Volume 3 Flashcards
How much carbon to High-C steels contain?
Between .5 and 1.05 percent.
Describe high-speed steel.
High-speed steal belongs to a group of tool steels with excellent red hardness. They retain hardness at operating temperatures between 1,100 and 1,200 F.
High-speed steals contain depth hardness.
What are the main alloying elements of high-speed steel?
tungsten (W), molybdenum (Mo), chromium (Cr), vanadium (V), and C.
What are the two classes of high-speed steel identified by the American iron and Steel Institute (AISI)? Please describe them.
T and M.
The class designated by the letter T has tungsten as its main alloying element.
The class designated by the letter M has molybdenum as the principal alloying element.
Describe cemented carbides.
Cemented carbides are chemical compounds of metals and C. They are harder and more wear-resistant than high-speed steel tools.
How do you select the carbides for an operation?
When you select a carbide for an operation, first select the group for the material on which you’ll use it, and then select the grade for the amount of hardness you’ll need.
Describe cemented carbide group 1.
Group 1 is known as the wear-resistant straight carbide grade. They are designed to resist edge wear, and contain straight carbide grade composed of W with Co binders.
These grades contain from 94 to 97 percent W, C, and Co.
The ones containing more Co are tough and shock resistant, which makes them ideal for heavy rough cuts.
The ones containing more W are hard and abrasive resistant, they are used to taking lighter finishing cuts.
This group is used for machining gray cast iron, 200-300 series stainless, high-temperature nonferrous alloys, and plastics.
Don’t use them to machine plain C and alloy steels. They crater the faces of the cutting tools.
Describe cemented carbide group 2.
Group 2 is known as Crater-resistant carbide grades.
Titanium (Ti) increases crater resistance and helps keep the tool’s cutting edge from deforming at the temperatures and pressures that result from heavy cuts.
These are used for machining plain C steels, alloy steels, alloy cast irons, cast steels, marensitic stainless steels, ferritic stainless steels, and all tool steels.
Titanium carbides?
These grades contain no W carbide. These have excellent crater and heat resistance, which permits you to use them at higher cutting speeds.
Describe tantalum carbides.
Tantalum carbide contain small amounts of W as an alloy. These carbides have high abrasion resistance and regularly perform machining operations at temperatures above 2,000 F.
Describe coated carbides.
Coated carbides have a cemented carbide insert, called the substrate, on which a thin coating of TiC, aluminum oxide, or titanium nitride has been deposited.
Coated carbides operate at higher cutting speeds than uncoated carbides without significant loss of tool life and, if they operate at the same cutting speeds as uncoated carbides, they last longer.
Why are coated carbides only available as inserts?
Because the thin layer prevents them from being reground.
What is sintering?
Sintering means to hold a material under high pressure at just below the melting temperature until it fuses into a solid mass.
Describe ceramic and cermet cutting tools.
Ceramic cutting tools, also known as cemented oxide tools, I made by sintering fine grains of aluminum oxide into a dense structure.
Ceramic cutting tools are used in operations where carbides wear quickly, but they’re not intended to replace carbides. Ceramics can cut at high speeds and high operating temperatures, but they’re brittle so they won’t withstand shock.
Why should you not use ceramics or cermets to Al or Al alloys?
Because the aluminium oxide in these tools reacts with the Al content in the metals, which may cause the tools and the metals to fuse together.
Describe cubic boron nitride.
Cubic boron nitride cutting tools are almost as hard as diamonds.
What is in cubic boron nitride? How is it made?
CBN cutting tools are a substrate of cemented carbide with an outside layer of CBN. The CBN is part of the tool.
Describe diamond cutting tools.
Industrial diamonds, also known as polycrystalline diamonds, machine extremely hard materials.
They are used mainly for finishing tools because they are brittle and don’t do shock or high cutting pressures.
What and why should you not use with polycrystalline diamonds?
They are not effective for machining cobalt or nickel, because these alloys can chemically react with the diamond and cause rapid tool wear.
When performing ordinary turning (i.e. straight turning, facing), what side does the cutting?
The side cutting edge does the cutting.
What does the nose on a lathe cutter do?
The nose of the it’s cutting tool connects the side cutting edge and the end cutting edge, and is a critical part of the cutting edge because it produces the finished surface in turning.
On a lathe cutting tool what does the end Cutting Edge do?
The end cutting-edge actually provides the clearance for the side Cutting Edge to work.
On a lathe cutting tool, what do the flanks of the tool do? And where are they located on the cutting tool?
They’re relieved to permit the cutting edges to penetrate into the material surface. They are located below the cutting edges on the sides of the tools.
On a lathe cutting tool, what does the face of the tool provide?
The cutting tool face provides a surface for chip formation.
On a lathe cutting tool what effect does a too steep of a Shear angle do on the face of the cutting tool?
If the shear angle is too steep, the cutting tool tends to “dig” out the chip, which puts additional cutting pressure on the workpiece and the cutter.
On a lathe cutting tool, what happens if the shear angle is too shallow on the face of a cutting tool?
If the sheer angle is too shallow, the cutting tool forms a long, shallow chip, and it tends to ride on the cutting surface instead of forming and falling off.
Describe a lathe right-hand cutting tool and a left-hand cutting tool.
Right-hand cutting tool has the side Cutting Edge on the left when viewed from the shank. The tool cuts from right to left. A left-hand cutting tool has the side Cutting Edge on the right when viewed from the shank.
On a lathe cutting tool, what are the relief angles? What do they do?
The angles formed by the intersection of the cutting edges in the plane perpendicular perpendicular to the tool shank are called relief angles. These angles allow allow the cutting tool to penetrate the workpiece.
On a lathe cutting tool what relief angle do you use for General turning?
For General turning, use a 10 degree relief angle.
For different material how must you adjust the relief angles?
Harder materials may require a smaller relief angle, while softer materials cut more successfully with a larger relief angle.
What is the relief angle for cemented carbide cutting tools?
The relief angle for cemented carbide cutting tools ranges from 5 degrees to 12 degrees.
What is positive-rake angle and a negative-rake angle on a lathe cutting tool?
The positive-rake angle causes the face of the cutting tool to slant downwards towards the shank, while the negative-rake angle causes this surface to slant upward from The Cutting Edge toward the shank.
What is the advantage of using a positive-side rake angle cutter and a negative-side right angle cutter?
Positive-side rake angles require less cutting Force then a negative-side rake angle. Also, positive-side right angle tools generate less heat and have a longer tool life than negative-side right angle cutting tools.
The advantage of having a negative side rake angle and negative back rake angle is The Cutting Edge is stronger and can withstand more severe cutting loads than a positive side cutting tools.
Negative rake angles are common in disposable carbide cutting tools because the top and bottom edges on the cutting tools can be used as cutting edges. Negative rake angle cutting tools have twice as many cutting edges as a positive rake cutting tools, which have cutting edges on only one face of the insert.
What does the end cutting edge angle do on a lathe cutting tool?
Tge End cutting edge angle slopes away from the nose of a tool so it clears the finished surface on the workpiece when you cut with a side Cutting Edge.
Why do lathes tool bits have a nose radius on them?
The nose radius is an extension of The Cutting Edge. The reason the nose forms radius is to keep the cutting tool for making small grooves in the workpiece as it passes, and also to keep the end Cutting Edge from breaking down while under pressure.
What happens when your lathe tool bit has a too large of a nose radius?
If the nose radius is large, it an form a thin chip and may not penetrate the workpiece during the cut. A large nose radius also causes the tool to chatter during the cut.
Too large a nose radius causes chattering, while too small a nose radius causes the point to break down quickly.
What nose radius should you use for average turning operations?
For average turning operations, use a nose radius of 1/64 to 1/8”.
There are two types of cemented-carbide lathe cutting tools, what are they?
Brazed-tip and indexable inserts.
For lathe cutting tools, there are negative and positive rake inserts. Which one do you use if you need a low cutting force?
If you need a low cutting force, use a positive rake angle.
Like if you are machining thin wall material.
What do you consider when determining the side cutting-edge angle to use?
Use a side cutting-edge angle large enough to permit the tool to be eased into the work;this he;[s to protect the nose of the cutting tool as it enters and leaves the work.
How do you set up your tool on a lathe?
Hold carbide tools in a sturdy tool holder, with the amount of tool overhang just enough for chip clearance. Set the cutting tool exactly on center because, when it is above or below center, there won’t be enough clearance for the cutting edges.
On a lathe, what happens when a cutting speed is too fast or slow?
A cutting speed that’s too high causes rapid tool failure, while a cutting speed that’s too low causes inefficient cutting action and low production rates. A feed that’s too light causes tool rub, which work-hardens the part. Feed that’s too heavy slows down the machine, creates excessive heat, and causes premature tool failure.
When grinding a lathe tool, what wheel do you select for rough and finish grinding carbides?
For rough grinding carbides, use an 80-grit silicon carbide (SiC) wheel. Use a 100-grit silicon carbide wheel for finish grinding carbides.
When grinding lathe cutting tools how should you dress the grinding wheel and why?
Dress the silicon carbide wheels with a 1/16”crown to minimize the amount of heat generated during grinding.
When grinding lathe cutting tools on a diamond wheel, what grit do you use?
With diamond grinder wheels 100-grit are excellent for finish grinding for carbides for general work. Use a 220-grit diamond wheel if you need a fine finish on the cutter.
When grinding carbide lathe cutting tools how much pressure do you use?
The cutting pressures required to remove carbides are 5 to 10 times as great as those required to grind high-speed steel tools.
When grinding carbide lathe cutting tools how should you move the bit?
When grinding, move the carbide tool back and forth over the grinding wheel face to keep the heat and friction down.
When grinding carbide lathe cutting tools how should you quench the tool?
Don’t quench carbide tools that become hot during grinding; allow them to cool gradually. The shock of quenching carbide tools creates small heat cracks and results in rapid tool failure.
After grinding a carbide lathe cutting tool why do you hone the edge?
After you grind carbide cutting tools, hone their cutting edges. The purpose of honing is to remove the ragged edge left by the grinding wheel.
When honing a lathe carbide cutting tool, when do you hone a chamfer in it?
On carbides used for cutting steel, hone a 45 degree chamfer 0.002” to 0.004” wide on the cutting edge. Carbide tools used for Al, Mg, and plastics don’t need it.
What is red hardness in high-speed steel?
The ability to retain hardness and strength at high machining temperatures.
What does depth hardness enable in high-speed steel tool bits?
The ability to be ground, used, and reground without losing hardness.
List the main alloying elements in high-speed steel.
W, Mo, Cr, V, and C.
When you select carbides for machining operations, how should you select them?
First, select the group based on the material you’re machining, and then select the grade for the hardness of the material you’re machining.
When selecting cemented carbide tools for light finishing cuts, which grade should you select?
Wear-resistant straight carbide with more W.
Briefly describe a coated carbide insert.
A cemented carbide insert, known as a substrate, coated with a thin layer of TiC, TiN, or Al2O3.
What’s the process of sintering?
Holding materials under pressure at just below their melting temperature until the materials fuse into one solid mass.
Why are ceramic tools ineffective in machining Al or Al alloys?
Because they contain Al2O3, which can react with the workpiece and fuse the cutter and the workpiece together
What cutting tool material is actually layered onto the base material and forms part of the tool?
CBN.
Why can’t you machine Co or nickel with PCD cutting tools?
Because Co and nickel chemically react with the diamond and cause rapid tool wear.
What does the side cutting edge do?
The edge that performs the cut
What does the nose do?
Connects the side cutting edge to the end cutting edge and produces the finish.
What does the end cutting edge do?
Provides clearance for the side cutting edge
What does the flank do?
The relieved surfaces below the cutting edges that permit the cutting edges to penetrate the work
What does the face do?
The surface for chip formation and determines the shear angle of the chip.
How can you identify a right-hand lathe cutting tool? A left-hand lathe cutting tool?
The cutting edge is on the left when viewed from the shank; the cutting edge is on the right when viewed from the shank.
What are relief angles and what is their purpose?
The angles formed by the intersection of the cutting edges and the plane perpendicular to the tool shank; allow the cutting tool to penetrate the workpiece.
What cutting tool has more cutting edges available, a negative-rake tool or a positive-rake tool?
Negative rake
How should you set the nose radius on a cutting tool to keep it from chattering?
Reduce the size of the nose radius.
What are the two types of cemented-carbide lathe cutting tools?
(1) Brazed tip. (2) Indexable insert.
What are the advantages of a negative rake insert?
They have twice as many cutting edges as positive rake tools, are stronger, and can withstand shock loads.
How can you keep long chips from forming when using carbide insert cutting tools?
Use positive-negative rake inserts with a chip breaker.
Why are carbide inserts replacing brazed tip inserts in machine operations?
They don’t require grinding, take less time to change, and are less expensive.
What occurs if the nose radius on the cutting tool is too large? Too small?
Too large causes chatter; too small causes the point to break down quickly
How should you set up carbide tools for machining?
In a tool holder with minimum overhang and exactly on center.
What are the effects of too light a feed? Too coarse a feed?
Too light causes work hardening; too heavy slows the machine, generates excessive heat, and causes premature tool failure.
How should SiC wheels be dressed? Explain why.
With a 1/16″ crown; minimizes the amount of heat generated during grinding.
List two important points to remember when you grind carbide cutting tools.
(1) Move the tool back and forth over the wheel face to keep heat and friction down. (2) Don’t quench hot cutting tools; let them cool gradually.
What are the two types of advanced ceramic materials in widespread use?
(1) Ceramic coatings. (2) Refractories.
List the most common nonoxide matrices that offer superior structural properties, hardness, and corrosion resistance.
SiC, silicon nitrate, boron carbide, and AIN.
Which is identified as the best ceramic for mechanical and wear applications, such as metal processing and cutting tools?
Si3N4.
What ceramic displays the highest corrosion resistance of all advanced ceramic materials?
SiC.
What ceramic is the most widely used, and is extremely hard and durable?
Al2O3.
What is the melting point of Ceramic inserts?
Ceramic inserts have a melting pint of 3,700 F and are capable of withstanding extremely high temperatures.
How hot can silicon carbide withstand and retain its strength?
Silicon carbide withstands very high temperatures and retains its strength at temperatures as high as 1,400 C.
What are the three classes of lathes?
Toolroom, engine, and turret.
What class of lathe is the most common in the Air Force?
Engine lathes
What are engine lathes used for?
They’re used for general purpose work in support of aircraft and support equipment (SE) maintenance.
What are toolroom lathes used for?
Toolroom lathes are more accurate than engine lathes, and have attachments and accessories for a broader range of precision work.
What are turret lathes used for?
Turret lathes are used mainly in production work.
What determines the size of a lathe?
The size of a lathe is designated by the maximum diameter workpiece that can be swung over the ways, distance between centers, and overall length of the bed.
Smaller lathes are sized using?
Inches.
Larger lathes are sized using?
Feet.
What are the major components of a lathe?
The major components include the bed and ways, headstock, tailstock, carriage, and gearbox.
Where is the headstock located on a lathe?
The headstock mounts on the operator’s left end of the lathe.
Why is a lathe headstock spindle hollow?
the headstock spindle is hollow to allow bar stock and spindle attachments to pass through.
There are three different kinds of headstock spindle noses, what are they?
Long tapered, cam-lock, and threaded.
What precautions should you take before mounting a chuck or a faceplate on a spindle?
Keep all spindle noses free of nicks and scratches, and carefully clean them before you mount a chuck or faceplate. Also, clean the surfaces of the chucks or faceplates, and keep them free of any nicks, scratches, or dents.
What function does the bed and ways serve?
The bed is the base for the lathe. The ways run the full length of the bed, and provide alignment and a bearing surface for the tailstock, carriage, and headstock.
How do you protect the ways on a lathe?
To keep a lathe performing accurately, protect it. Don’t use the lathe bed as an anvil or a tool shelf. Keep it clean and free of chips, and wipe it off daily with an oiled rag to preserve its polished surface.
The tailstock serves three functions what are they?
- It supports one end of a workpiece when it’s turned between centers.
- It supports long workpieces held in lathe chucks.
- It holds drills and reamers for machining operations.
What does the carriage on a lathe carry?
The carriage carries the cross-slide and compound rest.
What does the compound rest on a lathe carry?
The compound rest carries the toolpost and cutting tool.
How does the carriage on a lathe move?
Longitudinally on the bed ways by manual or power feed.
How does the cross slide on a lathe move?
The cross slide moves perpendicular to the perpendicular to the lathe axis.
On a lathe, what mounts to the cross slide?
The compound rest mounts on the cross slide.
with the compound rest what direction can you take cuts?
The compound rest permits you to take cuts parallel to, perpendicular to, or at angles to the workpiece axis.
When do you lock the carriage to the bed of the lathe?
Use the clamp screw only when performing facing or cutoff operations, since they don’t require longitudinal feed.
On a lathe what does the lead screw do?
The lead screw drives the carriage when you cut threads on a lathe.
When you inspect a lathe what do you check for?
Machine for level stance. Spindle bearings for play. Clutches for slippage. Gibs for wear and looseness Cross feed and lead screws for play and backlash. Gearing for lost motion and wear. Machine for lubrication.
How often should you change your lathes headstock oil?
Every six months.
How are lathe chucks identified and what are they?
Lathe chucks are identified by type which are universal, independent, combination, and collet chucks.
Describe Universal chucks.
On the universal chuck all of the jaws open and close simultaneously with the chuck key. You can quickly change workpieces.
Describe Independent chucks.
Independent chucks have jaws that move independently of each other, giving them a wide range of uses.
Which chuck has the greatest holding power of any chuck?
The four-jaw independent chuck has the greatest holding power of any chuck because you can tighten each chuck jaw independently.
What are the methods for aligning a workpiece in an independent chuck?
You can approximate how true you have the workpiece set by aligning the chuck jaws with a series of concentric circles machined on the chuckface.
You can get closer alignment by marking the workpiece with chalk or a marker.
For closer accuracy, align the work using a dial indicator.
Describe the combination chuck.
Combination chucks have features of both universal and independent chucks. The jaws can be adjusted independently or all together.
You can use the combination chuck for chucking duplicate pieces of irregularly shaped work.
Should you thread or part in a lathe collet? Why?
No, Threading and parting in collets can cause them to spring out of shape, or the workpieces can slip.
How do you select a collet for lathe work?
Don’t select a collet more than 0.005” larger than the workpiece, and never select a collet smaller than the workpece.
What are the three most common type of lathe collets are there?
- Draw bar
- Spindle-nose
- Rubber-flex
What type of lathe collet is the weakest?
Rubber-flex collets are the weakest collets, so don’t thread, part, or take heavy cuts while using them.
What should you do before mounting a workpiece on a faceplate?
Before you mount a workpiece, check the faceplate with a dial indicator.
When taking a truing cut on a faceplate how do you set the spindle speed?
Set the spindle speed based on the outside diameter of the faceplate, and set the cutting speed at about 50 fpm.
When taking a truing cut on a faceplate, how should the compound rest be set?
Set the compound rest parallel to the lathe axis and take the depth of cut with the compound rest dial.
When mounting work on the faceplate, what should you do if you will take heavy cuts?
If you’re going to take deep roughing cuts on a workpiece mounted on a faceplate, bolt a block or scrap material against one side of the workpiece to act as a driver to keep the workpiece form shifting while under cutting pressure.
When using lathe dogs, how can you protect finished surfaces?
Place shim stock between the lathe dog and workpiece to protect any finished surfaces.
How are driveplates different than faceplates?
A driveplate is similar to a faceplate and mounts on a lathe the same way. It has from one to four radial slots machined in it, but it doesn’t have T-slots, so you can’t mount work directly on it.
What is the advantage of turning work between centers?
The main advantage of machining work between centers is you can remove the work from the lathe and replace it later without affecting the trueness of the tuned surface in relation to the center holes.
How can you check the alignment of tailstock?
Cricket mark, visual, dial indicator, and cut-and-try.
What is the included angle on a male type center?
The male center has a conical point with a 40 degree included angle.
How do you repair a male tailstock center?
Use a toolpost grinder with the compound rest swiveled 30 degrees from the axis of the center; this gives you the included angle of 40 degrees. Ensure the spindle and grinding wheel are turning in the same direction at the point of contact. Take light cuts to keep from burning the center.
When drilling center holes, how do you determine the size of the hole?
Work diameter - The greater the diameter, the larger the center hole should be.
Material hardness - Softer materials need larger center holes.
Machining with heavy cuts or knurling need larger center holes.
When using a mandrel where should you use lubricant?
use a thin film lubricant film on the shaft and mandrel to keep them from galling as you press them together.
Describe the solid mandrel.
The solid lathe mandrel is hardened, tampered, and accurately ground with a 0.006” taper per foot.
Solid mandrels come in fractional sizes, with the size of the mandrel always marked on the large end to distinguish it from the small end.
On mandrels that are up to 1” in diameter, the small end of the mandrel is usually 0.0005” smaller than the standard size. On mandrels over 1”, the small end is ground 0.001” undersize.
Describe eccentric mandrels.
The eccentric mandrel is almost identical to the solid mandrel. The difference is an eccentric mandrel has a series of center holes at each end.
If you mount them using the offset center holes you can turn the outer diameter of the work eccentric to its bore.
Describe nut mandrels.
Nut mandrels hold work when you machine surfaces concentric to threaded holes. You screw the work on the mandrel, and the shoulder acts as a stop and helps drive the work.
Describe gang mandrels.
Gang mandrels hold several workpieces so you can machine them to the same outer diameter.
describe tapered plug mandrels?
A tapered plug mandrel is used to hold work that has tapered holes.
What’s the difference between a toolroom lathe and an engine lathe?
An engine lathe is a general-purpose machine; a toolroom lathe is an accurate lathe designed for precision work.
What kind of lathe is used mainly for production work?
Turret lathe
How is the size of a lathe designated?
By the maximum diameter workpiece that can be swung over the ways, distance between centers, and overall length of the bed
Which lathe headstock design permits you to mount driveplates with cam studs?
Cam-lock spindle nose.
What is the purpose of the ways on a lathe?
To provide alignment and a bearing surface for the tailstock, carriage, and headstock.
What lathe component supports long workpieces for production?
The tailstock.
How does a lathe carriage move?
Longitudinally on the bed ways by manual or power feed.
At what angle to the axis of the lathe does the cross slide move?
Perpendicular
What lathe component transmits power to the apron to drive the feeds?
The feed rod.
What type of threads are found on the lead screw of a lathe?
Acme.
To be sure a lathe remains in good condition, what should be included in the periodic checks?
Machine for level stance; spindle bearing for play; clutches for slippage; gibs for wear and looseness; cross feed and lead screw for play and backlash; gearing for lost motion and wear; and machine for lubrication.
What do gibs do? How do you adjust them?
Gibs take up wear between bearing surfaces; by loosening the lock screw, tightening the gib screw until you have smooth, snug fit, and then tightening the lock screw.
What condition can be checked by engaging the half nut and moving the carriage back and forth by hand?
End play in the lead screw.
How often should you change the oil in a lathe headstock?
Every six months
Which lathe chuck should you use to hold hexagonal stock on a lathe when you don’t need extreme accuracy?
Universal.
Which chuck is best suited for aligning off-centered workpieces?
Independent.
How should you adjust independent chuck jaws for indicating?
Adjust only two opposite jaws at a time to zero the high and low spots, and then adjust the remaining two opposite jaws.
Which chuck eliminates the need for truing?
Collet.
What is the maximum oversize steel collet you should select for a workpiece?
0.005
Which type of collet chuck has the weakest holding power?
Rubber-flex
When you’re truing a faceplate, what should you check before you take a light facing cut?
The spindle nose and the hole in the faceplate.
How deep should clean-up cuts be when you true a faceplate?
Shallow cuts 0.001 to 0.003″ deep.
What precaution should you take when you are taking deep roughing cuts on a workpiece mounted on a faceplate?
Bolt a piece of scrap material against the following side of the workpiece to act as a driver.
What precaution should you take when you’re machining a heavy workpiece off center?
Add a counterbalance.
What is the purpose of the slots in a driveplate?
They are used to drive a lathe dog.
How can you keep from damaging finished workpieces when you use lathe dogs?
Place shim stock between the lathe dog and workpiece.
What are the tailstock and headstock centers called?
Dead center; live center.
What alignment methods are used for approximation only?
Cricket mark and visual.
Which lathe center should you use for workpieces with pointed ends?
Female.
When facing work held between centers, which type of centers should you use?
Half.
What effect does the hardness of material have on the size of the center hole in a piece of stock?
The softer the material, the larger the center hole should be.
When drilling center holes, how does the size of holes subjected to heavy pressure differ from those subjected to light pressure?
Those subjected to heavy pressure are larger.
How is a part mounted on an eccentric mandrel?
By pressing it in with an arbor press.
How much TPF is ground on a solid mandrel?
0.006″.
Why is the size of a solid mandrel always stamped on the large end?
To distinguish it from the small end.
What is the diameter of the small end of a 1.250″ mandrel?
1.249″.
Which mandrel should you use to machine the surface of a part that has a threaded hole?
Nut.
What is the formula for cutting speed?
rpm = CFS X 4 / Dia.
What is the recommend CFS for low-C steel?
80-100.
What is the recommend CFS for medium-C steel?
40-80.
What is the recommend CFS for high-C steel?
50-40.
What is the recommend CFS for steel forgings?
30-40.
What is the recommend CFS for stainless steel?
100-150.
