u/LLLCNC

I’ve outlined my machining process in the video. You can review and learn from the steps. When machining thin-walled shell components, internal stress relief is absolutely critical. After roughing, I heat-treated the stock and let it rest overnight to fully release machining stress and prevent distortion.

I used a Dean 5-axis and DMG 3-axis machine. I had to machine very carefully to avoid part deformation from excessive cutting forces.

After I finally nailed this challenging job, the operations manager complained that it was a trivial part with just a -0.02mm tolerance, and asked why it took me three days. I stayed silent. This part is now in small-batch production. I’m trying to figure out what to say at delivery to make this arrogant person pause. I also want to ask everyone: do you think this lead time is reasonable?

You guys, guess how I should clamp this iron egg for the final operation. If it shifts mid‑machining, we’ll have total chaos and end up with an “asshole” instead of a finished part.

I machined the full internal keyway using 4‑axis simultaneous motion. If I need an even smaller corner radius, I can use a smaller end‑mill to clean up the fillets. Realistically, that radius can get extremely close to zero. I’m sharing my programming workflow so everyone can check out this really neat technique.
**（**Addendum: Truth is, I spent half an hour fixing the issue for the boss. You know how that scene went? The boss walked into the shop with the client, asking if anyone could sort out the problem. I stepped up and bet I could pull it off. Not only did we put our idle machine to good use, I also got to demonstrate my skills. So what’s wrong with me wanting to share this technique with others?

For context, that inner fillet was added at the client’s request. They were worried sharp‑angled corners would get clogged up with dirt during use. On top of that, we didn’t have a long‑enough R0.5 flat‑end cutter. The nearest tool suppliers and wire‑EDM shops were dozens of kilometers away. Wasn’t this the most practical solution available?）

Last week, an apprentice broke a micrometer and the boss fined him. That sparked an idea, so I machined some micrometer‑themed trinkets. I plan to give one to the boss and one to the apprentice as a gesture of comfort. I’m afraid this might come off as sarcasm, even though there’s a little bit of that intent behind it.

So here’s what happened. The work instruction told the apprentice to check the part on the machine every ten pieces. He did that perfectly. To avoid making mistakes, he practiced repeatedly on already‑inspected parts. Once the workpiece finished machining, he performed a solemn measurement and logged the readings. Then… then he hit cycle start with the part still clamped. His reasoning: the work instruction never said to remove the part before restarting the machine. And that’s how we got this one‑of‑a‑kind micromet

A traditional anniversary is coming up. I’ve made a ring for my girlfriend. I cast the 14K gold blank using lost-wax casting, then ran finish machining on a 5-axis machine. I plan to get it bright gold-plated so it shines just like the gold rings you see in mall jewelry displays.

Last time I gifted her an aluminum bracelet. It might have come off as too cheap, or she just didn’t find it wearable. Either way, she wasn’t all that excited. She thanked me, and that was it — she never wore it.

That’s why I went all out this time and modeled the design after commercial jewelry styles you’d find in shopping malls. I love putting together gifts with my own hands. I’m planning to tell her: this piece is handcrafted gold jewelry made with high-end 5-axis machining. Hopefully this won’t feel cheap. What do you guys think?

As you can see here, I machined this metallic watch case after someone mocked my cheap watch.
I started by 3D scanning the original watch to capture its model, then programmed the toolpaths in Mastercam.
But I quickly ran into issues: the STL file lacked sufficient precision, and programming with it turned out to be extremely cumbersome. In the end, I remodelled most of the curved surfaces manually using the STL only as a reference. It was a gruelling process, so I wouldn’t recommend programming directly off raw STL files.

My machining sequence began with the internal cavity. Afterwards, I milled a matching male fixture boss out of acrylic, shaped to closely follow the cavity profile. It fit perfectly inside, secured with adhesive, and only then did I machine the outer surfaces. The end result is a really nice-looking watch case.

That said, it’s not functional for assembly. I overlooked a critical detail: the original plastic case is flexible and tolerates minor dimensional shift, so parts slot together easily. Metal requires tight, precise fits, which is incredibly hard to achieve working from a scanned STL mesh.

This Casio watch was a gift from my best friend years ago. I’ve always cherished it and gotten totally used to wearing it every day.
My colleagues kept telling me I ought to switch to a solid metal watch with proper masculine heft, preferably an expensive luxury timepiece.
But I’ve always believed personal preference matters most. That’s why I machined this custom brass case for it myself.
I want them to understand: there’s no need to splurge on pricey brand-name watches. As a machinist, I’m fully capable of giving my beloved timepiece that rugged metallic feel with my own hands.

My young nephew said my car wasn’t luxurious enough, so I’m planning to upgrade it for a more premium feel. Lucky for me, I used to be a seasoned five-axis machining specialist capable of tackling just about anything.

I designed, modeled and machined this bracelet entirely by myself. I’d love to get your take on whether it actually has aesthetic appeal, which is why I’m asking all you experienced folks. I’m planning to give it as a gift. Right now it’s made of aluminum, and I’m also thinking about switching it to other materials. English isn’t my first language, so please excuse any odd phrasing in my writing.

My girlfriend’s birthday is right around the corner. Last year we walked past a jewelry store, and she casually said how beautiful a bracelet set there was — that line stuck with me. I spent a full week putting this together, from design and 3D modeling straight through to machining. I made this entire matching couple’s bracelet set completely by myself. They’re 6061 aluminum, machined full 5-axis simultaneous, and I used an MCD diamond end mill for high-precision milling to achieve this finish. I think it’s super meaningful because I put so much work into it, and I was set on giving it to her as her birthday present. But I can’t stop second-guessing myself. I’m worried aluminum will feel too cheap, that she’ll be underwhelmed and I’ll end up ruining her birthday. I’m wondering if I should pair it with a nicer, more expensive gift too. For the record, I do get her pricey presents all the time — I just think a handmade one like this means so much more. This is my first time ever making a handmade gift for someone, so I wanted to ask you all what you think. I really don’t want to mess this up. Also, English isn’t my first language — I’m using a translator to communicate here, so please bear with me if anything comes across off.

I took everyone’s advice from my last post. I called both my boss and the production supervisor over to the machine tool, broke down every single reason for our delayed project output one by one, and ran a live demonstration to prove the machine’s rigidity. I left them to negotiate and work out solutions between themselves.

For context: The beat-up no-name 3-axis linear guide CNC the production supervisor keeps complaining about is only used for roughing aluminum parts. All finishing work gets sent to our DMG 5-axis machine. Our 5-axis mill sits idle constantly, stuck waiting for this old 3-axis machine to finish stock removal first. That means maximizing material removal rate is our top priority here.

But the supervisor always runs cutting parameters far below what the cutting tool manufacturer recommends, claiming the machine is too worn out to handle aggressive feeds and speeds. Truth be told, this old girl has lost all its precision for fine work, but it’s just like an antique steam train — it’s got endless brute torque. I fully accounted for the machine’s mechanical limits when I laid out the entire machining process plan from the start.

Still, I do understand where he’s coming from. Who wouldn’t want to take it slow at work, sneak in World Cup viewings or grab extra coffee breaks while the machines run? That’s exactly why I chose to demonstrate the machine’s actual cutting capacity, pushing him and my boss to hash out the productivity issue head-on.

If I hadn’t done this, my boss would have blamed all the slow output on flawed process planning from my side. Unfortunately, I couldn’t afford to prioritize the shop crew’s easygoing rhythm. I feel terrible about putting him in this spot, but upholding production efficiency is my job responsibility. I have no idea if he’ll resent me for this, yet my boss has completely run out of patience with our glacial workflow.

Should I ask him out for a drink to explain everything and clear the air between us?

I’m not a native English speaker, so I use translators, sorry for any weird phrasing. This is all my own writing, no AI made this.

My boss constantly complains about poor machining efficiency, but the production foreman claims the machines he bought are cheap and lack rigidity, making higher cutting speeds impossible.

As a process R&D engineer, I’m stuck between the two sides. If I side with the boss and call out the foreman, I’ll easily burn bridges with him. Yet if I fail to fully unlock the machine’s full potential to prove that slow output isn’t caused by equipment limitations or flawed processes, I’m not earning my paycheck.

I’ve run a series of performance tests on this machine, as shown in the footage, and the results speak for themselves. Now I’m torn over whether I should show this video to my boss.

I shared my five‑axis machining video of the ashtray a couple of days ago, and most people were particularly curious about how I improved surface finish quality. In this post I’d like to share my practical machining know‑how.

The footage at the start shows mirror‑finish machining from a project I completed three years ago. The core secret lies in the cutting tool: it is an MCD diamond end mill made from the same material as diamond rings.
When using this cutter, tool run‑out must be kept below 0.01 mm, which is absolutely critical. Even though diamond is extremely hard, it has poor impact resistance. That means a high‑quality tool‑holding setup is essential, and your spindle cannot be overlooked either.

The spindle should run at a sufficiently high speed, ideally above 15000 RPM with a feed‑rate (F‑value) set between 200‑500. One thing you have to keep in mind: MCD tools are surprisingly fragile, roughly as brittle as regular household glass. Before finishing with the diamond cutter, reduce the remaining stock down to 0.02 mm to minimize the cutting depth for the diamond tool.

This is advanced machining technology normally used to produce high‑precision parts like optical mirrors. It’s overkill for making decorative artwork pieces such as my ashtray. Still, I don’t mind at all. It lets me demonstrate my skills and share hands‑on experience with fellow machinists.

A while back, I machined a custom art-style ashtray for myself that I absolutely love. My boss spotted it and kept dropping heavy hints about how much he wanted one for himself. I poured tons of time and effort into that piece, though.

Thanks to everyone’s advice from yesterday, I realized this little project is a great bargaining chip. It’s the perfect way to show my boss exactly what my machining skill set is capable of. As a thank-you for all your help, I’ve negotiated full permission to film in the workshop for extended stretches.

For anyone who works in R&D-focused manufacturing firms, you’ll know how rare and hard to get that filming clearance really is. I’m going to break down and demonstrate 5-axis machining techniques using this ashtray as my showcase part. Feel free to hit me with any technical tips, questions, or feedback you’ve got!

I’m a mechanical designer, and I machined this industrial art piece in my spare time. I sacrificed three full days of my free time on it, pouring tons of effort into designing the process and writing all the CNC programs. This isn’t my main line of work, and I haven’t touched a machine tool in ages, so I was pretty rusty the whole time.

The machine sat idle at our factory, so I took the chance to make this. I originally planned to take it home as a personal keepsake, but my boss has been dropping heavy hints that he really loves the piece. It’s easily my most satisfying machined art creation to date! Right now it’s tucked away in a drawer in my office, and I’m totally torn over what to do.

One more thing: I bought all the material out of my own pocket, and I’ve already restored the machine back to its original state—all fixtures and cutting tools have been removed. If I had to machine this piece again, you know just how much hassle that would be.