Foot Mechanism Prototype

 Quick and dirty prototype of a passive foot pitch mechanism:

CAD cross section:

To make a return spring I flattened the end of a 1mm spring steel rod and drilled a 1mm hole through the end for a dowel pin axle:

A drilled out screw acts as a guide bushing for the spring:

Motor housing

Organization

I was inspired by my friend Ethan to finally start organizing my fasteners and other little bits of hardware:

Ethan designed these 3d-printable stacking sub-bins - I have a lot of small fasteners, so these were really helpful:

Beginning of the stack:

 

Spinning things!

It spins!  A good end to the most productive week I've had in quite a while (on personal projects, at least):

More spinning things: turning the 3mm cam followers:

Tiny cam follower shafts done.  Thumb for scale:

Assembled cam follower "spindles" with a bearings:

Real blog post with more explanation coming soon-ish.

Undercutting tool

I needed an undercutting tool for the part in the last post, so I made one from an old HSS end mill.

ER32 chuck loosely held in an ER40 collet, serving as a manual rotary/linear axis.  Grinding wheel in the mill spindle:

One of the features it cut:

Screw mechanism progress

 Machining the rotor/cam nut for the screw mechanism:

Turned on a manual lathe to this point, then milled on the 5-axis:

Mid-finishing passes:

Today's contraption

The astute reader can probably figure out what this is and what it's a test setup for:

Oh how I missed you, MITERS Hardinge

It exists!

*gloop*

 

Espresso machine software testing

 Testing a mostly-functional espresso machine gui.  Somewhat Decent inspired.  While I don't have an interface for creating espresso profiles from within the gui, I can write arbitrary espresso profiles/state machines in python which is pretty powerful.  Testing with the Puck Simulator.

The profile in the video does the following:

• Cycle water through the tank at 2 mL/s until the water and the group head get up to temperature (I cheated this in the video and turned off heater power)
• Flow water through the group head to the drip tray at 2 mL/s for 2 seconds to purge the air from the group.
• Block off the drip tray, flow to the group at 2 mL/s until the pressure reaches 6 bars.
• Run at a flat 6 bars until the shot weight (estimated from the pump speed/pressure/flow curve since I don't have a built-in scale yet) reaches 32 grams.
• Open the valve between the drip tray and group head to rapidly purge pressure (so it doesn't keep dripping)
• Reset to the beginning and wait for input.

Adjustable Puck Simulator

Needle valve + basket with the bottom cut out + aluminum "puck" with an o-ring = adjustable coffee puck simulator.

Mill enclosure is almost done

 

Mill Enclosure

 Last Sunday I whipped up an enclosure design for the mill to replace the shipping crate.  It's entirely made from 2d laser cut panels (I used SendCutSend, introduced to me by Alex.  A+ would use again) standard lengths of 3d-printer aluminum extrusion, and off the shelf hardware.  I'll post CAD in case it's useful to anyone else with this mill once I've made any tweaks I need to:

Lit with an LED bar:

Half way done

One section done, one section half machined.  Now that I have working toolpaths, I can mostly copy/pasted between parts/sides and just re-select the appropriate geometry.  

The first finished section of the part:

Here's a quick look at all the toolpaths.  Once it's done I'll do a real blog post with machining details:

 

The scrap pile grows....

The most recent attempt was so close.  As usual, got wrecked by the final tool change.  Not sure what happened (maybe I just forgot to touch off?), but the final tool, which finished the linear guide grooves, was about 1mm too deep.  

This op is 1/6 of the whole part.  Eventually 3 of these, machined on both sides, will get joined by a tie rod.

3mm drill shank in the 3mm slot.  The walls are actually parallel now.

Face spline for locating the 3 pieces and transmitting torque: