Spinning bobbin kit: design & fit notes

An unusual spinning wheel can have perfectly usable mechanics and only one bobbin. This original design fits a measured straight shaft with two independently sized end flanges, a hollow winding core and an optional V brake groove on either or both ends. One PETG kit contains three printed pieces. Adhesive and the wheel’s shaft are separate; assembly is required.

Measure an existing working bobbin with calipers. Enter its finished end-to-end length, both end diameters and thicknesses, winding core outside diameter, and actual shaft diameter. Preserve the original axial free play and flyer/hook clearance. Running clearance is added once to shaft diameter; no clearance is automatically subtracted from assembled length. Bore polygons circumscribe the requested circular opening, so their minimum diameter preserves that clearance.

Measure a brake groove’s axial width, radial depth and center distance from that end’s outside face. End A and end B have independent center positions. The original groove profile must suit a straight-sided V; this design does not reproduce rounded or multi-step grooves. It does not include drive whorls, bearings, keyed drives or stepped bores. A double-drive or bobbin-led wheel may require a different design; do not infer compatibility from a preset or the presence of a groove.

The center tube length equals assembled length minus both flange thicknesses. Each tube end seats against the inside flange face within a raised collar. The end flanges locate the shaft; the tube has a larger bore that clears it. Recessed flange webs and the hollow tube reduce material. The joint clearance is diametral and separate from shaft clearance. Collars occupy the selected insertion depth at each end; the displayed winding span excludes both collars. No yarn capacity is promised.

Dry-fit and check that the tube seats fully, both end faces are square and the bore runs freely on the shaft. Use a PETG-compatible adhesive according to its directions, hold the parts square, keep the bore and groove clear, and allow a full cure before use. This is a bonded assembly, not a snap fit. Physical print, fit, bond, balance and spinning tests are pending; no operating speed is rated.

Print both end discs outside-face down with collars up, and print the tube upright. PETG at 100% infill, without supports. The upper V-groove wall is limited to 45 degrees from vertical, with at least 1 mm of rim on each side. Core walls and flange webs are at least 2.4 mm; each flange retains 3 mm beyond its collar at the groove root. Upright core length is limited to ten times its diameter. The complete layout, including two 4 mm gaps, must fit the store’s 245 mm usable envelope within the A1’s 256 mm bed.

The default kit is $20 before shipping and tax. Price follows the generated solid material volume and surface area of all three pieces, including hollow cores, joint collars and removed brake grooves. Checkout validates measurements and recalculates the price. Presets are examples without brand-fit claims.

Read the original CAD builder and shared profiles and pricing geometry. Live CAD and matching STL generation run locally in your browser.