I’ve seen a few threads about this, but I can’t find any real answers, and I’m losing (Well, if I’m honest have already lost) my mind breaking bit after bit.
I have been working on a brass branding iron. Roughed out with a 1/8" and then a 1/16" now I need to do the detail pass with w 1/32" to finish the small lettering.
I’ve seriously slowed everything down to the point where It’s barely moving, tried all kinds of different speeds on the dewalt 611, but nothing works. I’m getting kind of desperate. I’ve tried all kinds of different bits (7 in total) everyone of them snaps within seconds of starting.
My last test was about 1/5 of the recommended speeds for aluminum with the dewalt at about setting 3.
If anyone out there can help me get through this project I’ll really owe you one!!! Uploading…
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What kind of bit(flutes upcut etc). What is you feed, step over and depth of cut?
For a branding iron you don’t need 90deg walls, using a V-bit will work much better, be much stronger and and the bit point can give you plenty of details.
At work we make branding irons and V-bit is the only things we use for that.
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Thanks for the reply, Phillip! After breaking each bit I kept going drastically slower each time out of sheer desperation. My last try was 30, 10 & 0mm with the 611 at setting 3. That broken bit is still in my piece haha.
I’m just desperate to get this project behind me.
Haldor, I appreciate the advice. If I ever try to do this again, I’ll definitely approach the project from a v-bit design. I’ve seen other designs that were much more shallow, but I thought maybe making 90 degree walls and a deeper design would help prevent some over burn when using it.
If you’ve got any kind of tricks up your sleeve for saving this project, I’d really appreciate it. I’ve got the back tapped, the handle and everything ready to rock and roll, but I can’t seem to get over this hump. I realize I was a little ambitious and jumped the gun here.
I leave my Dewalt at ‘1’ speed. 16k rpm is pretty damn fast already
Just started trying out on alloy, but with a 30deg V-bit going 12in/min I have had decent success so far.
Details about your 32nd bit help (how many flutes/length/material/etc)
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Thanks Paul… I typically do to, but just before this I had done some 6061 aluminum for a toolbox badge and found that upping the drill speed helped the job run much smoother. I just assumed that effect would translate to brass. I realize it’s a whole different monster though…
Each bit I’ve tried has been different, the last one I tried was this bit from Niagra. I’ve also tried very different kinds of bits… Pretty much exhausted all of my 1/32" bits trying to finish this 
I can’t say much about the brass, I bought it used on eBay. It was surprisingly machined and cheap for the size, but unfortunately I can’t say much about what kind of brass it is.
I guess if I have to scrap this, then I have to scrap it and get on with life… Maybe I was too ambitious with the design. I thought I kept it simple, but I guess using larger lettering, a larger and/or v-bit and shallowing out the depth of cut would be wiser than throwing more money and time at this.
I know certain endmills depending where you get it from will be less durable then others. I just ordered a few for aluminum and brass milling and I haven’t had any problems but not with that size that your looking to get more detail. I know even on larger machine people do that with tiny endmills and I was like it for sure would snap. I’ve heard some need the router/spindle fast and have the correct rate of speed to get what you needing. I’m hoping to upgrade my z and beef up the sides of my x carve so it won’t have much flex in it.
could something like this work by chance?
https://www.toolstoday.com/ball-nose-conical-ball-solid-carbide-spiral-cnc-2d3d-carving-tapered-and-straight-zrn-coated-up-cut-router-bits.html
The tapered bits are quite a bit stronger I just do not know if a tapered ball will work for your particular situation. This link has some available in .8mm as well as 1/32 but are a bit pricey. I believe they could be sourced cheaper on amazon / ebay this was just the first results when I did a search.
Thanks Mitch!
If I were to try to use a tapered 1/32 bit like that and just shallow out my depth of cut, what kind of bit would you guys recommend? Is there any certain coating or number of flutes etc… that would be best for durability or getting through this piece of brass?
With the dewalt on lowest setting and cutting brass I would try a 2 flute. As far as the fancy coatings I do not think you would need that for this project. As far as DoC and feeds / speeds and such I don’t have any suggestions as I have not yet cut brass on my machine.
@FredrickHousel
With really thin (and weak) bits you real enemy is tool deflection (tool bend from sideway force)
Runout/chatter add to this further and small bits break quickly.
My only advice with small diameter bits is to go as shallow as possible per pass. High RPM will be suited here due to low surface speed of the cutting tip (at 10k RPM a 10mm bit will have a much higher surface speed than a 1mm bit at 20k RPM)
Try setting the Dewalt to max, Depth per pass 0.1mm and feed rate 200mm/min
But my main advice is => use V-bits 
Thanks Haldor/Everyone…
So, do you guys think if I went with a bit like this:
… and followed Haldor’s suggested settings Dewalt to max speed, .1mm DPP and 200mm/min, that I might be able to salvage this project?
Speaking of depth per pass, when I was having my bit breaking party, I lowered the rate to a value below .1mm and (I believe it rounded down to just 0mm). I’m not sure what kind of value that translates to, but it didn’t help. Do you guys think I should bump that back to .1mm or just leave at zero? I’m at a point where I don’t care if it takes a long time to cut, I just want to get this project completed and behind me haha
I appreciate everyone’s help and advice here.
This type is very common, 30-60deg mostly.
Feed and depth per pass is mainly governed by the rigidity of your system.
Thanks… I’ll look into these type of bits for the future. My only concern is that since I’m already into this project with most of the design already roughed that a bit with a high angle like this would remove more material than I can afford to take away. Sorry if that doesn’t make sense. I’m not good at explaining things. I think a bit with a smaller angle would help me save this piece… I could be wrong. I often am…
Do you think the bit that I shared would likely end up in my garbage can after 30 seconds like the others?
Tapered bits are much stronger than long 1/32" bits thats for sure. The one you linked to is expensive though and I wouldn’t get one without specific use/knowledge Hopefully others might chime in.
Thanks. Yeah, I realize this won’t be as strong as one with a bigger angle, but my concern is that for this piece, everything is roughed out in anticipation of using a straight 1/32" bit. If I go with a bit with a wide angle I think it would thin out the existing walls of the design. It’s only an issue because I jumped into this without doing enough research. I’m just trying to find a way out of the hole that I’ve dug myself into. I definitely see the merit of using something like that bit you shared, Haldor. I just think it might be something I’d have to plan around.
I did one in easel and used 5"/min feed rate 3"/min plunge and .01" depth of cut, .060" total depth.
~5626007|375x500
1/8 inch rough and 1/32 inch detail same settings for both, and a little cutting oil
Thanks Joe! Last night I finally got a nice tapered bit like the one I shared above, and started cutting. It seems to be doing the trick. Now I’m trying to figure out how deep I can go before the taper starts thinning the walls of the design. I really appreciate you sharing your project and sharing your total depth of cut.
