Download, Edit and Print Your Own Parts From McMaster-Carr




About: Artist in Residence at Instructables. I'm a hardware hacker, artist, illustrator, and cartoonist. I make things with whatever tools I can. I design and build interactive art pieces, from museums all the way ...

McMaster Carr is an amazing resource. It's well laid out, informative, comprehensive..but even better, they provide free 3D models for most of their parts. Not all, but many.

If you have access to a 3D printer, you can print these parts yourself. Pretty cool, eh?

Step 1: Find Your Parts

First, point your browser to...

See? Easy peasy. Just clickity click. Not all parts on McMaster have 3D models for download. For this example, I'm going to be looking for sprockets. I've navigated to the part I want, and clicked on the part number. A little box pops up with some information.

More importantly, this particular part has the little symbol next to it that denotes a 3D model is available. I've highlighted it with an arrow in the picture.

Step 2: Download the File

After you click the product detail icon, this is the page you come to. I want a STEP file, as I'll be going into Fusion360.

If you're a user of CAD software that takes any of the files shown, congrats! You can now take those files and use them for modeling or 3d printing. Me, I'm continuing on to Tinkercad, to edit the part a little and to 3D print.

To do that I need to convert STEP into STLs.

Step 3: Convert File to STL in Fusion360

Once you've downloaded your file, open up Fusion360 and click 'upload'.

When the upload is completed, open it. You can only export single bodies (solid shapes) so you have to either delete the ones you don't want, or download them one by one. In the navigator menu click on 'bodies'. In the tree that shows up select the bodies you want, either to delete or download.

In this case the sprocket came with a set screw in the model, which I removed.

In the menu that pops up, click refinement as 'high'. Do not change any of the measurement settings.

Step 4: Upload to Tinkercad

Head over to and open up a new project. On the right hand side you'll see an option for 'upload file'. Navigate to your STL and upload it, again without changing any size parameters.

Here is the file for this sprocket, uploaded to TinkerCad:

Step 5: Tinker!

If you need to, edit the model. For example I might want a different shaft diameter; but since I uploaded this as a solid body I'll have to do a little workaround. First filled the shaft bore that was there, and grouped the two shapes. Then I made a cylinder of the shaft size I wanted, made it a hole, centered it on the model, and grouped them.

In this step you could add multiple STLs if you wanted a complex part, say, where gears were interacting. The beauty of 3d printing is that you can both make multiple iterations of custom parts, that would normally take a lot of time and money otherwise.

You could even do specialized shape shaft drive- like a hex!

Step 6: 3D Print

I've printed the sprocket on an objet connex 500. The one on the left is the part as ordered from master, the one in the right is my printed part.
You can use this technique for all sorts of parts; and many on master will print just fine on a lower resolution/extrusion 3d printer like a makerbot. Kings like motor mounts, pillow blocks, chain tensioners, specialized brackets, pulleys- will all print well on an extrusion printer.
I encourage modification as well! Once you're 3d printing you can add decorative elements, or even combine parts!
Another thing you can do is use the product file as a subtraction/hole. For example, you can download the file for a press fit bearing, convert to 'hole' in TinkerCad, and subtract if from a base to make a perfect press fit. You can use that to create perfect recesses for bolts and fasteners, as well.
There are some more in depth techniques I'll post about in later instructables, but for now, go out and grab some parts!

Another website that offers CAD files is SDP (standard drive products):

Step 7: Some Other Websites to Check



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39 Discussions

As a product designer I often do this since I need to see how a part will work in a design. for example I'll print the shell of a blower and test mount it in a case.


1 year ago

Thank you for this information, I will share it with all my fellow hobbyists.


3 years ago

Anyone else know we're on the site,, are available cad 3d files of some of the basic hardware they offer? Thanks


4 years ago on Introduction

Some companies (SDP-SI for one) are a little smarter. The cad files they give you are incomplete - they show enough information to be useful in design but insufficient to be directly used for 3D printing. (I think this originated as a way to reduce transmitted file sizes but it works to avoid 3D plagiarism too).

For example a gear would show the basic disk/hub but only 3 actual teeth. Since the models generally come into the CAD program as an "import feature" there is no history for recreating the missing features ..... it's just a single solid. The work involved in converting it to a full model would be at least as much as creating one from scratch.

Gather ye rosebuds ....


4 years ago on Introduction

Seems like a wonderful way to pull files into cad apps permitting you quick solutions to use elements from existing designs a new item.

for example:

You want to use a specific tapered thread configuration to incorporate into a design of a new item, compatible with an existing product line....if the cad file for a product exists using that thread, one can clone a section for incorporation into the new design.


You need a project case, but nothing is size or mount post compatible....start with a cad file to break into pieces and resize to your needs, adding whatever ports or posts needed to meet your configuration.

This could greatly speed up design and prototype work.

Thanks for the suggestion and steps!


4 years ago on Introduction

This is an excellent idea for prototyping before purchasing parts, or doing one-offs for my own projects.

Regarding the legality issues: (with the standard IANAL disclaimer)
If I print out a copy of a part from a cad file for my own non-commercial use, who cares? I could just as easily use the cad files to machine a part out of metal if I was so inclined. I have built furniture for myself based on designs I've seen online.
Once I start to distribute, including online postings of images, then it gets complicated. Copyright is exclusive rights to use and distribution. Under this idea, we need to distinguish two separate items: the rights regarding the gear itself, and the rights regarding the drawings and models of the gear.
If I were to take the cad drawing of the gear, or the model file of the gear, and incorporate it into a larger piece, such as incorporating the gear into a larger 3d model of something steampunk, then I believe one could argue fair use for redistribution, since I am not directly affecting McMaster Carr's use and distribution of the file, their TOU not withstanding regarding derivative works.
If I were to take the drawing/model, and convert as in this instructable, where in I modify the file for use as intended (as a gear), then it's hard to argue that you are not in some way affecting McMaster Carr's rights.
Where it gets fuzzy is in the intersection: What if I use their 3d model to print out a bunch of gears and distribute those, while never distributing the file itself? My gut and common sense says yes, but I truly don't know.

Contra-ir-regardless, I'd ask a lawyer before using the files before any sort of distribution. Someone got paid to make these drawings, so it'd be bad to ignore that.


8 replies

I think regarding your "fuzzy" question it's pretty clear cut I think. As copyright covers derivative works, regardless of medium (i.e. make a sculpture based on a painting and it's still counted as derivative), it would indeed be a breach of copyright to print and distribute. If you think about it that's pretty much how Chinese knockoffs work.

Copyright covers artistic works, not useful things, useful things are covered by patent or registered design.

See this for a good overview.


Reply 4 years ago on Introduction

Copyright is used to protect not just artistic works, but anything 'intangible'. The code I right at work is copyrighted, and the 2d and 3d representations of the gear are copyrightable, as far as I understand it.


Reply 4 years ago on Introduction

I recommend reading the link I posted. It is based on UK law, but under the Berne convention other country laws tend to be similar.

further complication arises via CDPA 1988 s 51. This provides that
the copyright in a design document is not infringed by making
an article from it. Introduced to avoid the use of copyright to
restrict the sale of third-party spares
it means that even if prior graphical artwork exists of a product, if
it is deemed to be a design document for that product then its
copyright is not infringed by making a copy of that item. This was
the case in Lucasfilm where the concept artwork for the
Stormtroopers was held to be a design document for the helmets, so
copying the latter did not infringe copyright in it."


"Thus, although a 3DPDF
[3D Printer Design File] will be protected by copyright, as a design document its copyright
is, by virtue of s 51, not infringed by using it to make an item. It
is still an infringement of copyright in a 3DPDF to copy it without
authorisation, so trafficking in copies of a manufacturers’
official 3DPDFs for spare parts would be illegitimate."

Their TOU, see a few posts below, allow copying (to download) thus the printing, for non-commercial use, is legitimate.

Much of this will need to be tested in court tho.


Reply 4 years ago on Introduction

I've read the article, and it in fact doesn't disagree with my points. As I said in my first point, making the object itself is not violating copyright afaik. If someone has posted 3d files online, then it's neigh impossible to really prevent someone from creating for personal use, just from a logistical standpoint (would you sue everyone who printed from your file of a gear?).

My point about where legality matters and I would ask a lawyer is the distribution of:

* files translated from 3d models to 3DPDF (stl, g-code)
* files which use the designs supplied in whole or part
* physical items produced through the designs in part or whole

Basically, the moment that a creator uses something created by someone else (source) in something the creator then distributes (derivative) to a third party is the moment where one should be absolutely sure one are in the right, both morally and legally, regardless of whether the source is used in part or in whole, whether the derivative is distributed for free or profit (monetary, reputation, etc.), no matter what.

In this particular example, McMaster Carr's TOU and reasonable expectation is that their designs are going to be used for the purposes of engineering and design, with the hopeful goal of gaining customers for a creator's production products or for single sales after it's confirmed the part is a match. This most certainly includes 3d printing for prototyping, which is the case of a creator making it for their own use, and for a hobbyist to create something as their explore engineering and artistic pursuits.

The moment a creator wishes to use this design in something they want to distribute, however, is where trouble begins. As the article above mentions, making something is ok, but the moment you begin to distribute is where you should seek the advice of a lawyer. None of the authors of that article appear to have law degrees; this is not to say their arguments are flawed, but I'd certainly feel more assured getting advice from someone whose career is copyright law.

There are sites like and where you can get free answers from lawyers, and if you are about to sell something, paying for an hour or three for a copyright legal firm sounds like a good investment.


Reply 4 years ago on Introduction

I totally agree, you'd want legal advice before dipping your toe in the commercial stream.

However, the bit about "physical items produced through the designs in part or whole" is fairly clear, unless it is a registered design or patented device, e.g. the 3rd party spare parts.



MEng Electronic & Electrical Engineering (Imperial College)
MSc Satellite Communications Engineering (Surrey)
LLB (Hons), Open University
LLM Intellectual Property and IT Law (Edinburgh)
Chartered Engineer

Centre for Commercial Law Studies, Queen Mary, University of London.


Reply 4 years ago on Introduction

I couldn't find any bio page for Simon Bradshaw except for an article listing his engineering degrees, so I didn't want to assume he was a lawyer. Thanks for providing his credentials.

No really clear on the fuzzy, because again, you have to separate the tangible (gear) from the intangible (drawing of a gear). If I made my own gears like that particular gear without ever looking at their drawings or models, then they would need a patent on a particular aspect of the gear (the gear itself is a simple machine, so cannot be patented, but tooth designs, rib designs, etc).

Let us say for argument that there is nothing protected about the gear itself. The "fuzzy" argument I refer to is if I use their drawings and models to make the gear, can they claim the gear I made violated any of their rights, even though not using the drawings/models would not be protected in the absences of patents or similar protections? In that case, I do not know

As for Chinese "knockoffs", most are certainly violating patents and protected designs. However, given that one can "knockoff" a designer bag by changing the logo and other elements that are protected, even then it's less clear.

Ultimately, my rule is this: if I have the slightest doubt about whether something I do is legal, I will ask a lawyer who knows about this a lot better than I do.

I know enough to know that I know nothing close to enough.


4 years ago

Does this printer really cost $250,000 USD?

What is the legality of doing this though? In a sense aren't you creating pirated copies of something? I can see that being entirely fine with generic things such as nuts and bolts, but when it comes to more specialized things as gears and mechanical parts aren't they protected in the same way as for instance a painting would be, making it a breach of copyright for you to copy it?

2 replies

Their TOU says: "DOWNLOADING; OTHER USE "downloading CAD models, software or any other information does not give you title or any other rights thereto. Redistribution, making a derivative work from and any other commercial exploitation of any of the Content or Services are prohibited. Using scripts, bots, spiders, other indexing agents or any other device to copy any of the Content is prohibited. The use of any technology or other means to hide your identity when using the Services is also prohibited. You agree you will impose only that load on McMaster-Carr's servers that is necessary for your use in deciding whether to purchase products from us and in purchasing products from us."

Nowhere in the TOU does it expressly deny downloading for manufacture. The thing is, it's still MUCH cheaper, ultimately, in most cases, to buy the part from them then to 3D print it yourself or spend man hours fabricating it from those cade files.

"Redistribution, making a derivative work from and any other commercial exploitation of any of the Content or Services are prohibited."

I think that's exactly what that says. What you do is essentially making a derivative work, and you are also redistributing it through, both clear breaches of the TOU you quote.

Look, I'm not trying to be an ass, all I'm saying is that if you're going to show someone how to do something it's apt to mention that what they would be doing is at best only tangentially legal, and if push comes to shove they would likely not win if the company presses charges. Unfortunately, whether it's more expensive to make it yourself has little impact on this. I'm not saying it's right, I'm not even agreeing with the current copyright legislation, but it's still worth educating yourself for your own sake.