Dylan Banera

WorkBike Projects

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Dirt Jumper V2: machined junctions

The same V2 frame on carbon tubes, with 7075 aluminum junctions machined 5-axis from my CAM. Industry Nine showed it, unfinished, at Crankworx Whistler 2025.

Date
Aug 2025
Media
12 photos · 8 videos
CAD
Fusion 360
CAM
Programmed by me
Machining
Haas UMC-750 5-axis, by Gleb at Monster Hooks
Junctions
7075 aluminum, machined from solid
Tubes
Carbon
Disciplines
BikesCNC MachiningCAD3D Printing
Fig. 01The assembled bike: carbon tubes with the machined seat cluster and bottom bracket junctionsEnlarge

Notes

After Sea Otter I redesigned the frame as Dirt Jumper V2. This is the version with machined junctions on carbon tubes; the same geometry was also 3D printed almost entirely in aluminum, so the two are one frame made two different ways. I gave the bottom bracket lug a full redesign, designed a UDH-compatible dropout, and printed prototype dropouts and lugs to check the fit.

I programmed the CAM for the 5-axis parts, and Gleb at the Monster Hooks machine shop ran them on a Haas UMC-750. The junctions were machined from solid blocks of 7075 aluminum in 5-axis setups, with the tube stubs cut in, and sawn free of the leftover stock before assembly. The dropouts and their separate insert plates were machined too.

The bike wasn't finished in time for Crankworx Whistler in August 2025, but Industry Nine still displayed it in their booth. The renders of the design are by Carter Bilawchuk of Euler Bikes.

Photos and videos

19 figures

Fig. 02The design, side-on. Render: Carter Bilawchuk (Euler Bikes)
Video 0:59
Fig. 03The frame in Fusion 360, June 2025: junctions and dropouts on carbon tubes
Fig. 04The head tube junction, where the carbon top and down tubes meet. Render: Carter Bilawchuk
Fig. 05The seat cluster junction, below the seat clamp. Render: Carter Bilawchuk
Fig. 06The rear end: dropout, carbon stays and the bottom bracket junction. Render: Carter Bilawchuk
Fig. 07The dropout close up, on the rear hub. Render: Carter Bilawchuk
Video 0:34
Fig. 08CAD of the UDH-compatible dropout and the bottom bracket area, a printed dropout, and a packed print build
Video 0:39
Fig. 09June 2025: the bottom bracket lug redesign in CAD, FDM test prints, stock prep on the mill and saw for a test fit, and cleaning printed parts
Fig. 10Printed test versions of the dropouts and their separate insert plates
Video 0:24
Fig. 11Printed prototype dropout and seat lug, shop machining, CAM and a fit check
Clip 0:11
Fig. 12A junction being cut from my CAM on the Haas UMC-750 at Monster Hooks, in a tilted 5-axis setup
Clip 0:12
Fig. 13A machined junction in the 5-axis vise, turned to show each side
Fig. 14A machined junction, still attached to its leftover stock
Fig. 15A machined dropout, toolpath marks still on it
Clip 0:07
Fig. 16One of the machined dropout insert plates, turned to show both faces
Clip 0:08
Fig. 17Machined junctions, including the seat cluster
Fig. 18The machined parts laid out on a cart: junctions, dropouts and insert plates
Fig. 19Two of the machined junctions next to a clear printed junction. Photo: Wolf Tooth
Fig. 20Unfinished, on display in Industry Nine's booth at Crankworx Whistler, with machined junctions on the bench