Results

Don't use this kind of vise. It's garbage, doesn't hold things well, you will break it, and it's very hard to get things to settle in flat because when you tighten it one side lifts up. I expirimented with using ATF for machine fluid. It was better than nothing, but also not the right answer.

This is part of a throttle body bracket. It is currently installed on my car:

Some other parts machined out, after all the mods but with another issue we didn't discover until after these were done. No harm though, they came out quite good:

Ketchup 2

The next weak spot was that we were relying on the motor's bearings to take thrust forces being transferred back down the ballscrew. This works up to a point (although it puts some stresses on them that will shorten their life), but once you exceed a certain amount they will push back and forth about 1/8". Most solve this by having a mounting block with thrust bearings holding the ballscrew end, and then using a spider coupler between the motor and the ballscew to sort for misalignment.

And that would probably be prefereable, but I didn't design for it and had to get creative. So above you can see one end of my motor (fortunately it has shafts on both ends) with a stop I lathed out holding a thrust bearing against the motor casing. There is another one on the other side doing the same thing, trapping the shaft in place. This was actually completely effective, and likely how I will do things in the future too. It saves on parts so long as you have some alignment adjust-ability in your motor and/or ballnut mounts.

Ketchup

And other reasons I adore the English language. I am going to try to catch up on the progress the machine has made, because a lot has happened lately. The results are that we have a darn good working machine (as you can see in the previous video) and it's only getting better as we learn.

First, once we put the spindle on some new flaws became apparent. We were getting a lot of chatter, the source of which we determined by means of high speed film (thank you modern DSLRs). The rails on Z were flexing, the whole frame was flexing, and all of that was leading to problems. This wasn't apparent with the router tool because it was taking off so little at a time (and creating a ton of heat, and taking forever).

So I replaced the Z rails with the next size up and triangulated the frame, adding a truss to the back of one mounting beaml:

Quick video

I'm really really behind on posting anything about this project, or anything for that matter. So many things have happened, including finishing the new spindle install, bracing the frame to add stiffness, real milling vices, and much much more. I hope to get back to updating the things on this project.

The video above shows it cutting aluminum with a 1/4" end mill at about 11 ipm. The depth was somewhere around 1/16" at the time. It doesn't seem to have any trouble with this at all, and in fact for the video we were having some problems with the lower axis. Some time in the past, without anyone realizing it, we must have driven it off the lead screw part way and lost most of the bearings out of the ballnut. There were maybe 10 in there where there should have been 80ish. I suspect we can go faster and cleaner once we get that sorted out.

CNC Pt. 14: Upgrades

Which brings us to our next thing: upgrading to a real spindle.



This is the 4/5hp spindle assembly from an X2 mini mill. The cast iron has been chopped down a bit to reduce weight, and the gear drive replaced with a belt drive for reliability and sound. There are a ton of advantages to a real spindle over a crappy router, too many to list, but here are a few big ones:

1: Play. There is almost none, so chatter is cut down drastically. This is better for your finished product and better for your bits.

2: Torque. A trim router has none. A VFD controlled motor maintains most of its torque at any rpm.

3: Collets. Rather than a crappy, 1/4" only 'collet' (which is really a badly designed chuck), this uses R8 collets (I also have an adapter to go to ER32 collets). This means flexibility in what bits I can use, less chance of them coming loose, and less runout.

4: Sound. Routers sound terrible, this has a pleasing hum to it.

5: Motor placement & type. Since it's far enough away from the business end, and mostly sealed off from the elements, this will make running coolant much easier.

CNC Pt. 13: More Tests

With that done it was time for some real tests. First in wood:



Then in aluminum!





There's some chatter in the router, and of course the router has to be run well above the appropriate cutting speed for aluminum. But it gets us by for some messing around.

CNC Pt. 12: T-Slot Table

Next up was the T-Slot table. This was also the first time the machine could really be used for something meaningfull, as all the holes were drilled by program. This was exciting for a lot of reasons, not the least of which that it was drilling aluminum for the first time.

CNC Pt. 11: Enclosure

I didn't realize how far behind I was on updating this project, but much has happened since the last post. The plan was always to make this an enclosed machine, and to make it as quiet as we could manage. The sides were covered with sheet metal, the sheet metal lined with automotive sound deadening material, and the front with a big piece of 0.25" lexan. The lexan is held in place with magnet strip, which also insures perfect alignment without needing pins.





It has become known as "The Evil Dishwasher."

CNC, Pt. 10: First Test

Everything was moved back out into the garage and all the power supply, controller, and computer parts were mounted into a single tidy computer case.



You'll notice the computer we're using is one of those little ViaC3 mini-ITX setups. They're small, relatively cheap, and have everything built into the motherboard.

Mike made a quick model in Lightwave3D and imported it into DeskProto. DeskProto is a tool that creates machine code (in G-Code format) from 3d models. From there it's just a quick trip to the machine's hard drive to run the file. And here it is, our very first test cut, hacked into a 2x4.



It's fair to note that while the machine is far from done, this is a pretty significant milestone. The first goal: a machine that could cut intricate shapes into wood for use in furniture (or whatever) has been achieved. There are several other goals ahead though.

CNC, Pt. 9: Computer

After a great deal of debate, trial, and research, we loaded a computer with FreeDOS and TurboCNC. To sum up the argument, windows based controllers, in my experience, suffer from an endless chain of issues associated with the use of hardware abstraction layers to provide "security." Linux works well, and offers EMC2 (free), but after a few arguments between myself and the system I decided this was a good place for pure simplicity.

TurboCNC reads control code (G-Code), interprets and outputs directly to the controller. Simple, straightforward, constistant, and free to mess around with. Donate the guy some money once you decide TurboCNC is awesome. Same goes for FreeDOS. These guys put a lot of work into their software for our benefit, and should be rewarded.

It took less than 5 minutes to get TurboCNC moving the machine, where we ran a few test files just to see everything work together. Messing around we were able to achieve some pretty good speeds (up to about 140 IPM, not bad for a heavy machine under powering its motors). Also, at 75 IPM the machine feels totally unstoppable. You can push and pull with all your might and it just keeps tracking along regardless. Also, there is no discernible play or flex in any dimension. When the motors are held constant it feels like everything is just welded in place. I do believe this thing is going to work: