Sawmill Design Review

[bconway]

Hello All,

I have been looking over probably hundreds of posts and comments on FF gathering ideas for my upcoming sawmill build. I was hoping some of you might lend some experience to what I'm working on. My main inspiration is from Matt Cremona, the EZ Boardwalk 50, and Cooks, although aspects from a ton of others will surely find a way into the design. I am on the young side, so I want the mill to be able to outlast me with minimal failure points along the way. 

Basic overview-

• 24' track, 2x6x1/4" Rectangular Steel Tubing with Stainless Square Tube Bunk Covers
• 47" Wide Bunks for Material Usage so a little under 50" cut width
• 2x3/16" Square Tube Carriage Construction
• 36" Long Carriage with Saw Mast in front of Posts
• 4" Square Tube Saw Mast
• Chain Driven Lift System
• 19" Pulley Wheels with 1.5" Shafts on Pillow Block Bearings
• Hydraulic Blade Tensioning with Over-Center Belt Tensioner
• Around 25hp Gas Engine Driving Two Belts
• 1.5" Blade of Custom Length
• Cooks Blade Guides
• Driven Wheel with Sawdust Chute on Left Side from Operator's Perspective 
• Operated from Right Side behind Tensioning/ Tracking Wheel

A few things I have been contemplating-

• What is a good bunk spacing? Around 3'?
• Glide System to slide mast up and down. I have somewhat ruled out linear rails/ acme due to cost and complexity. I am torn between telescoping tube with UHMW slides or a bronze flange bushing that rides on a round bar. This is one the biggest things I'm hung up on.
• How recommended are power feed & up/down? I am thinking maybe power up/down with a redundant manual crank and just pushing by hand. 
• The mill will be constructed about 4hrs from its destination. Should I be thinking about putting an axle underneath or winching it onto a flatbed with the carriage off? I think I'll wire in trailer lights to be safe and it looks like I will be under max DOT width.

That's all I can think of for now. Any suggestions and thoughts are more than welcome. I'd be happy to turn this into a build post if there is interest. What a great forum!

[Digger Don]

I'm afraid I'm not qualified to offer you much advice, but I can be the first to welcome you to the Forum. I'm sure you will get lots of advice. I'm impressed that someone of your tender years would even consider building their own mill.

If you ever travel up here to the Shenandoah Valley, give me a shout. Don

[charles mann]

Id go 2" shaft and bigger band wheels if your budget will allow the extra price for larger wheels. I went with 26" but should have went 30", but iv got 80" between the guides and 72" of travel on the sawbeam, so it can accept an 80" wide, 72" tall log. 

[SawyerTed]

Welcome!  Many of us watch the sawmill builds with lots of interest even though we may never build a mill. 

Here are a few thoughts mostly relative to actually sawing.  

No mention of hydraulic log handling and turning?  With 40" plus logs, you will benefit greatly from any hydraulic log handling and turning you can incorporate in your design.  Rolling stock can be used for turning logs but it is a labor intensive and time consuming operation.   Hydraulic log handling and material handling is one of those things it's hard to have too much of.  

If you are going to cut near 50" wide, I would suggest more hp.  I ran an LT 35 with a 25 hp gas.  It cut 25" wide.  Keeping blade speed up could be difficult in wider cuts especially in hardwood.   The 36 hp diesel on the LT50 Wide is much better sawing but sawing wide logs even slows sawing speed.  If the cost of diesel counts it out, look at the 38 hp gas engines.

On item #3 - power feed and up/down?  Yes, anything that helps reduce the physical labor of sawing is a plus.  

It's inversely proportionate, every operation that takes heavy exertion reduces the sawing day.  

As physically demanding as small sawmill operations are, any choices you can make in your design to reduce the work should be considered heavily.  

I'm going to guess the typical sawmill head is a 500 to 800 pound (maybe more) unit.  Pushing all day AND manually cranking the head up and down would get old fast for me, more so in large logs. 

Of course people do manually operate mills everyday but why do that if you can make design choices now to have power feed and up/down and hydraulics.  

[bconway]

Thank you all for the warm welcome and suggestions.

I guess this gets to my mission. The mill will mostly see reasonable sized logs (lots of white oak and some pine in the 24-36" range). Since I was going to build to a similar spec of the Cooks MP32, I figured stretching the bunks a foot or two would be nominal in cost while allowing me to slowly saw any really big logs that might come along in the future. Does anyone regret making their mill too wide/ big?  I'll start looking at a bigger engine and wheels, although the price point is probably going to put me in the gently used market. The EZ-50 comes with a 25hp and the Cooks Super Wide has 19" wheels which is where those figures came from. 

I'm open to hydraulics in the future, but I was hoping to get started without them. I have access to a medium sized tractor with a grapple and forks that has lifted some impressively wide and long logs. That was intended to do most of the loading/ unloading. 

[ladylake]

 Cutting 50" wide go with a least a 35 to 40 hp diesel, maybe off a used riding lawn mower.  Use a spring tensioner that you don't have to babysit like a hyd one.   It's not real hard to add power feed and up  down.  Steve

[SawyerTed]

I encourage you to study log weights a bit.  Think about your tractor capacity.  Then evaluate hydraulics.   

A 35" diameter walnut log 8' long is a 3,500 pound log.  A white oak that size is 3,700 pounds.  Even a pine 28" diameter 8' long will be 1,400ish pounds.   

A 36" log is a BIG log when you have to move it, turn it etc. 

[jpassardi]

Welcome.

You may want to consider a more simplified/smaller build than what Matt has unless you intend to do primarily wide live edge. This would reduce cost and allow you to get going on it sooner. Take a look at all build types from the many manufacturers and use what suits you from each.

Regarding power up/down and carriage back/forth: I made mine from a used wheelchair motor and a dump truck tarp motor. They're controlled by DC pulse width modulating controllers - cheap from ebay and work very well.

Good luck!

[Southside]

When it comes to sawing, torque is king, there simply is no substitute for it.  Sawing slowly is actually counter productive in that bands heat up, sawdust packs in the cut from excess water use and overall it's just not an effective plan.  

I can't over emphasize the value of hydraulic log handling and head control, especially with the size material you are talking about. You roll a 3,000 lb log off the tractor forks and she falls onto the mill deck or strikes something there is a good chance repairs become a regular maintenance item, that's a lot of inertia to stop and the energy is going to go somewhere.  

[Ljohnsaw]

 :P
Absolutely power up/down. But it needs to be fast enough but not to fast! My lift motor is a wheel chair 24v running on 12v. Kinda slow but planning on adding a switch to bring in another battery in series. That will be perfect. Then switch it out for fine adjustment.

I used 19" wheels because the are common and priced right. I'd rather have bigger. I'm starting to have blade failures from fatigue. I don't think running 1.5 blade on 19s is a great idea.

I also built my mill to use standard blades. Easy to buy and less expensive. I'm running 1.25  184" WM 7° with an 18hp gas. Go look at a available sizes.

[Den-Den]

+1 on considering weight of logs.  Unless you have heavy duty support equipment and/or power log turning system, 30" diameter logs are approaching the maximum.  Remember that weight is proportional to diameter squared.

I believe that saying a certain HP is required for a certain size log is an over simplification.  That over simplification is probably valid IF you look at maximum band speed and go with that speed.  If you match band speed to power available, cutting width and wood hardness (this may take some  trial and error), it is possible to cut wide logs with less power.  Note that just slowing down the feed rate is a poor solution with poor blade life.  With that said, I have not heard anyone say their saw had too much power.

I started with a fully manual home made saw.  My first upgrade was power up/down as that was tiring me the most.  The next upgrade was power feed. Pushing the saw was not really that tiring but the upgrade was easy and not terribly expensive.  Power feed gave me a more consistent feed rate and better cut quality.  My most recent upgrade was hydraulic log turning, clamping and toe rollers.  This was only needed for the large logs (30" dia +), turning those was a challenge before and some of my efforts did not seem safe.

[rusticretreater]

I would recommend that you use the forum search engine to find the many threads of other members who have built their own sawmills.  You will find lots of designs, ideas and technical information.  Also for every thread you view, at the very bottom will be several links to similar subjects that the forum software supplies.

For your stated width of cutting, a much bigger engine(preferably diesel) will be needed.

There are so many areas of design and construction that we would need drawings, photos, etc to help out a bit.

The forum has a special section called tools that have some calculators for machinery. 
Use the menu at the top, extras->tool box, under calculator index, click machinery tools.

Also you cant just pull a sawmill down the road.  There will be state regs on that.  There have been forum discussions on that in the past too.  At 24', you probably should make the track in two sections to bolt together.  It will simply be easier to move then.

Big dreams, big projects. Good luck.

[RetiredTech]

Welcome to the forum. I think your gong to enjoy the FF. Good information and good people. Any problem you run into you can bet someone else has already been there, done that and found a solution.

[bconway]

Well this has been a cheap way to prevent me from doing something dumb. I appreciate the real world knowledge and suggestions.

I'm going back to the drawing board to scale down the dimensions closer to the 36" range. I thought pushing the envelope a bit would give me some cheap capacity to future proof this. It is pretty clear now that creates a bunch of problems I'm not sure I want to contend with. 

Onward! I will give this all some thought and keep researching. Plan on posting what I come up with

[SawyerTed]

Good luck and keep us updated!  

By the way, there's an unwritten Forum rule that is is perfectly fine to help others spend their money!  

[Ljohnsaw]

It's not obvious looking at my mill but my v.2 was adjusted to cut wider with the same blade and track. 

I built my tracks 42" wide to use the steel effectively. I.e. not waste short stuff. V.1 had the posts going straight up from the rails. Not all logs are straight and I'd hit bigger stuff with the posts.

V.2 I added some 2x4 steel blocks to cantilever the posts out and increased my capacity nearly 8 inches for rough logs. I'm only slicing down from the top and not full width but can process bigger stuff.

I also made the guides able to sit way back under the band wheel to allow for slicing wide slabs when needed. Cutting soft cedar I can do 38" but on pine that wide will give some wave.

Going big has a few drawbacks. More expensive wheels, bands and engine. But, if you make the frame big now, in the future, if you decide you need to, swapping wheels, guides, bands and engine would be an easy change rather than redoing the head and possibly track.

[TimW]

John is right.  Build future growth potential in so it is easy to upgrade later.
hugs,  Brandi

[thecfarm]

bconway, welcome to the forum.
I am always saying, Make it long, At 24 feet you are fine.  ;)
I have a sawmill that will cut a 20 foot log. That gives me 4 feet to spare when I cut a 16 foot log, instead of inches.
That also allows the head to get out of the way.

[charles mann]

I encourage you to study log weights a bit.  Think about your tractor capacity.  Then evaluate hydraulics.  

A 35" diameter walnut log 8' long is a 3,500 pound log.  A white oak that size is 3,700 pounds.  Even a pine 28" diameter 8' long will be 1,400ish pounds.  

A 36" log is a BIG log when you have to move it, turn it etc.

100% true. I under estimated logs, their wt. and loading with hyd but trying to turn by hand. Iv learned if my tractor cant pick it up, i CAN NOT turn it with my 78" log-rite cant hook and using my 240 lbs self to stand on the log and pursued the log to roll. 

[jpassardi]

Well this has been a cheap way to prevent me from doing something dumb. I appreciate the real world knowledge and suggestions.

I'm going back to the drawing board to scale down the dimensions closer to the 36" range. I thought pushing the envelope a bit would give me some cheap capacity to future proof this. It is pretty clear now that creates a bunch of problems I'm not sure I want to contend with.

Onward! I will give this all some thought and keep researching. Plan on posting what I come up with

I think that's wise.
Search winch claw turner - low dollar but big help turning large cants. My gallery has photos of mine that I built.

[scsmith42]

Danville is only a couple of hours from me.  I'd be happy to show you my Baker mill and demonstrate the issues with milling 36" diameter logs.

There is a lot more to milling / handling large logs than most folks realize.

Let me know if you're interested.

Scott