One evening of CAD. One evening of CAM. One evening of CNC. And it fit together (quite well). This is just held together with precisely located wooden dowel pins. We will add screws tomorrow.
The only missing piece is the actual guide for running the blocks through. That is separate so that it can be “dialed in” to the perfect cutting depth.
Working on another machine to speed up yet another tedious workshop process. Think of it as a special router table that takes 2 routers set to 45 degree angles. The guide (not shown) will allow precise alignment of the work piece AND cover the cutters to prevent injury.
The Barrel Sander is coming along again, after a small detour to build the (M003) Auto Loading jig. Here is the nine sides bolted inside the barrel. They do three things:
After years of making the same part repeatedly on the CNC router, I finally decided it was time to make the router load it’s own material.
Friction is a valid way to hold a part for routing. That is how most vices and clamps work. The key here is to calculate an amount of friction that will resist the cutting forces while at the same time keeping it low enough for the router to be able to overcome it while loading and unloading.
I’ll post more on this when we have it working. For now, here is a cool picture of the jig.
Most standard 60HZ AC motors come in approximately 3600 RPM or 1800 RPM. The barrel sander needs to spin at about 30 RPM. To achieve this, the following approximate pulley sizes will be used:
(This was from memory so might be fractionally off).
Here is a render of the pulley assembly (draft):
Machine M002 is in the works. It is a barrel tumbler for wooden parts. This project will allow us to knock sharp edges off of small wooden products by the hundreds at a time. More to come!
One of the great features of Python is Generator Functions. Generator functions allow you to convert any function to a generator function by simply including the yield keyword somewhere in the function body. When a generator function is called, the response is a generator object, which can be iterated over among other things.
To boil this down to basics, generator functions allow you the programmer to create a function which yields one value at a time (and pauses until the next value is requested) until you decide it is done. This opens endless possibilities for converting sequences, creating sequences, filtering, and more.
The following example is a generator function which will take a simple list or iterator and return pairs of (element, previous_element). This is a great use for generators and the yield statement.
Generator Function:
def lineandlast(listish, first=True, last=True):
iterator = iter(listish)
lastline = next(iterator)
if first:
yield lastline, None
for line in iterator:
yield line, lastline
lastline = line
if last:
yield None, lastlineExample:
for line, last in lineandlast([1,2,3,4,5]):
print(line, last)Output:
1 None
2 1
3 2
4 3
5 4
None 5Notes:
There are two keyword arguments, first and last, which can be used to control the output of the first and last items on the output example above.
Here is a screenshot of some of the parts we’ve designed for the Stain Dipper. All of the mechanical parts are in the design and correctly positioned and all the hardware has been ordered…
Here are several of the parts from Fusion 360
Here is a servo motor mount and custom made pulley.
Here is a small piece of Nylon used to connect a 1/16″ cable with a aluminum tube.
We’ve been doing some research into air knives and considering ways to make staining of thousands of small parts faster. Dip it into the stain, and have a captive air knife blow the excess off (dripping back into the bucket) as the part is pulled out.
The PVC tube will be hinged so it can be opened for cleaning. The air knife assembly will be near the top of the tube.
Did some checking on PVC compatibility with stain and it seems to be acceptable: https://www.berlinpackaging.com/insights/chemical-guidelines-for-plastic/
Here is a possible air knife kit. http://www.exair.com/index.php/products/air-wipes/super-air-wipe/saw-kit.html
Now just need to design the servo motor mounts, air knife mount, and misc. other structural components.
Fudge version 2. (Version one wasn’t good enough to write about).
This is a cross between two recipes that I learned about. I made use of some of the techniques but did not follow the recipe that Alton Brown explains so well in his episode “Fudge Factor” at https://www.foodnetwork.com/shows/good-eats/episodes/fudge-factor
… start with …
2 3/4 cups sugar
1 cup cocoa
1/4 cup corn syrup
1/4 stick butter
1 cup milk
… and later …
1/2 stick softened butter
1 tbsp real vanilla extract
… and if you want…
Cocktail peanuts (or walnuts or whatever)
Put the “start with” ingredients in a saucepan over high heat and stir constantly with a wooden spoon until boiling. I tried covering it as Alton Brown said, but it just tried to boil over, so maybe I did that wrong?
Turn heat down to medium low and DO NOT TOUCH IT. As soon as the temp hits 232F, turn off heat and just let it set there. Place a small amount of butter on the top to prevent it from drying out. Let it sit undisturbed until it is 110F…. then…
Dump in the “and later” ingredients and stir it AS HARD AS YOU CAN with a wooden spoon. When it starts feeling like it’s time, maybe losing it’s sheen, maybe starting to get stiff, it’s time to dump it into a parchment paper lined 8×8 pan before too late.
I then poured the peanuts on top and worked them down in with a spatula. I though it was ruined, because it just wasn’t setting up.
But I got up the next day and sure enough it was perfect.
The Gahooa Perspective 