Sawmill Analysis - Revision history

Elifarley: Text replace - "\[http:\/\/openfarmtech\.org\/wiki\/([^] |?])[ |]([^]])\]" to "$2"

2013-07-02T22:01:22Z

Text replace - "\[http:\/\/openfarmtech\.org\/wiki\/([^] |?]*)[ |]([^]]*)\]" to "$2"

← Older revision		Revision as of 22:01, 2 July 2013
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	Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative. The home-made designs are pretty close to what OSE design would be, in the sense of simple to build. Here is an example: [http://www.youtube.com/watch?v=G8oHnImafEY Garage Built Bandsawmill]		Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative. The home-made designs are pretty close to what OSE design would be, in the sense of simple to build. Here is an example: [http://www.youtube.com/watch?v=G8oHnImafEY Garage Built Bandsawmill]

	Portable mills require terrain within the leveling capability of the stabilizer feet. A moderate slope is useful to load logs in the absence of mechanized loaders. Any sawmill requires a power source. Portable mills can use whatever source powers the transportation vehicle, such as the [~~http://openfarmtech.org/wiki/~~Power_Cube_Intro OSE Power Cube].		Portable mills require terrain within the leveling capability of the stabilizer feet. A moderate slope is useful to load logs in the absence of mechanized loaders. Any sawmill requires a power source. Portable mills can use whatever source powers the transportation vehicle, such as the [[Power_Cube_Intro\|OSE Power Cube]].

	===Productivity===		===Productivity===

DanielRavenNest at 15:31, 13 May 2011

2011-05-13T15:31:20Z

← Older revision		Revision as of 15:31, 13 May 2011
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	A band saw blade is kept straight by tension, while a circular blade is kept rigid by it's diameter to thickness ratio. Therefore circular blades are generally 2-3 times thicker. This requires more power to operate and results in more kerf loss (sawdust created by the cut). Circular blades are limited to less than half their diameter depth of cut. Band saw depth of cut is determined by the full diameter of the wheels the metal band rides on. The perpendicular two wheel design proposed for the circular sawmill requires two drive motors, while a bandsaw requires one. So overall the bandsaw appears a better design.		A band saw blade is kept straight by tension, while a circular blade is kept rigid by it's diameter to thickness ratio. Therefore circular blades are generally 2-3 times thicker. This requires more power to operate and results in more kerf loss (sawdust created by the cut). Circular blades are limited to less than half their diameter depth of cut. Band saw depth of cut is determined by the full diameter of the wheels the metal band rides on. The perpendicular two wheel design proposed for the circular sawmill requires two drive motors, while a bandsaw requires one. So overall the bandsaw appears a better design.

	A ~~bandsaw has a much narrower kerf~~, which ~~means it produces less sawdust. However, the bandsaw may be prone~~ to ~~more breakage than a large circular blade~~.		A comparison of [http://www.srs.fs.usda.gov/pubs/ja/ja_steele007.pdf relative labor and maintenance costs] shows bandsaws are lower, which is why most commercial sawmills have converted to them.

	:'''Stationary vs Portable'''		:'''Stationary vs Portable'''
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	Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative. The home-made designs are pretty close to what OSE design would be, in the sense of simple to build. Here is an example: [http://www.youtube.com/watch?v=G8oHnImafEY Garage Built Bandsawmill]		Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative. The home-made designs are pretty close to what OSE design would be, in the sense of simple to build. Here is an example: [http://www.youtube.com/watch?v=G8oHnImafEY Garage Built Bandsawmill]

	Portable mills require ~~flat~~ terrain to ~~operate optimally, which can be difficult to find~~ in a ~~forest at times~~. Portable mills ~~also require their own portable power~~ source, ~~which can be provided by~~ the OSE Power Cube.		Portable mills require terrain within the leveling capability of the stabilizer feet. A moderate slope is useful to load logs in the absence of mechanized loaders. Any sawmill requires a power source. Portable mills can use whatever source powers the transportation vehicle, such as the [http://openfarmtech.org/wiki/Power_Cube_Intro OSE Power Cube].

	===Productivity===		===Productivity===

Mjn: /* Design Options */

2011-05-13T00:50:59Z

Design Options

← Older revision		Revision as of 00:50, 13 May 2011
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	A band saw blade is kept straight by tension, while a circular blade is kept rigid by it's diameter to thickness ratio. Therefore circular blades are generally 2-3 times thicker. This requires more power to operate and results in more kerf loss (sawdust created by the cut). Circular blades are limited to less than half their diameter depth of cut. Band saw depth of cut is determined by the full diameter of the wheels the metal band rides on. The perpendicular two wheel design proposed for the circular sawmill requires two drive motors, while a bandsaw requires one. So overall the bandsaw appears a better design.		A band saw blade is kept straight by tension, while a circular blade is kept rigid by it's diameter to thickness ratio. Therefore circular blades are generally 2-3 times thicker. This requires more power to operate and results in more kerf loss (sawdust created by the cut). Circular blades are limited to less than half their diameter depth of cut. Band saw depth of cut is determined by the full diameter of the wheels the metal band rides on. The perpendicular two wheel design proposed for the circular sawmill requires two drive motors, while a bandsaw requires one. So overall the bandsaw appears a better design.

			A bandsaw has a much narrower kerf, which means it produces less sawdust. However, the bandsaw may be prone to more breakage than a large circular blade.

	:'''Stationary vs Portable'''		:'''Stationary vs Portable'''
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	Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative. The home-made designs are pretty close to what OSE design would be, in the sense of simple to build. Here is an example: [http://www.youtube.com/watch?v=G8oHnImafEY Garage Built Bandsawmill]		Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative. The home-made designs are pretty close to what OSE design would be, in the sense of simple to build. Here is an example: [http://www.youtube.com/watch?v=G8oHnImafEY Garage Built Bandsawmill]

			Portable mills require flat terrain to operate optimally, which can be difficult to find in a forest at times. Portable mills also require their own portable power source, which can be provided by the OSE Power Cube.

	===Productivity===		===Productivity===

DanielRavenNest: /* Design Options */

2011-05-12T17:38:50Z

Design Options

← Older revision		Revision as of 17:38, 12 May 2011
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	The alternatives are to bring the logs to a stationary sawmill or bring the mill to the logs. In the first case we have to move 1 unit of log weight to the mill, and about 0.4 units of offcuts and sawdust back to the forest for recycling. In the second case we only have to transport 0.6 units of cut lumber out of the forest. Since the above analysis shows the mill will be sized for a large village, numerous forest locations and destinations for the lumber are likely. For a stationary mill the average distance is set by the entire radius of forest used by the village. For a portable mill the distance can be lower, down to zero if the trees are cut, and then a building put up on the same location		The alternatives are to bring the logs to a stationary sawmill or bring the mill to the logs. In the first case we have to move 1 unit of log weight to the mill, and about 0.4 units of offcuts and sawdust back to the forest for recycling. In the second case we only have to transport 0.6 units of cut lumber out of the forest. Since the above analysis shows the mill will be sized for a large village, numerous forest locations and destinations for the lumber are likely. For a stationary mill the average distance is set by the entire radius of forest used by the village. For a portable mill the distance can be lower, down to zero if the trees are cut, and then a building put up on the same location

	Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative. The home-made designs are pretty close to what OSE design would be, in the sense of simple to build.		Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative. The home-made designs are pretty close to what OSE design would be, in the sense of simple to build. Here is an example: [http://www.youtube.com/watch?v=G8oHnImafEY Garage Built Bandsawmill]

	===Productivity===		===Productivity===

DanielRavenNest at 16:36, 12 May 2011

2011-05-12T16:36:55Z

← Older revision		Revision as of 16:36, 12 May 2011
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	Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative. The home-made designs are pretty close to what OSE design would be, in the sense of simple to build.		Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative. The home-made designs are pretty close to what OSE design would be, in the sense of simple to build.

	~~:'''~~Productivity~~'''~~		===Productivity===

	The value of cut green lumber over raw logs is about $0.20/bf higher. At a daily production of 2230bf/day, that means an added value of $446 per day. With a crew of two working 8 hours, that is about $28 per hour, meeting the GVCS general productivity goal.		The value of cut green lumber over raw logs is about $0.20/bf higher. At a daily production of 2230bf/day, that means an added value of $446 per day. With a crew of two working 8 hours, that is about $28 per hour, meeting the GVCS general productivity goal.

DanielRavenNest at 16:36, 12 May 2011

2011-05-12T16:36:17Z

← Older revision		Revision as of 16:36, 12 May 2011
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	Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative. The home-made designs are pretty close to what OSE design would be, in the sense of simple to build.		Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative. The home-made designs are pretty close to what OSE design would be, in the sense of simple to build.

			:'''Productivity'''

			The value of cut green lumber over raw logs is about $0.20/bf higher. At a daily production of 2230bf/day, that means an added value of $446 per day. With a crew of two working 8 hours, that is about $28 per hour, meeting the GVCS general productivity goal.



	[[Category:Sawmill]]		[[Category:Sawmill]]

DanielRavenNest: /* Design Options */

2011-05-12T16:28:28Z

Design Options

← Older revision		Revision as of 16:28, 12 May 2011
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	The alternatives are to bring the logs to a stationary sawmill or bring the mill to the logs. In the first case we have to move 1 unit of log weight to the mill, and about 0.4 units of offcuts and sawdust back to the forest for recycling. In the second case we only have to transport 0.6 units of cut lumber out of the forest. Since the above analysis shows the mill will be sized for a large village, numerous forest locations and destinations for the lumber are likely. For a stationary mill the average distance is set by the entire radius of forest used by the village. For a portable mill the distance can be lower, down to zero if the trees are cut, and then a building put up on the same location		The alternatives are to bring the logs to a stationary sawmill or bring the mill to the logs. In the first case we have to move 1 unit of log weight to the mill, and about 0.4 units of offcuts and sawdust back to the forest for recycling. In the second case we only have to transport 0.6 units of cut lumber out of the forest. Since the above analysis shows the mill will be sized for a large village, numerous forest locations and destinations for the lumber are likely. For a stationary mill the average distance is set by the entire radius of forest used by the village. For a portable mill the distance can be lower, down to zero if the trees are cut, and then a building put up on the same location

	Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative.		Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative. The home-made designs are pretty close to what OSE design would be, in the sense of simple to build.



	[[Category:Sawmill]]		[[Category:Sawmill]]

DanielRavenNest at 15:21, 12 May 2011

2011-05-12T15:21:52Z

← Older revision		Revision as of 15:21, 12 May 2011
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	'''Power''' - The Wood Mizer product page shows engine power of 25-50 HP for the LT40SH bandsaw. A circular saw will require higher power, since the blade makes a wider cut. The required power is proportional to how much kerf (the cut away portion) is cut per second. A smaller engine will still cut a large log, just slower.		'''Power''' - The Wood Mizer product page shows engine power of 25-50 HP for the LT40SH bandsaw. A circular saw will require higher power, since the blade makes a wider cut. The required power is proportional to how much kerf (the cut away portion) is cut per second. A smaller engine will still cut a large log, just slower.

			===Design Options===

			:'''Circular vs Band Saw'''

			A band saw blade is kept straight by tension, while a circular blade is kept rigid by it's diameter to thickness ratio. Therefore circular blades are generally 2-3 times thicker. This requires more power to operate and results in more kerf loss (sawdust created by the cut). Circular blades are limited to less than half their diameter depth of cut. Band saw depth of cut is determined by the full diameter of the wheels the metal band rides on. The perpendicular two wheel design proposed for the circular sawmill requires two drive motors, while a bandsaw requires one. So overall the bandsaw appears a better design.

			:'''Stationary vs Portable'''

			The alternatives are to bring the logs to a stationary sawmill or bring the mill to the logs. In the first case we have to move 1 unit of log weight to the mill, and about 0.4 units of offcuts and sawdust back to the forest for recycling. In the second case we only have to transport 0.6 units of cut lumber out of the forest. Since the above analysis shows the mill will be sized for a large village, numerous forest locations and destinations for the lumber are likely. For a stationary mill the average distance is set by the entire radius of forest used by the village. For a portable mill the distance can be lower, down to zero if the trees are cut, and then a building put up on the same location

			Moving heavy logs tends to compress the forest soil and damage it. Cut lumber can be transported in smaller loads and so cause less damage. Although bad weather would interfere with using a portable mill in the field, it can still be used under a shed if you need to run it at times like that. On the whole, portable seems a better option. There are numerous commercial and home-made portable band sawmills that demonstrate it is a practical alternative.



	[[Category:Sawmill]]		[[Category:Sawmill]]

DanielRavenNest at 14:38, 12 May 2011

2011-05-12T14:38:16Z

← Older revision		Revision as of 14:38, 12 May 2011
Line 22:		Line 22:

	'''Power''' - The Wood Mizer product page shows engine power of 25-50 HP for the LT40SH bandsaw. A circular saw will require higher power, since the blade makes a wider cut. The required power is proportional to how much kerf (the cut away portion) is cut per second. A smaller engine will still cut a large log, just slower.		'''Power''' - The Wood Mizer product page shows engine power of 25-50 HP for the LT40SH bandsaw. A circular saw will require higher power, since the blade makes a wider cut. The required power is proportional to how much kerf (the cut away portion) is cut per second. A smaller engine will still cut a large log, just slower.

			[[Category:Sawmill]]

DanielRavenNest at 14:34, 12 May 2011

2011-05-12T14:34:58Z

← Older revision		Revision as of 14:34, 12 May 2011
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	This result is highly dependent on the assumptions made. Buildings can be primarily made from other materials than wood. Techniques like [http://www.theecologist.org/green_green_living/home/747067/roundwood_timber_framing_the_greener_way_to_build.html Roundwood Construction] use whole log segments without cutting. So the requirement for the sawmill will depend on how the rest of the Village is designed.		This result is highly dependent on the assumptions made. Buildings can be primarily made from other materials than wood. Techniques like [http://www.theecologist.org/green_green_living/home/747067/roundwood_timber_framing_the_greener_way_to_build.html Roundwood Construction] use whole log segments without cutting. So the requirement for the sawmill will depend on how the rest of the Village is designed.

			===Sawmill Specifications===

			'''Log Capacity''' - Freshly cut wood is called "green", and contains a lot of water. The densest green hardwoods have a density about 64 pounds per cubic foot. The Wood Mizer product page noted above shows a log capacity of 36 inch diameter x 21 ft long. This produces net lumber up to 20 ft long, allowing for some losses at the ends due to uneven cuts and splits. Thus the maximum log weight is 148.4 cubic feet x 64 lb/ft^3 = 9,500 lb. The lightest woods are at least half the density when green. If logs these weights are considered too heavy to handle, then a smaller dimensional capacity can be set for the sawmill. In that case, large logs would be quartered in the forest using a chainsaw or hydraulic splitter to reduce them to a size that fits the mill. Also, you can intentionally cut smaller dense hardwood logs than lightweight species logs to stay within whatever weight limit you need to work with.

			The log weight will determine how you transport them, how they get loaded into the sawmill, and how sturdy the sawmill bed and hold-downs (what keeps the log from moving while cutting) need to be.

			'''Depth of Cut''' - Some wood species will dry straighter if done in "flitch" sections. This is a slice through the entire log. Individual boards are then cut from the flitch after drying. If that is not required, then the depth of cut needs to be at least 1/2 of the largest lumber dimension you expect to need. You can get by with 1/2 the dimension by cutting from both sides, and cutting away the round edges of the log first.

			'''Power''' - The Wood Mizer product page shows engine power of 25-50 HP for the LT40SH bandsaw. A circular saw will require higher power, since the blade makes a wider cut. The required power is proportional to how much kerf (the cut away portion) is cut per second. A smaller engine will still cut a large log, just slower.

Sawmill Analysis - Revision history

Elifarley: Text replace - "\[http:\/\/openfarmtech\.org\/wiki\/([^] |?]*)[ |]([^]]*)\]" to "$2"

DanielRavenNest at 15:31, 13 May 2011

Mjn: /* Design Options */

DanielRavenNest: /* Design Options */

DanielRavenNest at 16:36, 12 May 2011

DanielRavenNest at 16:36, 12 May 2011

DanielRavenNest: /* Design Options */

DanielRavenNest at 15:21, 12 May 2011

DanielRavenNest at 14:38, 12 May 2011

DanielRavenNest at 14:34, 12 May 2011

Elifarley: Text replace - "\[http:\/\/openfarmtech\.org\/wiki\/([^] |?])[ |]([^]])\]" to "$2"