Drilling jigs are used to accurately locate and hold workpieces for drilling and other machining operations. There are various types of drilling jigs defined by their shape, construction method, and how they locate and support the workpiece. The most common types include template jigs, plate jigs, channel jigs, diameter jigs, solid jigs, and post jigs. Drilling jigs provide accuracy and repeatability for drilling multiple holes in production environments.

1. Drilling Jigs

2. Drilling Jigs :
• Drilling jigs are used to locate and hold the work piece for drilling,
reaming counter boring, counter sinking, spot facing and tapping
operations.
• With the exception of taps, tools are guided during cutting and jigs
should make provision for tool guiding elements in addition to
location, support and clamping systems.
• A drilling jig should be of light design with enough rigidity because it
has to be handled frequently.
• It should be stable since it is not normally clamped to the machine
table.
• The feet of the jig should extend well outside the holes to be drilled
to prevent rocking during operation.

3. Types of drilling jigs :
• Drilling jigs are named or classified on the basis of their
shape, shape of the major locating element, method of
construction and use.
• The major categories are given below:
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1.Template jig 2.Plate jig
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3.Channel jig 4.Diameter jig
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5.Solid jig 6.Post jig
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7.Angular post jig 8.Turn over jig
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9.Box jig 10.Latch or head type
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11.Sandwich jig 12.Indexing jig

4. 1.Template jig :
• This is the simplest type of drilling jig. It is simply a plate
made to the size and shape of the workpiece with the
required number of accurately made holes.
• It may or may not have bushings. When bushing is not used
the whole jig plate is normally hardened.
• For use, the jig is placed on the work piece and holes drilled
through the holes in the template.
• This type of jig is suitable only for a few parts.

5. 2.Plate jig :
• Instead of simple holes, drill bushes are provided in this jig
for accurately guiding the tool.
• The jig essentially consists of a jig plate or bush plate with a
provision for clamping and location.
• Plate jigs are used for drilling accurately spaced holes on
larger jobs.
• The jig is located and clamped to the work piece directly for
use.

6. 3.Channel jig :
• The channel type jig shown in Fig. is a slightly more
elaborate jig made of a channel section.
• This jig may also be provided with a swinging type leaf to
form a channel and leaf type jig.

7. 4.Diameter jig :
• Diameter jigs are used to drill radial holes on cylindrical or
special work pieces.
• As shown in Fig. the work is placed on a fixed V block and
then clamped by the clamping plate which also locates the
work.
• The guidance to the tool is provided by the drill bush
shown.

8. 5.Solid jig :
• Fig. shows a solid jig that is made from a block of steel in
which the work piece is clamped down by a strap clamp or
swinging clamp.
• Burr grooves are provided to remove the work piece easily.

9. 6.Post jig :
• In this jig the work piece is located on its bore on the post.
The post is also used to locate the drill plate.
• The swing washer makes it possible to remove the drill
plate without removing the hand nut.

10. 7.Angular post jig :
• Fig. shows an angular post jig of welded construction.
• An extended and shaped drill bush is used to prevent drill
run out and yet make possible the removal of work piece.
• A quick action nut is used as the bore in the work piece is
small and it requires the nut to be removed for unloading
the work piece.

11. 8.Turn over jig :
• Turn over jigs are plate jigs with jig feet. The feet provide
square resting surface to the jig when drilling holes.
• The jig is seated on four foot nuts while locating and
clamping the workpiece. It is then turned over to support
itself on its feet in the machining position as shown.

12. 9.Box jig :
• This type of construction is used when holes are to be
machined on a number of faces on the workpiece.
• The jig body is shaped like a box with one side open for
loading and unloading the workpiece.
• The box is closed and clamped by a hinged latch with
bushes and clamping screws.

13. 10.Latch type jig :
• In this type of jig the latch carries the drill bushes and
should be positively located (Face X and slot Y) so that the
drill bush bores vertical in spite of workpiece height
variation.
• The latch is clamped by nut A and the work piece by screw B.

14. 11.Sandwich jig :
• This type of jig is used for drilling holes in thin or soft parts
to avoid bending or warping.
• Support plate is provided at the bottom and the work piece
is sandwiched between the plate and the top which carries
the drill bushes.
• The top and bottom plates are located with the help of
locating pins as shown.

15. 12.Indexing jig :
• Used to drill a series of holes on a circle on the face of a
workpiece.
• Every time the jig is indexed, it brings a hole position under
the drill.
• In the design, drilling is performed by using each of the six
bushes successively with the work piece clamped in one
position.