Importance of single steel rail on sawmills

[Dgv11]

I'm curious to those who have used both sawmills that are single piece welded versus bolted sections. is there a significant difference in the amount of adjustment and alignment needed to avoid bad cuts? In particular, does a single welded steel frame significantly avoid the need to precisely level and align repeatedly after each use or several uses?

[YellowHammer]

In my experience, yes.

[ArkansasOaks]

I have not ran a bolted frame sawmill but this situation is not much different than most others where you are sticking a piece of equipment, foundation, building, etc somewhere. If you have points that can move they probably will move over time. Especially when continually having logs weighing anywhere from hundreds to thousands of pounds dropped on them. 

 You can mitigate that by providing a good foundation though.  I'm not sure about the left to right movement of a mill but if you started with a perfectly level and flat concrete slab your mill should not be able to move up and down on that slab. 

Granted if you have a spot in the yard with poor soil that you throw dunnage down to put a mill on top of that mill is going to move a lot.  Even some of the "heavier" built solid welded mills are going to sink or raise causing alignment issues along the bed.  At the end of the day your foundation has a lot to do with it. 

[jaciausa]

An excellent built band mill with a solid welded frame that is square plum and level on a solid foundation will still need aligned at times. I have not used a bolt together mill. If the fasteners supplied were tough enough and very little tolerances in the parts would still be inferior Imo. The color wouldn't matter.

[YellowHammer]

I had to weld full length steel rails under my bolted together rails.  

[Nebraska]

That was the reason my first mill was the brand it was, Blue, tough, no assembly (or reinforcement) required. 

[Dan R]

I can't see myself ever moving my mill (LT 15 )from the site it is at so what would be the thought on welding the three sections together to stop them from moving that little bit and causing that bump as the head moves down the track. 
One day I will lift it a bit and either pour concrete sleepers under it or H beam and bolt it down solid. It slides all over the concrete slab it is on 
Dan

[rusticretreater]

In the early use of my mill, a bolt together rail setup by Woodland Mills, I checked and adjusted a lot.  My three cents...

Problem 1 is the vibration causes the foundation to settle in unless it is concrete.  Posts set on concrete reduces this, but wood posts also move around, plus expand and contract.

Problem 2 is the construction of the railings themselves.  The bolt holes are wider to allow for easy assembly and the weight and vibration can make the rails/bunks move around no matter how tight you make the bolts.

Problem 3 is the frame under tension.  Ideally, you want both rails to be relaxed and settled. But when bolting all this together, things get pulled one direction or another dealing with variances to get things lined up and also trying to level it.  The rails and bunks might end up under tension and the vibration and weight push on that as well.

[jb616]

I have an older Woodmizer LT 30 that i just set up and run. Doesn't need to be level to cut well, but i don't have extensions. On the other hand I helped a neighbor put together a bolt together double rail mill with a trailer option that needs to be leveled and squared every time he moves it.

[YellowHammer]

I just went to my local steel outlet, bought a couple sticks of 2x6 rectangular tubing, put them under the mill rails, got everything straight and true, and then started tack welding the sections to the lower rail and before log, it was all done.

Two pieces of steel, one under each rail, made things 100% better with very little effort or time.  

[Magicman]

Even then you had better know your business or it will "heat draw" and you will have a permanently crooked sawmill bed.

[jaciausa]

I have my mill on concrete raised footing piers on each leg.
I tested it without tying it down and it about hit the cab. Cheap Lesson! They need anchored down when on concrete.