Spin the stock.Read the signal.

Simultaneous 4-axis rotary

Lay the part in a wireframe 3-jaw chuck along the C axis. Flip / 90° reorient carries into the G-code, and a spin-part playback view turns the stock while the cutter holds. Spiral finishing and radial roughing in the free edition; more finishing styles in Pro.

Rough, finish, engrave

Queue rough → finish with different tools into one program with tool-change pauses, a surface-following finish pass and spring passes. Engrave system-font text flat or wrapped around a bar with a real V-bit profile — rapids and cutter shape come straight from the actual .nc.

See it before iron does

A material-removal simulator runs the real G-code and colors the cut surface by deviation, with a timeline scrubber, live feed readout and a machining-time estimate. Backplot, feed check and sim are in both editions.

Rotary mounted along Y

Most rotaries are bolted down along X, and until now that was the only way RotatoCAM could post a job. Turn yours a quarter turn on the table and the new Rotary runs along setting rotates the finished program to match: the part's length comes out on Y, its cross-section on X, and Z and the rotary word stay exactly where they were. It's a true rotation, not an axis swap, so nothing is mirrored and the program cuts what the simulator showed you. A flat engrave is untouched either way, and the out-of-travel warning now names the axis the motion actually lands on. Experimental until somebody has cut with it, so air-cut the first one. Asked for by a user with exactly this machine.

HolzProfi CNC6090 / HC-204A

A post for the HC-204A handheld control, whose rotary runs along Y. Written from the controller manual rather than inferred, which matters here because its accepted command set is unusually small: no G93 or G94, so no feed-mode word is sent and rotary feeds are converted rather than relabelled; no G20 or G21, so it is metric-only; and no M06 or M00, so there is no documented way to pause for a tool change, and the post says so and refuses a multi-operation program instead of emitting a pause that might not pause. It does do simultaneous four-axis: the manual has a rotary speed parameter that applies "in 4-axis linkage". Experimental until somebody has cut with it. Setup notes →

The axis and its letter are two questions

Which way the chuck points and which letter the controller answers to are unrelated, and a rotary mounted along Y is still usually called A. They're two separate settings, side by side in Machine setup. The letter has always been there, just in Machine setup rather than next to the Controller dropdown, which is where people kept looking for it.

It plans against the stock now

Passes used to be worked out purely from the part surface, so nothing knew what material was really standing there. Roughing now starts at the metal that is actually left instead of the bar's original OD, and the empty passes above it are gone.

Operations chain

Queue rough then finish and the second operation begins from what the first one really took off, so a smaller follow-up tool re-cuts the leftover instead of skimming the whole part again. Retracts clear the stock rather than the model.

It says when a wrap can't cut it

Wrapped surfacing only reaches shapes that are star-shaped about the rotary axis. A column or a camshaft is 100%; a figure with ears and limbs can be 20%, and the rest won't appear at any setting. You're told before you generate, not after.

AtomStack C4 Pro support

Its rotary is treated as a real fourth axis in plain degrees, not a substituted Y and not a circumference conversion, and absolute angles past a full turn are kept so a continuous spiral keeps counting up instead of resetting every revolution. Built from a live-machine handoff by a C4 Pro owner who read his own controller rather than the documentation. Marked experimental until somebody has cut with it.

A French option, where it matters

Settings ▸ Language translates the safety gate and the getting-started guide, the two places where a misunderstanding is expensive, and Windows' own file dialogs follow along. Menus and parameter names stay in English on purpose: renaming a menu you can still see in English just sends you hunting for something that isn't there.

The sim stopped eating the part

A cutter working close to the rotary centreline could wipe most of the ring at that station, so a 3+1 job on a part with openings down the middle came out of the simulator as a thin pin. The G-code was right the whole time — only the picture was wrong, which is the worst way for it to fail, because it makes a good program look like a ruined part. A cut now only takes material the cutter can actually reach.

Tapered cutters, planned properly

A fine-tipped tapered bit — the standard tool for 3D relief — used to be treated as a blunt disc of its full shank diameter, so every detail narrower than the shank was written off as unreachable at any setting. Pick taper, give it an included angle and a tip diameter (or a corner radius for a tapered ball nose), and it plans as the shape it is. Pass spacing now hits the scallop you asked for on every cutter shape.

The example projects actually open now

Nine models and eighteen ready-to-run job sheets have been inside every download all along, but the portable build looked for them one folder too high and told you they weren't installed. Help ▸ Open example projects finds them. The offline user guide, the window icon and the startup splash were all missing for the same reason, and all of them are back.

A square billet checked as a square billet

Set box stock and the does-it-fit warning now compares your part against the block's Y and Z one axis at a time, names the one that's short and by how much, and quotes the smallest block that would take the part. It used to ask whether the part cleared the circle a rotating bar's corners sweep, which could wave through a part that was genuinely too wide.

Custom posts + more controllers

Drop a post file into ~/.rotatocam/posts/ to add your own controller — no rebuild. Built-ins: grblHAL, GRBL, Genmitsu / SainSmart (4040-PRO, 3030 PROVer MAX), AtomStack C4 Pro, HolzProfi CNC6090 (HC-204A), LinuxCNC, Mach3/Mach4, Centroid and MASSO (experimental).

Just need to view 4-axis G-code? The standalone viewer that actually works. Loads any rotary .nc, draws the true wrapped toolpath, and scrubs by machining time. Download free, unlock with a key. (Also bundled inside Pro.)

Did it earn its keep?

Maybe RotatoCAM saved you a CAM subscription. Maybe it cut something your old software couldn't — a wrapped nameplate, a clean 4-axis finish, or the roman columns for the miniature gladiator stadium you built in the garage over winter. CE stays free no matter what — if it made your machine do something worth doing, a coffee helps fund the next fix.

The F word changes every line

Rotary moves go out as G93 inverse-time, where F is not a speed at all: it means "finish this move in 1/F minutes". It reads like nonsense next to a normal feed rate, and it is the thing that holds the cutter-contact speed steady while the radius changes underneath it.

Degrees pretending to be millimetres

Under G94 a grbl controller works out how long a block should take from the axis deltas, counting one degree of rotary as though it were 1 mm of travel. Hand it an inverse-time number without converting first and it is not slightly wrong, it is wrong by orders of magnitude.

A720 is not a typo

A continuous spiral just keeps counting: A450, A720, A1080. Wrapping the angle back to zero every revolution looks tidier in the file and would have the machine unwind the part mid-cut, so the absolute value rides all the way up.

One radius per ray

A wrapped pass stores a single radius for every ray out from the rotary axis, so it can only ever describe shapes that are star-shaped about that axis. RotatoCAM measures your model and tells you the percentage before you generate, because the part it cannot describe is not recoverable with a smaller tool, a finer scallop or more passes.

4-axis finish (spiral)

A smooth helical finishing pass over a rotary part from an STL. Pick a ball end mill and round stock, then lower Scallop height for a finer finish.

4-axis rough (radial)

Hogs material off a round bar in radial layers before finishing. Set Depth per pass and Stock to leave; tick Finish pass to chase it with a spiral.

2D engrave (flat)

Engrave text or a DXF·SVG drawing into flat stock. Type your text (or load a drawing), choose a V-bit, set Engrave depth, Generate.

Wrap engrave (rotary)

Wraps text or art around a cylinder. Type text (or load a drawing), set Bar diameter and Engrave depth, Generate.

On the PC first — no machine

Open a model (or the bundled examples\), pick a tool + strategy, click Generate. Review the 3D backplot, run the feed check and the material-removal sim. Check rapids vs feeds, depths and units (G21 mm / G20 inch).

On the machine, dry — no material

Set work offset (G54) and tool length; confirm the correct controller. Air-cut — raise Z well above the stock and run the whole program, watching motion match the backplot. Hand on feed-hold / E-stop.

First real cut

Use soft material first (machine wax, foam, MDF, soft aluminum), shallow and slow. Start with 3-axis or wraparound engraving before any 4-axis surfacing. Light pass, stop and measure, then go deeper.

4-axis / rotary — extra care

In Machine setup, set your machine's max swing radius (spindle-to-table clearance); 4-axis jobs whose part radius exceeds it are blocked on purpose. Rotary moves use G93 inverse-time feed — a wrong rotary feed can snap an endmill, so make sure the feed check passes, air-cut the rotary motion first and start shallow.

Pre-cut checklist — every job

• Dimensions checked (measure thrice, cut once)
• Backplot + feed check + sim look correct
• Correct controller and units (mm/inch) selected
• Tool length & G54 offset set; stock clamped solid
• Air-cut done; motion matched the backplot
• E-stop in reach; eyes & hands protected