is some brass bad? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: July 26, 2025, 09:55:56 pm
content: I was working on making a custom little adapter for pipes out of brass (simple enough) and this rod I have just seems to suck the drill bit in like a fucking black hole.I made something similar out of copper before,. and it was a little touchy, but I could do it. However this brass is just infuriating (it broke a #8 drill bit and then sucked in a #16 drill bit).It is cheap brass rod stock from amazon or something.I feel like I drilled brass before which was not behaving like this. I would say its more difficult for me to make then then If I used a copper rodI can usually peck my way through. But this feels like uncontrollable.I am drilling in the middle of the rod. I feel like something is wrong with the material. Have you ever encountered material that seemed to be misbehaving?

author: langwadt
author_rank: Super Contributor
timestamp: July 26, 2025, 09:58:52 pm
content: https://youtu.be/pAngKHIZgyA?si=2VNwATzubQXFGfYm

author: coppercone2
author_rank: Super Contributor
timestamp: July 26, 2025, 10:00:31 pm
content: Ok but I made basically a very similar part out of soft copper (custom bus bar interconnects) and I had to do nothing to the drill bit of similar size from the same set. I thought copper is supposed to be the worst material there is.

author: TimFox
author_rank: Super Contributor
timestamp: July 26, 2025, 10:21:39 pm
content: “Free-machining brass” is often considered to be the best alloy for normal drilling, etc., but it probably isn’t good for making cymbals.Legitimate vendors of metal alloys have useful guides to their products by type for different applications. Saying “brass” just indicates that the alloy contains zinc.

author: coppercone2
author_rank: Super Contributor
timestamp: July 26, 2025, 10:42:42 pm
content: is there some kind that is commonly found that.... pulls like crazy? or is it possible to get unusually grippy stock for some metalurgical reason?I think this is 'yellow brass'

author: Whales
author_rank: Super Contributor
timestamp: July 27, 2025, 03:01:12 am
content: Brass, bronze and mentions of copper are used somewhat loosely, despite what they're traditionally supposed to mean. The alloy could be anything.> Have you ever encountered material that seemed to be misbehaving?Yes. Not a brass but instead the stainless steel of my vernier calipers. I had to drill some holes larger in the tail end. The first hole was a cinch but the second hole went halfway and then blunted 3 drill bits without proceeding any further. I realised I must have unintentionally hardened the stainless (either thermally or mechanically).Perhaps it's possible to anneal your brass rod? Try putting a bit on a gas stove (or similar) and see if it's much easier to drill afterwards.

author: coppercone2
author_rank: Super Contributor
timestamp: July 27, 2025, 06:26:23 am
content: ok I cut another piece out and completed the job, this time I used 3 step drilling process. It is just a reducer so I needed to stop drilling one of the holes about 3/4 of the way down.It still pulled like a MF. When I tried to enlarge the hole it kinda went crazy but it did not break the bit but it drilled off center for a little depth... then It was corrected.I used 3x mag squares and a 45 degree vector vise + vblock for drilling, when I tried to do it in a 3-jaw chuck it started to spin in the chuck on the larger drill bit. I guess its just not tight enough or messed up, I typically only use it for soldering connectors or drilling tiny holes.I think I made a mistake the first time though, because I lapped the surface for a few min before drilling on diamonds and carbide. I cleaned it off but I wonder if I should have used the ultrasonic. Perhaps some diamonds got stuck on the surface and ruined the drillbit.I just wanted to see how flat the sanding job I did (sander + v-block) was, and lapping shows you. (and it does not smell, like dye fluid does)For the 2nd one I did not lap it because I was convinced It is working well enough to make a gasket work flatness wise. I will have to lap and polish the face of this part now

author: 2N3055
author_rank: Super Contributor
timestamp: July 27, 2025, 10:50:31 am
content: Quote from: coppercone2 on July 26, 2025, 10:42:42 pmWatch the video langwadt posted link for.

author: coppercone2
author_rank: Super Contributor
timestamp: July 27, 2025, 03:47:11 pm
content: It does not appear he goes into some thing that I would be interested in like if its possibly to do a bad cast or extrusion of brass where it gets some unfavorable crystalline form or something perhaps from a certain cooling rate or composition. Its a metallurgy question that I have. I know how to make special tools but the point is that they have not been required. So that might solve the problem without answering the questionI knew for a very long time you can make a special drill for certain materials but my question is "why am i cold in july" and you keep saying to wear more layersCompared to other similar looking similar sized brass I have drilled, this one takes the cake.If I made the specialized tools, I would probably never have noticed that there might be a difference. For all I know it might be bad stock that can crack or something. Cooled to room temperature previous red hot electrical copper directly after brazing did not even pose a difficulty like this brass rod did.With aluminum welding, itswell knownyou can get some seriously unfriendly material types/qualities that will drive you insane if you try to work with them. Is this also possible to run into this problem but with machining brass?

author: coppercone2
author_rank: Super Contributor
timestamp: July 27, 2025, 04:06:19 pm
content: and I would love to try it but I don't need more brass and a 1 inch rod from mcmaster is $50 to $150. I thought someone might know about it as a general shop tip regarding brass.

author: coppercone2
author_rank: Super Contributor
timestamp: July 27, 2025, 04:14:21 pm
content: also can anyone give me a comparison to bronze? I have a rod of scrap bearing bronze with an acceptable diameter. For drilling on a drill press, is it also liable to do the same thing? The pulling I mean.It says its harder. But that tells me little, because steel is hard and it gives no trouble. I would have just made this part from mild steel but it would rust. It is alot more expensive then brass and I am not eager to waste it.

author: microwhat
author_rank: Contributor
timestamp: July 27, 2025, 07:18:23 pm
content: All brass does that when drilled. Drilling out an existing hole exacerbates the problem, since the drill point (where most of the drilling thrust ends up) is no longer supported by the material. If you must drill a hole with multiple sizes of drill, it is best to drill the first hole no larger than the point width on the next drill to be used.The solution is to grind a small flat on each lip of the drill, which reduces the rake angle. While you're at it, if you can thin the web, it will greatly reduce the required drilling thrust.Normally the rake angle is the helix angle of the drill flutes, but as you have observed, in brass that will suck the drill into the work. By reducing the rake angle, the drill should no longer dig in.Bronzes may behave differently, and might be more difficult to drill. If you happen to have a piece of AMPCO 18 / 954 bronze, commonly used for bearings, power transmission nuts, and such, it will wear forward taper on your drill. The drill will then want to bind and the required torque will go way up. You must then trim 1 or 2 diameters off the end of the drill, repoint it, and carry on. I have found it helpful to grind the drill point slightly off center when drilling such materials: the hole thus produced is somewhat larger than the drill, which can no longer bind. The hole will get bored or wired, so the oversize doesn't cause me problems.

author: microwhat
author_rank: Contributor
timestamp: July 27, 2025, 07:33:09 pm
content: unmodified.png is an approximate model of a drill.Grind a little flat as shown in brass.png. The plane along which you grind should pass through the axis of the drill. You don't want negative rake in a steel drill point.

author: Benta
author_rank: Super Contributor
timestamp: July 28, 2025, 06:35:38 pm
content: ALL brass "pulls in like hell" when drilled.You need a 0 degrees cutting angle like microwhat shows on his pictures.This goes for turning, milling, drilling... etc. All cutting ops.

author: TimFox
author_rank: Super Contributor
timestamp: July 28, 2025, 06:42:02 pm
content: I remember “brass drills” from my university days that had straight (not helical) flutes, but I haven’t seen them in a long time.The different types of drill bits now listed in McMaster-Carr for drilling brass all have helical flutes.Looking further, I find straight flutes, especially in carbide, with relatively short cutting edges sold for very difficult alloys.

author: antenna
author_rank: Frequent Contributor
timestamp: July 28, 2025, 06:52:06 pm
content: I always wanted to design a safe that had loosely stacked brass plates in the door so when a drill bit goes in, the drill bit goes between two of the plates and snaps.

author: joeqsmith
author_rank: Super Contributor
timestamp: July 28, 2025, 06:53:01 pm
content: Depends. We used some half hard temper 360 for a project. Things were fine, until we went into production. Purchasing had changed suppliers. Same alloy, temper. Totally different grain structure. I was basically trying to anneal the brass, similar to what you may do for ammunition to get a better grain structure. In the end, we changed the design.

author: coppercone2
author_rank: Super Contributor
timestamp: July 28, 2025, 08:11:47 pm
content: Well I thought it looked a little funny after I sanded it. I need to find some old piece of brass and look at it to see what it looks like after its pressed into a belt sander. You start to see 'something' after that which makes it look crystal-like on the surface.I know this brass is cheap because it was purchased for the lowest possible price available from random people.I thought about trying to lap it and use one of these to comparehttps://www.metallographic.com/Metallographic-Etchants/Metallography-Brass-Bronze-etchants.htmI don't know enough about lapping yet though (I finally got my first cast iron lapping plate this year), it gets flat but its scratched up from diamonds. But after that I dust it on the random orbital sander on 600, 800 and 1000 grit, then do a prepolish, polish and super polish on it with dealux orange, white and blue, and it looks basically like a mirror and makes a fine gas seal on the gasket.I just need to make some etchant and see if I can get something like the pictures jumping off from one of those steps

author: joeqsmith
author_rank: Super Contributor
timestamp: July 28, 2025, 08:46:15 pm
content: Shown are the same alloy but annealed differently.

author: thm_w
author_rank: Super Contributor
timestamp: July 28, 2025, 08:51:04 pm
content: You can also try using stub length/screw machine drills, where long reach isn't needed.But if the material itself is flexing that won't help.

author: MarkF
author_rank: Super Contributor
timestamp: July 28, 2025, 11:27:59 pm
content: I have not tried drilling brass.But, there is 'red' brass and 'yellow' brass.The 'red' brass is safe for drinking water.I have read that 'red' brass is easier to machine than 'yellow' brass.

author: cunningfellow
author_rank: Regular Contributor
timestamp: July 28, 2025, 11:34:50 pm
content: Wouldn't lead content make for easier machining?

author: Benta
author_rank: Super Contributor
timestamp: July 28, 2025, 11:54:47 pm
content: Quote from: cunningfellow on July 28, 2025, 11:34:50 pmYes... but in aluminium, not in brass.

author: TimFox
author_rank: Super Contributor
timestamp: July 29, 2025, 12:30:29 am
content: Quote from: Benta on July 28, 2025, 11:54:47 pmThe most machineable brass (alloy 360) has the highest lead component of commercial brass alloys.61.5 Cu, 35.5 Zn, 3 Pb, 0.35 FeIt is assigned a nominal machineability of 100, the highest value for Cu alloys.

author: MarkF
author_rank: Super Contributor
timestamp: July 29, 2025, 06:51:28 am
content: For reference:The 'red' brass safe for drinking water was Alloy 230.

author: Benta
author_rank: Super Contributor
timestamp: July 29, 2025, 06:26:47 pm
content: Quote from: TimFox on July 29, 2025, 12:30:29 amIt will still grab seriously. The right solution is cutter geometry, period.And that means a cutting angle of 0 degrees.

author: TimFox
author_rank: Super Contributor
timestamp: July 29, 2025, 09:26:23 pm
content: Along that line, I have seen “step drills” recommended for drilling 360 free-machining brass alloy.Also, to avoid pilot holes.

author: Benta
author_rank: Super Contributor
timestamp: July 29, 2025, 11:49:18 pm
content: Again:Just take a normal HSS drill and grind the cutting edges to 0 degrees as shown in post #12.This is common knowledge since the last +100 years.

author: TimFox
author_rank: Super Contributor
timestamp: July 30, 2025, 01:34:46 am
content: And 50 years ago, I could find HSS drill bits with non-helix straight flutes for drilling brass.

author: coppercone2
author_rank: Super Contributor
timestamp: July 30, 2025, 04:18:51 am
content: Does anyone know what parameters of the material change when it has the irregular grain structure?I mean engineering consequences. Other then workability differences, does it result in changes to performance parameters that you might expect from a brass alloy? Stuff like tensile strength, flexibility, susceptibility to corrosion, conductivity, etc.

author: MadTux
author_rank: Frequent Contributor
timestamp: July 30, 2025, 07:19:37 pm
content: Just use a rigid machine, big drill press, milling machine, CNC....If drill can't move in/out, because it's fixed to a chuck and no slop in drill press quill, it can't pull itself into workpiece, so pretty much any cutting edge geometry works, as long as it cuts.And use a vise, screwed to the table, so workpiece can't pull itself into the drill.

author: 5U4GB
author_rank: Super Contributor
timestamp: August 02, 2025, 12:29:30 pm
content: Just wondering, would a step point drill also deal with the problem of grabbing? These have what looks like a miniature step drill at the tip until they reach the full width of the drill, whereupon they turn into a standard twist drill.Great for drilling clean holes in metal, although I don't know what they do with brass.

author: EC8010
author_rank: Frequent Contributor
timestamp: September 18, 2025, 08:51:27 am
content: Allbrass snatches when a drill breaks through. Ideally, you have a set of brass drills ground as others have suggested. Alternatively, you make sure the work is clamped securely so that it can't snatch up the drill, and you go very gently as you feel the drill break through. In a similar vein, clockmakers know that it's essential to minimise backlash in the drilling machine's quill or little drills will break.Copper is a different kettle of fish because it is sticky, but lubrication with full-fat milk works when drilling or tapping. You need to clean upfullyafterwards to avoid nasty niffs.