Cutting brass.
I searched for all the threads I could find on this in our forum, but didn’t find anything very helpful for me.
I have three thickness of brass plate: .032, .010, and .016
I know I can engrave on any of them with my 120 McEtcher.
The question is how to hold down? ?blue tape?? and bit, speeds and feeds for my 3XXL machine?
Under the gun to finish for a graduation plaque so any help is greatly appreciated.
Thanks
No idea of cutting parameters. Check the defaults in the CC library.
Blue tape and ca glue will work. Tape table and part, glue in between
Also when contour cutting thin stock like that, zeroing from the bottom of the stock tends to cut into your tape less. Makes clean up a little easier as the adhesive doesn’t get smeared along the edges.
I fold a piece of tape over, that gives two plyes.
I use that to set the bottom of stock.
I don’t hit the table that way.
Appreciate all the responses. I’ll be giving it a go tomorrow.
Thanks
Well, as expected, the engraving was no problem, but trying to get it cut out has ruined 4 pieces so far, and broke 2 ,1/8" bits. Speeds and feeds for the brass thin plate are not working for me.
I’ll try again next week.
Is the material pealing up/folding over ?
That .010 and .016 is going to be interesting when it comes to getting cut out. If I was in a rush I think I would look to the jungle store for blanks to engrave on. Maybe one of these shapes would work.
I used some blanks like that in the past and they worked well. I created a pocket in a piece of MDF to hold the blank.
Whatever time CC and CM estimate you should multiply by 10 for the MCEtcher😂
That’s the trick. I knocked out mine that way, pretty quickly.
Well it turned out ok, but only thanks to a lot of input from the group. Thanks for you guidance and help.
This was the first time I tried to cut out any metal, and I have a lot to learn…but that’s the fun I guess.
Thanks again
Again thanks for those who tried to help. The problem of actually cutting out a piece of thin brass remains a challenge. Holding it down doesn’t seem to work with blue tape and ca glue. Brass either melts back together after the bit passes, or if you move faster, the bit breaks.
No good answer yet.
Do you know the exact brass? I’ve had some brass sheet that forms really well but it’s miserable to machine.
About the closest I can get to knowing the exact brass is that it was in isle 13 at Hobby Lobby. 
First time every trying to cut any metal so not very up to speed on different types.
Actually, that’s helpful enough! I’m fairly confident that’s your problem 
Hobby lobby stocks “K & S precision metals” brass sheet. Lots of reviews touting how soft it is would indicate it’s not a very machinable variety. Then checking K&S directly, they only ever reference 260 alloy sheets.
Alloy 260 is rough in my experience:
Appreciate that info. If I ever decide to do another plaque with brass, I think I will do more research for sure on getting the best type.
Thanks
I’m a model railroader and have 3 CNC machines. My second machine is a Comgrow Robo gantry router/engraver, In the assembly of a kit I made window frames for an engine house out of .010" thick sheet brass. The brass was purchased from McMaster Carr (https://www.mcmaster.com/). Search in the brass section.
I wrote up the procedure on the Modelers Fourm (a model railroad forum).
Here is the link to that thread: Comgrove’s ROBO Router/Engraver
Bernd
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