Frame
Steel tube, aluminium extrusion, timber or dowel along sketch lines or the edges of a box, each member its own part, mitred or butted where they meet, with a cut list.
- Frame AdvancedPart workspace toolbar
- Frame trim AdvancedPart workspace toolbar
- Gusset AdvancedPart workspace toolbar
- End cap AdvancedPart workspace toolbar
| SchoolCAD | Onshape | Fusion | SOLIDWORKS |
|---|---|---|---|
| Frame | Frame | – | Weldments Structural Member |
| Frame trim | Frame trim | – | Trim/Extend |
| Gusset | Gusset | – | Gusset |
| End cap | End cap | – | End Cap |
Frame makes a frame from standard lengths of material: steel square or round tube, angle and flat bar, aluminium T-slot extrusion, dressed pine or dowel. A member runs along each line you pick, each one its own part, and they are joined where they meet, as a fabricator would cut them. The cut list says how long to cut each member and how to cut its ends. It works like Frame in Onshape and Weldments (Structural Member) in SOLIDWORKS.
Frame is an Advanced tool. Its Frame ▾ menu on the toolbar has the frame's other tools, as in Onshape: Frame trim (cut the open ends flat to a plane, such as the floor), Gusset (a plate in each inside corner), End cap (a plate over each open end) and Cut list. Each opens the newest frame with that option turned on.
Two ways to lay out a frame#
- Lines in a sketch. Draw the frame's lines, such as a rectangle for a picture frame or a gate. Tick the sketch. Lines in several sketches (on different planes) make a frame in 3D.
- The edges of a box. Model a box the size of the stool, table or trolley, then click its edges, or click a face for all of its edges. Select the box before clicking Frame and its top edges and upright edges are picked for you. Each member sits in the corner inside the box, so the frame is the box's size. The box is used up.
Bent tube and rings#
Draw arcs as well as lines, and lines and arcs that run smoothly into each other (an arc drawn tangent to a line) are one bent member, the way a tube is bent on a tube bender: a U for a stool's sides, a rounded rectangle, the curve of a chair. A shape that comes back to its start, or a circle, is a ring (rolled, its ends joined). The cut list gives the length to cut before bending (along the tube's middle) and each bend, such as 2 × 90° bends R50.
- A bend's radius is measured to the middle of the tube, as a tube bender's is. With Alignment: Inside or Outside, it is the arc's radius less or more half the tube.
- An arc too tight for the profile is refused. A tube bent tighter than about one and a half times its width is flagged: most tube benders need a radius of at least twice the tube's width.
- Members meet a bent member as they meet a straight one. One ending on its side where it is bending is cut to the shape of the curve.
How to use it#
- Draw the lines, or model the box.
- Click Frame.
- Tick the sketch, or click the box's edges.
- Choose the Profile, such as SHS 25 × 25 × 1.6 (square steel tube), and the Default corner type.
- Click ✓.
Options#
| Option | What it does |
|---|---|
| Lines | The sketches whose lines, arcs and circles become members. Construction lines are left out. |
| Edges | The straight edges of a part picked in the view. Clear unpicks them. |
| Profile | The material and its size: steel square (SHS), rectangular (RHS) and round (CHS) tube, flat bar, angle, aluminium T-slot, dressed pine and dowel. Custom size sets your own. Drawn in a sketch uses a closed shape you draw, such as a moulding or an extrusion of your own: draw it round the sketch's origin (the frame's lines run through the origin, and the sketch's up is the member's up), choose the sketch and the Material. |
| Default corner type | Mitre: both members cut at half the angle, like a picture frame. Butt: one member runs through and the other is cut square against it. To change just one corner, click it in the view (a diamond is a mitre, a square a butt): each click goes from a mitre to a butt with one member through, then the other. Reset puts every corner back. |
| Alignment | For sketch lines: the line runs down the Centre of the member, or the member is Inside or Outside the shape with its edge on the line. |
| On the edges | For a box's edges: each member In the corner inside the box, flush with its faces, or Centred on the edge. |
| Keep the part the edges are on | Keeps the box (hide it to see the frame). Off: the box is used up. |
| Cut the ends to | A plane the open ends stand on, such as Top for the floor. Each end on it is cut flat to it, so a splayed leg's foot sits flat on the floor instead of on one corner (Onshape: Frame trim). Offset moves Top, Front or Right; or choose a Plane you made. |
| End caps on the open ends | A plate over each open end of a tube or extrusion (the feet of a stool, the top of a leg), the tube's outside shape. The member is made shorter by the cap, so the frame keeps its size. Steel caps on steel tube, plastic on T-slot. |
| Cap thickness | How thick the end caps are, in mm. |
| Gussets in the corners | A triangular plate in each inside corner, its two legs along the members' inside faces, in the middle of the members: two at each leg of a stool, one each side of a T. Plywood on a timber frame. |
| Gusset size / Gusset thickness | How long the gusset's legs are, and how thick it is, in mm. A gusset is made smaller where there is not room for it. |
| Angle | Turns the profile about its length, such as 90° to stand a rectangular tube or a board on its edge. ⟲ 90° turns it a quarter turn. |
| Load test | A weight on top, and how the frame takes it: see below. |
Load test: will it hold?#
Tick Load test: a weight on top and set the Weight (80 kg, a person, to start). The frame stands on its feet (its lowest points) with the weight spread along its top members, and each member is worked out as a beam, welded to the others where they meet. It says:
- how far the frame bends under the weight;
- which member works hardest, and how many times stronger than it needs to be it is: its factor of safety, against the stress the material yields (steel, aluminium) or breaks (timber) at. Each member is tested in its own material, so change a member's material to try it in aluminium or pine;
- a slender member that could buckle (bow sideways) under the squeeze.
While the dialog is open, the members are coloured by how hard they work: green is far stronger than it needs to be, yellow half way, red at what the material can take. A factor of safety under 1.5 is warned about: aim for 2 or more (a person dropping onto a stool pushes harder than sitting still), with a bigger profile, a rail or a brace.
The test is a guide for comparing designs, not a certificate: the joints are taken as perfect welds, the feet as held where they stand, and the weight as spread along the top.
How the members meet#
- Two at a corner: mitred or butted, as you choose.
- Three or more at a corner (a table's two rails and its leg): the most upright member (the leg) runs through and the others are cut against it.
- One ending on the side of another (a T, a brace or a cross rail): it is cut against the other's face.
- Round tube ends are cut to the shape of the tube they meet, the "fish mouth" a welder cuts so the joint fits.
- Two in a straight line are cut square where they meet.
Tips#
- The parts list and cut list give each member's length and its ends, such as 45° mitre both ends or square both ends, grouped so identical members are counted together.
- Steel members are costed by weight, and timber and dowel by the metre.
- A brace across a corner is a line from one member to another: it is cut against both.
- Use Fillet or Hole afterwards on any member, as on any part.