Why is power scraping superior to hand scraping?

by Peter A. Gees
NEMTR President/ Owner/ Scraper

March 2009

In my 30-plus years scraping machinery throughout the United States and Canada, I’ve noticed that everyone, from laymen to experienced scrapers, is fascinated by the process. They all have questions or comments either about my style and method of scraping, or about the trade in general.

I almost exclusively power scrape, so I typically hear the following:

"Isn’t that cheating?" Or "Isn’t hand scraping more accurate than machine scraping?"

No and no.

Primarily it comes down to two basic things:

(1) Time is money, and

(2) Why work harder than you have to?

My experience with scraping began in 1974 in Geneva, Switzerland, at the SOCIÉTÉ GENEVOISE D’INSTRUMENTS DE PHYSIQUE, established in 1862, commonly known as SIP. There they produced the most accurate and most versatile Jig Borers and Measuring Machines in the world. As a two-year apprentice, I was taught all aspects of the machine-tool trade including; filing and fitting, turning, milling, grinding and scraping. I also learned the art of hand-scraping, while at the factory they had already begun the transition to power scraping, beginning with their super-sized 8000 series, Precision Machining Centers.

Throughout my apprenticeship, and two years into my career of machine tool overhaul, I only hand-scraped jig borers, but I needed to expand and start rebuilding other types of machinery that had much greater wear. Because of the substantial corrective scraping involved, I saw the need to acquire the art of power scraping and I quickly realized the advantages; within two year's time I was employing the full versatility of this fabulous invention in nearly every aspect of my scraping.

Quite simply put:

A power scraper in the hands of a qualified tradesman is much faster than hand scraping and it requires much less effort. It can remove volumes of stock that no hand scraper could ever achieve. It facilitates scraping in awkward positions and hard to reach places, while it allows for the most accurate point picking and point splitting. It also has potential to be used like a hand held milling machine, to remove many thousandths of material at a pass.

The final appearance of power scraping, performed by a properly trained scraper who has a passion for their work, compares very closely to manual Swiss-style pull or hook scraping, as seen in the older SIP, Dixi and Hauser machines. Still, to an observant individual, it is quite distinctly different. This power-scraped appearance is also completely different from American-type push scraping, like that seen on Moore Machines with the classic half moon or quarter moon pattern. There is a power flaking machine whose sole purpose is to replicate this American quarter moon pattern, while also creating the required oil pockets on guide ways that were milled or ground to achieve accuracy, as typically seen on the Bridgeport Mill. This type of power flaker cannot scrape surfaces conventionally, as in corrective scraping for geometrical accuracy.

Since my transition from hand to power scraping, I only hand scrape when there’s no other choice, such as round bearings or Turcite--unless of course someone has a lot of money to burn on nostalgia, but no one has requested that yet!