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Chuck Keysor
03-05-2013, 01:15 AM
Hello Shopbotters: A friend of mine has asked me to engrave a simple brass plaque for him. (The brass will be common "free machining" brass.) An Aspire simulation is shown using his Rhino supplied artwork. The plaque is 3" by 8", the capital letters are .28" high, and the lines that make up the letters are about .02" wide. He is looking for a simple groove to form the letters, but is open to using V carving.

1) My first question is, is V-carving appropriate? I have done lots of V-carving, to the point whenever I look at lettering, I only think of V-carving. Would something else be appropriate, such as a pocket tool path approach? I'd like anyone who is more experienced and open minded than I am to comment!

2) My second question is one I have kind of asked before, but it had been in the context of doing V-carving, hence the super fine tips, that seem to cause me problems (except for my CMT Laser bit). What bit would you recommend for this work since it is not as fine as the V-carving I have been doing? I would assume an engraving bit would be in order, but would a little ball end mill work? (Again, I am just trying to be open minded....)

I have purchased two different brands of "engraving" bits, with a .005 flat on the tip, and on both, the fine tip chipped, either when cutting vinyl floor tile OR maybe when using my Z-zero plate. So I want a bit that is appropriate to the width of these rather chunky letters, that will simply not snap before I even get going.

3) Searching past posts on brass engraving, it seems as though a feed rate of .3IPS to .5IPS, a plunge rate of .1IPS, a step-down of .01" to .02" and a ramp-in length of .5" But these may have been with an assumption of V-carving, so could these setting change if pocketing is used?

I am being cautious, since I have broken little bits before. And I don't want to look like a total klutz in front of my friend by breaking more bits!

Thanks, Chuck

Bob Eustace
03-05-2013, 02:54 AM
Chuck, Vectric have a fantastic feature - Quick Engrave. Suggest you try depth of cut of 0.02 for trials. Try your various bits to find the best. We do lots of acrylic just using simple 90 degree carbide tipped v bits with zero failures. Suggest you experiment with single stroke fonts.

Chuck Keysor
03-06-2013, 01:43 PM
Hello Bob. Thank you for your helpful suggestions! I was hoping to experiment in Aspire before replying, but haven't yet gotten there. I have to go shovel snow. I'll get back with what I find. Thanks again! Chuck