machine
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
Not Makin’ It
After working in my shop on a successful project I sometimes ask myself if I could make a bunch of this or that and sell them for a profit. It’s fun to think about a running a little cottage industry. I bet any reader of this blog has thought the same thing about something they enjoy doing and making.
I have published many times my thought that most of the hobbies I do involving manufacturing are not because it is the least expensive way to make something. Usually it is the only way. The onsies and twosies items hobbyists make are more like expensive prototypes than mass production.
Examining all the costs and time involved, I have satisfied myself that most people including myself won’t pay for all the costs of something that can clearly be mass produced at a lower cost. The perceived value must be greater than the cost to produce plus reasonnable profit.
What we call “original art” falls into that category. There is an emotional value with original art that makes it worth owning at higher than mass production price. A plain wooden mass produced box can probably be imported to the USA, completely built for $0.99 and after hand carving, painting or finishing at a cost of $10.00, can be sold for $25.00 at a boutique. Making the box from scratch, one at a time may have a COST to produce of over $25.00. If you are an artist with talent, the same box may be worth $250.00 to someone.
So the options are to become very good and fast at duplication or provide something special that has far more value than the cost of the time and material. I think it takes a little of both. Actually, getting paid well to make prototypes… Continue reading
Just a Coupler of Things
Helical Beam Shaft Couplings
These are the Helical Beam Shaft Couplings I ordered for the HB2 project. The size is 1 inch in diameter and one inch in length. These are the clamp on type and so will not mar the 1/4 inch shafts like a set screw.
These couplings are rated to withstand 42 peak inch/pounds of torque. That’s 672 in/ounces. The holding power of the steppers is a little over 300 oz/inches so there is a 2X safety margin in my selection.
The helical in the name implies a coil and if you look close you can see there are two coils cut into each coupling. The material is anodized aluminum and adds very little weight to the rotating mass.
This may be a bit deluxe, but the motor drive train is a critical operational part in the design of any CNC machine and I want zero binding between the motor and the screws. No steps dropped because of alignment problems.
Heat Sinks
Keeping my steppers cool.
This is a rendering from Rhino. I haven’t made one yet but the drawings are complete and so is the CNC program to produce this part. Material is on order.
It is a combination heat sink (stepper motors get very hot) and a shaft spacer to let me install a larger shaft coupling on my HB2 motor to screw connection.
The overall size is 4″ x 4″ and is 1″ thick. The inset is to fit a NEMA #23A style motor. There is also a recess on the underside for the standard spacer which will be used.
I figured why just do a spacer when here was a chance to get some aluminum fins on the stepper motors. Many CNC designs just hang the motors out on some thin rods, nothing to pull heat from the motor. The motor manufacturers recommend mounting the face of the motors on a metal surface of enough mass to act as a heat sink.
I need four of these for HB2 and if they work as intended, I will market them in the THMStore.