This is a hopper that I made as part of a qualification. I was working towards my Level 3 in Engineering Technology, with a plate fabrication module.

Producing Drawings

The first step was to take the engineering drawings given and reproduce them at 1:1 scale on 5mm squared paper. This helped to familiarise myself with the measurements and also produced a template to check the size of parts later on.

Marking out components

Each plate component was then marked out onto an appropriate piece of sheet metal. This was done using the same drawing techniques as before.

Cutting out plate components

The components were cut from the plate using a plasma cutter. Each piece was supported by hand while being cut to prevent warping in the piece. Each piece was then smoothed with an angle grinder to remove roughness produced by cutting

Cutting out the angle iron

The angle iron was cut on a band saw. An initial cut was made in the angle iron to create a 45 degree mitre. The piece was then rotated 180 degrees, so it was upside down, and the longest edge measured to 400mm and marked. This piece was then also cut on a 45 degree angle. The rotation of the piece creates the opposite facing mitre. The cut angle iron was then remove, and the remaining piece rotated back 180 degrees and fed through the band saw. The end was then mitred again to produce the correct angle on the correct orientation for the next piece.

Marking out holes

The locations for drilling the holes on both the flange and the base (angle iron) were marked out by measuring against the drawings. These were then punched with a centre punch to give an accurate centre and guide mark for the drill.

Drilling the holes

A pillar drill was used to drill the holes in both the flange and the angle iron. Each piece was placed in the work area, and a hole to be drilled was lined up with the drill bit, and clamped in place. This was done by carefully lowering the drill bit to ensure it came down on the centre punched hole. Then the guard was put down, the drill was turned on, and then carefully guided through the metal. This was repeated for all of the holes on both the flange and the angle iron pieces.

Tacking the base

The base needed to be completely flat when tacked together, so a wooden board was placed on top of the workbench before welding to create a flat surface. This meant that the return lead for the welding machine needed to be clipped directly to the work piece. The pieces were then laid out to ensure a smooth fit. Once a smooth fit was found, each corner was given 3 tacks at equal distances along the horizontal part of the diagonal join. The piece was then rotated, and the smooth fit found again before welding the next corner.

Tacking the pyramid

Rather than trying to tack each side of the pyramid in the correct place, the triangles were centred on their side of the base and then tacked in an upright position with a single tack. Once all four sides were tacked they could be bent into the correct position and tacked properly. Each side was tacked 3 times along the base, one in each corner and one in the centre. Tacks were then run up the joins between each triangle, placed where necessary.

Producing the pipe

The pipe plate needed to be rolled to produce the cylindrical pipe. This was done by passing the plate through a metal roller of increasing tightness to create a tighter and tighter curve on the pipe, until the two sides of the plate met. It is incredibly important to ensure both the rollers are level, and that the plate was passed through the roller straight, to ensure the metal curved correctly. Once the two sides of the plate were brought together, the pipe was held together with a clamp and tacks run along the join to keep it together.

Check fit

The pipe could then be placed on top of the pyramid to check the fit. One end of the pipe had curves cut in it to create a smoother fit with a pyramid shape, so the corners of these curves had to line up with the sides of the pyramid. Once the pipe was settled on top of the pyramid, the join between the bottom of the pipe and the sides of the pyramid could be marked, as these would need to be cut out.

Cutting out the pyramid

The lines marked out on the sides of the pyramid can be cut using a plasma cutter. It is important to cut above the line, rather than on it or below it, to prevent gaps in the final hopper. This is due to the lines being marked below the end of the pipe, i.e. beyond the furthest reach of the pipe.

Attaching the pipe

Once the top of the pyramid had been cut off, the pipe could be tacked onto the pyramid to attach the two together. Before tacking, it is important to check the line up of the pipe by eye, and ensure the pipe goes as straight as possible. The pipe can then be intermittently tacked in place, with tacks were deemed appropriate.

Checking the height

The total height of the assembly is 420mm as per the drawings, so any extra height given by the pipe needs to be found and removed. This cut can be made using a plasma cutter. It is important to account for the fact the flange is not attached yet, and that that will add an extra 2mm of height.

Attaching the flange

Once the extra height has been removed from the pipe, the flange can be attached. This is done by centring the inner diameter of the flange on top of the plate and running intermittent tacks around the inside.