Good morning all,
Ok im looking at two different circular mills to buy. not sure the years or models yet but my big question is which is better. The first one has a 42" blade and is run off the PTO of a tractor. The tractor i would be using is a 1958 JD 620 with about 48 HP at the shaft. The second is the same size blade but is ran off a 4 cylinder gas engine with a flat belt drive. i have heard that you loose power with the belt drive systems, not sure if this true or not thats why im asking. any advice whould be great. Thanks
Hi,
Are we to assume,that both mills are belsaw?Sometimes a pic. or two would be helpful..
I would not want to tie up a tractor. If you went with the one with the engine you could always change it to a Diesel engine or any other engine. You could always make the pto one run off an engine instead of the tractor. So you could go both ways.
Im totally new to the sawmill world so maybe a dumb question but what is belsaw? i will try to get Pics and add them.
It was a brand of circle mill, a very basic mill designed for farm use using farm power. Generally a tractor.
The mill is only tying up a tractor when the mill is running. Thousands of mills have run on tractors without the need of an additional power unit. That was part of the appeal of belsaw and the like.
Belt power is about as efficient as anything. Very few mills are run on a direct drive. They all have belts of some kind somewhere.
Well if you are new,think i would look at Band-mills-I have had both and like Band mills much better.....
Welcome to the Forestry Forum, Kauff44. What has driven you to deciding that you even want a sawmill? Need for personal lumber, starting a business or??
I am sure that there are various sawmills that you can visit and get a general idea as to their operation.
Since you are new to sawmilling, welcome aboard. A couple of things for you to consider. First, a gasoline engine powering a circle mill is a fuel hog. Unless you only need to saw the occasional log, the fuel expense will become onerous. Second, many veteran sawyers have been maimed/killed by circle mills. I know that a vintage circle mill looks cheap when compared to new band mills, but you must remember that a sawmill operation is simply a material handling problem with a saw sitting in the middle of it, (Front end loader, log lift, edger, stacker, chip blower, slab chewer, chip trailer, fork lift, flat bed truck, log truck, etc.) Let us know what you decide on and keep us informed on your progress and challenges. Remember, we love pictures, especially of pretty boards. Regards, Clark
Well im new to the owning my own but been around them since i was young. i used to cut with my uncle and grandfather on their circular mill and my dad on a bandsaw. The purpose of my own is for personal use. i Enjoy seeing a log take shape into a beautiful piece of lumber. i Understand how dangerous they are but they are a part of our history and to me it is just cool to see them at work. i have a few idea on making them a little safer, granted it hard to make a 42" spinning blade safe but every bit helps i guess. im looking at adding a conveyor so the material is carried away from the blade before moving it, also adding E-Stops to both ends. Thank you all for the insight.
Welcome Kauff44
Of-course both types of mills have their pluses and minuses.
I started with a small band and moved to circle saw swing mill.
For me I'm a circle guy,
Dan
"...you must remember that a sawmill operation is simply a material handling problem with a saw sitting in the middle of it, (Front end loader, log lift, edger, stacker, chip blower, slab chewer, chip trailer, fork lift, flat bed truck, log truck, etc.) "
Sealark,
I like that. Had never thought of sawmilling in those terms but is very true.
Thanks Kauff44 for the additional information. Having some insight helps with answering questions plus you will find that this group is warm hearted and will readily offer valid information and suggestions. :)
I sure am looking forward to getting one of these two mills and sending some pics. been browsing all of yours and they are awesome!! i have about 30 logs piled up ready to be cut, just need the mill.
My friend, John, has a home-built circle mill, which he powers with his tractor. The mill is under a roof and he has built a covered pad beside it where he can park the tractor. When he wants to mill, he just backs the tractor onto the pad and hooks up a drive shaft to his PTO.
The biggest issue here is horsepower. John can saw an 8x8 out of a 12" log, but nothing bigger than that. That was never a problem because he has a long term contract with the local smelter to supply 2x6's for rail car dunnage. That's his main work.
I was kind of thinking the same thing as Brucer, 48 PTO hp is probably not enough to do anything but very light sawing. Around here at lot of those mills were powered with a minimum of a 3-71 Detroit, which is around 115hp as I recall.
i seen a 56" saw with a 50 hp electric motor one time :o i think it was a frick but not sure
48 hp will pull it but t will be SLOW :)
Electric motors have better torque characteristics and so are better for powering a mill. As they load up the torque actually increases, while a gas engine tends to drop in torque and bog down. This seems to let you power though tough cuts better even though the hp rating is technically the same.
With a gas engine you seem to need 2 -3 hp per tooth to power them properly. This seems to be the case with a small swing blade with 4 teeth and 12 hp, or a larger 40-50 tooth circle blade with ~115 hp.
When you are underpowered and have to slow the feed you have an issue that the every cut still needs to slice through all the fibres each time. Means you end up slowing down to 1/4 speed if you only have 1/2 the power. Now a different blade design could be made to still work efficiently, by having 1/2 the cutters. It would only cut at 1/2 the speed, but it would at least be working efficiently with the engine power that was available.
Welcome the reason I found this great place for info and reading is now on bussy road.
Quote from: Ianab on February 24, 2016, 03:38:12 AM
Electric motors have better torque characteristics and so are better for powering a mill. As they load up the torque actually increases, while a gas engine tends to drop in torque and bog down. This seems to let you power though tough cuts better even though the hp rating is technically the same.
With a gas engine you seem to need 2 -3 hp per tooth to power them properly. This seems to be the case with a small swing blade with 4 teeth and 12 hp, or a larger 40-50 tooth circle blade with ~115 hp.
When you are underpowered and have to slow the feed you have an issue that the every cut still needs to slice through all the fibres each time. Means you end up slowing down to 1/4 speed if you only have 1/2 the power. Now a different blade design could be made to still work efficiently, by having 1/2 the cutters. It would only cut at 1/2 the speed, but it would at least be working efficiently with the engine power that was available.
i agree with you on most of that. but there is alot of difference in 42" saw and a 56" ;) saw and 48 pto hp is more than 48 engine hp because if gearing. but as i said it is going to be slow and probably about the minimum he could get by with. on the electric motors we normally put 2-3hp per inch of blade with the biggest one i installed was 200hp electric on a 56" saw ;D it would cut ;D we never had any complaints about power but did have some twisted mandrels :D :D :D
Rule of thumb is 5 hp per inch of wood cut for the circle mills. I believe that's the optimum, and anything less slows you down. We used a 125 hp electric and our maximum cut was 21". Species being cut would also need to be factored in.
Thanks all that makes my decision a bit easier to make.
Quote from: Ron Wenrich on February 24, 2016, 08:54:06 AM
Rule of thumb is 5 hp per inch of wood cut for the circle mills. I believe that's the optimum, and anything less slows you down. We used a 125 hp electric and our maximum cut was 21". Species being cut would also need to be factored in.
This is what I have always been taught too, 5 to 6 HP for inch of saw in a cut.
Here's the thing with circle saws: too much HP just wastes a bit of fuel. But too little HP the saw can bog down in the cut. When a saw gets bogged down like that and then hits a hard spot like a big knot or a lump of steel... thats when things get exciting, whole logs being thrown backwards out of the saw exciting. It's underpowered mills that kill ya, if you've got plenty of power you can just saw right on through most anything even with the teeth mostly gone.
Quote from: longtime lurker on February 24, 2016, 03:57:58 PM
if you've got plenty of power you can just saw right on through most anything even with the teeth mostly gone.
I'm guessing that statement is meant to be a hyperbole.
in my post earlier i said we used 2-3 hp per tooth and it should have said per inch of blade sorry :-[ ;D i will go back and fix it
That is practically the case with a swing mill, but this is with 6-10" deep cuts and 30 HP. I finished sawing a log once with 2 teeth, after a metal strike that took out the other 4 teeth. The cut was somewhat rougher but still accurate.
I don't know if it is true but I heard a story that Mr. Peterson figured out that relatively few teeth were necessary on a swing mill blade when he was at a show with only one blade and had to keep cutting after losing most of them.
I have sawed with every thing from a A John Deere at 32 HP to a 120 hp Detroit . You can run a circle mill with whatever you got . Just can't feed it as fast .
Quote from: sandsawmill14 on February 24, 2016, 07:11:52 PM
in my post earlier i said we used 2-3 hp per tooth and it should have said per inch of blade sorry :-[ ;D i will go back and fix it
That was my "rule of thumb"..
But when you do the maths on a conventional circle blade, you end up needing a similar sized engine in the end.
20" of cut capacity @ 5 hp per inch =~100 hp.
40 cutters @ 2.5 hp per cutter = ~100hp.
It when you take things to extremes that those models fall down. For example my old mill had an 8" depth of cut, with only 8 hp. Admittedly it wasn't fast, but because it only had 4 cutters it was still working efficiently (as well as you could expect 8hp to cut). But obviously not as fast as 20 cutters and 40 hp would have.
But in theory you could design a full size ~20" cut saw blade, with less cutters, what would take a lot less power to drive it. OK it's only going to feed at 1/2 the speed, but it won't be bogging down and having to slow down drastically.
my hudson bandmill has a 8hp engine it it cuts just as good of lumber as the timberking or the s&w but when you were making a 18"+ wide cut it was REAL slow :) i think we can all agree more is better up to a point ;D but you can almost always get by with what you have :)
Quote from: sandsawmill14 on February 24, 2016, 08:11:51 AM
...and 48 pto hp is more than 48 engine hp because if gearing....
Actually, it's not. Horsepower always decreases through a power train (due to friction losses). If there were no friction, HP would remain exactly the same.
What changes is the torque. As you gear down the drive to a slower speed, the torque increases. It's the torque that drives a blade through the wood.
smiley_thumbsup sort like downshifting a truck ;D
Wow that's a lot to take in. Well the mill I thing I'm going with is a circular sawmill 40' long with a 48" blade. It come with a blower, an edger, and a power unit. The pwr unit is a 6 cyl international and and would run all three units at the same time. I will send pics when I get it home. Might be in March, we just got hit with about 12" of white stuff so will have to wait till its gone. Thanks for all the info. It been a big help!!!!
I have a vance 52 inch circle mill. Handset. I am fairly new as well, and let me tell you there are many things to account for when operating a circle mill. The main thing is maintenance and preventative maintenance on the saw.
OK so how do i add pics to my post? it only lets me put a path in not the actual pic
Well here is my Circular mill. looking forward to getting it set up and going.
(https://forestryforum.com/gallery/albums/userpics/42299/image~5.jpeg)
(https://forestryforum.com/gallery/albums/userpics/42299/image~6.jpeg)
(https://forestryforum.com/gallery/albums/userpics/42299/image~7.jpeg)
(https://forestryforum.com/gallery/albums/userpics/42299/image~8.jpeg)
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Kauff are you setting the mill up on thiem road?
Yep hopefully going to get started soon. Waiting for the weather to break for a bit. It needs a few things yet but I would like to have it running in a month or so. My job keeps getting in the way HA
Been awhile since you posted wanted to give you a heads up their is a auction the 14th at the cedar mill selling two complete mills with edgers and cutoff saws. I am taking my splitter to my goddaughters this weekend its a mile or so from you I might swing by .