I love my Lucas!! ...just ask me!
    Allan.

  5. #4
    Join Date
    Apr 2008
    Location
    Canberra
    Posts
    816

    Default

    Thanks Gents!

  6. #5
    Join Date
    Apr 2008
    Location
    Canberra
    Posts
    816

    Default

    That tree mentioned above came good after a heavy prune and is safe from the mill for now Ė however I have my eyes on some fallen trees at a mates property which I want to test my CS mill out on.


    Re dimensioning timber, I have a couple of questions.



    1. When you slab a log I understand you end up with a couple of quarter sawn boards, a couple of back sawn boards and a couple of boards in between. Will the quarter sawnboards cup more when drying than the back sawn boards? When stickering the slabs for seasoning is it worth putting the quarter sawn ones on the bottom so that the weight of the others keeps them flat?
    2. How long should I make my slabs? I did a quick calculation based on a 65mm slab thatís 2400 long and 500mm wide and thatís nudging 100kgs green which is a bit unwieldy. Are there any benefits of long slabs besides being able to make long tables?


    Brendan

  7. #6
    Join Date
    Aug 2011
    Location
    bilpin
    Posts
    3,261

    Default

    Quartersawn material will be more stable than backsawn.
    100kg would be about normal (welcome to the world of the miller.) A few pieces of water pipe make good rollers for shifting slabs off the log.
    When determining length allow for end checking.

  8. #7
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    27,253

    Default

    Quote Originally Posted by 19brendan81 View Post
    When you slab a log I understand you end up witha couple of quarter sawn boards, a couple of back sawn boards and a couple ofboards in between. Will the quarter sawnboards cup more when drying than the back sawn boards? When stickering the slabs for seasoning is itworth putting the quarter sawn ones on the bottom so that the weight of theothers keeps them flat?

    Yes. The outer 3/4 section of the quarter sawn slabs away from the heartwood should dry the most even - However the heart wood can move all over the place badly cupping the whole slab.The flat sawn boards may cup the most across the whole board. You should try to get as much weight as possible on the whole stack. Derek Doak the timber Bloke uses section of concrete wall and floor slabs to weigh his down.

    How long should I make my slabs? I did a quick calculation based on a 65mmslab thatís 2400 long and 500mm wide and thatís nudging 100kgs green which is abit unwieldy. Are there any benefits oflong slabs besides being able to make long tables?
    2400 x 500 x 65 = ~0.078 m3 or about 78 kg
    I find I can move these around with a sack trolley and lift one end at a time onto a low stack.
    You don't have to cut everything at 65 mm. I've cut most of my stuff at 50 but what I do wish I had done more of is milled some shorter stuff into 75 and 100 mm for table legs etc.

  9. #8
    Join Date
    Apr 2008
    Location
    Canberra
    Posts
    816

    Default

    Thanks for the replies fellas. I am going to stack these under my house somanouvering weights under there will be a nightmare but its good to know that weight does help.I will make my stacks quite high so the bottom boards are under as much compression as possible.

    Re the calcs I did it based on a wet weight of 1100kgs per cube for green timber which is why I came out to the higher figure. Good tip re the water pipe rusty - I'll make sure I have that at hand on the day.


    Also good thinking re table legs Bob - I will definitely do this.Do you think a mix of 100mm x100mm and 75mm x 75mm is a good start for table legs?


    Quote Originally Posted by BobL View Post
    Yes. The outer 3/4 section of the quarter sawn slabs away from the heartwood should dry the most even - However the heart wood can move all over the place badly cupping the whole slab.The flat sawn boards may cup the most across the whole board. You should try to get as much weight as possible on the whole stack. Derek Doak the timber Bloke uses section of concrete wall and floor slabs to weigh his down.



    2400 x 500 x 65 = ~0.078 m3 or about 78 kg
    I find I can move these around with a sack trolley and lift one end at a time onto a low stack.
    You don't have to cut everything at 65 mm. I've cut most of my stuff at 50 but what I do wish I had done more of is milled some shorter stuff into 75 and 100 mm for table legs etc.

  10. #9
    Join Date
    Dec 2014
    Location
    Willunga, Australia
    Posts
    725

    Default

    Quote Originally Posted by 19brendan81 View Post
    Thanks for the replies fellas. I am going to stack these under my house somanouvering weights under there will be a nightmare ...
    I was watching a video on timber stacking and the guy was using trailer tie downs on the stack. He said that this kept the wood stable. He also noted that you need to be careful when you undo the ties since the wood can contain a lot of spring and it can be dangerous when removing the ties.

    You may need something on the corners to stop the ties cutting into the wood. Say 90 deg wood blocks with a rounded corner would be ideal, or in a pinch small squares of old carpet, multiple layers maybe, over the corners.

  11. #10
    Join Date
    Apr 2005
    Location
    Nerang Queensland
    Age
    65
    Posts
    10,763

    Default

    Quote Originally Posted by Yanis View Post
    I was watching a video on timber stacking and the guy was using trailer tie downs on the stack. ...
    I use tie-down straps all the time, around decent timbers above and below the slab stack at each sticker line, to ensure uniform distribution. Just make sure you retighten them regularly as the timber shrinks and moves.
    Neil
    ____________________________________________
    Every day presents an opportunity to learn something new

  12. #11
    Join Date
    Apr 2011
    Location
    McBride BC Canada
    Posts
    3,537

    Default

    Sticker quality matters = you get staining (sticker shadow) and kiss the wood good bye.
    If I came to you looking for a slab for a serious relief carving, 60 - 90mm thick gives me room to play.
    In any case, paint some sort of slop on the cut ends to slow down the checking.

  13. #12
    Join Date
    Apr 2008
    Location
    Canberra
    Posts
    816

    Default

    Thanks for the info here everyone - I really appreciate it and I like the idea of the straps. Re sticker quality - I was just going to use some virgin tomato stakes. Or failing that, some old fence pailings that I have. Would that be sufficient?

    Will definitely paint the end grain.

  14. #13
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    27,253

    Default

    Quote Originally Posted by 19brendan81 View Post
    Thanks for the replies fellas. I am going to stack these under my house somanouvering weights under there will be a nightmare but its good to know that weight does help.I will make my stacks quite high so the bottom boards are under as much compression as possible.

    Re the calcs I did it based on a wet weight of 1100kgs per cube for green timber which is why I came out to the higher figure
    'Fair enough

    . Good tip re the water pipe rusty - I'll make sure I have that at hand on the day.
    Yeah these are VERY handy.

    Also a cant hook is a good investment to move slab as well as logs.

    Also good thinking re table legs Bob - I will definitely do this.Do you think a mix of 100mm x100mm and 75mm x 75mm is a good start for table legs?
    It depends what you have in mind for the timber. If the table is big enough even 125 x 125 or 150 x 150 look really good.
    These of course do not need to be full slab lengths, 100 x 100 can be half length (1.2m) and 150 x 150 can be half a slab and this can be cut length wise to make 1/4 (1/2 length and 1/2 width) slabs to keep them manageable.

    If you use tie straps they need to he HD - its not much use using ~ 400 kg rated straps especially on wide slabs.

  15. #14
    Join Date
    Mar 2017
    Location
    Tamborine Mountain
    Age
    43
    Posts
    13

    Default

    This is fascinating. Is it possible to mill logs of about 150 -180mm. I once saw a verandah rail made from slabbed red gum about that wide and 50 or so thick that had the natural curved outer wood for effect on th sies, without the bark of course. It was just beautiful. Is there anywhere you could source such a product in south east qld. I'd love to find some.

  16. #15
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    27,253

    Default

    Quote Originally Posted by Rubyrose View Post
    This is fascinating. Is it possible to mill logs of about 150 -180mm. I once saw a verandah rail made from slabbed red gum about that wide and 50 or so thick that had the natural curved outer wood for effect on th sies, without the bark of course. It was just beautiful. Is there anywhere you could source such a product in south east qld. I'd love to find some.
    Unlikely you will find it as a stock item so 150/180 mm is most likely to come from branches meaning is likely to spilt when milled.
    If you could find a tree lopper who had to take trees that size down then trunks could be used which would be better, even so splittage will be high.

Similar Threads

  1. Thick Silky Oak Slab - what to make?
    By illcrabmagik in forum WOODWORK - GENERAL
    Replies: 7
    Last Post: 5th January 2013, 04:26 PM
  2. FREE SLABS - MELBOURNE - not beer slabs
    By sailor in forum TIMBER
    Replies: 28
    Last Post: 11th July 2009, 10:17 AM
  3. Replies: 8
    Last Post: 23rd April 2007, 12:04 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •