Centroid Community CNC Support Forum

I had some other business to attend to for the last couple months but I am now back to this project. I may have to take another break in the near future but hope to have everything working and mostly all of my goals accomplished by spring.

Last February I started on a project to build a CNC lathe with the following goals in mind:

1. Portable. It needs to be able to be carried by two to four people. (I added the handles in October. However,
the final version will have better integration of the handles as I was originally planning to use something
off-the-shelf and found out that most handles are for drawer pulls.)
2. Compact. It needs to be able to be placed on a heavy bench, table, etc., and be mostly in the same "container".
3. 5c Collets. 5c collets are very versatile but are only supported on bigger machines.
This machine needs to support them.
4. For small parts. While larger parts can be fitted, the main goal is to support
a work envelope of 1" diameter by 2" long. Even though it's small, it still can make
millions of possible parts.
5. Turret. It needs to have a turret so as to better automate operations.
6. Collet closer. It needs to have an automated collet closer and still be compact.
7. Threading Support.
8. Tapping Support.
9. 115 VAC. It must not have any special power requirements. So, by being able to plug it into
115 VAC that eliminates that problem. I will have to figure the final amperage to see
if it will still be ok on 15 amp circuits, though. My current believe is that it's ok but
I haven't checked into it yet. The power cord also unplugs from the back so there aren't
any dangling cords if the machine is moved.

I am going to add support for an external coolant system to be hooked up as well. (i.e. The external tank and pump Grizzly sells.) The final version of this machine will have a built-in coolant trough and plexiglass windows. This is the second version of the prototype. Extra, unused, holes are visible as I re-used a lot of parts from the first version.

Thus far, I have everything but tapping support. However, a new VFD is ordered as well as the braking resistor. Everything will still fit in the case.

The left cover will eventually have a hole in it for running stock in from the back of the spindle as well. I need to add support for this on the frame.

Also, some way wipers have been 3d printed but not yet fitted to the machine and the final version will have better support for oiling the ways and bearings.

I have a concept for a better turret, as well. I am not sure if it will make it into Version 1.0 or not.

I found out I couldn't find any off-the-shelf cut-off tool holders that would fit, either. So I had to make one. In retrospect, I should have figured out how to make such a tool holder part of the turret and am going to see if it's possible for another version of the turret.

cnckeith asked me to post some more pics, so here they are....

Right on! Thanks for posting! Cool little machine!

Very interesting. I've been thinking about something similar without the turret but with a quick change tool post and with linear flat rails instead of round rails. Your design looks much better than what I have been thinking about.

I’d love to see some pics and details of the turret, if you could.

I'll post some more pics soon. I just modified the turret and would call it version 1.5 of the turret. It isn't "perfect" as there was some trial and error making it. Tonight, I'll finish re-installing it on the lathe. Tomorrow, I should get some aluminum in so I can make up the rocker adjustments to adjust the center height of the tools.

ScotY wrote: ↑Thu Mar 26, 2020 8:22 pm I’d love to see some pics and details of the turret, if you could.

I'll soon have pics of the next frame revision, as well. The 3rd prototype frame has integrated carry handles, a spot on the front panel for an accessory port (i.e. probe), will have the spindle motor inside the main frame, will have most of the electronics together on the top left under the cover, has threaded holes to mount other options above and below the spindle (i.e. a coolant nozzle), and will use a magnetic ring encoder.

Pretty cool. Look forward to following your progress...
Marty

Cool, thanks. Curious how the turret works. Quite an ambitious project...very nice work!

Here is a picture of the modified turret. I added rocker tool posts to all 8 of the 3/8" tooling slots so as to allow for adjustment of the center height. Prior to this change you could use the lathe bits or the round tooling but not both as the center height was not adjustable.

Since this is a modified turret the rockers had to be on top. In the final release, the rockers will be on the bottom and I'll add just a little more adjustment.

Also, the threading insert holder is shorter than expected so it is partially shimmed in this picture. The final turret will have the inner clamping set screw closer to the outer edge.

Here's a test of the machine turning down a shoulder, tapping out a 1/4-20 hole, and threading 1/2-13 on the OD.