Some useful formulas are listed below for figuring out how to size a hydraulic motor for your auger or other grain handling equipment.
Gallons per minute of supply x 231
RPM = Cubic inches of motor displacement
Gallons per minute x 231
Motor cubic inches = RPM
RPM x cubic inches of motor displacement
GPM required = 231
PTO Shaft
A common question is, "How long can I expect my PTO shaft to last?" While there are many factors that contribute to that answer, there are a few rules of thumb that should be kept in mind.
Grease! Grease! Did I mention grease? The more often the better. The number one thing you can do to extend the life of your PTO shaft is to grease it often. Want to make sure it gets done? Hang a grease gun on the equipment with a PTO shaft.
Some information regarding how operating angle contributes to the life expectancy of a PTO shaft:
At 540 RPM and transmitting 40 HP, a category 4 PTO shaft at 22 degrees has a 12% decrease in life expectancy when the angle is changed by 3 degrees.
At 540 RPM and transmitting 24 HP, a category 3 PTO shaft at 22 degrees has a 22% decrease in life expectancy when the angle is changed by 6 degrees.
Showing posts with label auger flighting. Show all posts
Showing posts with label auger flighting. Show all posts
Wednesday, June 13, 2012
Thursday, March 15, 2012
Screw Conveyor Lump Size Limitations
The size of a screw conveyor not only depends on the capacity required, but also on the size and proportion of lumps in the material to be handled. The size of a lump is the maximum dimension it has. A closer definition of the lump size would be the diameter of a ring through which the lump would pass. However, if a lump has one dimension, much longer than its transverse cross-section, the long dimension or length would determine the lump size.
The character of the lump also is involved. Some materials have hard lumps that won't break up in transit through a screw conveyor. If that is the case, provision must be made to handle these lumps. Other materials may have lumps that are very hard, but degradable in transit through the screw conveyor, thus really reducing the lump size to be handled. Still other materials have lumps that are easily broken in a screw conveyor and therefore impose no limitations.
Three classes of lump sizes apply as follows:
Class I - A mixture of lumps and fines in which not more than 10% are lumps ranging from maximum size to one half of the maximum; and 90% are lumps smaller than one half of the maximum size.
Class II - A mixture of lumps and fines in which not more than 25% are lumps ranging from the maximum size to one half of the maximum; and 75% are lumps smaller than one half of the maximum size.
Class III - A mixture of lumps only in which 95% or more are lumps ranging from maximum size to one half of the maximum size; and 5% or less are lumps less than one tenth of the maximum size.
Table III shows the recommended maximum lump size for each customary screw diameter and the three lump classes. The ration, R, is included to show the average factor used for the normal screw diameters which then may be used as a guide for special screw sizes and constructions. For example:
Radial Clearance, Inches
Ratio, R = Lump Size, Inches
The allowable size of a lump in a screw conveyor is a function of the radial clearance between the outside diameter of the central pipe and the radius of the inside of the screw trough, as well as the proportion of lumps in the mix. The following illustration shows this relationship:
The character of the lump also is involved. Some materials have hard lumps that won't break up in transit through a screw conveyor. If that is the case, provision must be made to handle these lumps. Other materials may have lumps that are very hard, but degradable in transit through the screw conveyor, thus really reducing the lump size to be handled. Still other materials have lumps that are easily broken in a screw conveyor and therefore impose no limitations.
Three classes of lump sizes apply as follows:
Class I - A mixture of lumps and fines in which not more than 10% are lumps ranging from maximum size to one half of the maximum; and 90% are lumps smaller than one half of the maximum size.
Class II - A mixture of lumps and fines in which not more than 25% are lumps ranging from the maximum size to one half of the maximum; and 75% are lumps smaller than one half of the maximum size.
Class III - A mixture of lumps only in which 95% or more are lumps ranging from maximum size to one half of the maximum size; and 5% or less are lumps less than one tenth of the maximum size.
Table III shows the recommended maximum lump size for each customary screw diameter and the three lump classes. The ration, R, is included to show the average factor used for the normal screw diameters which then may be used as a guide for special screw sizes and constructions. For example:
Radial Clearance, Inches
Ratio, R = Lump Size, Inches
The allowable size of a lump in a screw conveyor is a function of the radial clearance between the outside diameter of the central pipe and the radius of the inside of the screw trough, as well as the proportion of lumps in the mix. The following illustration shows this relationship:
Wednesday, January 9, 2008
Calculate Horsepower For Inclined Screw Conveyors
Screw conveyors can be used to convey bulk materials at an inclined angle, but several areas of design should be examined first.
Because of the incline of the screw, several conveying problems begin to occur.
1. The horsepower per unit of material increases
2. The efficiency of moving the material forward decreases.
A U-trough conveyor, because of its shape allows the material to flow back over the top of the screw when the angle of incline increases. This problem is complicated by the presence of the hanger bearing which speeds up this fall back.
One way to avoid this is through the use of a tubular housing, or round tube conveyor. This prevents the material from riding above the screw and slows the turbulence caused by the fall back. Although the type of material being conveyed greatly effects the amount of fall back incurred, a general area where the U-trough conveyor starts to lose significant efficiency is 15 degrees of incline.
Round tube conveyors are available with and without intermediate hanger bearings. One instance would be in the conveying of stringy or fibrous materials where the material will wrap around the bearing and eventually cause plugging. Elimination of the hanger bearing may cause excessive deflection of the central screw pipe and cause a vibration or chatter as a result of the screw hitting the tubing. This can be avoided by the introduction of most materials which will tend to lift and support the screw, provided the material is introduced upon start-up of the conveyor and fills the entire length. Care should be taken to empty the conveyor before shut-down to avoid overload start-up conditions.
Due to the fallback created in inclined screw conveyors by tumbling and agitation, the amount of material being pushed forward through the conveyor is reduced. To offset this loss of capacity, increased screw rotation is applied. This increased rotation creates a greater forward material velocity, the net result being greater capacity.
In general, as the angle of incline of the conveyor increases, the greater the loss in the percentage of fill of the screw.
The flowability of a material affects the percentage fo fill greatly. The greater the flowability, the more quickly the screw pitches become filled before conveying the material along the length of the screw. Also, at some inclines, depending on pitch and diameter, a section of the helical flight is actually at a near horizontal plane. This tends to slice or sling the material outward, rather than to move the material forward.
Several things can be done to maintain the fill percentage of an inclined conveyor.
1. Completely cover the screw intake to prevent spatter and fallback.
2. Increase the length of exposed intake screw.
3. Force feed the incline conveyor by means of a pressure fed boot supplied by a horizontal intake screw.
4. Use a close tolerance between screw and tube.
5. Increase RPM (revolutions per minute).
In general the horsepower and capacities of incline conveyors depends on the characteristics of the material being conveyed and may require consulting the manufacturer.
Horsepower, Inclined Conveyors
To calculate the horsepower of the inclined conveyor, use the method as described for horizontal conveyors. See this post.
HPF =
L X N X Fd X Fb
------------------
1,000,000
HPm =
C X L X W X Fm
------------------
1,000,000
Inclined conveyors require additional calculations to measure the horsepower required to elevate the material.
HPh =
C X W X H
-------------
1,980,000
Where: H = Discharge height in feet
Total Incline HP =
(HPf + HPm + HPh)
---------------------
e
Hanger Bearing Factors (Fb):
Ball Bearing - 1.0
Babbitt - 1.7
Bronze - 1.7
*Graphite bronze - 1.7
*Canvas base phenolic - 1.7
*Oil impregnated bronze - 1.7
*Oil impregnated wood - 1.7
*Plastic - 2.0
*Nylon - 2.0
*Teflon - 2.0
No bearings - 4.0
"*" = Non-lubricated bearings, or bearings not additionally lubricated.
Conveyor Diameter and Diameter Factor (Fd)
4.0 - 10
5.0 - 13
6.0 - 16
8.0 - 24
10.0 - 33
12.0 - 49
Because of the incline of the screw, several conveying problems begin to occur.
1. The horsepower per unit of material increases
2. The efficiency of moving the material forward decreases.
A U-trough conveyor, because of its shape allows the material to flow back over the top of the screw when the angle of incline increases. This problem is complicated by the presence of the hanger bearing which speeds up this fall back.
One way to avoid this is through the use of a tubular housing, or round tube conveyor. This prevents the material from riding above the screw and slows the turbulence caused by the fall back. Although the type of material being conveyed greatly effects the amount of fall back incurred, a general area where the U-trough conveyor starts to lose significant efficiency is 15 degrees of incline.
Round tube conveyors are available with and without intermediate hanger bearings. One instance would be in the conveying of stringy or fibrous materials where the material will wrap around the bearing and eventually cause plugging. Elimination of the hanger bearing may cause excessive deflection of the central screw pipe and cause a vibration or chatter as a result of the screw hitting the tubing. This can be avoided by the introduction of most materials which will tend to lift and support the screw, provided the material is introduced upon start-up of the conveyor and fills the entire length. Care should be taken to empty the conveyor before shut-down to avoid overload start-up conditions.
Due to the fallback created in inclined screw conveyors by tumbling and agitation, the amount of material being pushed forward through the conveyor is reduced. To offset this loss of capacity, increased screw rotation is applied. This increased rotation creates a greater forward material velocity, the net result being greater capacity.
In general, as the angle of incline of the conveyor increases, the greater the loss in the percentage of fill of the screw.
The flowability of a material affects the percentage fo fill greatly. The greater the flowability, the more quickly the screw pitches become filled before conveying the material along the length of the screw. Also, at some inclines, depending on pitch and diameter, a section of the helical flight is actually at a near horizontal plane. This tends to slice or sling the material outward, rather than to move the material forward.
Several things can be done to maintain the fill percentage of an inclined conveyor.
1. Completely cover the screw intake to prevent spatter and fallback.
2. Increase the length of exposed intake screw.
3. Force feed the incline conveyor by means of a pressure fed boot supplied by a horizontal intake screw.
4. Use a close tolerance between screw and tube.
5. Increase RPM (revolutions per minute).
In general the horsepower and capacities of incline conveyors depends on the characteristics of the material being conveyed and may require consulting the manufacturer.
Horsepower, Inclined Conveyors
To calculate the horsepower of the inclined conveyor, use the method as described for horizontal conveyors. See this post.
HPF =
L X N X Fd X Fb
------------------
1,000,000
HPm =
C X L X W X Fm
------------------
1,000,000
Inclined conveyors require additional calculations to measure the horsepower required to elevate the material.
HPh =
C X W X H
-------------
1,980,000
Where: H = Discharge height in feet
Total Incline HP =
(HPf + HPm + HPh)
---------------------
e
Hanger Bearing Factors (Fb):
Ball Bearing - 1.0
Babbitt - 1.7
Bronze - 1.7
*Graphite bronze - 1.7
*Canvas base phenolic - 1.7
*Oil impregnated bronze - 1.7
*Oil impregnated wood - 1.7
*Plastic - 2.0
*Nylon - 2.0
*Teflon - 2.0
No bearings - 4.0
"*" = Non-lubricated bearings, or bearings not additionally lubricated.
Conveyor Diameter and Diameter Factor (Fd)
4.0 - 10
5.0 - 13
6.0 - 16
8.0 - 24
10.0 - 33
12.0 - 49
Tuesday, January 1, 2008
Horizontal Auger Horsepower Requirements
Horsepower Requirements, Torsional Ratings for Conveyor Screws, End Thrust.
HORSEPOWER REQUIREMENTS, HORIZONTAL SCREW CONVEYORS
The horsepower required to operate a horizontal screw conveyor is based on proper installation, uniform and regular feed rate to the conveyor and other design criteria.
The following factors determine the horsepower requirements of a screw conveyor operating under the foregoing conditions.
C = Capacity in cubic feet per hour.
e = Drive efficiency.
Fb = Hanger bearing factor.
Fd = Conveyor diameter factor.
Fm = Material factor
L = Total length of conveyor, feet.
N = Operating speed, RPM (revolutions per minute).
W = Apparent density of the material as conveyed, lbs, per cubic foot.
The horsepower requirement is the total of the horsepower to overcome conveyor friction (HPf) and the horsepower to transport the material at the specified rate (HPm), divided by the total drive efficiency, e, or:
HPf =
LN Fd Fb
------------
1,000,000
HPm =
CLW Fm
------------
1,000,000
Total HP =
(HPf + HPm)
---------------
e
Note: Inclined Auger HP Requirements are higher than for horizontal augers.
It is apparent that with conveyor capacity, size, speed, and length, all known that factors Fm, Fd and Fb are quite important. Small changes in these factors cause significant changes in the required horsepower. A discussion of these factors follows.
The factor Fb is related to the friction in the hanger bearing, due to rubbing of the journals in the bearing metal and including, for sleeve type hanger bearings, an allowance for the entry into the bearing of some foreign material. This factor is empirically derived.
Factor Fd has been computed proportional to the average weight per foot of the heaviest rotating parts and to the coupling shaft diameter.
The factor Fm depends upon the characteristics of the material. It is an entirely empirical factor determined by long experience in designing and operating screw conveyors. It has no measurable relation to any physical property of the material transported.
While it is good procedure in conveying of bulk materials to run the conveyor until it is empty, prior to a work stoppage, frequently conveyors must of necessity be stopped while fully loaded. In that event, starting the conveyor again may possibly cause a serious overloading of the Drive and motor. The characteristics of the material have much to do with the restarting of a fully loaded screw conveyor. Some materials will settle and pack or otherwise change their "as conveyed" characteristics. For example, Portland cement may take on the characteristics of a solid. Granulated sugar may pick up moisture from the atmosphere and form a crust or cake. These situations will require a larger than normal driving motor.
It is important that a conveyor system operate as demanded by its controls. Start-up conditions or temporary overloads should not cause interruptions in service, so all components of the drive, as well as, the motor, should be chosen accordingly.
It is generally accepted practice that most power transmitting elements of a screw conveyor be sized and selected to handle safely the rated motor horsepower. If, for example, a screw conveyor requires 3.5 horsepower as determined by the horsepower formula, a 5 horsepower motor must be used, and it is desirable that all power transmitting elements be capable of safely handling the full 5 horsepower. However, on a screw conveyor made up of several lengths of conveyor screw, only the drive shaft has to handle the full motor load. The succeeding screw lengths and couplings only have to handle loads proportionate to the distance these parts are from the drive shaft. For economy, ease of design and maintenance, it is usual to select conveyor couplings, coupling bolts and other rotating parts such that all are of the same size and interchangeable, even if they are a bit larger than necessary.
NOTE: The foregoing load carrying requirements really constitute a minimum shock loading, metal fatigue from 24 hour per day continuous service, etc., must be considered in addition.
HORSEPOWER REQUIREMENTS, HORIZONTAL SCREW CONVEYORS
The horsepower required to operate a horizontal screw conveyor is based on proper installation, uniform and regular feed rate to the conveyor and other design criteria.
The following factors determine the horsepower requirements of a screw conveyor operating under the foregoing conditions.
C = Capacity in cubic feet per hour.
e = Drive efficiency.
Fb = Hanger bearing factor.
Fd = Conveyor diameter factor.
Fm = Material factor
L = Total length of conveyor, feet.
N = Operating speed, RPM (revolutions per minute).
W = Apparent density of the material as conveyed, lbs, per cubic foot.
The horsepower requirement is the total of the horsepower to overcome conveyor friction (HPf) and the horsepower to transport the material at the specified rate (HPm), divided by the total drive efficiency, e, or:
HPf =
LN Fd Fb
------------
1,000,000
HPm =
CLW Fm
------------
1,000,000
Total HP =
(HPf + HPm)
---------------
e
Note: Inclined Auger HP Requirements are higher than for horizontal augers.
It is apparent that with conveyor capacity, size, speed, and length, all known that factors Fm, Fd and Fb are quite important. Small changes in these factors cause significant changes in the required horsepower. A discussion of these factors follows.
The factor Fb is related to the friction in the hanger bearing, due to rubbing of the journals in the bearing metal and including, for sleeve type hanger bearings, an allowance for the entry into the bearing of some foreign material. This factor is empirically derived.
Factor Fd has been computed proportional to the average weight per foot of the heaviest rotating parts and to the coupling shaft diameter.
The factor Fm depends upon the characteristics of the material. It is an entirely empirical factor determined by long experience in designing and operating screw conveyors. It has no measurable relation to any physical property of the material transported.
While it is good procedure in conveying of bulk materials to run the conveyor until it is empty, prior to a work stoppage, frequently conveyors must of necessity be stopped while fully loaded. In that event, starting the conveyor again may possibly cause a serious overloading of the Drive and motor. The characteristics of the material have much to do with the restarting of a fully loaded screw conveyor. Some materials will settle and pack or otherwise change their "as conveyed" characteristics. For example, Portland cement may take on the characteristics of a solid. Granulated sugar may pick up moisture from the atmosphere and form a crust or cake. These situations will require a larger than normal driving motor.
It is important that a conveyor system operate as demanded by its controls. Start-up conditions or temporary overloads should not cause interruptions in service, so all components of the drive, as well as, the motor, should be chosen accordingly.
It is generally accepted practice that most power transmitting elements of a screw conveyor be sized and selected to handle safely the rated motor horsepower. If, for example, a screw conveyor requires 3.5 horsepower as determined by the horsepower formula, a 5 horsepower motor must be used, and it is desirable that all power transmitting elements be capable of safely handling the full 5 horsepower. However, on a screw conveyor made up of several lengths of conveyor screw, only the drive shaft has to handle the full motor load. The succeeding screw lengths and couplings only have to handle loads proportionate to the distance these parts are from the drive shaft. For economy, ease of design and maintenance, it is usual to select conveyor couplings, coupling bolts and other rotating parts such that all are of the same size and interchangeable, even if they are a bit larger than necessary.
NOTE: The foregoing load carrying requirements really constitute a minimum shock loading, metal fatigue from 24 hour per day continuous service, etc., must be considered in addition.
Intermediate Auger Bearing Recommendations
Selection of bearing material for an intermediate hanger is based on experience, together with a consideration of the characteristics of the material to be conveyed. Normally, the bearing selection will be made from one of the following three bearing types:
A. Babbitted or Bronze Bearings
Lubricated babbitted bearings are very frequently used, but have a maximum operating temperature of 130° F; lubricated bronze bearings may be operated at temperatures up to 225° F. This temperature figure for bronze bearings may be exceeded by the use of appropriate high temperature lubricants. CARE MUST BE EXERCISED IN THE USE OF BABBITTED OR BRONZE BEARINGS WHEN THE CONVEYED MATERIAL MUST NOT BE CONTAMINATED BY THE PRODUCTS OR BEARING WEAR OR THE LUBRICANTS USED.
B. Self Lubricated Bearings
Self lubricated bearings are available in several types.
1. Oil impregnated hard maple wood has a maximum operating temperature of 160° F.
2. Oil impregnated sintered bronze has a maximum operating temperature of 200° F.
3. Plastic and reinforced fibre compounds are available in a wide variety of compositions and constructions, and can be obtained from many sources. They require no grease or oil lubrication and are usually run dry. They are best suited for use in conveyors wetted with water. Maximum operating temperatures vary with the composition and construction of the bearing. When appropriately used, the wear rate is usually low.
C. Ball Bearings
Ball bearings are preferably used when handling granular or pelletized materials not containing any fine powder. Maximum operating temperature is 225° F with petroleum based lubricants, or 270° F with high temperature synthetic lubricants. When appropriately used and sealed against loss of lubricant, ball bearings usually involve no contamination of the material conveyed.
A. Babbitted or Bronze Bearings
Lubricated babbitted bearings are very frequently used, but have a maximum operating temperature of 130° F; lubricated bronze bearings may be operated at temperatures up to 225° F. This temperature figure for bronze bearings may be exceeded by the use of appropriate high temperature lubricants. CARE MUST BE EXERCISED IN THE USE OF BABBITTED OR BRONZE BEARINGS WHEN THE CONVEYED MATERIAL MUST NOT BE CONTAMINATED BY THE PRODUCTS OR BEARING WEAR OR THE LUBRICANTS USED.
B. Self Lubricated Bearings
Self lubricated bearings are available in several types.
1. Oil impregnated hard maple wood has a maximum operating temperature of 160° F.
2. Oil impregnated sintered bronze has a maximum operating temperature of 200° F.
3. Plastic and reinforced fibre compounds are available in a wide variety of compositions and constructions, and can be obtained from many sources. They require no grease or oil lubrication and are usually run dry. They are best suited for use in conveyors wetted with water. Maximum operating temperatures vary with the composition and construction of the bearing. When appropriately used, the wear rate is usually low.
C. Ball Bearings
Ball bearings are preferably used when handling granular or pelletized materials not containing any fine powder. Maximum operating temperature is 225° F with petroleum based lubricants, or 270° F with high temperature synthetic lubricants. When appropriately used and sealed against loss of lubricant, ball bearings usually involve no contamination of the material conveyed.
Monday, November 5, 2007
Figuring Auger RPM
A very common problem. How do I figure my auger's RPM?
Use these formulas to figure auger RPM.
For straight pulley reduction:
Drive pulley x motor RPM = SUM ÷ driven pulley diameter = auger RPM
For auger with a reduction gearbox:
Drive pulley x motor RPM = SUM ÷ driven pulley diameter = SUM ÷ gearbox reduction ratio = auger RPM
To use the auger RPM you've figured to figure capacity, click here.
Use these formulas to figure auger RPM.
For straight pulley reduction:
Drive pulley x motor RPM = SUM ÷ driven pulley diameter = auger RPM
For auger with a reduction gearbox:
Drive pulley x motor RPM = SUM ÷ driven pulley diameter = SUM ÷ gearbox reduction ratio = auger RPM
To use the auger RPM you've figured to figure capacity, click here.
Wednesday, October 31, 2007
Thickened Edge Flighting Review
I recently took a look at some testing done by an accredited agency in Canada regarding the durability of thickened edge flighting versus traditional helicoid style flighting. Following is an article I wrote in regards to that.
The Myth of Thickened Edge Flighting
"Up to 50% thicker", "longer life augers", "improved wear resistance", are the features the manufacturers of thickened edge flighting tout as advantages over traditional helicoid style flighting. However, are these features actually fact and advantage, or is thickened edge flighting simply marketing hype?
First one has to understand what traditional helicoid ribbon style flighting is. Traditional helicoid style flighting is flighting rolled from a rectangular piece of steel to create the flighting, or "auger part" of the auger in a long, unbroken, ribbon. To produce this flighting, the traditional method of production rolls flighting that is thicker at the base, or core, than it is at the outer edge. So, if you say, "10 gauge flighting," generally speaking, you are talking about the flighting thickness at the base, where it is welded to the center flighting pipe. This is how flighting has been produced for the grain handling industry for many years.
Recently, thickened edge flighting, also known as Super-Edge or Dura-Edge amongst other names, has been introduced and promoted as an improvement on this process. Thickened edge flighting is helicoid style flighting rolled in such a manner as to leave a thicker strip of material at the outer edge of the flighting. The intended purpose of this thicker strip along the edge is to give you more material where flighting wear is normally most apparent. Sounds like a good idea right? Add more material to the edge for more wear? Unfortunately, it seems, this is not necessarily an advantage.
A study conducted by an independent, accredited, agricultural testing agency compared traditional helicoid style flighting and thickened edge helicoid style flighting. The findings were somewhat surprising.
A metallurgical report on the steel of both respective types of flighting was done. Breaking down the numbers into a manageable format that the average person can understand, the traditional helicoid style flighting tested as using a harder base material than the thickened edge flighting's material. Additionally, the report refers to differences in the "work hardening" at the edge of both flightings. The thickened edge flighting product showed less work hardening at the outer edge of the flighting than the traditional flighting. Specifically, the thickened edge tested at a softer 91-91, versus the traditional flighting at 95-95. Presumably, to accomodate the manufacturing process of leaving more material at the edge of the flighting, the thickened edge flighting has to be rolled from a softer grade of steel, and because it is "worked less" at the edge to leave the remaining thickened band, it is less dense at that point.
A mechanical test to identify differences in the durability of the traditional and thickened edge flighting was done by running identical flightings, with the exception of the edge type, in aggregate for 85 hrs. Visually, after running for the same amount of time, it was very difficult to tell the difference between the two flightings. Beyond the visual, weighing the flightings showed that the thickened edge flighting actually lost material 10% faster than the traditional flighting when compared on a weight basis.
So, what does all this testing mean? Essentially, this is a case of perception, marketing perception. Considering the information mentioned above, thickened edge flighting offers no real, definitive advantage over traditional helicoid style flighting. Realistically, one could point to subtle points of superior wear characteristics for the traditional flighting. So, if you are paying more for, and expecting more life out of your thickened edge flighting, you may be disappointed.
Wednesday, October 10, 2007
Auger Flight Rotation and Material Flow
The above diagrams are a simple means of determining screw rotation. When the material flow is in the direction away from the end being viewed, a RIGHT hand screw will turn counter clockwise and a LEFT hand screw will turn clockwise rotation as shown by the arrows.
How to Identify Right Hand or Left Hand Flighting
A picture is worth a thousand words. Below is a picture of how to tell if your auger has right hand, or left hand flighting.
A conveyor screw is either right hand or left hand depending on the form of the helix. The hand of the screw is easily determined by looking at the end of the screw.
The screw pictured to the left has the flight helix wrapped around the pipe in a counter-clockwise direction, or to your left. Same as left hand threads on a bolt. This is arbitrarily termed a LEFT hand screw.
The screw pictured to the right has the flight helix wrapped around the pipe in a clockwise direction, or to your right. Same as right hand threads on a bolt. This is termed RIGHT hand screw.
A conveyor screw viewed from either end will show the same configuration. If the end of the conveyor screw is not readily visible, then by merely imagining that the flighting has been cut, with the cut end exposed, the hand of the screw may be easily determined.
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