• How Much Would This CNC Machining Work Cost?
    19 replies, posted
I need a part fabricated for a project I've been working on, most CNC websites offer price estimates, but without a CAD file to upload I can't get a price so I figured the next best option would be to describe the part and see if anyone here with experience would have an idea of the cost. The piece is essentially a block of steel, 6" long and 2" wide.. It has two 1/2" holes drilled lengthwise from one end to the other and threads (3/8 fnpt) on all four exit points. I only need one. 20 coins to whoever can give me a decent answer.
Can you draw a rough diagram of the part in Paint or something? I have lots of CAD experience and can at least make a model for you to share.
Fusion 360 is super easy to use. Just sketch it out in there, export it, and bam you have your CAD file.
It'd be helpful if you drew a simple diagram of what you want. I can easily wip something up in solidworks but I have no idea where to position the holes on either end.
We need a lot more information to even begin giving you an answer. Without knowing what you are doing, and at least a rough sketch of the part with critical dimensions listed, we can't really go anywhere. This sounds like a really basic block, but there's tons of other things that could crop up as well if it's more complicated than that. In addition to the above, what sort of material are you planning on making this out of? What are the tolerances? Do you care about surface finish (IE is this going to be sliding in/alongside something else)? Do you care about the hardness, heat resistance, etc of the material? Does it need to be resistant to corrosives?
I just threw together a basic model of what I assume you want, you are looking at $320+ from a random CNC service I found online: https://get.xometry.com/quote/00000-205CB
Okay sorry about the lack of details, I realize these are really basic specs but I'm really just looking for a ballpark estimate to see if this is within the realm of financial possibility for me. Here's a quick drawing after 20 trillion ms paint hours, the threads can just be any threads, I don't think it'll change the cost very much. https://i.imgur.com/E1Xx5pu.png
You don't need CNC machining for such a part. Normal machining would work just fine.
Most cnc machinists will overcharge you for that because they think you're wasting their time, you can do this in about 30 minutes on a regular mill and most of that will be tapping the threaded holes. If you get the stainless bar (standard 304 would be about $30 I think) could you get someone with access to a workshop to do it for you?
Something I forgot to ask, what it the purpose the part? Because if the part won't be in any high-wear or load bearing situations, you could just make it out of 3D-printed plastic which would be much cheaper.
If you gave me the center-center spacing between the holes and desired thread depth, I could probably make this in about 20 minutes out of scrap aluminum bar stock.
Go find yourself a drill press at a shop near you, or a university shop, or a friend's garage and you could do this yourself. If you give it to a shop it'll cost at least a couple hundred bucks.
Depends on how precise you want things really. If square to 1/64 is good enough it's literally just roughing with a fly cutter and flipping it a few times then plunging the holes. If you need it within .0005, it's going to take time.
Do the holes need to go all the way through or do you just want them aligned? I could make this in 20 minutes with a regular milling machine. If you live near a high-school with metal shop class you might be able to contact the teacher to have the part made. In shop class I made quite a few things that were for people outside the school, good old child labor.
This will be a pneumatic air chamber so it needs to tolerate at least 1000 psi within both of the drilled holes when plugged, steel is an absolute must. As for getting a drill press, I have nowhere to work where I live.
I can (most likely) do it sometime next week if you are willing to provide a shipping label. The only annoying thing is going to be lining up and reaming the 6 inch holes. Do they have to be 1/2, or is 37/64 fine? I ask because 37/64 is the tap for 3/8-18 pipe threads, and it's generally easier to just shove a drill completely through than to start fiddling with depths. How deep do you want the threads? Do you want chamfers?
37/64 will do. The only function the two drilled out spaces serve is to hold air pressure, the only requirement is that it doesn't have any leaks when plugged and brought to pressure, the larger volume will have no noticeable effect. The threads only need to be 1/2" deep but must be 3/8" 18 fnpt. Chamfers aren't necessary. I can provide a shipping label and payment for your work.
What's your steam?
Xamllew Here's a more detailed plan, hopefully understandable https://i.imgur.com/46nF053.png
I'm not a machinist, but I don't think the tube connecting the longer tubes is possible. Don't see how you'd get a tool in there to drill it out.
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