Chainsaw Mill





Introduction: Chainsaw Mill

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Many times a project calls for materials of specific dimensions and quality that can't be obtained, financially or logistically. A chainsaw mill is a tool that can be utilized to produce beams for timber framing or to cut slabs for wood working. Being mobile, it can be on site or right where the tree falls. This instructable shows how to construct a 20 in bar , variable height chainsaw mill.

There is an update  in the mill post section.  The post clamps now have bolt pins to secure the mill to the bar.

There are details in the pictures so mouse over the yellow image notes to get a clearer explanation.

Step 1: Measure & Cut

(This is for a 20 in bar) Accounting for the width of the square stock, the diameter of the largest tree that is able to be milled is 14.5 in.


(4) 8 in square stock
(2) 12 in pipe
(1) 3 in wide by 8 in long sheet steel
(4) 2 by .75 by .25 in bar stock
(4) 4 in bolt, (4) nuts, (8) washers , (4) lock washers

Guide bed:
(2) 9 in square stock
(2) 14.5 in square stock
(1) 6.6 in square stock
(1) 5 in pipe
(1) 1.25 in square stock
(1) 2.5 in square stock
(2) .5 in nut and bolt

Square stock is (1.25 by 1.25 in) 
Pipe is (1 in) outer diameter

MIG welder
Vice grips
Chop saw
Drill press and drill bits
Ruler and wax pencil

Ear plugs
Clothing to cover entire body (closed toe shoes)
Welding jacket
Welding mask

Step 2: Mill Posts

The Mill Posts attach to the bar of the chainsaw and is what the guide bed attaches to when adjusting the depth of the cut.

(4) 8 in square stock
(2) 12 in pipe
(1) 3 in wide by 8 in long sheet steel
(4) 2 by .75 by .25 in bar stock
(4) 4 in bolt, (4) nuts, (8) washers , (4) lock washers

Drill holes an inch away from the ends of your 8in square stock, while having them clamped together.  Make these holes slightly larger than your bolts.

Weld your 12in pipe on center to your 8in square stock, the bottom of the pipe needs to be flush and should stand up on end on its own. Tack weld your pipe to the square pipe in 4 places first and then weld around the pipe.

The short bar stock pieces (that clamp the chainsaw bar) should be centered and welded onto each piece of square stock. Tack weld first and then weld across the bar stock making sure to keep the weld under the height of the bar stock.

As a safety precaution, a chain tip protector was added on, hammer the 8in by 3 in sheet steel into a half circle over an anvil. Weld only to the top 8 in square stock on the outer post.

Update: Securing the post clamps to the chainsaw with bolt pins!
Drill holes in chainsaw bar with a 1/4 in drill bit (or a bit bigger than the bolt you are using).
These holes are located using the post clamps and marking their centers.
With the chainsaw mill attached mark the outside of the post clamps, take the mill off and mark the halfway point of the clamp using a ruler.
Find half the width of the chainsaw bar and align it with the center marks of you post clamps.  Indent the point with a metal punch so the drill wont walk off the center mark. Go slow, use oil, and let the drill do the work (don't push the drill into the bar too hard).   

Drill holes in flat stock, about .25in deep, on center. (4 holes) (2 post clamps, top and bottom)

Cut 2 sections of bolt with a hacksaw a little less than an inch long.  Using a 2 part metal epoxy compound, secure these bolts on the top post clamps, in the holes you drilled.

To make sure the bolts line up with their holes: Drill the hole next to the plastic teeth in the chainsaw bar first, then put the post clamp with the bolt sticking out in the hole in the bar.  Then mark exactly where the bolt on the post clamp hits the bar near the tip.  You can score the bar with the bolt by dragging it back and forth.  Drill the hole near the tip.  Go slow, use oil, and let the drill do the work (don't push the drill into the bar too hard)

The second bolt should seat in the hole perfectly.  The bolt goes through the bar into the bottom post clamp's hole.  Now your mill is going to stay centered on your chainsaw bar.

Put your washer and lock washer on your bolt and secure them with the nuts and you have your mill posts!

Step 3: Mill Guide Bed

The Mill Guide Bed keeps the blade of the chainsaw at a constant depth when slab cutting down the tree.

Guide bed:
(2) 9 in square stock
(2) 14.5 in square stock
(1) 6.6 in square stock
(1) 5 in pipe
(1) 1.25 in square stock
(1) 2.5 in square stock
(2) .5 in nut and bolt

Drill hole larger than nut's hole on 1.25 in and 2.5 in square stock, on the 2.5 in it will be on center for the top half of the piece, imagine that half of it isn't there and drill on center for the top half.

Vice grip the nut over the hole. Tack weld 3 of the 6 faces of the nut, keeping the side that will seat on the square stock free of welds. Weld them on to the 9 in square stock. Notice that both nuts are facing the same direction and that the 1.25 in one is flush on top and bottom.

Arrange the 9 in square pieces over the 14.5 in pieces and tack weld 2 points on all of the corners, then come back and complete the welds across the joints.  Weld the center piece, the 5 in pole handle will weld to this similar to when you welded the posts.

You have completed your Chainsaw Mill!

Step 4: Attach Mill to Chainsaw

Now that you have your mill posts and guide bed, the 20 in bar on your chainsaw is waiting for the Chainsaw mill to be attached.  Take one post and secure on the bar as close as you can to the body of the chain saw.  The second post attaches near the tip of your bar, attach it loosely and put your guide bed onto the posts, this will dictate the position of the post close to the tip.  Tighten all bolts securely but not overly tight as this will bind the roller wheel of your bar.  Now you have a mill to make your own dimensional lumber and larger beams for timber framing!

Step 5: Preview of Milling Instructions

The next instructable will include:
How to fell a tree
Making a milling rail
Preparing/Scribing a tree for a timber frame beam
Milling beams for timber framing
Milling lumber such as 2 by 4 and slab wood
Wax coating timber ends for even drying of wood

Another Instructable will cover critical tools for moving and positioning lumber:
Log carrier
Cant hook
Log Stands

Here's a preview


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Please be positive and constructive.




Just building one for myself. Question is, is the drilling of the bar necessary? Or it can hold the bar without it? Thanks

What are the maximum dimensions to make boards.

Whoa! Now THAT is a winner! Would love to see a video of how you handle it!

(4) 2 by .75 by .25 in bar stock i dont understand this part of the post system the bar stock is 1.25 in by 1.25 in as said in the note . can someone explain this part better for me please this is my first project like this since high school (25 years lol ) and im not sure what this is asking

Thats 4 pieces of 1/4 inch flat bar stock at 2 inches long by 3/4 of an inch wide by 1/4 inch thick

thank you for taking the time to respond

Any plans on putting on a video of the Chainsaw-mill in action? Keep up the good work.

Just 'Google' it ,there are alot of them out there.

Looks like a good project. I have a minor comment on the Tools List. It says you need a MIG welder. Any kind of welder will work on this project, a MIG welder isn't necessary.

I know it don't require to be be had but it helps.But also it helps if you have a chop-saw ,Cause it works good but you can still use hand hack-saw.And flat file with a hand drill,I know I've used them and still got them ,But now I got a Arch welder along with mig welder ,along with a electric chop saw x 2 ,plus a 1/2 dozen drills plus a couple drill presses list goes on And I acquired them over time also thanks to my late father,Between him and me when we needed a tool we bought it.Then we used it and cared for it.So that way I could hand it all to the next in the family to use.