Flanged Hub

A flanged hub connects a rotating shaft to a larger component. This recipe builds a complete hub with bore, keyway, and bolt pattern.

The Design

A typical flanged hub has:

• Cylindrical hub section (grips the shaft)
• Flange with bolt holes (mounts to mechanism)
• Center bore (shaft passes through)
• Optional keyway (prevents rotation on shaft)

use vcad::{centered_cylinder, bolt_pattern};

// Hub body
let hub = centered_cylinder("hub", 15.0, 30.0, 64);

// Flange at base
let flange = centered_cylinder("flange", 35.0, 6.0, 64)
    .translate(0.0, 0.0, -15.0);

// Center bore for shaft
let bore = centered_cylinder("bore", 6.0, 40.0, 32);

// Bolt pattern in flange
let bolts = bolt_pattern(6, 50.0, 4.0, 10.0, 24)
    .translate(0.0, 0.0, -15.0);

let hub_assembly = hub + flange - bore - bolts;

Adding a Keyway

A keyway prevents the hub from spinning on the shaft:

use vcad::centered_cube;

// Standard keyway dimensions for shaft diameter
let keyway = centered_cube("key", 4.0, 6.0, 35.0)  // width, depth, length
    .translate(0.0, 4.5, 0.0);  // Positioned at bore surface

let hub_with_key = hub_assembly - keyway;

Set Screw Holes

For additional grip, add radial set screw holes:

let set_screw = centered_cylinder("set", 2.5, 20.0, 24)
    .rotate(0.0, 90.0, 0.0)  // Point radially inward
    .translate(0.0, 0.0, 5.0);  // Position along hub

let with_setscrew = hub_with_key - set_screw;

For two opposing set screws:

let set_screws = set_screw.circular_pattern(0.0, 2);  // 180° apart

Stepped Hub

For different bearing surfaces:

let hub_lower = centered_cylinder("lower", 20.0, 15.0, 64)
    .translate(0.0, 0.0, 7.5);

let hub_upper = centered_cylinder("upper", 12.0, 20.0, 64)
    .translate(0.0, 0.0, 25.0);

let stepped_hub = hub_lower + hub_upper + flange;

Lightening Holes

For weight reduction, add radial pockets to the flange:

let pocket = centered_cylinder("pocket", 6.0, 10.0, 24)
    .translate(22.0, 0.0, -15.0);  // Between bolt holes

let pockets = pocket.circular_pattern(0.0, 6);  // Same count as bolts, offset

// Rotate to sit between bolt holes (30° offset for 6-hole pattern)
let pockets_offset = pockets.rotate(0.0, 0.0, 30.0);

let lightened = hub_assembly - pockets_offset;

Complete Parametric Hub

use vcad::{centered_cube, centered_cylinder, bolt_pattern, Part};

struct HubParams {
    shaft_dia: f64,
    hub_dia: f64,
    hub_length: f64,
    flange_dia: f64,
    flange_thickness: f64,
    bolt_count: usize,
    bcd: f64,
    bolt_dia: f64,
    has_keyway: bool,
    has_set_screw: bool,
}

fn flanged_hub(p: &HubParams) -> Part {
    // Main hub cylinder
    let hub = centered_cylinder("hub", p.hub_dia / 2.0, p.hub_length, 64);

    // Flange
    let flange = centered_cylinder("flange", p.flange_dia / 2.0, p.flange_thickness, 64)
        .translate(0.0, 0.0, -p.hub_length / 2.0);

    // Bore
    let bore = centered_cylinder("bore", p.shaft_dia / 2.0, p.hub_length + p.flange_thickness + 5.0, 32);

    // Bolt holes
    let bolts = bolt_pattern(p.bolt_count, p.bcd, p.bolt_dia, p.flange_thickness + 5.0, 24)
        .translate(0.0, 0.0, -p.hub_length / 2.0);

    let mut result = hub + flange - bore - bolts;

    // Optional keyway
    if p.has_keyway {
        let key_width = p.shaft_dia / 4.0;  // Approximate
        let key_depth = key_width;
        let keyway = centered_cube("key", key_width, key_depth, p.hub_length + 5.0)
            .translate(0.0, p.shaft_dia / 2.0, 0.0);
        result = result - keyway;
    }

    // Optional set screw
    if p.has_set_screw {
        let set_screw = centered_cylinder("set", 2.0, p.hub_dia, 24)
            .rotate(0.0, 90.0, 0.0)
            .translate(0.0, 0.0, p.hub_length / 4.0);
        result = result - set_screw;
    }

    result
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let params = HubParams {
        shaft_dia: 12.0,
        hub_dia: 30.0,
        hub_length: 25.0,
        flange_dia: 60.0,
        flange_thickness: 6.0,
        bolt_count: 4,
        bcd: 45.0,
        bolt_dia: 5.5,
        has_keyway: true,
        has_set_screw: true,
    };

    let part = flanged_hub(&params);
    println!("Volume: {:.1} mm³", part.volume());
    part.write_stl("hub.stl")?;
    Ok(())
}