.45 or. 55 blades for lt40

[Joey Grimes]

Wandering what everyone's preference is on blade thickness for Ltd 40 w 25 hp Koehler. What would be advantage be to running thinner blades other than a slightly thinner kerf. Would I see a noticeable power loss going from .45 to. 55?

[bkaimwood]

I would be almost certain you would experience noticeable power loss. I notice it on my home made mill and that runs a 38 hp diesel engine. You wouldn't  think .010" would make a difference, but its alot...an example would be the notable difference in resistance when bending the blade, such as coiling it, or uncoiling it...that smaller diameter the bandwheels, the more notable it may be. My bandwheels on said mill are 28", I know the lt40 has significantly smaller diameter wheels...the only benefit to using a .055" blade would be utilizing this increased rigidity to eliminate waves in tough logs and/or wide cuts. Possibly others may chime in on their needs for and experiences with thicker blades. All the other things I can think of are downfalls...increased blade heat, possibly more blade lube needed, increased wear and tear on the saw due to heat and tensioning changes, less bfpg, increased cost, increased lumber loss, and so on...

[Brucer]

I run 1-12/" x 0.45 blades with the 28 HP Kohler (same as your engine, only fuel injected). Wavy cuts are rarely a problem as long as I keep on top of the mill alignment and make sure the blades are set and sharpened properly.

My friend John has the identical mill and started off with 1-1/4" x 0.45 blades, switched to 1-1/2" x 0.45 blades, and then switched again to 1-1/2" x 0.50 blades. He saws mainly Aspen (a very light, soft hardwood) and really pushes the blade. He was having a lot of problems with wavy cuts (and still had them with the thicker, wider blade).

We both used the same sharpening service and we both noticed that as the guy expanded his business his quality went way down. I cut fed up, bought a used sharpener and setter, and started doing my own. Problem solved. John heard about this and I ended up sharpening his blades for him. No more wavy cuts.

The thicker blades probably help John saw a little faster but they won't compensate for bad sharpening/setting, or for mill alignment issues.

I can coil my 0.45's with no problem. First time I tried to coil one of John's I dislocated my shoulder . Seriously.

[YellowHammer]

I keep both on hand, depending on the wood species.  045's have a significantly better fatigue life, are a little more inexpensive, and generally last longer than 055's, at least in my experience.  055's are straight cutters in hard wood like hickory or pecan, but I don't use them for easy wood like cherry or maple, even red oak is pretty soft and cuts fast and well with 045's.  I'm using an LT40 with Diesel engine, so I can saw with either, no problem.   
The best blade I've run is the 055 7° turbo in hard, knotty wood, but for 85% of all my day to day sawing I use the 045's in 1 1/4", reshapened to 8°.  I've found that most times when I'm sawing waves, it's not the blade's fault, it's the guy who sharpened and set them (me) ;D. 
YH

[petefrom bearswamp]

I find that yellowhammer is correct on blade life the .055s dont take as many sharpenings. I am on my 4th sharpening of some .055 7x34 and am expecting breakage any time when i next use them.
I bought them to saw Norway spruce which i find makes wavy boards whether the blades are sharp or not.
I only have 7 left and wont buy more.
I currently use .045 7degree 34 blades and will try the 7x 39 next.
I am slowly converting my older blades to this profile even some Cooks.
Of course as stated alignment and sharpening are paramount to a good product.

[Joey Grimes]

Do you change your rollers when going from 1.25 blades to 1.5?

[Percy]

I cut pretty much softwood all the time on my LT70 diesel. I use the 13 degree blades in 1.5x.050. The 050s are a compromise between the 045s and 055s. I tried the 055s for quite a while and allthough they dont last as long as the thinner blades, you can cut much faster with them if you have the power and lumber handling capacity. I find that the cost factor vs increased production can easily offset the shorter blade life of the 055s. I quit using them because when they break, they seem to bust something on the mill as well. Sheared all the door bolts off once and another time, the blade ruined a drive belt(lt70 problem only)which is costly. The 050s last longer than the 055s and cut straiter than the 045s and a given feedrate....

[Cypress Man]

My first mill was a LT40 with a 25 hp kohler. I would run 10 degree 1 1/4 x .045 woodmizer blades. I don't think Woodmizer would recommend using .055 blades with a 25 hp gas motor. The thicker blades require much more hp to handle the extra thickness. I now only use 1.5 x 055 x 10degree blades  with 1 1/8 tooth spacing on my LT 70 with a 25 hp 3 phase motor. I also used .055 with my LT40 Super but it had a 25 hp 3 phase motor also. I think the thicker blades perform much better than 045s but you have to have a big motor to push them.