There are many types of wear surfaces that require scraping such as turcite, brass, rulon, moglice or even cast iron ways. The blue or green wear material you see on your machine is called Turcite, and this is the most common wear material on machines. The first signs that scraping could be needed are loss of accuracy and squareness, stick slip, lost repeatability or even back lash in an axis. It is important to be aware of the wear and tear in your machine tools so rebuilds are quicker and less costly. Contact Summit Machine Services for any of these issues to get an inspection or quote!

Way scraping is the process of physically mating two surfaces together by removing high spots until the surfaces match each other with an even contact area. More importantly, the mated surfaces need to achieve a very precise geometry that will ensure the machine alignments are correct and within tolerance. The scraping is done with a carbide blade on either a hand-held scraper or a power-scraper. The highs and lows created by this process create space for lubricating oil that will allow machine axes to move freely and eliminate stick-slip that hinders CNC machine tool accuracy.

Why Choose Scraping Over a New Machine?

The main benefit in choosing to scrape or rebuild an older machine compared to buying a brand new one is cost. Typically it is more than 50% cheaper if you choose this option instead of purchasing a brand new machine. Also, you will save the valuable production time lost waiting for a new machine to be built, along with the headache that comes with rearranging equipment around your facility to make room for rigging and moving. An overlooked factor in buying new machines is that they simply aren’t made like they were in the past. Older machines were designed with rigidity and functionality in mind. If you have a CNC or manual machine that has the capacity and size you need but it has lost it’s accuracy over the years, it is likely a good candidate for re-scraping and alignment- not to be thrown out!

Previous Scraping Projects

Blanchard Rotary table

Blanchard Grinders are known for being heavy duty and reliable grinders. But even these well built machines require scraping after many years of non-stop production. Over time the moving parts get worn down by grinding swarf which then abrades the contact surfaces and leads to loss of accuracy. This machine was in an automotive industry plant where we disassembled the machine, meticulously scraped the table to the bed and had it up and running in under 3 days.

Kuraki Kv-2000

This Kuraki vertical mill was heavily used in an aerospace manufacturing facility for many years without the necessary preventative maintenance. The machine could only be used for roughing parts until Summit completed an inspection and concluded all 3 axes needed to be rebuilt. During tear down we found that the way lubrication system was clogged, turcite was peeling away and the ball screws and bearings needed repaired. After completion of the project this mill was put back into production with the rigidity and accuracy for a complete rough-to-finish part process.

In a 6 week time window a Summit technician performed the following;

• Disassembled and thoroughly cleaned

• Lubrication systems flushed and repaired

• All 3 axis’ scraped to better than OEM specifications <0.0003“/ft

• Ball screws and bearings were replaced

• Precision leveled and aligned

cincinnati od grinder

These Cincinnati CNC grinders are commonly utilized across the country in a variety of grind shops. They are great because they can go through several rebuilds in their lifetime without requiring any modification to the structure of the machine. This auto-parts manufacturer had noticed stick slip and loss of motion on the table and wheel head. The root cause can be seen in the pictures below, the bed was worn and the factory scraping marks were hardly visible. Summit Machine Services travelled to this facility and performed a field rebuild in a few weeks time. By completion of this job the “V and Flat” cast iron ways were true and parallel to each other from end to end within the manufacturers specifications and ready to perform accurately for years to come.