Centerless grinding…..what does that term mean to you? Is it Voodoo or magic?? Really, how can you possibly grind something if you are not holding onto it? Okay, you probably get the whole concept that long bars are ground that way, but what about short parts, or parts with super-tight tolerances, or parts with a head on them (like a bolt), or even tiny parts or wires that look like a tiny splinter, or a hair?? Yes – you probably can guess – we mentioned all of those other variations because it isn’t just the bars, or dowel pins that we grind – we grind bolts….and “splinters”…..and “hairs”….all day, everyday.

Below are a few reasons why we may be asked to add our skill set to a project, and a couple examples of projects that may provide a surprise.

First and foremost –  reason #1 would be to achieve a much tighter diameter tolerance and surface finish than traditional machining can achieve. The grinding process – especially the centerless grinding process – makes it possible to hold extremely tight tolerances. Sub-micron level on the diameter and roundness are common – we hold as tight as 30 millionths tolerance total on diameter, and less than 20 millionths on roundness. And, depending on the material type, surface finishes to less than 2 Ra are achievable right off the grinder – no polishing.

Reason #2 – are the limitations that other processes may have with difficult-to-machine materials. With the proper abrasive, and a little ingenuity, any material can be ground. Steels and stainless steels for sure, but add hardened tools steels, Titanium, Aluminum, exotic alloys, super alloys (Inconel, hastelloy, etc), glass, plastic, carbide (though M&S does not grind much carbide), ceramics, (and many others) to the mix as well.

The cost savings that centerless grinding can provide on processing features like the diameter of the body of a bolt, or a stepped down mandrel  over more traditional grinding operations would be reason #3 on our list. Wide width centerless grinding wheels used for “plunge” or “infeed” grinding allow up to 14” lengths to be ground in 1 shot! This provides an extraordinary cost advantage over OD grinding  with a grinding wheel that would traditionally be something like  2” wide  and would require 7 plunges, and a few traverse passes to achieve what the centerless can do in a single grind.

Believe it or not, extremely intricate or micro-sized parts are the focus of reason #4. A good example of this would be a guidewire for a catheter. Think about a wire that is about 5-6 feet long, and has 5 different diameters and tapers on it that range from .0030” to .010” – yes, .010” is the biggest diameter! How can you take a .010” diameter wire 5 feet long and machine it or grind it?? Believe it or not, we do this every single day at our Meron Medical division. Centerless grinding is the only way to produce these parts – keep that in mind you when you are thinking that something is too long and skinny to possibly make!

There are many more variations on the theme. We could go on all day! The very simple thing to keep in mind is that grinding technology has changed. The options that centerless grinding provides for completion of a project today are extensive – M&S Grinding stays at the forefront of this technology so we can provide you – our customers – with the best possible solutions for your projects!