Move the rails by their cross

WhereThe top bar: the row of words that begins File, Edit.

DoDownload p4-03-start.blend from Files above and open it. Then choose File > Save As and save it under the name below, in a folder of yours. Open an exercise file and keep the start file safe (P0-07) shows how.

Typemy-rails.blend

You should seeThe 3D view shows a round stone standing in four claws, with nothing selected. The title bar, the strip above File and Edit, begins my-rails. The first picture is the 3D view and the second is the title bar.

It worked whenThe title bar, the strip above File and Edit, begins my-rails.

WhereThe sidebar: press N with the pointer over the 3D view if it is shut, click the CAD/CAM tab, then Setting. Scroll to the foot of the Head Builder panel: More is a closed fold with an arrow.

DoSelect the head (click a claw, as in Drag a number on the model (P4-02), step 2), then click More at the foot of the panel.

You should seeThe handles show on the head, and More opens the panel’s other numbers. Two of the handles are crosses: a dot with an arm each way. The picture marks the seat rail’s cross and the second rail’s. More holds the same numbers as typed fields: Rail in and out, Rail drop, Second rail in and out and Window. More holds more numbers than this page uses: the rest come later, or are not needed here.

It worked whenTwo crosses show on the head and More is open.

WhereThe 3D view: rest the pointer on one arm of a cross, a little out from the dot, without pressing.

DoRest the pointer on an arm until a label shows. The four pictures show the four arms.

You should seeEach arm has its own label: Rail in and out and Rail drop on the seat rail’s cross, Second rail in and out and Window on the second rail’s. Rest on the arm, not on the dot: the dot belongs to both arms, and a press on it may take either one. Read the label first; if the wrong one shows, press Ctrl+Z.

It worked whenA label shows beside an arm.

WhereThe 3D view, the arm of the seat rail’s cross that points away from the stone.

DoPress and drag as in Drag a number on the model (P4-02), step 4: press on that arm, drag it outward, and let go. Then press Ctrl+Z once.

You should seeThe seat rail grows outward past the claws. The label reads “Rail in and out -0.75 mm, the stone does not rest on this rail; this rail shows from above default 0.00”, and the panel’s Rail in and out reads the same. Out reads as a minus number and in as a plus. The rail now stands outside the stone’s edge, so it shows from above: the head says so. Inward the arm cannot go at 0: the label says “lower the rail to move it in”. The picture shows the head just before the Ctrl+Z.

It worked whenRail in and out is no longer 0 mm: it reads a minus number (here -0.75 mm), and after Ctrl+Z it reads 0 mm.

WhereThe 3D view, the button on the model Second rail: on, one of the words to the right of the head.

DoClick the button once.

You should seeThe second rail goes, and the button reads “Second rail: off”. One ring of metal is left inside the claws, the seat rail. The panel’s More has the same choice as a tick box, Second rail. The head holds with one rail, and the bench often builds it so on a small stone. Leave it off for the next step.

It worked whenOne ring of metal is left inside the claws, and the button reads “Second rail: off”.

WhereThe 3D view, the arm of the seat rail’s cross that points down: Rail drop.

DoPress and drag as in P4-02, step 4: press on that arm, drag it down, and let go. Then press Ctrl+Z once.

You should seeThe seat rail goes down the claws. The label reads “Rail drop 0.71 mm, the stone does not rest on this rail default 0.00”. With the second rail on, the seat rail has no room to drop; that is why it is off. At 0 the stone rests on the seat rail. Above 0 the label says it does not. Ctrl+Z takes back the drag and the switch together: the second rail is back, and the button reads “Second rail: on”. The picture shows the head just before the Ctrl+Z.

It worked whenRail drop is no longer 0 mm: it reads a number above 0 (here 0.71 mm), and after Ctrl+Z it reads 0 mm and two rings of metal stand inside the claws.

WhereThe 3D view, the arm of the second rail’s cross that points up: Window.

DoPress and drag as in P4-02, step 4: press on that arm, drag it up toward the seat rail, and let go. Then press Ctrl+Z once.

You should seeThe second rail rises toward the seat rail and the gap between them narrows. The label reads “Window 0.33 mm default 0.80”, and the panel’s Window reads the same. The Window is how far the second rail’s top stands under the seat rail’s foot. A gap under 0.30 closes in the cast, so on a head you will cast keep the Window above that. The picture shows the head just before the Ctrl+Z.

It worked whenWindow has changed from 0.8 mm: it reads a smaller number (here 0.33 mm), and after Ctrl+Z it reads 0.8 mm.

WhereThe 3D view, the arm of the second rail’s cross that points toward the stone.

DoPress and drag as in P4-02, step 4: press on that arm, drag it toward the stone, and let go. Then press Ctrl+Z once.

You should seeThe second rail draws in under the stone. The label reads “Second rail in and out 0.28 mm default 0.00”, and the panel’s Second rail in and out reads the same. It stops where it would touch the stone or stop holding the claws. The picture shows the head just before the Ctrl+Z.

It worked whenSecond rail in and out reads a number above 0 (here 0.28 mm), and after Ctrl+Z it reads 0 mm.

WhereThe 3D view: move the pointer over it.

DoClick the button Done on the model, so that the handles go (P4-02, step 11). Then look from above: click the blue Z ball of the gizmo, then press Home.

You should seeFrom above you see only the stone and its four claws: both rails are back under the stone, and no pink mark is left. The thin lines inside the stone, if you see any, are the rails seen through it. The panel’s line begins “Seen from the top only the stone and the claws show: every rail stands 0.12 mm or more inside the girdle line, the seat rail’s top 0.56 mm under the girdle’s lower edge, the stone resting on its inner edge.”. A rail left outside the stone would show here as a ring.

It worked whenYou see the stone and four claws, and no metal ring round the stone.

WhereThe 3D view: move the pointer over it.

DoPress Ctrl+S.

You should seeBlender writes your copy at once, with no question, because the file already has a name. An asterisk, *, in the title bar marks changes that are not saved, and it goes now. Save your work and get it back (P0-12) says more about saving.

It worked whenThe title bar begins my-rails and carries no asterisk.