17 Job Planning, Benchwork & Layout Practice Questions & Answers

1. 1. A print calls for a 0.500 in hole finished by reaming. What is the correct order of operations?

   • A.Drill the hole undersize but on location, then ream it to 0.500 in, since a reamer cannot correct location✓ Answer
   • B.Drill the hole at the finished 0.500 in size, then pass the reamer through it to improve the surface finish
   • C.Ream a pilot hole first to establish the location, then drill the hole out to 0.500 in and deburr both edges
   • D.Center punch and drill at 0.500 in, then file the hole to size with a round file to remove the drill marks

   A reamer only sizes and finishes a hole that already exists, so it must be given stock to cut. If the hole is drilled at the finished size the reamer has nothing to remove and rubs, chatters and dulls instead of cutting. A reamer also follows the existing hole and cannot correct its location, which is why the drilled hole must be undersize but on location.

   Source: NIMS Machining Level I Standards, Duty 2.1 Benchwork (hole operations); Machinery's Handbook, Reaming — reaming allowancesReport a problem with this question

2. 2. On a job routing sheet (traveler) prepared during job process planning, what information belongs on the sheet?

   • A.Only the finished dimensions of the part, because the machinist decides everything else at the machine with no written record
   • B.The sequence of operations, the machine or work center for each operation, and the tooling and inspection required✓ Answer
   • C.Only the raw stock size and the material specification, since the order of operations is fixed by the print itself
   • D.The operator's time card and the daily machine maintenance log for the shift on which the part is run

   The routing sheet is the plan that carries the part through the shop, so it must state what is done, in what order, on which machine, with what tooling and workholding, and where the part is inspected. Leaving any of that to be decided at the machine makes the process unrepeatable and puts inspection points out of sequence.

   Source: NIMS Machining Level I Standards, Duty 1.1 Job Process Planning (routing and operation sheets)Report a problem with this question

3. 3. A rectangular block must be laid out from two edges that the print identifies as datums. What should be done first?

   • A.Scribe every layout line from the as-sawn edges first, then square the block on the mill afterward so that the finished edges end up parallel to the scribed lines
   • B.Center punch every hole location before any edge is machined, so that the punch marks are not lost while the block is being squared
   • C.Square and finish the two datum edges, then apply layout fluid and scribe all dimensions from those edges✓ Answer
   • D.Drill the holes first and lay out the outline afterward, using the finished holes as the reference points for all dimensions

   Every layout dimension is measured from the datum, so the datum surfaces must exist and be true before any line is struck. If lines are scribed from a rough sawn edge and the edge is machined afterwards, the stock removed shifts every dimension by an unknown amount and the layout is scrap.

   Source: NIMS Machining Level I Standards, Duty 2.2 Layout (layout from a datum edge); layout accuracy ±0.015 inReport a problem with this question

4. 4. A shaft must be hardened and must also hold ±0.001 in on a ground diameter. Where does heat treating belong in the operation sequence?

   • A.After all machining is complete, including the final grind, so that the finished size is not disturbed by later handling
   • B.Before any rough turning, so that the tool is cutting hardened material and leaves a better finish on the diameter
   • C.It does not matter, because hardening does not change the size or the shape of a steel part by any measurable amount
   • D.After rough machining but before the finish grind, so the distortion and scale left by hardening are cleaned up by grinding, the process able to cut hardened steel✓ Answer

   Hardening distorts the part, forms scale and changes size, so any surface held to a close tolerance must have grinding stock left on it and be finished after heat treat. Grinding is also the process able to cut hardened steel, while roughing is done while the material is still soft and easy to machine.

   Source: NIMS Machining Level I Standards, Duty 1.1 Job Process Planning (operation sequencing, heat treatment placement)Report a problem with this question

5. 5. A blind hole must be tapped with usable threads as close to the bottom as possible. Which tap is used, and when?

   • A.A bottoming tap, run last, after the taper and plug taps, because its 1 to 1.5 chamfered threads will not start square✓ Answer
   • B.A taper tap, because its 7 to 10 chamfered threads let it start straight and cut full threads all the way to the bottom
   • C.A plug tap by itself, since its 3 to 5 chamfered threads are enough to reach the bottom of any normal blind hole
   • D.A bottoming tap used first, so that the full-form threads are cut before any chips have collected in the hole

   A bottoming tap has only about 1 to 1.5 chamfered threads, which is what lets it cut full-depth threads almost to the bottom of a blind hole. That same lack of lead means it will not start square and would have to cut the whole thread form at once, so the taper and plug taps are run first to start and open the thread.

   Source: NIMS Machining Level I Standards, Duty 2.1 Benchwork (hand tapping); hand tap set — taper, plug, bottomingReport a problem with this question

6. 6. A job calls for tapping at the standard 75% thread engagement. A machinist instead picks a drill smaller than the tap drill on the print in order to get a higher percentage of thread. What is the most likely result?

   • A.The tap will cut more freely and produce a smoother thread, because there is less material left in the hole for its cutting edges to remove
   • B.Tapping torque rises sharply and the tap is far more likely to break, while thread strength gains very little✓ Answer
   • C.The thread becomes measurably stronger, roughly in proportion to the extra percentage of engagement that was gained
   • D.Nothing changes as long as the same tap is used, because the drill size only affects how deep the tap can reach

   A smaller drill leaves a smaller minor diameter, so the tap must cut away more metal on every flute and the torque climbs steeply. Beyond about 75% engagement the added thread strength is marginal because the joint fails in the fastener or by stripping the shallower material anyway, which is why 75% is the standard target.

   Source: NIMS Machining Level I Standards, Duty 2.1 Benchwork (tapping); Machinery's Handbook, tap drill sizes by percentage of thread engagementReport a problem with this question

7. 7. Why does the NIMS benchwork job require the edge of a hole to be countersunk before the hole is tapped?

   • A.So that a flat-head machine screw will seat flush with the top surface of the finished part when it is assembled
   • B.It removes enough metal that a smaller tap drill can then be used without increasing the tapping torque
   • C.It helps the tap start square to the surface and protects the first thread from being chipped or burred✓ Answer
   • D.It relieves the bottom of a blind hole so the bottoming tap can reach full depth without binding

   The countersink gives the tap a chamfered seat that guides it into the hole and lets the machinist see and correct any lean before the thread is committed, so the thread ends up perpendicular. It also removes the sharp corner where the first thread would otherwise be raised as a burr and easily broken.

   Source: NIMS Machining Level I Standards, Duty 2.1 Benchwork performance requirements (countersink holes prior to tapping)Report a problem with this question

8. 8. A hand tap has broken off inside a tapped hole in a finished part. What is the proper tool for removing it?

   • A.A center punch and hammer, driving the broken piece out from the opposite side of the hole
   • B.A pair of needle-nose pliers gripping the flutes while the part is clamped tightly in a bench vise
   • C.A screw extractor (easy-out) turned into a hole drilled through the center of the broken tap
   • D.A tap extractor, whose fingers slide down into the flutes so the hardened, brittle tap can be backed out with steady torque and without shock✓ Answer

   A tap extractor has fingers that slide down into the flutes of the broken tap so the piece can be backed out with steady torque and without shock. A tap is hardened and brittle: hammering it or forcing a hardened easy-out into it usually shatters the tap and damages the threads, leaving a hole that cannot be salvaged.

   Source: NIMS Machining Level I Standards, Duty 2.1 Benchwork (tapping and thread repair)Report a problem with this question

9. 9. A bushing must be installed in a reamed bore with a 0.001 in press fit, must finish flush within ±0.03 in, and must not be pushable out by finger pressure. How should it be installed?

   • A.Press it in squarely with an arbor or hydraulic press, using a flat bar or a driver✓ Answer
   • B.Drive it in with a ball-peen hammer, tapping around the flange a little at a time until the face is flush with the part, needing no extra equipment
   • C.File the outside diameter until the bushing slides into the bore by hand, then stake the edge of the bore to hold it in place
   • D.Coat it with thread-locking compound and push it in by hand, then let the compound cure before the part is used

   A press applies steady axial force through the center of the bushing, so it enters square and the 0.001 in interference is preserved along the whole length of the bore. Hammering cocks the bushing and upsets its end, and filing the outside diameter destroys the interference that is the only thing holding the bushing in.

   Source: NIMS Machining Level I Standards, Duty 2.1 Benchwork performance requirements (0.001 in press-fit bushing; arbor/hydraulic press use)Report a problem with this question

10. 10. A 0.500 in hole is to be finished with a HAND reamer. About how much stock should the drilled hole leave for the reamer to remove?

    • A.About 1/64 in (0.015), the same allowance normally left for a machine reamer of this size
    • B.About 0.004 in, since a hand reamer is turned with a tap wrench and the torque available is only enough for a few thousandths✓ Answer
    • C.About 1/32 in (0.031), so that the reamer has enough material to correct the location of the hole
    • D.About 0.0005 in, since a hand reamer is only meant to polish the wall of an already finished hole

    A hand reamer is turned with a tap wrench, so the available torque is small and it is given only a few thousandths — roughly 0.001 to 0.005 in — with its long starting taper doing the alignment. Machine reamers, driven by a spindle, take far more: about 1/64 in for holes up to 1/2 in and about 1/32 in above that.

    Source: NIMS Machining Level I Preparation Guide, Reaming (hand vs machine reaming allowances); Machinery's Handbook, Reaming AllowancesReport a problem with this question

11. 11. Compared with the speed and feed used to drill the same hole, how should a reaming operation be run?

    • A.About twice the drilling RPM, with roughly half the drilling feed, so that the reamer takes a light finishing cut
    • B.The same RPM and the same feed as drilling, since the reamer simply follows the hole the drill has already made
    • C.About half the drilling RPM, with roughly twice the drilling feed✓ Answer
    • D.About half the drilling RPM and about half the drilling feed, to keep heat out of the finished hole

    The lower speed keeps heat and chatter down and protects the reamer's margins, while the heavier feed forces every cutting edge to take a real chip. If the feed is light the reamer rubs and burnishes instead of cutting, which work-hardens and glazes the hole and dulls the tool quickly.

    Source: NIMS Machining Level I Preparation Guide, Reaming (reaming speeds and feeds relative to drilling)Report a problem with this question

12. 12. After filing a surface, the work shows deep scratches. What causes this, and how is it prevented?

    • A.The file is too fine; a coarse double-cut file should be used instead, keeping heavy pressure on both the forward and the return stroke so the surface stays flat
    • B.There is not enough cutting oil on the file; the file should be flooded with oil before every stroke so the chips are floated away
    • C.The file has no handle fitted; a handle steadies the file and keeps the teeth from digging into the surface of the work
    • D.The file is pinned — chips wedged in the teeth stand proud and plough a groove on every stroke; clean it often with a file card✓ Answer

    A chip that wedges between the teeth stands proud of the cutting face and is dragged across the work, ploughing a groove with every stroke. The cure is mechanical: brush the teeth out frequently with a file card, and rub chalk into the teeth on soft materials so chips cannot lodge in the first place.

    Source: NIMS Machining Level I Standards, Duty 2.1 Benchwork (filing); file card use and pinningReport a problem with this question

13. 13. A hole center must be laid out 2.375 in from a finished datum edge as accurately as possible. Which method should be used?

    • A.A vernier height gage fitted with a scriber, used on a surface plate with the datum edge held against an angle plate✓ Answer
    • B.A steel rule and a scriber, carefully aligning the 1/64 in graduations of the rule with the finished datum edge before the line is struck
    • C.Dividers set from a steel rule, stepping the distance off from the datum edge in two equal steps
    • D.The blade of a combination square extended to the dimension, with the square head held firmly against the datum edge

    Precision layout is done on a surface plate, which supplies the flat datum from which heights are measured, and the vernier height gage discriminates to 0.001 in. Rules, dividers and combination squares are semi-precision tools good to about ±1/64 in, an order of magnitude coarser than the height gage.

    Source: NIMS Machining Level I Standards, Duty 2.2 Layout — precision layout (surface plate and vernier height gage)Report a problem with this question

14. 14. How should a hand hacksaw blade be installed in the frame and used?

    • A.With the teeth pointing toward the handle, cutting on the pull stroke so the blade is always in tension while it is cutting
    • B.With the teeth pointing away from the handle; the blade cuts on the forward stroke and pressure is eased on the return✓ Answer
    • C.With the teeth pointing away from the handle, keeping heavy pressure on both the forward and the return stroke so the cut goes faster
    • D.Either direction will work, as long as at least three teeth stay in contact with the work throughout the cut

    Hacksaw teeth are formed with their cutting faces toward the front of the frame, so the blade only cuts when it is pushed. Keeping pressure on the return stroke rubs the teeth backwards and strips or dulls them, and the blade should also be chosen so at least three teeth are engaged in the work at all times.

    Source: NIMS Machining Level I Standards, Duty 2.1 Benchwork (hand hacksawing technique and blade selection)Report a problem with this question

15. 15. A 14 in diameter arc must be scribed on a layout plate, well beyond the capacity of the dividers on the bench. Which tool is used?

    • A.A hermaphrodite caliper with one leg riding along the finished edge of the plate
    • B.A surface gage, with its scriber swung around the work while it sits on the surface plate
    • C.Trammel points, two adjustable points carried on a beam, so the radius they can scribe is limited only by the beam length✓ Answer
    • D.The center head of a combination set, rotated around the center point of the plate

    Trammel points are two adjustable points carried on a beam, so the radius they can scribe is limited only by the length of the beam. Dividers are limited by the spread of their legs and are used for small and medium circles and for stepping off distances.

    Source: NIMS Machining Level I Standards, Duty 2.2 Layout (dividers, trammel points)Report a problem with this question

16. 16. Which layout tool scribes a line parallel to a finished edge and can also be used to locate the center of round stock?

    • A.Dividers, with both legs set to exactly half the width of the stock
    • B.The protractor head of a combination set, set to 90 degrees against the edge
    • C.Trammel points, with one point riding along the finished edge while the other scribes
    • D.A hermaphrodite caliper, whose bent leg rides the reference edge while the scriber leg strikes the parallel line✓ Answer

    A hermaphrodite caliper has one bent leg that rides the reference edge and one straight scriber leg, so the line it strikes stays a set distance from that edge no matter how far along the part it is moved. Setting it to slightly more than half the diameter and swinging arcs from several points on a round bar brackets the center.

    Source: NIMS Machining Level I Standards, Duty 2.2 Layout (hermaphrodite caliper)Report a problem with this question

17. 17. The layout lines are scribed and the hole locations are marked at their intersections. What is the correct way to prepare those locations for drilling?

    • A.Mark the intersection with a prick punch, then enlarge that mark with a center punch✓ Answer
    • B.Use a 90 degree center punch on the intersection first, then reduce the size of that mark with a prick punch before drilling
    • C.Press the scriber point into the intersection to make a deep dimple, which gives the drill something to start in
    • D.Skip punching altogether and start the hole with a center drill, which will find the scribed intersection on its own

    The prick punch has a sharp point of about 30 to 40 degrees, so it makes a small mark that can be placed exactly on the intersection and checked, and nudged over if it is off. The 90 degree center punch then opens that mark into a cone wide enough for the chisel edge of the drill to seat in, which is what keeps the drill from walking.

    Source: NIMS Machining Level I Standards, Duty 2.2 Layout (prick punch and center punch; punch marks centered on intersections)Report a problem with this question

Practice questions based on NIMS/ANSI 101-2001, Duties and Standards for Machining Skills Level I, and the published content of the NIMS Machining Level I theory exams, together with standard precision-machining practice. NIMS is a mark of the National Institute for Metalworking Skills; this site is not affiliated with or endorsed by NIMS. Machining Level I is a set of separate credentials, and most of them also require a hands-on performance test that this bank does not cover. The NIMS theory exams are open-reference, but questions here never depend on recalling a handbook table value, a citation number or a machine rating — always work from the print in front of you, your employer's written procedures, and the machine's own documentation, and confirm current requirements before testing. About the NIMS machining credentials →