CustomPartNet
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August 5, 2026
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Updated August 5, 2026
Before you get to the supplier search, most machinists and engineers need to work out the practical details: what speed to run the spindle at, which tap drill to use, how to set up a sine bar for an angled cut. CustomPartNet's widgets page collects a set of free calculators built specifically for these day-to-day machining questions, so you can get answers on the shop floor or at your desk without digging through a reference book. Once your part is designed and your process is planned, browse our supplier network to compare qualified machining shops and request quotes.
Machining success comes down to getting a lot of small numbers right: cutting speed, feed rate, tap drill size, setup angle. Get one of them wrong and you risk tool wear, poor surface finish, scrapped parts, or a part that's out of tolerance. Reference charts and manual calculations work, but they're slow and easy to miscalculate under time pressure. A set of purpose-built calculators lets you plug in your actual numbers, whether that's tool diameter, material, or part geometry, and get a reliable answer in seconds.
Below are seven of the most useful machining widgets on CustomPartNet, grouped by what stage of the job they support.
This tool determines spindle speed (RPM) and feed rate (IPM) for a milling operation, along with cut time for a given cut length. You enter tool diameter, number of teeth, cutting speed, and cutting feed, and the calculator returns the settings your mill should be running at.
Use it when: you're programming a new job and want to confirm your speeds and feeds before you cut metal, especially when switching between tool or workpiece materials with different recommended cutting parameters.
Try the Milling Speed and Feed Calculator →
For lathe work, this calculator estimates the surface roughness produced by a turning operation based on tool nose radius and cutting feed (IPR). Because a single-point tool's rounded nose leaves small peaks and valleys as it cuts, this relationship determines your finish quality directly.
Use it when: you need to hit a specific surface finish callout and want to know what feed rate will get you there without an extra finishing pass.
Try the Turning Surface Roughness Calculator →
A reference chart of standard tap sizes across fractional, metric, and screw sizing systems, including diameter, thread spacing, and the recommended tap drill size for each. It also gives decimal equivalents in both English and metric units.
Use it when: you're prepping a hole for tapping and need the correct drill size for a given thread callout, without flipping through a printed reference card.
This widget calculates the gauge block height needed to set a sine bar to a specific angle, or works backward to find the angle from a known gauge block height. It also suggests a gauge block stack using standard imperial or metric block sets.
Use it when: you need to set up a precise angular measurement for machining or inspection and want to avoid manual trigonometry or gauge block stacking errors.
This tool calculates run time, down time, total production time, and production rate (parts per hour) based on cycle time, defect rate, machine uptime, and number of machines. It doesn't include setup or post-processing time, so it's focused specifically on production run duration.
Use it when: you're quoting a job or planning a production schedule and need a realistic estimate of how long a given run quantity will actually take.
Try the Production Time Calculator →
Since most manufacturing processes lose some material to feed systems and defective parts, this calculator determines total raw material required based on part weight, defect rate, and parts per cycle. It also returns shot weight, material yield per cycle, and scrap weight.
Use it when: you're budgeting material costs for a run and need to account for scrap and yield loss rather than just the finished part weight.
Try the Material Usage Calculator →
This tool calculates volume and weight, in English or metric units, across more than 40 geometric shapes and a range of metals and thermoplastics. You can dimension a single shape for raw stock weight, or combine multiple shapes to approximate a part's total weight.
Use it when: you need a quick weight estimate for shipping, material cost, or stock sizing without building a full CAD model.
Try the Volume and Weight Calculator →
Yes. All of the widgets on CustomPartNet, including the speeds and feeds calculator, tap size chart, and sine bar calculator, are free and don't require an account.
Milling speed and feed calculations account for a rotating multi-tooth cutter moving through a stationary workpiece, while turning calculations account for a rotating workpiece and a stationary single-point tool. The two widgets use different inputs because of this, so use the one that matches your operation.
The tap size chart lists the recommended tap drill size for each standard thread, based on the diameter and thread pitch or thread count. Matching the correct drill size to your thread callout helps ensure proper thread engagement without excessive tap breakage.
A sine bar is a precision tool used to set up or measure exact angles in machining and inspection. It works with gauge blocks stacked to a calculated height, and the sine bar calculator removes the manual trigonometry from that setup.
No. It calculates run time based on cycle time, defect rate, and machine uptime, but does not include initial setup or post-processing operations, since those vary significantly by shop and job.
Yes. While shot weight is specific to molding processes, the broader calculations for raw material required, yield, and scrap weight apply to a range of manufacturing processes where feed systems or defect rates affect total material consumption.
It's designed for standard geometric shapes and combinations of shapes, so it gives a strong approximation for parts that can be broken down into basic forms. For highly complex geometries, a CAD-based weight calculation will be more precise.
Once you've worked out your process parameters, the next step is finding a shop that can run the job. Search our supplier network for CNC machining capabilities that match your part, or upload your CAD file for an instant machining cost estimate.
Get Quotes Now → or Register for a Free Account → to save your calculations, build supplier shortlists, and manage RFQs in one place.