Upload a STEP File, Get a Quote

What happens after you hit upload

Your file lands with the team, and a person opens it: checks the geometry, the material callout, the quantities, anything in your notes. Within 24-48 hours you get either a quote (price, material, lead time) or a specific question if something needs clarifying. No robo-estimate, no “a representative will contact you” limbo. Lead time starts at order approval. Put your need date in the part description and the quote answers it. The upload card on the MI CNC Parts homepage takes the same files and carries them into the quote form.

Why STEP is the favorite format

STEP (or STP, same thing) is a widely used neutral exchange format for 3D CAD data, and it can describe a part as a solid model (source 2), where an STL file holds only a mesh of triangles that approximates curves (source 3). That makes it the file to send for a machined part.

A STEP file can also carry annotations such as dimensions and tolerances (source 1), but don’t count on them coming through. Tolerances, thread specs and finish callouts belong on a 2D PDF print or in the quote notes. Pair the model with the print and the quote reflects everything that matters, first pass.

Can a STEP file with no drawing be quoted?

Yes. A STEP file on its own is a normal way to ask for a quote, and plenty of parts are quoted from the model alone. A person reads the model for size and features; material, quantity and finish come from the quote form and your notes. Every dimension is taken from the model at nominal, and the quote states that it is quoted to the model with no drawing, so the basis is in writing before anything is ordered.

With no drawing, one general tolerance covers every dimension: ±0.005 in, the typical machined band. If your notes name a different general tolerance, ±0.002 in on everything for example, that number is quoted instead and the quote says so. Every part is inspected against your model before it ships.

A drawing is asked for, before a number goes out, when the model cannot say what the part needs: a threaded or tapped hole (the thread size and class go on a print or in the notes, not read off the model), a bore or pin that has to hold a fit tighter than the general tolerance, a surface finish or coating with masked areas, datums that set where dimensions are measured from, or a cosmetic face. A marked-up screenshot or a line in the quote notes often answers it, and a full print is only needed when there are several. Where none of those apply, the quote goes out from the model.

Which file to send, by what you have

STEP or STP: the one to send if you can. It is the format CAD and CAM software use to exchange models (source 1), and it carries the solid model. SLDPRT: SolidWorks native, works as-is. IGES or IGS: an older exchange format, last published as a standard in 1996 (source 4), that still quotes fine, though STEP from the same model is cleaner. X_T or X_B (Parasolid text and binary files, source 5): fine too. STL: a mesh of triangles with no units in the file (source 3), so it shows overall form but approximates curves and holes; send it only when nothing else exists, and pair it with a drawing for the dimensions that matter. DXF or DWG: AutoCAD’s drawing files (source 6), the right file for flat parts, which usually means laser cutting rather than milling; the laser file guide covers that file question. PDF: a fully dimensioned drawing quotes on its own, and next to a model it carries what the model leaves out. ZIP: everything for a multi-part job in one upload.

The quote form accepts any file type, so if you have something not on that list, send it and say what made it. No CAD at all? A dimensioned sketch, a photo with measurements, or a new sample part works: the team can build the model, quoted as its own line, and get a custom part made walks that route. The sample ships back with the parts.

What a good print includes

A model carries the shape; a print carries everything the shape cannot say. The drawing does not need to be pretty, it needs to answer the questions that would otherwise come back as an email. Material and condition, for instance 6061-T6 or 17-4 PH H900. A general tolerance note for everything not called out, which the title block carries as the default for any dimension with no tolerance of its own (source 7), and tight tolerances only on the features that mate, seal, or locate, each with its own callout. Thread size, class, and depth for every tapped or threaded feature. Surface finish or coating, with any masked areas marked. Quantity. A revision letter and date, so a reorder matches the right version. Reorders at the same revision: send the last quote or PO number and it’s requoted.

Datums and geometric tolerances go on the print too, where ASME Y14.5 sets how they are stated (source 8). Position, perpendicularity and runout callouts are quoted from the print. Two more things people forget: which surfaces are cosmetic (so a fixturing mark does not land on the face that shows), and an edge-break or deburr note (a plain "break all sharp edges" saves a question). A print that covers those and the list above quotes sooner and comes back with fewer surprises, and where a callout is tighter than the part needs, the free DFM review says so and suggests a change, and whether to make it is your call. The tolerances guide covers where the tight-versus-general line sits.

Who sees your files

The person quoting the job. Your files are used to quote and make your parts (nothing else) and aren’t shared beyond what the job requires. The privacy policy sets out how files and contact details are handled.

Sources

All accessed 4 October 2026. Where a figure here differs from your print, the print governs.

1. National Institute of Standards and Technology, "STEP File Analyzer and Viewer": nist.gov/node/413991 (STEP files are used for data exchange between CAD, CAM, analysis and inspection software, and represent parts, assemblies and product and manufacturing information, which includes dimensions and tolerances).

2. Wikipedia, "STEP-file": en.wikipedia.org/wiki/ISO_10303-21 (a widely used data exchange form of STEP, which can represent 3D objects in CAD; .stp and .step extensions; the article’s example file is a solid model of a cylinder).

3. Wikipedia, "STL (file format)": en.wikipedia.org/wiki/STL_(file_format) (a triangulated surface that cannot represent curves exactly; no scale information, units arbitrary).

4. Wikipedia, "IGES": en.wikipedia.org/wiki/IGES (vendor-neutral CAD exchange format; version 5.3 of 1996 was the last published; interest declined after STEP appeared in 1994).

5. Wikipedia, "Parasolid": en.wikipedia.org/wiki/Parasolid (.x_t text and .x_b binary files; the modeling kernel used by SolidWorks, Siemens NX and others).

6. Wikipedia, "AutoCAD DXF": en.wikipedia.org/wiki/AutoCAD_DXF (Autodesk’s drawing exchange format for the data in AutoCAD’s native DWG file).

7. Wikipedia, "Engineering drawing": en.wikipedia.org/wiki/Engineering_drawing (the title block can carry default tolerances for dimension callouts with no tolerance specified; the revision block).

8. ASME, "Y14.5 Dimensioning and Tolerancing" (2018, reaffirmed 2024): asme.org/codes-standards/find-codes-standards/y14-5-dimensioning-tolerancing (symbols, rules and practices for stating GD&T on drawings and on models defined in digital data files).