Instruction example 2.3. Drill stand

To practise scribing of straight and parallel lines with scribing blocks, based on datum edges.

Material

U-section (approx. 380 MPa)
Web width: 80 mm
Flange height: 45 mm
Length: 120 mm
(see also training example 4.2.)

Figure

Hand tools

Scribing blocks (marking gauge and steel scriber or caliper gauge or height gauge), centre punch, engineers’ hammer.

Measuring and testing tools

Steel measuring tool

Accessories

Surface plate, whiting, brush

Required previous knowledge

Reading of drawings, measuring

Sequence of operations	Comments
1. Arrange the working place, prepare the working materials.	- Check for completeness.
2. Check datum edges/datum faces for flatness and squareness.	- If necessary re-work(file).
3. Coat surface with whiting and let it dry.
4.1. For scribing blocks without scale, set the distances according to drawing by means of steel measuring tool and scribe step by step, based on the datum edges.	- Line up exactly with the datum edges! Do not cant!
4.2. For scribing blocks with scale, set the distances according to drawing directly at the gauge and scribe step by step, based on the datum edges.
5. Prick-punch points of intersections of scribed lines heavily by means of centre punch
6. Final inspection.	- Dimensions, parallelism and cleanness of scribed lines.

Completion

Drill the holes with drill diameters as required (to be specified by the instructor or as per instruction example 7.4.). Produce a stringer plate to support the tools to be inserted. Clean the surface and mark for identification.

Drill stand