Belt Drives
Pulley & Belt Ratio Calculator
Driven RPM, speed ratio, and open-belt length from pulley diameters — plus reverse mode to hit a target RPM.
Open Pulley & Belt Ratio ->TestTalkHQ • Machining & Fabrication Hub
Machining & Fabrication Calculators and Practical Tools
Speeds, feeds, bending math, and tolerance checks for lathe, mill, drill, tap, press brake, and tube work — plus concrete volume for pads and footings. Built for shop setup and quoting, not textbook-only theory.
30Live Calculators
SFMCutting speed
IPTChip load
BABend allowance
RaSurface finish
Start Here
For most jobs, pick the operation first (turn, mill, drill, tap, bend, or stack tolerances), set SFM or chip load from material and tooling, then verify feed, depth, and machine limits before you cut air. Sheet metal and brake work usually flows from bend radius → allowance or deduction → flat length; hole work from drill → ream → tap in that order when precision matters.
Main Machining & Fabrication Tools
Lathe
Lathe Turning Speed and Feed Calculator
Turning RPM, IPR feed, depth of cut, and MRR from diameter, material SFM, and insert limits.
Open Lathe Turning ->Milling
Milling Speed and Feed Rate Calculator
RPM, IPM, and chip load for end mills — slotting, profiling, and adaptive paths by flute count.
Open Milling Speed/Feed ->Drilling
Drill Speed and Feed Rate Calculator
Drill RPM and IPM from material, drill diameter, and practical peck or coolant assumptions.
Open Drill Speed ->General Cutting
Metal Cutting Speed Calculator
Baseline SFM and feed targets across common materials when you need a quick speed sanity check.
Open Cutting Speed ->Speed & Feed
Cutting Speed and Feed Rate Calculator
Combined SFM → RPM → feed workflow with chip load for milling and general machining operations.
Open Speed & Feed ->Milling
Chip Load Calculator
Feed per tooth (IPT) and table feed from spindle RPM, flute count, and target chip load.
Open Chip Load ->Boring
Boring Bar Speed and Feed Calculator
Boring RPM and feed with L/D and rigidity in mind — internal holes without chatter surprises.
Open Boring Bar ->Reaming
Reaming Speed and Feed Calculator
Reamer RPM, feed, and stock allowance for size and finish on pre-drilled holes.
Open Reaming Speed ->Tapping
Tapping Speed and Feed Calculator
Tap RPM and synchronized feed by thread pitch, material, and hole type (through vs blind).
Open Tapping Speed ->Lathe
Knurling Calculator
Starting diameter and pitch for clean knurl patterns — avoid doubled or torn knurls on the first pass.
Open Knurling ->Lathe
Parting & Cutoff Speed Calculator
Parting blade RPM and feed for stable cutoff without rub, chatter, or blade breakage.
Open Parting/Cutoff ->Hole Prep
Countersink & Counterbore Depth Calculator
Countersink depth for flush flat heads and counterbore depth for socket-cap and shoulder screws.
Open Countersink Depth ->Finish
Surface Finish Ra Calculator
Theoretical Ra from nose radius and feed — compare to print callouts before you chase the comparator.
Open Surface Finish Ra ->Tapping
Tap Torque Calculator
Estimated threading torque by tap size and material — torque limits, tap breakage, and driver choice.
Open Tap Torque ->Threads
Thread Pitch Calculator
TPI, metric pitch, and major/minor/pitch diameters for standard inch and metric threads.
Open Thread Pitch ->Pipe Threads
NPT Pipe Thread Calculator
ASME B1.20.1 tap drill, TPI, major/minor diameter, hand-tight L1 and wrench-makeup L2 for 1/8"–4" NPT.
Open NPT Pipe Thread ->Threads
Thread Engagement Length Calculator
Minimum engaged thread length by material and load — stripped threads vs adequate grip in tapped holes.
Open Thread Engagement ->Angle / Inspection
Sine Bar / Sine Plate Angle Calculator
Convert target angle to gauge-block stack height (or reverse) for 5" and 10" sine bars — with 81/83-piece suggestions.
Open Sine Bar Angle ->Tolerance
Tolerance Stack-Up Calculator
Worst-case and RSS stack of part tolerances — will the assembly fit before you cut multiple setups?
Open Tolerance Stack-Up ->Press Brake
Press Brake Tonnage Calculator
Air-bending tonnage from material thickness, width, die opening, and tensile strength.
Open Press Brake Tonnage ->DXF · Measure + Cleanup
DXF Viewer, Measure & Cleanup
Pan, zoom, measure, toggle layers, delete stray lines, and export a clean DXF — nothing uploaded. Sanity-check pierce count and cut length before nesting or quoting.
Open DXF Viewer ->Cutting · Estimating
Cut-Cost & Time Estimator
Laser, plasma, or waterjet cut time and cost from manual length or DXF upload — PDF and CSV export for shop estimates.
Open Cut-Cost Estimator ->Cutting · CNC plasma
CNC Plasma Pierce Height & Cut Speed Calculator
Gantry pierce height, pierce delay, cut height, and IPM starting range from material, thickness, and 40–105A — distinct from handheld torch amps.
Open CNC Plasma Calculator ->Sheet Nesting · Export
2D Sheet Nesting Optimizer
True-shape nesting for sheet metal and plate — rectangles, circles, and DXF/concave parts with kerf, multi-sheet overflow, and PDF/DXF/CSV export. Pairs with the 1D Cut List Optimizer for bar and tube.
Open 2D Sheet Nesting Optimizer ->Sheet Metal
Sheet Metal Bend Allowance Calculator
Bend allowance, bend deduction, and flat blank length from angle, radius, and K-factor.
Open Bend Allowance ->Sheet Metal
Bend Deduction & K-Factor Calculator
Bend deduction and K-factor from inside radius and material thickness for flat-pattern layout.
Open Bend Deduction ->Sheet Metal
Sheet Metal Bend Radius Calculator
Minimum inside bend radius by gauge and material — cracks, coining, and grain direction limits.
Open Bend Radius ->Tube
Tube Bending Calculator
CLR, arc length, bend deduction, and wall thinning estimates for round tube and pipe bends.
Open Tube Bending ->Project
Concrete Volume Calculator
Cubic yards, cubic feet, and bag counts for slabs, footings, and pads — shop floors and equipment bases.
Open Concrete Volume ->Printable Templates & Export Tools
When the deliverable is a printable template or export file — not just a number — use the Interactive Tools Hub. Flat-pattern unfolders, tube notch wrap templates, cone/transition developments, cut-list optimizers, and pipe miter templates live there only: bend-allowance flat-pattern unfolder, tube notch template generator, cone/transition flat-pattern generator, square-to-round transition flat-pattern generator, cut list optimizer, and pipe miter template generator export PDF, DXF, CSV, or JSON.
Use the calculators above for speeds, feeds, tonnage, and dimensions; switch to /tools/ when you need a file you can print, nest, or hand to a customer.
Supporting Guides and Resources
Carbide vs. HSS ToolingWhen carbide pays off and when HSS still wins in the shop.
Pulley and Belt Ratio GuideDiameter, target RPM, and belt-length math.
Pulley and Belt Problems and SolutionsSlip, squeal, wear, misalignment, wrong RPM.
V-Belt vs Flat vs Timing BeltWhich belt type fits your shop drive.
Pulley / Sheave Size ChartCommon sizes with ratios at 1725 / 3450 RPM.
Lathe Turning Speeds and Feeds GuideRPM, IPR, SFM, and DOC by material and insert type.
Lathe Turning TroubleshootingTaper, chatter, finish, chuck slip, and insert failures.
Milling Speeds and Feeds GuideSFM, RPM, IPM, and chip load for common mill operations.
Milling Speed & Feed TroubleshootingDeflection, RPM caps, flute packing, and rub marks.
Climb Milling vs Conventional MillingWhich direction to cut and when backlash matters.
Chip Load GuideIPT, feed rate, and flute-count math for milling.
Chip Load TroubleshootingChip welding, breakage, finish, and premature wear.
Drill Speeds by Material ChartRPM and SFM reference by drill size and stock.
Drill Speed TroubleshootingBurns, walking, breakage, and poor hole finish.
Cutting Speed & Feed Rate GuideSFM, RPM, and feed across materials and operations.
Cutting Speed TroubleshootingBUE, chatter, chip color, and rub when SFM looks right.
Boring Bar Speeds and Feeds GuideRPM, feed, L/D ratio, and chatter control.
Boring Bar TroubleshootingChatter, size, finish, tolerance, and chip issues.
Boring Bar Types — Which One for the JobSteel, carbide, damped, and indexable bar selection.
Reaming GuideSpeeds, feeds, and stock allowance for precision holes.
Reaming Speed TroubleshootingOversize holes, chatter, and reamer breakage.
Hand Reaming vs Machine ReamingWhen to hand-ream and when the machine must drive.
Tapping Speeds and Feeds GuideRPM, sync feed, and fluid by thread and material.
Tapping Speed TroubleshootingRPM, heat, chip welding, and poor thread finish.
Knurling GuideWheel types, speeds, and diameter prep for clean patterns.
Knurling TroubleshootingTorn/doubled patterns, crush, walk, and chatter.
Parting Off GuideBlade choice, speed, feed, and setup for lathe cutoff.
Parting & Cutoff TroubleshootingBlade breaks, chatter, rub, and taper on cutoff.
Countersink & Counterbore GuideAngles, depths, and common flush-head mistakes.
Countersink TroubleshootingProud heads, chatter, and break-through blowout.
Surface Finish GuideRa, Rz, callouts, and how to hit the spec.
Surface Finish Ra TroubleshootingComparator vs profilometer, lay, and Ra vs Rz.
How to Read a Surface Finish CalloutRa vs RMS and what the print actually requires.
GD&T Symbol Reference ChartAll 14 symbols, MMC/LMC/RFS modifiers, and datum frames.
Tap Torque GuideTorque drivers, breakage causes, and material factors.
Tap Torque TroubleshootingTap breakage, stripped threads, and torque errors.
Thread Pitch & Engagement GuidePitch, depth, and minimum engagement by application.
NPT Pipe Thread Sizing GuideTaper, callouts, tap drill, and makeup depth.
NPT Pipe Thread Problems and SolutionsLeaks, cross-threads, cracked fittings, BSP mix-ups.
NPT vs BSPT vs Straight ThreadIdentify the thread before you force the joint.
Tap and Drill Size ChartUNC/UNF and metric tap drill plus close-fit clearance.
NPT Tap Drill Size Chart1/8"–4" TPI, tap drill, major/minor diameter.
Thread Pitch & Engagement TroubleshootingCross-threads, strips, and bottom-out failures.
Sine Bar Setup GuideH = L × sin(θ), wringing, and plate technique.
Sine Bar TroubleshootingWringing gaps, thermal drift, dirty rollers.
Sine Bar vs Digital Angle GaugeAccuracy vs speed — pick the right tool.
Tolerance Stack-Up TroubleshootingWrong signs, distortion, and RSS vs worst-case traps.
CNC Plasma Dial-In GuidePierce height, delay, cut height, and IPM on a gantry.
CNC Plasma Cut-Quality TroubleshootingDross, blown pierce, bevel, eaten nozzles.
CNC vs Handheld Plasma SettingsWhy table numbers are not torch numbers.
Press Brake Tonnage GuideAir bending, V-die opening, and capacity planning.
Press Brake Tonnage TroubleshootingOverload, wrong V-die, and air vs bottom bending.
Square-to-Round Flat-Pattern GeneratorRect / square / offset-to-round DXF + PDF.
Square-to-Round Flat-Pattern GuideTriangulation method and print checks.
Square-to-Round TroubleshootingScale, seam, degenerate geometry.
Square-to-Round vs Cone — Which to UsePick by opening shape; many jobs need both.
Sheet Metal Bending GuideRadius, springback, K-factor, and brake setup.
Sheet Metal Bending TroubleshootingFlat pattern errors, cracks, and springback.
Tube Bending GuideCLR, deduction, wall thinning, and mandrel basics.
Tube Bending TroubleshootingWall thinning, wrinkling, ovality, and springback.
Concrete Volume TroubleshootingShort pours, leftover yardage, and dimension traps.
Practical Notes / FAQ
Do chart speeds replace test cuts?
No. Calculators and guides give validated starting points — always prove feed, depth, and tooling on scrap or a test pass before production.
Why do RPM and feed both matter?
SFM (via RPM) controls heat and tool life; feed and chip load control finish, engagement, and whether chips clear. One without the other misleads you.
Bend allowance vs bend deduction — which do I use?
Both describe the same flat-pattern correction from different reference faces. Pick the mode your print or CAM expects, then stay consistent through the job.
Where do flat-pattern PDFs and notch templates live?
On the Interactive Tools Hub — not in the calculator grid above. Size bends and tube here; export templates there.
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Interactive Tools HubBuilders that export PDF, DXF, CSV, JSON, and printable templates.
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