Workshop
HB2 Milling Heat Sink
I spent the weekend getting the last of the CNC milling bugs out of making the stepper mounts/heat-sinks for the HB2. Here is a picture of the trial version. I finally have all the speeds and feeds correct for the fragile little 3/32 end mill I am using to cut the fins. This thing is beginning to look like the cylinder head on a lawnmower.
The oversize holes near the top were a mistake. I could also say they were an experiment.
I use mist cooling when doing the milling. The air compressor broke on Saturday that sprays the mist. Today with the new compressor everything went fine. The DeWalt is a good brand. I really like the lower noise level. It is not silent but a lot more bearable than the Kobalt.
Here is a link to a short video showing the milling of the heat sink above. There is actually a fine cooling mist coming out of the nozzle as well a good bit of air. The air compressor was NOT running in this video.
I have the four blanks cut today for the real parts. I feel confident in starting on the real product.
Bad Air
The blue compressed air system shown on the right is the Kobalt system I purchased at Lowes in January of this year. There is another posting in this blog when I made the purchase. It was the replacement for a very old compressor that was blowing oil. That compressor is show in the previous post.
I had some bad luck with this new machine. A few months ago the pressure switch failed and it wouldn’t let the compressor restart at the low pressure point. I disassembled the switch which was made from pot metal. The diaphragm plate had warped and was leaking air. Some work with a file flattened the plate and let the gasket seal the chamber again.
This picture is the Killer. These are parts of the reed style discharge valves from inside the compressor itself. The heavy metal at the left is the back-up plate and the object to the right is the reed valves. Only the middle two valves on my machine had ports behind them. The outside two were dummies. You can see the heat patterns are different between the inside and outside valves. Yep, that is a broken valve. The compressor stops pumping when that happens.
Readers here know I like to take things apart, especially my tools. I suspected this broken valve was the problem as I have worked with air conditioning compressors all my life and know the symptoms. I had to see for myself. I also discovered the cylinder wall is plastic and the piston is a flat plate with a rubber O-ring for a piston seal. No problem there. It seemed to work well enough. The intake valves are a different style reed valve.
I called the Lowes 800 number for warranty/repair information. I had a printed three year… Continue reading
Getting Together HB2
Making Progress
The parts are going together for the HB2 assembly. At last is is starting to look like a router machine. I like the yellow but no one else has to agree.
The biggest problem has been the bolt sizing. The shopping list wasn’t exactly correct but close enough. I am using Alan cap screws where possible and some Phillips head. Almost all the nuts are nylon lock type.
The rails are extreamly nice and should prove to be very accurate. More pictures as I get it closer to finish.
10/28 – Update from this mess!
Follow this link: HB2 Section #3
Time to Clamp Down
Low profile CNC vise
Today I spent most of the day laying out, milling and assembling this CNC machine vise/clamp. It is low profile to stay out of the way of machining actions. The rest of the day was spent publishing it in my The Hobbyist’s Machine Shop web page and several other links including here.
Some times making the parts that make the parts is required. This was one of those times.
Columbus Day
Its Columbus Day (the real date) and its been a busy weekend so far the The Hobbyist’s Machine Shop. (My playroom 🙂
I broke two more of the tiny mill bits on the heat sink milling for the HB2 . I am going to have to stop doing that. It is really a “dumb me” problem. The last one was because I did not have the part I was milling suitably (meaning rigidly) attached to the bed of the mill. It came loose whilst milling. Poo!
So now I am taking the time out to build the correct clamping system to hold the heat sink blanks. It is a project I wanted and needed to do anyway, but the lesson is I should have done it first. It’s just a reminder that the set-up is everything.
The clamp can and will be used for holding other projects on the mill so it will be a great addition to the tool box. It will be a larger version of the clamping system I used to make the A3 locomotive wheels. That clamp is just a tiny bit too small so I resorted to a less than satisfactory clamping method. It worked… for awhile. 🙁
The new clamp will take advantage of the machined plate (with all the threaded holes) that I made for the Taig. Then I will not have any clamping gadgets sticking up in the way of milling. Of course I will post some pictures in a about a week when I have got it working.
This weekend I also ordered all the nuts and bolts for assembly of the HB2. I went with stainless for most bolts but had to select “oil black” metric sockets heads to mount the linear rails. (Not available in… Continue reading