Dear total of our experience explain this

[Ianab]

Just to illustrate the difference, here is some "sawdust" from the re-sawing I did yesterday. This is DRY hardwood (walnut).



VERY different to what a band mill will spit out, you can almost see how it could be made by hand with a small chisel or rabbet plane. A band saw would be more comparable to a hand rip saw, as far as the tooth action is concerned.

Not saying which technology is best, as there are things that a band does that a swingblade can't, like cut a 24" wide board and takes out a thinner kerf... Just showing how they work in a different way, at the level where the tooth meets the wood. The hand tool analogy is to help visualise what is happening as we saw. With either sawmill the cutters are going through the wood at ~75 mph, and you can't really see what they are doing inside the log anyway. But if you visualise a hand tool attacking the wood the same way, you can actually see how the cutting action works.

Who knows, if people understand this better some bright spark may come up with a new idea that dose work better. 

Ian

[zombie woods]

Dutchman speed is not even a concern , personaly I would be happy to just get through with moderate devation .

FWIW the harmonics comeing  through the mill suggest way to many teeth in the cut ,
imho.
I had hoped someone has tryed running a blade with 1/3 or 1/2 of the teeth ground down , guess I will give it a try .

[zombie woods]

Ianab
whats the largest dia ft swing style blades have seen .
could tou run one on a frick type mill ?

[Ianab]

Usually a 10" cut is as big as they go, although Turbo-saw have a 12" cut model now. I think the blade dynamics get a bit weird when you try swinging a bigger blade than that into the horizontal. Or at least it would need to be much thicker, and then you loose too much kerf.

The other factor is the a swingmill cuts with the outer rim of the blade, while a conventional circle mill making a shallow cut does so near the hub. This affects the angle the cutters are meeting the wood. Cutting near the rim means the longer strips being cut, and less power needed. Cutting near the hub means a more cross grain cutting action, and smaller chips being produced.

I have wondered how a larger circle mill would function if the smaller cants where cut at the rim of the saw? Probably impractical to have the carriage adjust the height as well as sideways, but for a resaw operation I think it might cut more efficiently?

Ian

[JohnM]

Ian, wide angle lens on that camera or a ruler made for measuring bowed cants?

[hackberry jake]

If you space your teeth out too far on a band mill or chainsaw mill, they don't work too well in narrower cuts. They grab too hard and try to throw the work piece. I have been thinking about a new style saw that cuts say 9' material. It would be a band about 2" thick under considerable tension and would cut through the log perpendicular instead of parrallel. Log diameter wouldn't be an issue and as Ian said it would cut long slivers of wood out. Maybe too long and bog up the whole works. It would have to have extreme gullet size and tooth spacing. Impracticle? Probably so. Fun to think about though.

[Jay C. White Cloud]

I had hoped someone has tryed running a blade with 1/3 or 1/2 of the teeth ground down , guess I will give it a try .

WZ, I'll do it if you will.  I just have to find a pattern to make it work.  I have a Left, Right and No Set tooth configuration.  Now I just have to figure out which teeth to take out and in what pattern.

Jake,

We do hope to own both mill again.  We sold the 250 mm (8") Peterson, and now are looking at a 180° swing blade giving us a 500 mm (~20") width of cut. It is made by EZ Forestry, (http://ezforestry.com/sawmill_products.html). Because of cost most folks go with a band mill, I did, and still own my Oscar 760 mm (30".)  They two saws with an assortment of chainsaw mills and hewing blades are more than enough to do commercial sawing for timber frames and specialty milling.

[tyb525]

Dutchman speed is not even a concern , personaly I would be happy to just get through with moderate devation .

FWIW the harmonics comeing  through the mill suggest way to many teeth in the cut ,
imho.
I had hoped someone has tryed running a blade with 1/3 or 1/2 of the teeth ground down , guess I will give it a try .

With a properly adjusted band mill, you really shouldn't feel too many harmonics. If the blade is vibrating, it means the tension is wrong.

Based on your thinking, why do metal cutting blades have much more teeth than wood blades? Metal is certainly very hard and dense.

The circle mill that had trouble cutting compared to the swing mill, was it set up correctly, did it have enough power, was it sharp with correctly set teeth? Way too many variables to say the swing mill was definitely better.

Now I have nothing against swing mills, I think they are really great for a wide range of things. But I don't understand the vendetta you have for American band  mills and circle mills.

We had a member on here who owned a tropical hardwood business, he had several crews cutting the stuff on bandmills.

Like Ianab has said, the way a swingmill cuts is different from a bandmill and circle mill. It's the same as ripping with a chainsaw. Ripping with the grain makes long shavings but a rougher cut, and ripping into the end grain makes a smoother cut bit makes fine sawust.

[zombie woods]

No vendetta I am operateing a woodmizer for 20+ years .
I would inot trade it for a swing mill for the for what I primarily mill .
my original quiery is how can a blade concept so radically different develop in one reigon with reletivity little acceptance the North America /South America.
and could this general concept be somehow be  transfered  to improve our thin kerf band mill blades for milling the ultra hard South American timbers .
As i said current thin kerf band mill blades cant hack it

Any one that thinks otherwise send me a 158 inch blade I will pay retail + s&h and give it a go .

Trust me the South American market could be  massive .
I read were Guyana is the worlds biggest importer of stil chain saws for example .
This thread has given me some good insight and avenues to persue so far .
Nothing ventured nothing gained .

ZW

[JustinW_NZ]

I see what you were getting at Zombie woods, its funny to think of a "saw doctor" looking at one of the saw blade patterns and laughing at it 
being in NZ you mostly see swing mills running those "funny blades" out and about.

And yes, those 5 tipped saw blades just chisel stuff really well as Ianb points out.
They act very consistant on the more annoying timbers out there in my view.

Cheers
Justin

[giant splinter]

I am following your thinking on this subject Zombie Woods and at the same time I am thinking to myself:
"We have some of the greatest engineers and Saw Blade manufacturers in the world right here in North America as well as many overseas blade manufacturers and in todays world wide markets with UPS and FedEx you can manufacture it in one place and send it where ever you want or where there is a demand for your products, so it occurs to me that if there was a worthwhile demand it would be over-run with blade manufacturing companies trying to meet that demand. I noticed that you run a Wood-Mizer mill and I have to ask if you considered taking up this topic with one of the leaders in band mill blade technology, I am sure that they will do everything possible to help you with your specialized interest band mill saw blades for extreme hardwoods and exotic hardwood milling."

I think you can find out where the hardwood sawyers are on this forum and ask them a few blade questions to see what is being used around the world.
I hope this helps shed a little light on your efforts to find the perfect blade

[customsawyer]

I have tried lots of different blades. One of the worse ones on hardwood was 1 1/8" tooth spacing. A friend of mine cuts mostly pine and it is the only blade he uses. So in that little bit of real world application I don't think your line of thinking will work. I do like the way you are looking at things and maybe that wasn't a large enough tooth spacing for what you are trying to accomplish. The blades that I have found to work the best on the  densest hardwoods we have is the WM 4° blade.

[ely]

along those lines, i had a friend once that brought me a band to sharpen and set, he had hit some steel with it previously. it had several spots around the band missing 4 and 5 teeth continuosly. i sharpened and set what was left of the band and he said while cutting pine that was the blade he always went to... because it cut so well in pine. hardwood he would not even try it with the band.

[LeeB]

Maybe try taking out every 4th tooth on a band blade. That would leave less teeth to drag through but not alter the geometry too much. Another approach might be a veriable tooth spacing.

[Gus]

Very interesting & thought provoking discussion here guys!

gus

[hackberry jake]

Alright, I think I have the difference. If you look at a rip blade for a table saw, it has few teeth per inch. If you buy a trim knife for a miter saw, it has a bunch of teeth per inch. It's all about weather it's cross cutting or ripping. I have an old "buzz saw" and it has a bunch of teeth. American circle mills have more teeth because they are usually cross cutting. Southern hemisphere saws have fewer teeth because they are usually ripping. Am I close?

[LeeB]

Jake, American circle mills have more teeth because of the size of the blade. They rip just the same. Just a guess here because I don't own or operate one, but I would say the bigger blade is used kinda like a large flywheel, in that it's mass helps keep up the rpm once it starts in the cut and also to wider cuts.