As a result, customers can expect longer-lasting wear parts in some of the toughest applications. I have some 5/8" solid carbide endmills that i would like to try a trochodial tool path with, basically just for practice and to test this kind of tool path. AR400F is a through-hardened, abrasion-resistant plate with a nominal hardness of 400 HBW. Chrome levers for half-nuts, tool post and tailstock. More products like this. 8 in/min with 0. Mill top and discharge flanges allow easy mounting of in-feed and discharge chutes or hoppers . Cobalt alloys are widely used because of such reasons: Cobalt alloys have high hot corrosion resistance. More Info. 06 0. Apr 30, 2012 #1. A line drawing showing some basic concepts of speeds and feeds in the context of lathe work. Due to its extreme hardness, AlgoTuf 500 is rarely machined. I drilled a 1/4" pilot, and then drilled to 1-1/8" with a 118 deg 1/2" shank S&D bit. Throw away those old speeds and feeds charts and pdfs. 0020)I drilled some 1/2" AR400 plates for a teletram truck. 001" on the total. It is about the same hardness as Titanium Carbonitride (TiCN,) but maintains. 030" radial step at 3000 rpm and 30 ipm. G-Wizard’s cutting physics engine considers nearly 60 variables. If it seems to jerk around too much, set your max high speed to a slower value like maybe 100 ipm as this affects how fast the machine loops around when the tool is out of the cut. I also do a peck of Q. 004-. 0025 in 1018 CRS. The phrase speeds and feeds or feeds and speeds refers to two separate velocities in machine tool practice, cutting speed and feed rate. Using these speeds & feeds as a starting point, cutting conditions can be gradually adjusted until the optimum settings for the application are found. Category overview ; List of all discussion forums ; The 100 latest forum topics ; IndustryArena. 350 mm 3/8 in. AR400 steel is an abrasion-resistant steel with high levels of carbon and manganese. I need to turn AR400 Plate with a 5° angle on the edge. I drilled a 1/4" pilot, and then drilled to 1-1/8" with a 118 deg 1/2" shank S&D bit. Titanium Aluminum Nitride (TiAlN) coatings are high-performance coatings used for all types of materials. Speed and Feed Calculator for Drilling and Milling,easyspeedsandfeeds. So cobalt drill bits better absorb stresses to higher absolute temperatures. Not commercial, just for me. AR400 is a very hard abrasion resistant steel used for rock truck beds and other high wear items. Choose either HSS or Carbide, depending on what material your V-Bit is made from. 5" wide x 20" long 1" thick AR-400 plates that need a centered slot cut completely through them 3. I have some 5/8" solid carbide endmills that i would like to try a trochodial tool path with, basically just for practice and to test this kind of tool path. The term "feeds" refers to the feed rate or the relative linear speed between the tool and the workpiece. 0008─. RPM - Revolutions per Minute (Speed) IPT - Inches Per Tooth (Chip Load) IPR - Inches Per Revolution. RECOMMENDED CUTTING CONDITIONS (inch) I drilled some 1/2" AR400 plates for a teletram truck. 069 1/2 1 18 141 24 139 0. Speed and Feed Calculator for Drilling and Milling,easyspeedsandfeeds. Optimizing feed rates and speeds: 1. g. 520 mm 1/2 in. I assume the spring-loaded holder helps cushion the V-Bit's delicate tip from undue shocks and lets it sort of find its own feedrate that works by backing off the depth if there is too much force involved. Surface Speed (SFM) cutting tools, speeds and feed rates. Let's go to the low end of a variable speed router: Feed Rate = 12000 * 2 flutes * . 95. When applying oil manually (as in the lab), scale the feed and speed back to 60%, so N = 330 rpm and f = 2. * Feeds and Speeds are starting points for Overall Lengths of 4” and shorter. 25mm pitch tap. Cermet EvolutionLinear feed 54. 061 3/8 0. What is Wearalloy AR400 Steel? AR400, also known at Ford Steel as Wearalloy 400, is a high-carbon steel with a nominal hardness of 400 and a minimum hardness on the Brinell scale of 360 to 440. 05 DOC. , for drilling) or the workpiece (e. For instance my shop neighbor’s calculator says to run a 1. Calculate the Speeds and Feeds of Carbide End Mills, Diamond End Mills, and Plastic Cutting Carbide End Mills with these General Machining Guidelines. These values correspond to a cutting speed of ~6m/min, which is a ~1/15 of the cutting speed needed for steel. 0625" wide by half inch deep. Speeds and feeds charts for end mills from The Carbide End Mill Store. The next issue would be the feedrate. Speeds To determine optimum speed, start at the lower end of the speed range, and then increase speeds until performance is maximized. Power Route 1/4" 2 flute at 24000 rpm (max speed) on MDF is 172. 5mm DoC (320mm/min per tooth). The highest deposition rate gas-shielded flux-cored wire is E70T-1. The machinability rating attempts to quantify the ease of machining of a range of metals. One solution is using sharp tooling and replacing tools the moment they start to wear down. 0 in/min (final answer). A tough and highly wear resistant grade. The Speeds and Feeds Calculator uses the following formulas: RPM = (12 * Surface Speed) / (PI * Tool Diameter) [revs/min] Feed Rate = RPM * Chip Load * Number of Teeth (Flutes) [in/min] Where PI is the constant (3. Compared to E70T-4, they offer slightly lower deposition rates of up to 30 pounds per hour, but they offer a smoother welding arc and Charpy impact toughness properties. 001" (0. Here’s a typical cut set up for 90 degree Face Mills / Shell Mills: G-Wizard set up for a 90 degree face mill…Guideline 4 – Set The Correct RPM. 0mmx10 IPM feed. Carbon Steel/Alloy Steel ~750N/mm2. Dive into the world of spade drill bits, and explore their design, usage, and. Does anyone know what the proper speed and feed and depth of cut should be for a gear cutter with the following specs: #3 cutter. Joined Oct 31, 2007 Location Miami Fl, USA. We have found that the optimal cutting RPM for acrylic with the recommended O-Flute bit above is 18,000 RPM. Milling operations remove material by feeding a workpiece into a rotating cutting tool with sharp teeth, such as an end mill or face mill. Feed Rate f (mm/rev) H Type L Type G Type ACP300ACP300 ACM300 ACK300 DL1500DL1500 M Stainless Steel Steel P (High-speed Drilling) Cast Iron K (High-speed Drilling) Cast Iron K (General Drilling) Non-Ferrous N Metals Grade Work Material P Steel (General Drilling) ACP100ACP100 L Type P K G Type P K H Type P K H P G P M L Type P M Type L Type P K. Cermets should not be used for rough copy turning. 48DP. Spade Drill Speeds and Feeds and Ultimate Guide. 250 sfm 175 feed . Levers: M8 threading. None of the chip load charts that I have seen are compiled with those high speeds in mind. 052 drill bit (#55). 5 Same as above. 005" per tooth or probably about 50 ipm on your machine. And, depending on the machining application and workpiece material, feed rates in excess of 0. AR400- better for impact applications, AR500- better for sliding applications. G-Wizard's Feeds and Speeds for V-Bits assume a rigid holder, but you can double the feedrate if you have a spring-loaded holder. Directions. Aluminium. Branches featuring AR400 | AR400F Steel Plate products. 5" wide x 20" long 1" thick AR-400 plates that need a centered slot cut completely through them 3. IPM = Inches Per Minute (Feed) D - Cutter Diameter. The next issue would be the feedrate. Speed for gear cutter. 004-. A588 is a high strength, low alloy steel plate that was developed for use cases demanding higher strength and a longer life cycle. Cut dry, air blast or MQL with your TiAlN carbide mills. Questions? Contact Cleveland technical support at 888-434-8665. Section 1 – Main parameters: Cutting speed, feedrate, Feed per Tooth, spindle speed, and table feed. Machining Advisor Pro quickly, seamlessly, and accurately calculates recommended speeds and feeds for running your Harvey Tool and Helical Solutions end mills. To navigate to this tool page, right-click on the current operation you want to view in your CAM Tree and select “Edit”. Anodized handwheels for apron and tailstock. IC903 H01-H10 P05-P15 M10-M20 S10-S20 AL-TEC TiAIN Ultra-fine grain carbide with 12% cobalt, TiAlN PVD coated grade. 053 14 GA 0. Used for up to 62 HRc hardened steel, titanium, nickel-based alloys and stainless steel at high speeds and medium feeds. AR450: 430-480 BHN Typically. May 5, 2023. 1. Will take about 5 hours overall. 69 Linear feed • ((Major thread Ø - Tool Ø) / Major thread Ø) Z axis move on arc on 0. They are time savers, especially for larger size holes. I am using an off the shelf Bosch router at 8K rpm. But running work at proper feeds and speeds is the best way to cut clean holes and tap stainless steel most efficiently. 150. ( guessing AR400). Machine type, horsepower, spindle speed limitations, tooldholding & workholding devices all may impactHere is a diagram showing the effective diameter for a 90 degree V-Bit with a 0. Learn about our quality system and how we can deliver next day! A basic Feeds and Speeds Chart like what’s in your tooling catalog is a 2 dimensional entity. 015 inch/revolution Tooling C6 (Cutting Fluid: Soluble Oil 1:20) Drilling – Point Angle 118°, relief 12° Helix Angle 29° point: plain Feed . Worked fine. Category overview ; List of all discussion forums ; The 100 latest forum topics ; IndustryArena. Always use the speeds and feeds recommended from your tool manufacturer. 125”) diameter cutter instead of a ¼” (. I've heard the rule of thumb is twice the feed and half the RPM. The carbon content of 0. (3. A lathe feeds and speeds chart is a handy tool that provides the necessary information regarding the appropriate feed rate and spindle RPMs to optimize machining performance. IPM = inches per minute IPT = inches / tooth. With the map. Screw Size Series 67 Size All other C’sinks Size #4 7/16 1/4 #5 9/16 5/16Speeds and Feeds Charts: Obsolete. com website, you can access this tool online and open it in your browser. Geoff brings up a few good points that I left out, the number of flutes a cutter has can make a difference. Simply choose the required refrigerant, hook up the service hoses,0. The chart includes a range of materials, cutting operations, and corresponding recommended feed rates and spindle speeds. For hard metals reduce cutting speed. If not, stop regularly to reapply oil or coolant. I'm gonna disagree with machinability, we've been able to mill, drill etc 400, 500 and 600 there's not a great deal of difference between machining them. 5" wide x 20" long 1" thick AR-400 plates that need a centered slot cut completely through them 3. Carbide – Depth of Cut . 0625" wide by half inch deep. 015 inch/revolution Tooling C6 (Cutting Fluid: Soluble. They are 1/4 " thick, and stick out 5/8". Both of which are sold and stocked in dFab. need a little help feeds/speeds in ar400. Carbon steel, Alloy steel ~30HRC. Introduction . Example 1A: HSS drill bit Example 1B: HSS reamer Example 2A: HSS endmill Example 2B: Carbide. 27. Click Here to find the right drill size for you reamer. 5. g. (mm per tooth) Z= RPM, the speed at which the cutter revolves in the spindle. AR400 steel is also highly abrasion-resistant, making it ideal for applications. From a reference, 'Machining Stainless Steels' here are some feed and speed suggestions; Carbide Turning doc . TV . T-1 steel, unlike AR400, is an alloy steel covered by ASTM A514 / A514M - 05 (2009) Standard Specification for High-Yield-Strength, Quenched and Tempered Alloy Steel Plate, Suitable for Welding. 1416 x Part Diameter, Divided by 12 x RPM HORIZON CARBIDE TOOL, INC. 6. 005 IPR. Specs are: Total Length: 50MM. Determine the spindle speed (RPM) and feed rate (IPM) for a milling operation, as well as the cut time for a given cut length. milling speeds & feeds carbide tipped class of materials material application - mills and saws brinell surface feet per minute (sfpm) inches per tooth (ipt) non-ferrous (soft) aluminum alloy - wrought 30-150* (500kg) 1000-2000 . The slowest the Makita will turn is 10,000 rpm. Originally posted by Sonora Iron View Post. By referring to the chart, you can select. Easily weldable with an E7018 rod. I don't have any data on feeds and speeds - currently using 500 rpm ( 114 SFM ) with F. AR400F is produced through austentizing, water quenching, and tempering. Feeds and speeds and calculators are a good starting point but it all depends on what the machine can actually handle. Cut about 20% stepover amount in your toolpath settings. 012 ipr limit, the cutting speed should be reduced. Then decrease speed by 10%. and thru coolant. Forming can be done in cold forming conditions. N = number of cutting edges (flutes) T= chip load (chip per tooth) is the amount of material, which should be removed by each tooth of the cutter as it rotates and advances into the work. 0063 (Pitch / 8) Z axis move for full thread 0. T-1 steel, unlike AR400, is an alloy steel covered by ASTM A514 / A514M - 05 (2009) Standard Specification for High-Yield-Strength, Quenched and Tempered Alloy Steel Plate, Suitable for Welding. 2 225 128 320 125 0. The first plate I cut was fine the angle was fine, but it looks blistered. 9. com Cut about 20% stepover amount in your toolpath settings. harveyperformance. pak Cast Iron. Carve King: 1/4" 2 flute at 27000 (max speed) on MDF is 140. Weldox 700 Weldox 900/960 Weldox 1030 Weldox 1100 Hardox HiTuf Hardox 400 Hardox 450 Hardox 500 Cutting speed, vc [m/min] and Feed rate, f [mm/rev] v So I used the search function and dont think this has been posted and the one post nobody really answered the question. 012 ipr should be avoided, because thicker chips may damage the cutting edges. 18, Chipload 0. Therefore, it only covers 2 variables. I have some 5/8" solid carbide endmills that i would like to try a trochodial tool path with, basically just for practice and to test this kind of tool path. All I had for my mill at the time was a 1/2" chuck. zip (792 Bytes) Here is a version which has the Amana feeds and speeds copied into it — breaking this up and naming it appropriately by appropriate materials. • Speed equals 80 surface feet per minute in 100 Brinell hardness material and the speed should be reduced 10 surface feet per minute for each additional 50 points Brinell hardness. Its tangential linear equivalent at the workpiece surface (m/min or sfm) is called the "cutting speed", "surface speed", or simply the "speed" by machinists. 5" wide x 20" long 1" thick AR-400 plates that need a centered slot cut completely through them 3. 0005″, or 5 ten thousandths of an inch, we can reduce tool life by up to 40%. 25 cutting diameter increase feed and speed Blue material box indicates coolant is required for proper operationx-speed, carbide multi flute extended reach fine pitch roughing end mill view speeds and feeds data x-speed, carbide multi flute extended reach fine pitch roughing end mill - inch od: sd: loc: oal: lbs: corner: flute: edp no. For End Mills with Overall Lengths over 4” decrease the Feeds and Speeds. The premier source of tooling, parts, and accessories for bench top machinists. 4 in/min with a 0. 0016 (. Alpharetta (Atlanta Plate Processing) 2005 Grassland Pkwy. Given the surface speed, you can calculate the spindle. The Brinell Hardness Number (BHN) is the technical difference between AR400, AR450, and AR500. 053 14 GA 0. 0017, SFM 350Enter feeds and speeds into RhinoCam. 005" The milling values are for uncoated high speed steel. com is the easiest speeds and feed cacuator to use. Using a ⅛” (. 010″ depth of cut: The effective diameter in an 0. Tweet. Regularly $84. 4 - 62kW (83Hp) Stage V and Tier 4: Caterpillar C2. The maximum cutting speed depends on the type of coating on the tool and the maximum temperature it can safely withstand. 0256 (Major thread diameter - Tool diameter) / 4 Full rotation value. The speeds and feeds should be calculated before you ever turn on the machine. New and popular video trends• Wear liners: AR400 steel • Welded frame including heavy steel profiles • Stroke length is adjustable by adding extra weights • When grizzly separation is over 130 mm, the grizzly bars and side plate will be higher than std. 4 flute mill. 5" wide x 20" long 1" thick AR-400 plates that need a centered slot cut completely through them 3. AR400 steel is known for its exceptional mechanical properties, particularly its high tensile strength and hardness. The formula for spindle speed (rpm) is cutting speed (sfm) 5 3. If they don’t click the “Getting Started” button near the top right corner of the G-Wizard window. 0625" wide by half inch deep. The CoroPlus®. According to the accompanying table, the maximum cutting speed is 280mm/min and the chip load is 0. 5425 N Whitaker Road. Always start with your feed at 50% or below. Start off using an RPM derived for the chip load for the material being cut (see charts). The carbon content provides strength and hardness, while the manganese. And, depending on the machining application and workpiece material, feed rates in excess of 0. The formula for feed per tooth (fpt) is table feed (ipm)/number of flutes/spindle speed (rpm). AR400 steel target, exceptional portability and . 010-0. New and popular video trendsAR400 Steel Plate AR400 Steel Plate – Hardness 360-444 Brinell. 061 3/8 0. It refers to choosing the speed at which to spin the cutting tool, and how. This velocity is called the "feed" by machinists. According to the chart, if the sum of runout and chipload is just 0. RPM = Of the tool or workpiece. AR600: 570-625 BHN Typically (less common, but available) Therefore, what does this mean in terms of usability? AR400 can be used as a basic component or as a liner in all types of material handling equipment. 007 chipload per tooth = 168 IPM. Liberal amounts of a good coolant are essential. ” Soft wood Name SB# Onsrud Series Cut Chip Load per leading edge Flutes Feed Rate (ips) Feed rate (ipm) RPM Max Cut 1” 60 degree Carbide V cutter 13648 37-82 1 x D . 170 mm 1/4 in. Extremely loud; no doubt of hits and misses. 5" wide x 20" long 1" thick AR-400 plates that need a centered slot cut completely through them 3. Feedrate: This is how fast the machine is moving on any of. Alpharetta, Georgia 30004. MMPM = RPM X number of teeth X CLF X MMPT. Sophisticated feeds and speeds software lets you master a lot more variables than you could manage by hand. 500SFM X 3. Feedrate about . 875 dia indexable drill in the Haas ST 10 Lathe. 25" bit at 500 IPM and 1/2"+ DOC with ease. #1 Drilling AR400 Steel 10-30-2006, 02:36 PM Anyone know whether AR400 (abrasion resistent, BH 400) can be drilled easily with HSS or cobalt drills? Got some. technology and incorporated state of the art features while improving reliability and speed. 75 inches diameter. Feed Rate = RPM x Chip Load x Number of Teeth. 03-. 002 - . Using an RPM of 15,280 would give a feedrate of 122 in/min. 9km/h Speed High: 1. 005” Chip Load. That is a chipload of 0. , for turning on a lathe). 5" wide x 20" long 1" thick AR-400 plates that need a centered slot cut completely through them 3. Alro Industrial Supply specializes in cutting tools, abrasives, coolant and MRO supplies. 0 amps is almost 700 watts, so about max hp on this machine !!!! Anyway, stalled the drive a couple of times at 3. $69. Cutting speeds greater than Algoma’s recommendations can cause rapid tool deterioration. 005" per tooth or probably about 50 ipm on your machine. Algoma recommends the following milling speeds, feed rates, etc. Speeds and feeds, mfg charts are there for a reason. More products like this. 5 amps. The feed rolls on each side have these worn gripper strips that need replacing. Adjust RPM & Feeds after Setup to achieve Optimum Tool Life. I'm. Machining AR400 steel plate. Material Aluminum/Aluminum Alloys Aluminum Alloyed > 10% Brass Bronze Cast Iron (Soft) Cast Iron (Medium) 570 Series # 5510 Series # 5511 Material group Hardness SFM Feed Rate - IPR HRC BHN 1/16 in. AR400F is quenched and tempered through hardened wear resistant grades of abrasion resistant steel plate used for high impact and abrasion resistance. Create a tool for side cutting HIGH or Side cutting LOW. gatz said:Speeds and Feeds Charts: Obsolete. 004-. I've been working with AW36 steel and 304 Stainless. Number of Flutes – If you were to look at a job that would be setup on a CNC Milling Machine, you might find that the correct feed and speed from a purpose-made calculator will tell you that you can use an. 0625" wide by half inch deep. 0008─. 0625" wide by half inch deep. 010-0. 125”) diameter cutter instead of a ¼” (. 002] and stepdown [0. 2-0. 5 inch (63. I only have a few to make and no time restraints, so this is a. It offers higher deposition rates than GMAW, handles dirtier plates, and uses lower cost 100% carbon dioxide. [email protected] reamer should I go 4500 RPM and 26 in/min feed rate?medium to high cutting speeds. Forum - The expert community . (See Fig. Cut Speed Voltage Cut Speed Voltage inches inches inches % seconds in/min volts in/min volts inches 16 GA 0. 007 chipload per tooth = 350 IPM. Speeds and feeds for your austentic stainless will suffice for annealed A2 machining. Milling operations. 1 – Feeds and Speeds options on the Tool Page for a Profile Rough Operation. 8 33 136 38 133 0. In most standard cases choosing a speed in the middle of the range would be a good choice for a start. 5 mm) thick plate, and at least 110 ksi (758. The main results are the cutting speed and feedrate, secondary results such as power consumption and operation time, and carbide grade recommendations. Liberal amounts of a good coolant are essential. 008 lead alloy 10-20* 300-1000 . pdf. I have a 4. In carbon steel, the carbon content is King. Jan 3, 2023 #1 Hi guys, Whenever I try to do my finishing cut on a hardened steel (63HRC) using a cnc lathe machine, my tool inserts always break. A588 is known for its atmospheric corrosion resistance thanks to a natural patina of rust that forms when exposed to outdoor weather conditions. Mechanical Properties Hardness 360-440 BHN Yield Strength 140 ksi Drilling with HSS bits isn't bad. It’s easy to compute Feeds and Speeds to compare these two face milling solutions using our G-Wizard Calculator software (click the link for a free 30-day trial if you’ve never played with G-Wizard). 8-0. 95. This product is intended for applications where a good combination of abrasion. To machine 304 stainless steel, you should machine it at slower speeds. 5. 008 non-metal and plastic – 1500. RPM - Revolutions per Minute (Speed) IPT - Inches Per Tooth (Chip Load) IPR - Inches Per Revolution. 150” Speed 70 fpm Feed . I am thinking we need to be much faster RPM but I don't want to go. This makes TiAlN very effective in high-temperature alloys, high-speed machining, and dry milling applications. 1 249 128 320 124 0. 82 / . 0394 1. The "speeds" part of the speeds and feeds calculator is the rotation speed of either the tool (e. If process temperatures get too high hardess drops significantly. 22 rimfire use. with a 18/" 2F. For the feed rate per revolution, please set up within the recommended feed rate of the closest diameter appropriately. AR400F is quenched and tempered through hardened wear resistant grades of abrasion resistant steel plate used for high impact and abrasion resistance. 6km/h OPTIONS • 6mm AR400 steel wear feedboot liners • 20mm rubber wear feedboot liners • Feedboot extension c/w steel wear linersI am using a Techniks Nexus . Cobalt alloy has higher melting point than other HSS alloys. 0080 5375cutting tools, speeds and feed rates. Choose speed setting #1 (16k RPM) Try 1200mm/min, keep plunge/DOC as-is and see how that works out. AR400 steel has a variety of benefits that makes it an ideal substitute for almost any application where excessive wear is a problem and ease of fabrication is needed. I have a 4. I have a 4. The Calculator divides the results into 3 sections. . Now I usually trust FSWizard for flat end mill and twist drill feeds/speeds. Overall height of 14. Example for the 1/4-20, you should use . Optimizing feed rates and speeds: 1. x or even . Carbide – Depth of Cut . These straps are 15-1/2" long. A chart is only 2 dimensional. AR400 steel has a variety of benefits that makes it an ideal substitute for almost any application where excessive wear is a problem and ease of fabrication is needed. SFM: Tool Diameter: RPM: = Surface Feet per Minute: RPM : Tool Diameter: SFM: = Revolutions Per Minute: IPM (Drilling) IPR:A basic Feeds and Speeds Chart like what’s in your tooling catalog is a 2 dimensional entity. 012 ipr limit, the cutting speed should be reduced. Regularly $84. 0625" wide by half inch deep. Seems a bit fast. 5 mm) thick plate, and at least 110 ksi (758. 005 inch/revolution Adjusting feed rate to about 3. 568. The 30hp variable volume piston pump provides maximum oil flow and power throughout the baling process, resisting the dramatic loss of power and500 ft/min. . I have a 4. RPM = Of the tool or workpiece. High Strength Ferritic, Martensitic, and PH Stainless Steels 350-450 HB; 35-43 HRC; 900-2400 N/mm^2 UTS (354) In actual use, depending on the machine environment and workpiece material, significantly higher speeds & feeds may be achievable. ago. If you are going to use performance carbide drills in that material, 28-32 HrC use 225 as a starting SFM and the feed rate is always a percentage of the drill size. 020″! To select a V-Bit in G-Wizard, treat it like an endmill. Acron Nuts: M8 threading. 150” Speed 70 fpm Feed . The machinability rating attempts to quantify the ease of machining of a range of metals. 70: Thickness: 2-4 microns: Surface Roughness (R a mm):. SG2141 SG1851 SG2151 SG2451 SG2751 Max Feed Size (mm/one dim.