it’s that thing you never use use, with lots of paper, delivered into that other thing you barely use made out thin metal, that collects packages that are small enough for the lazy delivery persons not to knock on your door for = D
I am basically going through one of these ‘titanium coated’ bits every time. I have lowered the feed rate to like 10 or even 5 inches/min and no dice. I am only left to assume they are not made to be used on brass. The first plate I mill with a new one looks great, the next, does not.
Do I need to use cutting lubricant?
This one marked is from a fresh bit, and so is the last one, all these use the same settings.
Ideally I would like to bang out 8-10 of the marked quality, but it’s challenging. I have ordered these bits, hoping they are a bit stronger (pun intended):
This is how I am milling, I would need to make this out of corian or something if I had to use lubricant:
You should be moving faster - 30-50 ipm. Also, your machine needs to be very rigid. Vibration is probably banging that bit into the brass, the brass is probably vibrating as well. This will lead to excessive bit wear. Also, I bet that is really hard brass, not free machining brass. That makes a difference. You could probably get .625" free machining brass, face plane it, engrave it and cut it out with much better results and do several at one time. Here is a soft temper, workable brass sheet:
https://www.onlinemetals.com/merchant.cfm?pid=23624&step=4&showunits=inches&id=1776&top_cat=79
Do you know a site where I can buy 1mm machineable brass sheets? I am buying blank brass tags that say they are made for machining. But yeah they could be too hard.
Found this on amazon, this looks good?
https://www.amazon.com/Texas-Knifemakers-Supply-Machining-projects/dp/B01N0B60EA?th=1
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I just now saw this topic. Looks like it is almost 2 years old. Is Earwigger still around?
In my bunker making coins!
I am new to machining. I was wondering how you avoided stepover lines? I use a 0.01mm stepover, and you can still see machining lines. How long did this take to engrave and what speeds/feeds did you use? Thanks! 
Have you trammed your Z-Axis to the best of your ability? That will ensure that you are dealing with just the flex of the machine.
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Brandon Parker
Hey Hannah - Just seeing this. If you are working with metal and have questions, I can probably help and should get notifications if you reply. I apologize for letting this drop.
Answer: The engraving bit looks like a v-bit, but it has a “flat” at the end. Every bit will specify the size of the flat. Stepover, should be around 50% of the width of the flat. Engraving bits have such small flats that any lines can be easily remedied with a blast of sand OR one of those fuzzy wheel things - like these guys:
https://www.amazon.com/gp/product/B010AHSB5S/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Tramming your z axis is important.
Hello @Earwigger , I have been looking for right parameters to engrave on silver with vbits and found this discussion. Looks like you have alot of experience with cnc engraving with metals. Can we contact and get some advise from you?
Hello - Silver is tricky. Most of my experience is in fine silver. Sterling was a mess to work with. Let me know how I can help.
Hello @Earwigger I just came across this thread and, as Daward said, looks like you have tons of experience in machining metals. I am new in this CNC world, and I’ve trying to engrave some brass wax seal stamps for a client with no luck. Is there any chance we get in touch to get some advice? Thanks a lot in advance.
Hello Juan!
Sorry it took so long to respond. Let me know if I can help.
@Earwigger I wondered if you were around for some assistance about engraving brass ? - happy to buy you a virtual coffee. Would be great to make contact. Paul.