Week07 lecture notes

3/4/2026 Lecture https://fabacademy.org/2026/classes/computer_machining/index.html

https://fabacademy.org/2026/classes/computer_machining/CNCSlidesTony.pdf

I'm trying out this new connector for ATtiny, it lets you flash+communicate: https://gitlab.cba.mit.edu/quentinbolsee/updi_uart_programmer/

https://www.tooltrace.ai/ Traces image of tools

https://gitlab.cba.mit.edu/pub/libraries/-/tree/master/python

https://fabacademy.org/2021/labs/waag/students/nadieh-bremer/blog/week-7/

Lecture:

Tom Bodett - wood worker tom's video can be watched after class: https://fabacademy.org/2026/classes/computer_machining/TomToolTalk.mp4

Tony Schmitz - machining expert -Slides Tony Schmitz

Machining is a subtractive process Waste is called “chip”

More force needed for harder material More force makes more heat in chip (fire!) Tools wear out Sharper, harder tools Can coat tools to reduce friction and increase longevity of blades.

Free downloads of his books:

machining Dynamics by Tony Schmitz

Cutting speed is the speed at the part being cut. Tangential speed. Therefore faster the farther from the axis of rotation.

5-axis milling machines!

Cutting edges called flutes or teeth -

Tom Wood machining:

6 types of grain: important to consider grain when milling/ cutting because the grains will peel, chip. -slow at edges of cuts to prevent tear out -choose bits for different pieces

Video on what wood material to choose, and basic tools

Upcut bit causes feathering of wood (chipping) because chips go up, and cause pressure to build at top

Down bit keeps chips at bottom, pressure at bottom, (fire) Compression causes pressure in the middle

Tony: CNC and CAM introduction: (11:25)

https://fabacademy.org/2026/classes/computer_machining/index.html

video tom mentionedhttps://fabacademy.org/2026/classes/computer_machining/TomToolTalk.mp4

quick note that few controllers support canned cycles. cheap grbl controllers don't. FreeCAD has it turned on by default so if you it for CAM you may need to manually edit the post-processor (which doesn't take long but still)

11:41: wood joints Mortus and tenon Doweling Combinined mortus and tenon and doweling Dovetail Knapp Joint, very tricky, looks like half circle with dot Japanese joints- artistic joints, look up

https://thejoinery.jp/ https://fablabifurniture.org/images/Educacion/50_digital_joints.pdf

Is this the joint software you mentioned Tom, https://www.ma-la.com/tsugite.html

Use pva glue or epoxy for joining

Screws Knock down bolt and plug (Ikea furniture!)

Speeds/ feeds for milling table is generic, not exact for your setup:

https://www.machiningdoctor.com/calculators/chip-load-calculator/

A beautiful real examples of CNC products: https://www.ifurniture.la/peru @Vaneza Caycho Ñuflo is the founder 😍

Use clamps to hold material, lots of types. Use table to hold material, and cut later