small mill, big log?

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Frank33

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Hello all, I may in the future try milling small logs with an Alaskan mill for a 20" bar, my question is has anyone used something like this on a log larger than 20", say on a log maybe 30" wide? It seems like you may be able to cut one side then from the opposite side make another cut thereby finishing the slab. Or would this cause the chain to catch or any kickback issues?
 
Putting a conventional alaskan (where the bar is held in the mill at both ends) on a 20" bar will restrict the cut by about 6" so the widest cut you will be able to make is ~14"

In theory it is possible to mill a log (by as you say making a cut on one side and then the other) that is the square root of 2 times bigger than the widest possible cut, so in theory the maximum diameter log that can be milled with a conventional alaskan will be 14*SQRT(2)=20"

However, in practice the bar clamps get in the way and don't permit the bar to do this on a log bigger than the max with of cut so the widest log you will be able to cut will be less than 20" in diameter, maybe only bearound 16" in diameter.

To improve this you have two options
1) Bolt the bar to the mill
This requires the the mill to be modified by cutting away the bar clamps and welding on a solid block of metal that can be drilled and tapped with a thread. Then drill holes in the bar and bolt the bar to the mill. This has other advantages as well, such as being able to remove the chain while the CS in on the mill, and being able to move the out board mill mount point to the middle of the bar nose (hole drilled thru the middle of the bar nose) . This will give you somewhere around 16" of normal cut width and allow you to tackle a 16*SQRT(2) = 22" diameter log

2) Use a single ended alaskan
To get a longer cut you can fit a one ended CS mill which will give you 17" of normal cut. However the bar clamp will still get in the way and cannot be removed such as is possible with the "double-ended bolt the bar to the mill alaskan" so it won't quite give you the Sqrt(2)*17" log diameter.

I personally don't like single ended alaskans as they wander around too much in the wood I cut and they cannot be used with bars more than about 25" long but I hear they go OK in softer woods.

This diagram might help explain it.
cutwidth.jpg


In practice I find turning the log is a PITA and it's just easier to use a wider bar.
 
I'm not sure if he isn't asking about using the Granberg "Small Log Mill" from both sides of the log. i.e., BobL's depiction of the Single ended Alaskan. It is suggested for a maximum 20 inch bar. As BobL says the bar wanders up and down in the cut giving you a board of varying thickness. Cutting from the other side of the log doesn't match up well. It has been tried. You will need a bigger saw and bar and a bigger double ended mill frame. Bolting the mill to the bar has definite advantages. You can build your own mill frame. And who doesn't "need" a bigger saw anyway?

Cutting from both sides of the log also has the disadvantage of not being able to use slope at least one way when you are cutting.

I have had no problem drilling bars using carbide masonry bits in a small drill press. Just did one yesterday.

There are plenty of ideas on the forum here for building your mill frame, from simple to fancy. Read the Chainsaw milling 101 sticky. Read everything you can find here. And ask questions. People are really helpful and willing to share.
 
As the others have said, it has been done (I've done it, regretfully). I had no kickback issues. In theory it should work, but in reality you'll end up with varying degrees of kerf overlap. Then many trips through the planer. The small mill has its place, but it's not for the bigger logs you describe if you have any desire to produce quality lumber. This is one of those great opportunities to learn from the mistakes of others. Good luck and enjoy.
 
Thanks for the info, I was thinking along the lines of a single ended Alaskan just to clarify, I will either purchase one or create my own design. I make furniture so quality lumber, especially for slab tables tops, is definitely desirable. BobL thanks for the images, they helped to clarify some stuff.
 
BobL
I'm designing on making a homebuilt "single ended alaska mill" (sorta like the Norwood Portamill, but for lots less than $999); for the rails using the end-columns from warehouse "gorilla racks" -- carrying a welded-up tricycle using poly sliders instead of wheels and a vertically-mounted square-tube top-wind trailer jack; normal to that jack's outer shaft will be a shelf which carries the chainsaw via bolt-downs in a manner that keeps the plane of the saw-bar paralell to that of the tricycle and rails. (log is dogged-down on a second set of rails) I've toyed with several options to strongly and squarely hang the saw (my Huski 575XP) onto the shelf, but am not yet happy with what I've conceived. Are there plans out there for doing that? How does the Norwood do it?
 
With a timber jig or an Alaskan mini mill you could quarter large logs the saw the quarter to get quarter sawn wood by cutting off of alternate faces on the quarters with either the timber jig or an Alaskan. Unless you want big slab tables with are very hard to keep from cracking wide slab lumber is going to need to be re ripped anyways although a track saw works better than a chainsaw. By using a timber jig to quarter first you eliminate this step as you end up with-varied widths that is much more conducive to regular furniture anyway. Quartersawn looks better and is more stable to boot.
 
Putting a conventional alaskan (where the bar is held in the mill at both ends) on a 20" bar will restrict the cut by about 6" so the widest cut you will be able to make is ~14"

In theory it is possible to mill a log (by as you say making a cut on one side and then the other) that is the square root of 2 times bigger than the widest possible cut, so in theory the maximum diameter log that can be milled with a conventional alaskan will be 14*SQRT(2)=20"

However, in practice the bar clamps get in the way and don't permit the bar to do this on a log bigger than the max with of cut so the widest log you will be able to cut will be less than 20" in diameter, maybe only bearound 16" in diameter.

To improve this you have two options
1) Bolt the bar to the mill
This requires the the mill to be modified by cutting away the bar clamps and welding on a solid block of metal that can be drilled and tapped with a thread. Then drill holes in the bar and bolt the bar to the mill. This has other advantages as well, such as being able to remove the chain while the CS in on the mill, and being able to move the out board mill mount point to the middle of the bar nose (hole drilled thru the middle of the bar nose) . This will give you somewhere around 16" of normal cut width and allow you to tackle a 16*SQRT(2) = 22" diameter log

2) Use a single ended alaskan
To get a longer cut you can fit a one ended CS mill which will give you 17" of normal cut. However the bar clamp will still get in the way and cannot be removed such as is possible with the "double-ended bolt the bar to the mill alaskan" so it won't quite give you the Sqrt(2)*17" log diameter.

I personally don't like single ended alaskans as they wander around too much in the wood I cut and they cannot be used with bars more than about 25" long but I hear they go OK in softer woods.

This diagram might help explain it.
View attachment 330071


In practice I find turning the log is a PITA and it's just easier to use a wider bar.

Bob, l admire your posts and the time you take to help people you have never met. l went to a good private school and rarely met someone with the teaching ability you have. l wish Bob was my teacher at school.
 
. . . . . I've toyed with several options to strongly and squarely hang the saw (my Huski 575XP) onto the shelf, but am not yet happy with what I've conceived. Are there plans out there for doing that? How does the Norwood do it?

I don't know about the Norwood. You might like to look at the minimill thread in my signature which shows what I did for my vertical mono-rail mill.
Bob, l admire your posts and the time you take to help people you have never met. l went to a good private school and rarely met someone with the teaching ability you have. l wish Bob was my teacher at school.

Cheers CR888, I was a high school science teacher for 7 years and taught at Physics University for nearly 23 years so I guess I've had some practice.
 
Seeing BobL's engineering and craftsmanship gave me the inspiration to build my own mill. He keeps the bar high.
Phil
 
l just love the mills he makes...puts all the brand name ones to shame. l think we should organise an internation milling gtg where we can all sit down with our note books and just listen to Bob. l'd pay good money for a ticket...Thing is he's happy to help us all on AS for free. l feel like we all owe him something.
 
Crikey! Thanks for all the complements guys.

My head grew so big after reading that lot I had trouble getting thru the door so's I could get a cup of cold Joe. Yes cold because it's been really hot here and I've become sort of addicted to iced coffee, handful of ice cubes in a large mug, run a double shot of espresso over the top of the ice and then top off with milk.

But seriously - if you guys had been around when I joined in 2007 and I had been lurking for at least a year before then you'd understand I'm standing on the shoulders of giants, guys like Woodshop, Aggiewoodbutchr and Railomatic.

As for owing me something, just keep posting those great pics of wood grain and interesting mills.
 
Enjoyed this thread; thanks all!
Also in a situation in which a longer bar would be ideal and brainstorming ways around it.
48-60" log, 35" of cut on the mill.
Imagining fabricating attaching to the drilled bar tip a tapered stick to push and support the nose through the cut.
Make-shift, but could save half a grand.
Best to all,
 
Since this thread is up and since bobl may be monitoring:

I recently became the robotics teacher and was saddled (well, maybe that's the wrong term) ;) with a bunch of equipment in my room including a metal lathe, a 3 axis computer controlled metal milling machine, a nice drill press, a cold saw and a cnc wood router. It got me thinking: I've been admiring bobl's csms for years. I should use this windfall to make something similar. I know I've probably asked this before, but where's the best collection of close-up images of bobl's bilmill (or whatever the latest version is) that I can copy (since I think he encourages that) and what improvements could I make given that I'll have computer controlled cncing at my disposal? I am particularly interested in supporting the power head at the clutch plate and in extending the reach of my 60" bar (and/or others). I might also want to do rollers.

I'm guessing that the place to look is in tips and tricks but if there's another place in particular... I think bobl has basically answered this before but I can't find the post. Sorry.

Thoughts?

Thanks in advance.
 
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