Part 2 of our series on how to choose a scrap shear goes inside the shear itself. It is the most punished part of the machine, and the part that decides what you spend on maintenance for the next twenty years. New, they all look up to the job. Time is the real judge.

Two cutting cylinders, not one. Twin cylinders balance the cutting system, cut contact friction and improve the piston guiding ratio for the same frame size. They also come out one at a time — a small cylinder is far easier to pull than a large one.

The guide ratio. Guide length to cutting width should be greater than 1.5. Below that, stress concentrates on the guides and the blade holder, and both wear out early. Six-sided prismatic guides, precision machined, spread the cutting forces into the structure and make adjustment simpler.

Synthetic on hardened steel. Dust particles embed in the plastic instead of seizing the guide, and the guides are self-lubricating. Steel on steel and bronze on steel are obsolete.

The blade angle. Reputable builders stay between 7° and 10°, with 9° to 10° the right compromise. Past 10°, the small gain in cutting capacity goes straight back out as friction and wear. Near 12°, material is driven against the shear wall and loads the blade holder off-centre.

The one to walk away from: welded guides, or no interchangeable wear plates on the surfaces that touch the scrap. Cheaper to buy, far more expensive to own.

ERS partners with TAURUS in the U.S. for shear balers and inclined shears, and engineers the feed, separation and dust collection around them as one line.

Parts 3 to 5 follow weekly.

ERS designs and builds e-waste recycling systems in the United States, and the question we are asked more than any other is what one actually consists of.

It is five stages, not one machine.

Shredding reduces whole devices — towers, drives, boards — to a controlled particle size. Fines removal screens out the small, high-value fraction before it is lost downstream. Metal separation takes the ferrous out magnetically, then aluminium and mixed metals by eddy current. Density separation splits the remaining metal from plastic. Dust collection handles the fine, abrasive dust the process generates, which on electronics is a safety question, not housekeeping.

Get the sequence wrong and material leaves the building as mixed scrap at a mixed price. Get it right and every fraction leaves as a clean, saleable product.

The picture above is typical incoming material: boards, RAM, hard drives, small motors, power supplies and cable. Each one needs a different route through the line.

ERS engineers the whole line for processors across the US and Canada — feed, shredding, separation and dust collection as one system, from one supplier.

Friday 2 October is National Manufacturing Day, and recycled material sits at the centre of it. Steel, aluminium, copper and fibre recovered in this country go straight back into American production.

None of that happens on its own. ERS builds the equipment behind two industries, and neither of them runs without it.

In scrap and metals recycling, we design and install the separation lines that pull clean metal out of mixed material — feed, shredding, milling, air density tables, metal separation and dust collection, engineered as one line.

In paper and paper converting, we build the trim removal, vacuum transfer dust collection and scrap system dust collection that keep high speed machines running and the plant clean.

Both photographs above are our own crews partway through an install: a metals separation line on top, a paper dust collection system below. Not renders, not brochure shots. That is the work, and the people doing it are why the equipment is still running twenty years later.