Thursday, April 25, 2013

Milling wood

Gustav have finished the holders for the obstacles for the horses to jump over. And I promised him that we could make some new booms as well.
The old booms were some 1x2" strips that I had, but they were soft and flexed when mounted on the holders.
I decided that the new booms will be 3x3", and the plan is to make an attachment that will allow me to make them octagonal using the sawmill.

The following is a description of how I mill wood, to use for my various projects.

The sawmill is powered by my old Volvo BM 400 tractor (diesel), the PTO shaft is connected to an angle gearbox from an old grass cutter (for making grass for silage).

The sawmill itself is a BMR 900, and old Danish sawmill with a circular blade of 900 mm diameter (36"). The sawmill can handle wood of up to 8.5 m (roughly 28 feet), and a it has a maximum riving capacity of approximately 12". So the wood can be of a diameter of up to about 16", since normally you don't split it right down the middle anyway.

The log is hoisted onto the sawmill by means of a
manually operated chain block and a home made
crane beam.                                                            

The log is positioned on the moving table and is
secured by means of some small wooden wedges.

The first cut is made near the edge of the log.
Note that the fence is retracted all the way.   

This is how the log looks like after the first cut.
The log is then rotated 1/4 of a turn, so the flat 
side is facing down. Then another cut similar to
this one is made, so the log has got two flat sides
meeting in a 90 degree angle.                               
 

Now the fence is set to the desired thickness of the
finished board which is 3" in this case. The log is   
positioned so it is resting on a flat side, and the other
flat side is against the fence.                                       
 

Now the narrow board is 3" thick, and
it will be parked on the table beside the
saw while another one like it is being    
made                                                      

Now the board which is 3" thick is    
placed flat on the saw mill. The fence
is once again set to 3" to make the boom.
 

If the off cuts are a little wide, I will usually rip them
in order to make them more suited as firewood (then 
they need no splitting). In addition to this it produces 
some more sawdust which is used in the stalls for the 
horses. If the size of the off cuts permit it, I normally 
try to make a board e.g. 1x4" out of it.                         
 
If it is hardwood (elm), which I would like to use for
making furniture, then there is a small pause in the    
process (2-3 years) to allow the wood to dry.              
 


8 comments:

  1. Very interesting explanation. Thanks Jonas.

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    Replies
    1. You are welcome. Thanks for commenting.

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  2. It must be nice to be able to quarter saw your own stock if you need to. Do you ever mill wood for others? Or possibly sell it? Portable sawmills are a fairly nice little business in upstate Pennsylvania because most of the larger mills won't take the time to saw one or two logs for private use.
    Bill

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  3. I have sold a little, but being that I am away half the time at sea, I haven't done much to get a business started.
    I have tried to make some quarter sawn stock, but it drastically increases the time it takes to mill a log. Most of the boards I have milled have been used for the stable and for other construction purposes. But I made our kitchen out of home sawn elm.

    I have heard that the band saw mills are more sensitive to dirt on the logs than the older type circular saws. But then they don't waste as much wood since the kerf is very narrow. My sawmill leaves a kerf which is a little wider than 1/4". So I am glad that I can use the sawdust so it doesn't seem wasted.

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    Replies
    1. My mother and father in-law own a large piece of land in upstate Pennsylvania. There are thousands of trees and my wife's uncle, who unfortunately passed away, would sometimes cut them down and hire a portable saw mill to come in and saw the boards to be used in woodworking. There is a large amount of Cherry and Ash that is still setting in their barn. I always mean to take some home with me but I never do.

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    2. I think it would make your wife's late uncle proud, if you made something out the wood he had cut down. A keepsake box for memories made out of some wood that he had cut down would make a real nice present for his family.
      Ash should be really stable wood according to my knowledge, and a very clear light/white colour. I have never worked in Cherry.

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  4. For some reason I thought you had a band saw mill. Or is this the one you are rehabbing?

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  5. Hi Brian.
    I don't have a band saw mill. The circular saw has been up and running for about 6 years.
    The one I am restoring is a horizontal single blade reciprocating saw (a mule saw or mulesaw whichever is the correct spelling?)
    I do have a band saw though, but not a saw mill :-)

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