Is there an after market chain log roller that could be made to fit a wood mizer lt40?
Not sure you would call Cook's Saw Mfg. aftermarket, but they make an excellent chain turner that may be fitted to your mill. i do not know of anyone other than mill manufacturers who would have chain turners.
The 50 comes with one and I am pretty certain is a 40 lower frame, so no need to do all the R+D on something else to make it fit.
Not sure about the chain turner source or addition but somewhere in my enfeebled memory I thought I heard (I want to say at the dealership) that the 50 & 70 are on the same frame and the 28's through 40's were on the same frame. I am not sure what the differences would be. I do know on the 50 there are 7 joysticks for the hydraulics and the center one was the chain turner. My 35 has 6 joysticks and uses the claw like your 40 I think. (I know abo9ut mine but won't swear about the 40).
I've never got to look at a 50 or 70 other than pictures, but the frames look the same as the 40 except they have the vertical backstops and chain turner.
I saw a guy using a 48" farm jack to roll logs, he attached the hook of a cant hook to a metail chain, hooked it around the cant, and jacked it up and it looked very easy. But it sounds like you want aomething automatic.
I recently built 2 chain style log turners for my mill. I bought the chain from Connexus. Others make it too. Google "sharp top chain" to find it.
Sharp Top Chains | Connexus Industries (https://www.cnxsind.com/chain/sharp-top-chains/)
(https://forestryforum.com/gallery/albums/userpics/65416/IMG_20210118_160307735.jpg?easyrotate_cache=1622758439)
I was told I could not get the chain turner on my 40. Yet I have the suspension of the 50 as I have the large motor.
Let us know what you find out.
To clarify all '97+ lt28-70's share the same basic frame. Its what is added to them or modifications are done to them that makes them different.
A wm chain turner off a 50 or 70 will fit a 40 but the 40 does not have the mounts for the chain turner on it, but they can be added
Wm will likely tell you it won't fit, and it won't just bolt on but it will "fit", you'll have to make it.
You'll also need another valve for a total of 7, depending on the vintage of your mill you may have to replace the entire valve block.
Can it be done? yeah but it ain't cheap, the turner assembly from wm is $1800 with no hoses or mounts.
You should look at the Resch & 3 chain log rollers. It definitely won't fit a woodmizer, but maybe some welders could build a double log turner for you. If my turners will break I will build turners like these, they look really cool. And with heavy logs they aren't pushing the vertical stands over. My stands are bended because of the log turners pushing the logs against them. This system will avoid that.
(https://www.resch-3.com/media/d44ca0fb-9a8b-4a74-96f2-71ea386d981c/blockbandsaege-resch-3-wendeketten-s-m-e.jpg)
They use them to offload boards and beams as well, you should take a look at some youtube vids they have. If you decide to let them built, please send me the drawings :D