How I Built a Giant Sawmill in my Backyard

Today we’re going to be talking about the saw itself! I started the build of this saw seven years ago, and I figured this will be a nice quick refresher. 

Some quick background: I got into chainsaw milling over a decade ago, which was a really easy and convenient way for me to cut wood in my own backyard. At the same time, I got into urban logging, which entails picking up logs and trees that were being removed from people’s properties. And it felt like the logs kept getting bigger and bigger

One day, I came across a stack of logs which had been removed for a street widening project in Lake Elmo, Minnesota, and I started hauling those home on my log trailer. Every week I’d stop by and grab another log. I ended up pulling five logs out of that pile, and the only reason I stopped is because the logs got too big for my trailer. I started to put together a bigger chainsaw mill to cut these, because they were too big for the existing chainsaw mill that I had. But in the end, I decided that I would design and build a giant bandsaw mill in my backyard. 

So first let’s cover the construction of the bed, which is what the logs sit on and what supports the carriage. I had the steel yard cut all of my pieces to length for me, which was a lot easier than trying to cut it all myself, especially with the heavier gauge steel. 

So I prepped all of the frame pieces out of 2×6 ¼-inch wall thick tube. I had several holes to drill and tap into the cross members for the runners which will sit on top of them. I also drilled some holes on the underside for the leveling feet. 

One of the reasons I went with a heavier gauge tube was to make sure that I could make a frame that was going to be flat and stay flat. It wouldn’t warp under its own weight, which made the bed really easy to level. I used a string line to bring the whole thing into flat, and then I could lay in all the cross members at their spacing and then go about the welding process. 

I also didn’t want the welding to distort the frame at all, so I added some pieces of angle iron on top to help add some rigidity. I also darted around back and forth in order to distribute the welding stress as it went along to help prevent distortion. 

Next I added the track for the carriage. This is some two by two by three inch thick angle iron, which got bolted to the frame. 

For the cross members, I went with full stainless steel. I drilled an access hole in the top, and then a through hole in the bottom that would match up with the tapped hole in the cross member beneath. And that’s about it for the bed. 

Next I’m making the fenders for the rollers which will protect them and also support the shaft on the opposite side of the uprights.

The uprights are prepped next by drilling the holes for the roller shafts. 

The material for one of the carriage sides is laid out and welded together. James Wright came to help me for a few days, and it was nice to have an extra set of hands for erecting this carriage. Once one side is welded, it can be used as a template for the second side. 

Now we’ll go about standing the two sides up and connecting them with the cross members. We put some temporary bracing to hold the uprights in place while getting everything installed. Last of the four braces are installed. The temporary stuff can be pulled off and the carriage can be rolled on the track. 

Next I’ll knock out some of the prep work for the saw head. I’m installing a third upright which will support these linear rails. The bearings that ride on this rail will guide the saw head through its vertical travel. I cut the rail to length and used it as a template to drill and tap the mounting holes. 

I’ll get these stood up on the carriage into a rough position and clamp them in place with bracing. That 12 foot long tube there will become the beam for the saw head, and I’ll use it to help align these rails. 

I’ll make the mounting plates for the bearings next. Nothing super crazy here, just four tapped holes into a piece of plate. I’ll slide the bearings onto the rails and weld the plates to the beam. 

I set a chain hoist up so I could run the beam through its travel, tweaking the uprights until they were parallel. Once I had the motion feeling pretty smooth, I tacked the uprights and moved the beam again and made sure nothing moved. I gradually welded the uprights and moved the beam until they were fully welded. That’s going to do it for the carriage. 

Now we’re adding the wheels, starting with the idle wheel, which needs to be able to move in and out to tension the blade. So I’m creating a box that’ll slide over the saw beam. 

The beam is wrapped with a few index cards to create a bit of clearance and then the beam is wrapped with a 1/2-inch plate. 

Now this is the premade wheel shaft that I’ll be using. I’ll add a second plate to mount the shaft to which will also give me room to add alignment adjustment screws. That plate is welded to the box, and then the four bolt holes are drilled and tapped. To make the adjusters I tapped holes in 1/2-inch bar stock and then cut them to length and added some shaping. A pair of these are added to each side to allow the shaft to be rotated left to right. Also added an adjuster to the back to set the in and out position. On the prefabricated shaft plate, I tapped holes for jack screws, which will allow for the wheel to tilt. 

The whole assembly slides onto the beam and then the wheel can be mounted to the shaft. Seeing this wheel spinning was a joyous moment. 

Now we can hop over to the other side and add the drive wheel. This is the shaft that I had machined for the saw, and it gets mounted in some pillow block bearings. I originally planned for three, but there is plenty of support with just two, which makes the mounting easier. The bearings get bolted to a 3/4-inch thick plate with 3/4-inch bolts. 

Back at the saw beam, I’ll cut and add an additional section of tube to support the mounting plate. I’ll clamp the assembly to the beam to get it aligned and to test it out before welding the plate to the beam. Lastly, I’ll add tabs for bolts, which will allow for tracking adjustment on this wheel as well. 

This is the motor I’m going to use to power the saw. It’s a 10 horsepower three-phase motor off an industrial buffer. I’ll power it with a VFD, which will handle the phase conversion and allow for a few bonuses, like slow start, braking, and variable speed. This is my first experience working with VFDs, so I mocked everything up in the shop to make sure it would work before taking it outside. 

Back on the saw, I next needed some way to mount the motor to the saw. I created a platform above the beam to keep the belts out of the way of the sawing area. On top of the platform, I attach a motor mount which slides the motor back and forth to tension the belts. With the motor in position, I can measure for and calculate the belt length that I need. And that takes care of the motor and transmission. 

Let’s add the blade guides next. The blade guides will move across the saw and be supported by the same type of linear bearings as the saw head. Similarly, I’ll drill and tap the mounting holes for the rail on the underside of the saw beam. I’ll make a couple more mounting plates for the bearings out of 1/2-inch plate. 

This is the pre-made blade guide assembly, and I’ll use a blade on the wheels so I can mock things up. I need to cut a post which will drop down from the bearing and connect to the blade guide. 

Once I have things figured out, I can weld the post to the blade guide assembly and the mounting plate. With that bearing, the guide moves smoothly with no play. 

Next, I’ll add the adjustment post, which will allow for the blade guides to be moved from outside the cutting area and held in place right where I want it. This is the telescopic tube type setup. I drilled and tapped for some locking bolts in the bigger tube, and welded a post to it. I’ll clamp the post to the saw head and get everything aligned, and then weld the assembly to the saw head and to the guide. I repeated the same thing on the other side so I have adjustable guides on both sides of the saw. 

At the base of the carriage, I added a couple pieces of scrap tube to create a platform which will be the base of the lifting column. I’ll mount a thrust bearing, which will support the weight of the saw head. I made a bearing holder from a piece of round tube and a plate. 

Now jumping over to the beam, I’ll drill a hole through it on both sides for the rod to pass through. The undersides of these holes are where I mount the nut for the screw. I made a nut holder out of some scrap pieces of plate, and that gets bolted in place. To start on the lifting column, I made a step shaft for the bearing by welding a piece of shaft stock inside a piece of tube. That sits on top of the bearing, and I made a cover that slides down to keep it clean. 

Next, I’ll feed the acme rod through the saw beam and start threading on the nut. The rod meets up with the step shaft below with a coupler. On top of the acme rod, I added another coupler, joining it to a piece of shaft stock where I’ll mount the upper bearing. I made a bearing mount which will offset the bearing the right distance from the carriage. 

And next is the motor for the lift. It’s another three phase motor that’ll run off a VFD, and it also has a gearbox. I’ll make a mounting plate for it with a slide mechanism to tension the chain. The mount is bolted to the side of the carriage and then the motor can be bolted to the mount. I ran some chain between the screws and ran the motor to test the setup. 

Next up is the proper chain linkage though. The chain will follow along the front so the motor can be lifted past the top of the carriage. I have four upper sprockets to install. These first two are going to be on mounts with one adjustable for tensioning. These get bolted to the upper corners of the carriage, and the movable one also gets a piece of angle nearby for the tensioning screw. The two other sprockets get attached to the underside of the carriage with tapped holes and bolts. 

With all those sprockets installed, I can start adding the roller chain, snaking it through all those sprockets. I cut the chain, made the final connection, and gave the tensioner a try. Another thing that worked! 

Lastly, I can connect the motor to the driven sprocket and tension this chain by moving the motor on its mounting plate. 

The tensioning mechanism is based off of this 10 ton Porta Power-type ram. The first thing I need is something for the ram to push against on the beam and the idle wheel mount. I’m using a scrap piece of heavy gauge angle for this, which I’ll bolt on. I’m using eight half inch bolts purely for aesthetics, because I think it just looks way cool. On the beam, I’m adding an extra piece of plate to bulk up the area with the angle will bolt on. I drilled the bolt holes with this plate tacked on so I could later use it as a template on the beam. Those eight holes get tapped and then I can repeat a similar process on the idle mount, drilling and tapping the holes to mount that piece of angle. 

Next, I need a way to mount the ram. I use a piece of tube to create a holder for the base. And I’ll make a mount for the other end out of a piece of scrap rectangular tube. I’ll do the final install, bolting the holder to the beam and welding the ring to the angle on the beam. I also add some gussets to the angle for some bonus points. So that’s how the blade tensioner came together. 

Now when I operate the pump, the ram will push the idle wheel out along the beam. I use a blade tensioning meter to figure out the proper tension for the blade. And that works out to be around two and a half thousand pounds of force to tension an inch-and-a-half blade. 

Next up are the blade guards. I made these out of 10 gauge steel as I wanted them to be difficult to damage. The guards are made in three sections: the drive wheel, the idle wheel and the transverse area. The drive wheel and idle wheel are pretty much the same, with the drive wheel having a dust chute, and the idle wheel having a little bit of an oblong shape to allow the wheel inside to move as the blade is being tensioned. The middle transverse area is pretty simply a box. The wheel guards get a bump out in the back to make room for the wheel mounts, and I’ll form the perimeter with some strips. 

Next, I’ll make the doors which are just a little bit bigger than the backing plates. Those get wrapped in a narrow strip which will overlay the main body of the guards. I’ll add a hinge to the transverse guard and box in the clearance areas in the wheel guards. 

Later on I painted them and added some latches to hold the doors closed. And that takes care of the work on the saw head. 

Next we’ll finish up the build by adding the log clamps. So I’ll start off by adding the side stops. This is a telescopic tube type setup again, with the outer tube made out of a two and a half inch square tube. I need to add three tap holes to this. In the back, I’ll tap two half inch holes for bolts. These bolts will allow me to adjust the upright, which will be clamped in here, bringing them into square to the bed and all in the same line. Another hole will be tapped and drilled to the front edge. This will be for the locking bolt, which will push the upright into the corner and hold it in position. Those outside tubes get welded to the bed, and I used a scrap piece of two by four to space them all the same distance from the side of the bed. The vertical posts are just two inch square tubes, and I put an angle cut on one end, which allows for logs to roll easily and not get hung up on any corners. 

Next up are the clamps. I wanted these to be pretty quick and simple and cheap, so I made them out of some gas pipe and fittings. For whatever reason, I decided to make my own flanges because they’re overpriced, so I welded some plate to some pipe and then had a coupler to make a simple flange. A piece of pipe gets joined between the two flanges, and those flanges get bolted to the bed. I slide a T fitting over the pipe in the middle, and that allows me to attach the actual clamp upright. The nice thing about this is it’s kind of modular, so if you need longer clamps or shorter clamps you can adjust the size of the pipe here in the middle. 

On top, for actually clamping logs, I made these screw and spike things which worked out okay, but I never ended up using them the way I originally intended. I ended up just using these things with a hammer by hammering the spike into the log and then hammering along the bottom to set the clamp. And because I don’t really saw a whole lot of small stuff, I don’t ever use the clamps anyway. 

With the log clamps installed, that really is about it for the construction of the saw. I could get it calibrated and dialed in and turn this thing on to make a few test cuts. And I have to say, this is probably one of the happiest days of my life after spending months building this thing. Having this thing actually turn on and cut nice and straight and flat was an amazing feeling. 

After I finished up the build and I had it running, a lot of people were interested in the plans for this, so I did develop a full set of plans for the saw. If you want to build your own giant band saw mill in your driveway (or wherever you want), I have this full set of plans available. It’s always fun for me when someone builds one of these things and shows it to me. 

So that’s the abbreviated build of the saw! This has been operational now for six and a half years. Every time I get something on here that’s big and huge, the saw cuts absolutely perfect, I am just happy all over on the inside. 

Over the years I’ve been asked a lot if I have any regrets or if I would do anything differently. 

The answer to that for all practical purposes is no. There really isn’t anything on here that I think I should have done differently or better. As I was thinking about this and doing the research and design, the overarching theme was to not make compromises that would lead to regrets in the future. I feel like as soon as you start compromising on some design aspect, you end up regretting it in the future. 

The only minor thing I might’ve done differently was make it just a little bit bigger. I designed the saw to be able to cut a six foot diameter log comfortably. I gave it four inches of comfort above that six feet, and I don’t think that was necessarily quite enough. You probably need about a foot over the intended cut capacity, because once you get a log that big on the saw, getting it positioned two inches one way or another is kind of tedious and annoying. But in reality, that hasn’t been too much of an issue. If I do have something that’s too big on here, maybe a small trimming cut is all I really need to be able to complete that cut, and it’s not really that big of a deal. 

So let me know if you have any questions on the saw or anything else back in the shop. I’d be happy to answer any questions that you might have. And until next time, happy woodworking!