u/Less_Spread_2691

I run a manufacturing startup in Bengaluru. There are four of us, we do all sorts of 3D printing work with partner shops for CNC, sheet metal , composites and other fabrication.

I spend a lot of time looking at drawings from hardware teams before they go to manufacturing, and the same mistakes keep showing up.

The frustrating part is that most of them don't cause an obvious failure. The shop just quotes higher, takes longer, or makes assumptions you didn't know they were making.

Here are 8 that I see repeatedly:

1. Tight tolerances everywhere

±0.05 mm across the entire drawing when only two or three features actually mate with something.

Tight tolerances can mean slower machining, additional passes and more inspection. Identify the critical interfaces and tolerance those properly. Don't make the whole part unnecessarily precise.

2. Deep pockets with small internal corner radii

Deep features combined with small corner radii can require long, small-diameter cutters. That increases the risk of chatter and slows machining.

If the design allows it, use larger internal radii and avoid unnecessarily deep, narrow pockets.

3. Sheet metal bends without proper relief or realistic bend radii

Sharp corners and missing bend relief can lead to tearing, distortion or parts that are simply difficult to manufacture consistently.

The material thickness, bend radius and fabrication process all need to be considered while designing the feature.

4. Material specified before understanding the actual requirement

I've seen expensive materials specified when a more readily available alternative would meet the actual mechanical and environmental requirements.

Instead of starting with “this part should be SS316”, start with “what does this part actually need to survive?”

Strength? Corrosion? Temperature? Weight? Wear?

Then select the material.

5. Fine surface finish specified everywhere

Usually, only certain faces actually need a controlled finish — sealing surfaces, bearing interfaces, mating faces, etc.

Specifying a fine finish across the entire part can add unnecessary machining operations and cost.

6. Threads designed without enough engagement

This is especially common with thin sections, soft materials and parts that will be assembled repeatedly.

Depending on the application, threaded inserts, helicoils or other fastening methods may be a better choice than simply tapping directly into the material.

7. No clear datum scheme

If the drawing doesn't clearly communicate what the critical features are referenced from, the manufacturer may interpret it differently from the designer.

Then the part arrives, everyone measures it differently, and suddenly you're arguing about whether it's actually within specification.

A few minutes spent defining datums properly can save a lot of back-and-forth later.

8. Choosing the manufacturing process after the design is finished

This is probably the one I see most often.

A one-off complex part might be perfect for 3D printing.

A flat part with simple holes might be better laser cut.

A high-strength, low-volume component might make more sense machined.

The expensive mistake is often designing the part first and only then asking, “How should we manufacture this?”

I'm curious what other engineers and hardware founders keep running into.

If anyone wants a second pair of eyes on a drawing or STEP file, feel free to DM me. No charge and no obligation.

We're early, and honestly, reviewing real-world designs helps us understand the problems people are actually facing.

For context, we currently print in-house and work with manufacturing partners for CNC machining, sheet metal, composites and fabrication.

Happy to answer questions in the comments.

Hi all,

I'm one of the founders at a hardware company in Bengaluru. Over the last couple of years we've built an industrial  3D printer and a VTOL drone platform. Both took longer than they should have, and a big reason was procurement.

The loop looked like this: send a STEP file to five vendors on WhatsApp. Two never reply. One replies in four days with a number and no breakdown. One quotes a price that changes after they "check the material." One is great but booked for three weeks. Then you do it again for the next revision.

None of that is the vendors' fault. Most of them are good machinists running a shop, not a sales desk. The coordination layer just doesn't exist.

So we built Hanzof. You upload a part file, tell us the material and quantity, and an actual engineer on our side reviews it and comes back with a quote — we're holding ourselves to 6 business hours. Right now we cover CNC machining, sheet metal, 3D printing, and composites.

What I'd rather be upfront about than have you find out:

We are not going to be the cheapest quote you get. We're trying to be the one where the price doesn't move and the part shows up when we said it would.

We're early. If something is broken on the site, it's because we built it recently, and I'd rather hear it from you than not hear it.

Two things I'd genuinely like to know from this sub:

When you source custom parts, what actually kills you - the price, the lead time, or the back-and-forth?

What's the longest you've waited on a quote that eventually came back useless?

And if you've got a live part you need quoted, send it through and use it as a test. No obligation, and I'll personally look at it. Worst case you get a second data point on pricing.

Link's in the comments.

Thanks for reading.

Hi all,

I'm one of the founders at a hardware company in Bengaluru. Over the last couple of years we've built an industrial  3D printer and a VTOL drone platform. Both took longer than they should have, and a big reason was procurement.

The loop looked like this: send a STEP file to five vendors on WhatsApp. Two never reply. One replies in four days with a number and no breakdown. One quotes a price that changes after they "check the material." One is great but booked for three weeks. Then you do it again for the next revision.

None of that is the vendors' fault. Most of them are good machinists running a shop, not a sales desk. The coordination layer just doesn't exist.

So we built Hanzof. You upload a part file, tell us the material and quantity, and an actual engineer on our side reviews it and comes back with a quote — we're holding ourselves to 6 business hours. Right now we cover CNC machining, sheet metal, 3D printing, and composites.

What I'd rather be upfront about than have you find out:

We are not going to be the cheapest quote you get. We're trying to be the one where the price doesn't move and the part shows up when we said it would.

We're early. If something is broken on the site, it's because we built it recently, and I'd rather hear it from you than not hear it.

Two things I'd genuinely like to know from this sub:

When you source custom parts, what actually kills you - the price, the lead time, or the back-and-forth?

What's the longest you've waited on a quote that eventually came back useless?

And if you've got a live part you need quoted, send it through and use it as a test. No obligation, and I'll personally look at it. Worst case you get a second data point on pricing.

Link's in the comments.

Thanks for reading.

Specifications:

Max acceleration: 55000 mm/s2
Max speed : 800mm/s
Max nozzle : 450 c
Max Chamber: 90c
Bed size : 350 x 350 x 370
Integrated dryer box with upto 120 c

We’ve been working with a bunch of early-stage hardware teams lately, and one thing keeps coming up — moving from prototype to actual production is way harder than expected.

Things like:

finding reliable CNC vendors

getting consistent 3D prints

small batch production (vacuum casting / injection moulding)

managing multiple vendors without delays

Curious — what’s been the biggest bottleneck for you?

Happy to share what we’ve learned / help out if anyone’s stuck.

(Attaching a few builds we’ve worked on recently)