What causes ridges in the bottom of the cut on characters using a multi-line font?
There are several possible causes for experiencing ridges in the bottom of the engraved cut. The first and easiest to correct is caused by using a cutter that is not wide enough to touch or overlap the adjacent pass (Figure 1). Simply use a cutter with a larger tip and the problem will be eliminated.
Figure 1
The second is using a depth nose that is too small. Consider the example of a five-line font that is being engraved with a .060" cutter. The finished width of the letter will be approximately .300" wide, but if the nose is only 1/4" (.250") in diameter it can drop into the letter and engrave deeper if the middle line is the last to be engraved (Figure 2). The best solution is to use a nose large enough to span the entire width of the cut. An alternative solution is to engrave the innermost lines first if that is an option. This isn't an ideal situation since the nose will only be supported on one side after the material in the center is removed.
Figure 2
The third possible cause is that the material is not flat on the engraving table. Any bubble or bowing of the material allowinf it to rise away from the table will cause the tool to cut deeper in those raised areas. The obvious fix is to make sure that it is being held properly in the vise or use double sided tape to hold it securely in place.
The last major cause of the problem is a misaligned spindle that is not perfectly perpendicular to the work surface of the machine (or the material). See Figure 3. If this is the case the spindle should be aligned according to the machine manufacturer's recommendations.
