How to buy a Disc: Top 10 things to consider when buying an Offset or Tandem Disc

1. Why buy a Disc?
   1. Residue Management: Discing is an effective, responsible way to manage crop residue in your fields: Discing sizes and buries residue, helps with wind and water erosion management and improves soil health by mixing organic matter into the topsoil.
   2. Weed Management: Managing weeds with a Disc means precious soil nutrients and moisture is directed to your crops – where it is needed most. Discing is also desirable to clean up any herbicide resistant weeds left in the field or for organic producers to plow down green manure crops.
   3. Seedbed Preparation: Most often maximizing yield potential begins with preparing the best seedbed possible and this can begin right after harvest is over. Discing can mix in valuable crop residue, open the ground so moisture can penetrate instead of run off and manage Fall weed growth.
   4. Insect/ Disease Management: Plant disease and insects can significantly lower crop yields. Discing reduces many insect and disease problems by mixing crop residue that disease and bugs live on into the soil.
   5. Incorporation: Discing is a cost effective, proven way to incorporate manure, herbicide or other nutrients into the soil. Incorporation reduces runoff, fertilizer and herbicide losses and odors associated with manure application.
   6. Improve Soil Health: In some areas, no-till and direct seeding into standing stubble has resulted in the ground not warming quickly enough in the Spring, runoff problems, too much organic material sitting on the top of the ground and disease/ insect problems associated with excess residue on the soil surface. Discing helps manage all of these problem areas.
   7. Breaking Land/ Pasture/ Alfalfa: Discing has proven to excel in this application: producers in most areas have found they can pull a Disc at least twice as wide compared to a moldboard plow, at a faster speed (4-6 mph/ 6.5-9.75 km/h) with considerably less maintenance costs.
2. Type of discing job to be done: Try to match the job that needs done with the type of ground on your farm to the model of Discs available in your area. If a Disc is needed to clean up field edges, slough bottoms and low spots, you likely don’t need a machine that weighs 1,000 lbs per foot. A Disc in the 500 to 600 lbs/ ft class, 9” to 10.5” blade spacing with 24” or 26” blades will likely do the job nicely. And the opposite holds true: if the job is to break up old pasture in heavy clay ground or for use as a primary tillage machine to manage high levels of Bt corn residue, the Disc being considered should have wider blade spacing (12”) with larger sized blades (at least 26”, but possibly 28” or 30” – depending how deep you want to work the ground) and be in the 650 lbs/ ft weight class, minimum.
1. Light work: Secondary tillage: seedbed preparation/ finishing work, discing up light stubble, herbicide incorporation, some types of reclamation or pipeline cleanup work
2. Medium work: Primary tillage such as discing up slough bottoms, low spots, cleaning up field edges, discing heavier amounts of crop residue (heavy stubble, some types of corn stalks, old pasture/ grass in lighter land, vegetable residue such as sugar beets, potatoes, etc)
3. Heavy work: Discing large amounts of difficult crop residue in harder ground or at a deeper depth: Bt corn stalks, breaking up larger amounts of grass/ pasture/ alfalfa, plowing down heavier crop residue such as sugarcane, cotton, etc. light industrial applications such as site preparation work, mix and dry clay soil on construction sites, and reclamation work
4. Breaking/ Construction: breaking up new land for agriculture, re-forestation, working up old fence lines or other agricultural work in very rocky conditions, building road beds, dams or levees, more demanding site preparation work or mining/ industrial land reclamation, or other extreme duty applications in agriculture where maximum cutting depth/ ground penetration is desired
3. Weight Classes: Tandem and Offset Discs are grouped into classes of weight per blade or weight per foot:
1. Light Duty: 300 to 450 lbs/ ft (120 to 180 lbs/ blade); 8” or 9” blade spacing
2. Medium Duty: 500 to 700 lbs/ ft (200 to 300 lbs/ blade); 10.5” to 12” blade spacing
3. Heavy Duty: 700 to 1,050+ lbs/ ft (300 to 650 lbs/ blade); 12” to 14”+ blade spacing
4. Blades: Spacing, Type & Thickness: look for a Disc that has the blade spacing, type and thickness required to do the specific job you have in mind. Notched or smooth blades should be available as options:
1. Spacing: generally speaking, wider blade spacing requires taller blades while narrow blade spacing uses smaller diameter blades. This is because taller blades tend to cut deeper and therefore will push more residue or material through the opening between the blades. If the spacing is too narrow the Disc gang(s) will tend to plug up. The exception to this is in places like Australia where they use tall blades with narrow spacing because depth of cut is only 2”-3” (3-8cm) – either 26” blades on 9” spacing or 28” blades on 10.5” spacing.
1. Wider blade spacing and taller blades are generally used in heavy residue applications such as breaking up grass/ pasture or on construction/ reclamation projects to lift/ dry/ mix heavy clay soils while narrow blade spacing is more desirable for seedbed preparation or finishing type work where smoother field finish is desired.
2. How to match blade size to spacing:
   1. 8” to 9’ spacing: 22” or 24” blades
   2. 10.5” spacing: 26” or 28” blades
   3. 12” spacing: 26”, 28” or 30” blades
   4. 14” spacing: 32’ blades
   5. 14”+ spacing: 36” blades
2. Type: Notched vs. Smooth Blades; Cone style:
1. Notched: commonly found as standard equipment on Offset Discs because they tend to cut and penetrate better in hard ground or demanding tillage situations compared to smooth blades. Notched blades will throw more crop residue back up on the surface of the ground than smooth blades will. This is desirable if residue is needed on the surface of the ground for protection against wind or water erosion or if grass roots or other root material needs to be exposed to sunlight/ air to maximize root kill.
2. Smooth: better in rocky conditions because they won’t ‘hook’ and pull rocks out of the ground the same way a notched blade will. Smooth blades also leave somewhat smoother field finish because they tend to bury more crop residue. This is why it is common to see producers choose notched blades on the front and smooth blades on the rear – especially on Tandem Discs.
3. Cone blades were introduced by manufacturers to cut and penetrate the ground more aggressively. When installed on a light or medium duty Disc the blades would cause the Disc to perform like a much heavier unit would – penetrate the ground deeper and move more soil. These blades work well in areas with NO rocks, roots or stumps. Because of the high likelihood they will be damaged from rock impact, very few manufacturers offer this type of blade any longer.
3. Thickness: To determine which blade thickness is right for your application, first find out what type of blade the Disc manufacturer you are considering is using on their Discs.

Disc blades are built by a whole host of manufacturers world-wide. Most high carbon steel blades (from places like Spain, India, England, France and China) are quite thin (up to a maximum ¼” = .256 or 6.5mm thickness) and are manufactured to a very hard specification so they will wear well over time. But if they encounter rocks they don’t stand up so well – because the blade is so hard, it is brittle and will often split, crack or break from impact. If you have very few rocks, then this type of blade is a good choice – because they are thin they cut aggressively and wear very well. Common sizes are 20”, 22” and 24”. 26”x¼” and up won’t work very well because the blades can break at the centre from simply cutting deep into hard ground.

Common blade thickness used on lesser Discs:

7 gauge = .176”
5mm = .197”
6 ga = .203”
6mm = .236”
(Remember, .256” = ¼” = 6.5mm)

When a Disc blade hits a hard object like a rock, something has to give and it should never be the Disc blade. Broken blades can cost considerable down time to replace. This is why Ezee-On only uses blades that are made with unique boron alloy steel. These blades are very hard – Rockwell hardness up to 52 Rc – but with a special boron alloy mixed in with the high carbon steel that allows the blades to flex without causing brittleness or loss of elasticity. These blades have been engineered for the ideal mixture of hardness and flexibility so they will wear very well over time yet stand up to rock and impact stress without splitting, cracking or breaking.

Ezee-On believes that producers don’t want to spend time replacing disc blades. Therefore the thinnest blade we use is ¼” (6.5mm) on our very lightest Disc model and the most common blades we use are 5/16” (8mm) and 3/8” (9mm) thickness.

Blades available from Ezee-On:
22” x ¼” Smooth (6.5mm)
22” x 9/32” Smooth or Notched (7mm)
24” x 9/32” Smooth or Notched (7mm)
24” x 5/16” Smooth or Notched (8mm)
26” x 5/16” Smooth or Notched (8mm)
26” x 3/8” Smooth or Notched (9mm)
28” x 3/8” Smooth or Notched (9mm)
30” x 3/8” Smooth or Notched (9mm)
32” x ½” Notched (12mm)

5. Bearings and Bearing Hangers:
1. Spacing: generally speaking, wider blade spacing requires taller blades while narrow blade spacing uses smaller diameter blades. This is because taller blades tend to cut deeper and therefore will push more residue or material through the opening between the blades. If the spacing is too narrow the Disc gang(s) will tend to plug up. The exception to this is in places like Australia where they use tall blades with narrow spacing because depth of cut is only 2”-3” (3-8cm) – either 26” blades on 9” spacing or 28” blades on 10.5” spacing.
1. Application: how many acres per year need to be disced? What kind of work will the Disc be doing? How long do you plan to own this unit? Is downtime an issue? How heavy (weight class) is the Disc you are planning to buy? All of these questions will affect the type of bearing required. The more acres disced per year, the longer you plan to own the disc, the heavier the Disc, the better the bearing that should be considered.
2. Ball Bearings vs. Tapered Roller Bearings (Oil bath): Disc bearings must be capable of withstanding a combination of two load components – RADIAL (vertical or from above) loading and THRUST (horizontal or from the side) loading. As the Disc moves forward and penetrates the soil, the thrust, or side load exerted on each gang bearing can be considerably greater than the corresponding radial load. It is therefore important that any bearing used in this application have a high thrust load capacity relative to its radial load capacity.
1. Tapered Roller Bearings (Oil Bath): tapered roller bearings are generally used in applications where the thrust load is minimal. For example, a wheel or axle bearing. Any amount of thrust load will ‘squeeze’ the rollers of a tapered roller bearing inward, thereby reducing the bearing’s life expectancy. Even the addition of a second tapered roller bearing in a back-to-back arrangement (ex: Oil Bath), does not improve life expectancy as the thrust load is NOT shared equally by both bearings. As the thrust load increases, the outer tapered roller bearing carries the entire load while the inner bearing carries little or no load at all and, in fact, moves away from its race or cup.
2. Ball Bearings: Ball bearings, by contrast, are designed for both high radial AND thrust load capabilities. Most large manufacturers of Discs continue to use ball bearings because of their high thrust load capability and a round ball bearing is just about impossible to crush. Ezee-On’s exclusive trunnion mounted T2-215 bearing features two 215 series ball bearings in a back-to-back arrangement which have a combined load rating of 22,800 lbs. Unlike the Oil Bath type bearing, this configuration allows both bearings to share the load equally. (each 215 series bearing has 11 x 11/16” ball bearings x 2 = 22 large diameter ball bearings in each assembly). This design has proven to be so trouble-free that it is not uncommon for Ezee-On owners to never need to repair or replace a T2-215 bearing during the entire life of the Disc. In fact, large acreage owners in Australia and the USA as far back as 1984 report never having encountered a single T2-215 bearing failure. Originally designed for large Offset breaking Discs with 32” diameter blades, this bearing is available on other Disc models with 24”, 26”, 28” and 30” blades.
3. Bearing Types: Discs on the market today utilize 3 different style of bearings:
1. Cast steel pillow block bolted to a hanger, greaseable. Most manufacturers design these so that the housing is designed to allow the bearing to self align around the gang shaft when deflection is encountered.
1. Positives: quite easy to replace the bearing if it wears out and replacement parts are reasonably in-expensive. Good bearing choice for light or medium duty applications.
2. Negatives: bearings require daily greasing. However, if the bearing is equipped with a triple-lip seal, this daily greasing will push any fine grit or particles out past the bearing seal which ensures longer bearing life and will NOT damage the bearing seal(s). DO NOT purchase a disc that does not use triple-lip bearing seals. If a power grease gun (electric or air) is used, it is very easy to over grease the bearing and push the seal off the bearing requiring the complete bearing to be replaced. Most often use of this type of grease gun on this kind of bearing will void manufacturers warranty.
2. Oil bath: utilize back-to-back tapered roller bearings operating in gear oil inside a cast housing which is bolted solid onto a rigid hanger.
1. Positives: No daily greasing required
2. Negatives:
1. As discussed above, tapered roller bearings are generally used most successfully in applications where load is applied vertically or in a straight line – think a truck axle: weight is from the top, there is no side load and the bearings stand up well. Load in a discing application is vertical AND from the side (radial and thrust load) because the gangs are set at an angle to ensure proper ground penetration. In this situation one tapered roller bearing carries the majority of the weight or thrust load, often leading to premature bearing failure. Further to this, in extreme-duty applications it is very difficult to crush a round ball bearing, while it is common to see tapered roller bearings fail because side load wants to pry the bearing apart and flatten the rollers.
2. Discs work in the soil and this soil is often abrasive and whenever there is a shaft turning against a seal, grit and fine particles tend to work their way through the seal - causing premature bearing failure.
3. Cost: oil bath bearings are very expensive to replace and rebuilding a bearing assembly is often NOT possible to accomplish easily: shims or gaskets need to be installed to set bearing pre-load correctly – this often requires the bearing unit to be sent back to the Factory or done by a trained technician at an authorized repair centre/ dealership.
3. Trunnion mounted housing, greaseable. The trunnion style housing has two pivot points to keep the trunnions centered. This design is able to handle greater amounts of gang shaft deflection compared to the cast steel pillow block style or oil bath bearings because the gang shaft can move just enough to offer protection to bearings and blades if shock load from hard ground or rocks is encountered.
1. Positives: bearing housings handle shock and thrust load better than a bearing that is bolted solid to a hanger.
2. Negatives: when deciding on a particular Disc manufacturer, make sure the trunnion mounted housing has a single bolt fastening the housing to the bearing hanger. This makes removal or installation of the gang assembly from the gang beam simple, quick and easy. Otherwise, gang shaft disassembly or reassembly can be very time consuming and difficult.
2. Load rating: bearings are rated using radial load rating @ 33-1/3 RPM, in pounds:
1. 211 series: 7,520 lbs
2. 214 series: 10,000 lbs
3. 410 series: 14,100 lbs (Ezee-On exclusive)
4. T2-215 series: 22,800 lbs (Ezee-On exclusive)
3. Grease type: if the Disc you purchase has greaseable bearings, be sure to use a high quality lithium based grease that will handle moisture, temperature and pressure. Usually pressure resistant grease is also high-temperature grease.
4. Hangers: three types available.
1. Rigid: This type of hanger should be constructed of high-tensile steel for strength and contoured to the blade curvature for maximum residue flow. There is disagreement about how hangers should be mounted: welded to the gang beam or u-bolt mounted. Based on years of building Discs and extensive testing, Ezee-On believes hangers should be u-bolt mounted for ease of installation, removal or adjustment. Welded solid hangers will not allow the gang to shift upon impact from hard ground or rocks and welded solid hangers are difficult to bolt bearing housings to if blades or bearings should need to be replaced.
2. Rigid with spring loaded gangs: hanger design and construction should be the same as described above, with the exception that heavy springs are mounted such that the entire gang assembly will travel back and up in an arc should hard ground or rocks be encountered by the Disc. This design works well for smaller sized/ lighter Disc models (300 lbs/ ft class). The problem with this design for heavier Discs is threefold:
1. For the springs to offer protection to the blades and bearings, the spring has to be set at a fairly low number – usually 550 lbs. This means the disc gangs want to constantly arc back out of the ground when the Disc travels across the field which often leads to uneven penetration and inconsistent depth of cut.
2. Spring loaded gangs offer protection from front or vertical shock force only. They do not provide protection from horizontal or side stress. Discs experience constant horizontal stresses because the gangs are set at an angle in order for the Disc to penetrate the ground successfully.
3. Spring loaded gangs are designed to be quite small – usually 4 to 6 blades to a gang, maximum – so that if a blade hits a rock, only that particular gang will be affected and spring back. The problem with small gangs is that they tend to plug more than larger gangs. A larger gang has more blades that want to cut, grab and keep rolling through the ground – even if the disc should encounter hard spots, rocks or wet spots that would otherwise cause a smaller gang with fewer blades to stop rolling, skid and plug the machine.
3. Stone-Flex (otherwise known as rock flex, c-flex, etc.): Stone-Flex Hangers are a ‘C’ shaped spring steel hanger which is designed to absorb both vertical and more importantly horizontal (side) forces without compromising disc blade penetration. Therefore, Stone-Flex hangers offer additional protection for blades, bearings, spools and gang shafts because Discs, especially in rugged conditions, can encounter extreme and repetitive shock forces from hard ground and ground embedded rocks and roots. Stone-flex hangers are the perfect choice for cushioning those shock loads and averting costly damage to expensive gang components while maintaining even, consistent depth of cut.
6. Gang Shafts: Two options are available in the industry: round or square, that come in a variety of diameters/ sizes.

   Remember: the gang shaft does not carry direct load like a truck axle does. The gang shaft should be designed to hold the entire gang assembly together in a manner such that the gang acts like a single entity/ unit.

   For example, an Ezee-On Disc gang is Factory torqued to 3,200 ft/ lbs of torque – this causes the spools, blades, bearings, etc to be tightened together into a single massive unit. This way if the Disc hits a rock, stump or hard spot in the ground, the impact is absorbed across the entire gang assembly and the shock load does not affect only one certain spot on the gang: the entire assembly absorbs the shock load.

   Square vs. Round: With the above in mind, there is no good engineering or design reason to ever use a square gang shaft – the Disc owner should not have to depend on a square shaft through the bearing to ensure the Disc gang continues to turn through the ground.

   Bearing sleeves: most manufacturers use a sleeve that runs over top of the gang shaft where the bearing is mounted to provide support for the bearing. Some manufacturers make a big deal out of how much this increases the structural strength of the gang shaft assembly and causes the shaft to resist bending at the bearing hanger. The fact is that if the gang is designed, built and tightened properly there should be very little chance that the gang shaft would ever bend at the bearing hanger. The Disc gang would have to strike an object with tremendous force to ever bend a gang shaft that is part of a properly designed and built gang assembly.

   Ezee-On gang shafts are 1-15/16” high carbon alloy steel supported with a 3/8” thick, 60,000 psi yield steel sleeve under each bearing. This design successfully allows the gangs to be tightened more than any other Disc in the industry. (3200 ft/ lbs)

   One final note about gang shafts: some producers may think their gang shaft has stretched because the gang nut appears to be tight and locked into place but the gang components have become loose. It is pretty much impossible to stretch a gang shaft, regardless of size. What you will find upon examination is that the half spool has started to slip and wear against the bearing sleeve or else the full spool has started to slip and wear against the adjacent blade. The result is premature wear of the affected components and it will appear that the gang shaft has stretched because the gang nut on the end of the shaft is still locked into place. The cause of this is often that the gang was not tight enough from the manufacturer and when the Disc was put into service the components became loose due to hard ground, rocks, stumps, roots, etc.

7. Spools and Half Spools: Spools are a very important part of the gang assembly. There is a half spool on both sides of each bearing that runs from the bearing sleeve to the disc blade and a full spool between each disc blade. Spools hold the blades in place, maintain correct blade spacing and add structural strength to the gang assembly.
1. Cast Ductile Spools: commonly found on light to medium duty discs where more extreme-duty field work is not required. Cast spools are heavy, less expensive and easy to make. However, cast spools have some inherent weakness: cast is a porous material that is subject to crushing under load; cast is very hard, but that means it is brittle and will crack or break if subjected to impact and lastly cast can only be torqued to a maximum of 1600-1800 ft/ lbs. This means it is not uncommon to see Disc gangs become loose over time when cast spools are used.
2. Fabricated Steel Spools: Ezee-On uses only heavy-duty steel fabricated full and half spools as standard equipment. Unlike ductile cast spools, fabricated steel spools can withstand for greater ‘shock loads’ – impact force - from rocks or stumps thereby eliminating spool breakage. These fabricated steel spools are compressed to maximum density prior to assembly, squared and beveled for positive fit against the Disc blade. This enables the Disc gangs to be torqued to 3,200 ft/ lbs to ensure it will not shift or become loose.
3. Interlocking Half Spools: when a Disc is equipped with large sized blades (28”+) and/ or operating in heavy duty or extreme duty applications, there is potential for the half spool to slip against the bearing sleeve – especially for Discs with gangs torqued in the 1200 – 1600 lbs/ ft range. If this slippage occurs, the parts will wear against one another and the gang will become loose. Once this happens it is impossible to re-tighten the gang such that it will remain tight over time: once steel rubs against steel the parts MUST be replaced in order to tighten the gang successfully.

To counter this occurrence, Ezee-On’s engineering team developed Interlocking Half Spools. Each bearing sleeve is upgraded to 120,000 psi yield steel with drive lugs built into each end that are pressed into corresponding slots machined into the half spool. This prevents the half spools from ever turning against the bearing sleeve. Thus, when the Disc gang is fully assembled the effective diameter of the gang shaft becomes the diameter of the spools themselves.

8. Hitch Type: Floating or Fixed?
1. Fixed: A fixed hitch works well on smaller/ lighter Offset Discs or on Tandem Discs where a second implement such as a harrow drawbar needs to be towed behind the Disc. The drawback to a fixed hitch on Tandem Discs is that it requires gauge wheels on the front gangs to keep the front of the Disc from digging too deep – which causes plugging/ ridging/ rough spots in the field.
2. Floating: The floating hitch on an Ezee-On Disc is designed to perform in much the same manner as a cultivator or chisel plow with a floating hitch – designed to allow the Disc to cut level front-to-back in all types of terrain without the need for front gauge wheels. A floating hitch sharply reduces plugging/ ridging/ rough spots and leaves a much smoother field finish compared to a fixed hitch machine. This is because the hitch moves up or down with the tractor without interfering with the operation of the Disc. When obstructions such as rock or stumps are encountered or when irregular ground conditions such as washouts, terraces, low spots or hills exist, the Disc simply rolls over or through them without transferring weight to the front gangs. The chance of costly damage to both the disc blades and/ or gang bearings is significantly reduced. Also incorporated into the floating hitch is a spring-cushioned screw crank which makes quick work of front-to-rear leveling of the Disc.
9. Scraper Type/ Adjustment:
1. Type: most reputable Disc manufacturers have a selection of scrapers that will perform well in a wide variety of field conditions. Some things to watch for:
1. If you have an extreme duty application – heavy clay ground, wet conditions, heavy or excessive amounts of crop residue, etc., make sure you chose a heavier, more aggressive scraper. A light duty scraper in a heavy duty application will not work successfully.
2. If you have an extreme duty application – heavy clay ground, wet conditions, heavy or excessive amounts of crop residue, etc., make sure you chose a heavier, more aggressive scraper. A light duty scraper in a heavy duty application will not work successfully.
2. Adjustment: the tip of each scraper should be adjusted so that it is in contact with the adjacent disc blade. This is so materials cannot come between the scraper and the disc blade and force/ bend the scraper away from the blade, causing the Disc to plug. If the Disc appears to plug due to large volume of residue, try removing the scraper from this area. Often allowing the residue to flow through the blades unimpeded will solve the plugging problem as long as the ground is not too wet and sticky.
10. Warranty: it’s easy to talk about how good your equipment is built and how well it will stand up, but will the manufacturer stand behind their equipment? Ezee-On warranty is as follows (for North America)
1. 3 year warranty on all Disc models. Defective parts and/ or workmanship will be repaired or replaced for the original, non-commercial owner. Coverage is: 1-12 months: 100% parts & labor, 13-24 months: 100% of Ezee-On manufactured parts, 25-36 months: 50% of Ezee-On manufactured parts.
2. 7 year T2-215 bearing warranty: Extended coverage (13-84 months) on T2-215 series bearing is limited to the replacement of ball bearings and seals for the original, non-commercial owner.

Final notes about purchasing a new Disc: the majority of North American Disc manufacturers are reputable, respected companies that care about the equipment they build and their customers. They put a considerable amount of time into writing a complete and comprehensive Operators Manual. Read this manual carefully and follow the operation and maintenance directions found in it.

When taking delivery of your new Disc, MAKE SURE your dealer has completed a full and complete PDI (pre-delivery inspection) of the Disc. Even if the unit has been assembled/ setup at the Factory, each new machine should be gone over and checked to ensure all bolts have been tightened to Factory specification, tires inflated to specified pressure, all bearings have been properly greased, scrapers adjusted, unit leveled, and the safe and proper operation of the unit explained to you in detail.