TOP TEN BORE GRINDING PROBLEMS and how to solve them…TODAY! (part-8)

Noisy Grind

Noisy grind and chatter frequently go hand in hand. Chatter is usually something you see on the part. Noisy grinding occurs when you are standing outside the grinder and the machine is howling. Usually if you hear that, you’re also going to see chatter marks on the part but not always.

ear-protectionSometimes something just doesn’t sound right. Usually in the grinding process you shouldn’t hear anything unusual. But if you hear a high-pitched squeal like someone is dragging their fingernails across a chalk board, then something is probably not right.

One thing that can cause noisy grind is a wheel that is not round. This will cause an interrupted cut; in other words, the wheel is only going to hit on the high spots. At 60,000 revolutions per minute, this is going to sound like a scream. To fix this condition you may just have to dress the wheel until it is round.  To help ensure the wheel is round after dressing you can use a crayon or paint pen to lightly mark the wheel first before dressing.  After a few normal dress passes, stop and check the wheel to see if the markings are gone.  Any isolated spots of color left will indicate a low spot in the wheel.

If noise persists, check your wheel, quill, and spindle nose for runout. Any of these components being out of round will cause noise. Place a dial indicator on each. The needle should be steady as you rotate these components. If one of the components does not pass the dial indicator test, it may be bent, improperly mounted, or in the case of the spindle nose the bearings could be worn out.

Finally there is the “old standby” solution for many grinding problems…sharpen the wheel. If the wheel is dull and rubbing instead of cutting, it might actually deflect and bounce on the surface of the part. This situation can manifest itself in many ways (e.g. chatter, roundness and/or taper problems). However, the screeching wheel may be your first alert.

About joelcassola

Joel Cassola is a commercial journalist who has written feature articles and case histories for clients in more than 100 trade magazines.
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One Response to TOP TEN BORE GRINDING PROBLEMS and how to solve them…TODAY! (part-8)

  1. Tom Cappadona says:

    The other thing you can check is the work holding, centers, chuck, ect. In the case of OD grinding make sure the centers are clean and round, both in the part and on the grinder. In the case of ID grinding make sure the chuck and jaws are secure, clean and are clamping the part correctly. One other way of isolating the problem is to vary the work piece speed. Typically a faster work piece speed will improve roundness, however the trade-off is the faster the work piece speed the greater the chance of chatter – Tom Cappadona

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