Hi guys,
Thought it was about time that I put up some info on what I have been working on. I always wanted to build a mini CNC and fortunately I was able to start it not long ago.

So far I'm really happy with how it is coming along. I have had a dial indicator mounted an X axis bearing and ran it across the surface plate. It barely moves by +-0.01mm, so it looks like the plate and everything is running very nicely.
I had the z axis running just the other day and set the MPG to 1mm and 0.1mm movements, each step moved damn on exactly 1 and 0.1mm on the indicator, I have not even looked into backlash comp. yet too. Hopefully the X and Y are that good!

Big thank you to the following people who have helped me along the way:

- Dad, he is the guru when it comes to machining and has been a big help. We have made all the parts on his kingrich mill.
- Mactec54
- PeteEng
- Fox (aka Fox3d on here), I've watched his videos on his granite CNC build about a million times. My machine is heavily based on his!
- Everybody else on this forum who has taken the time and effort to reply to my questions!

Here are some details on it:

Approx. 425 x 425 x 215mm X-Y-Z travel and 250kg machine weight. The enclosure and frame that is sits on is around 150kg.


Materials:
- 900x600x100 cast iron surface plate base
- 50x650x127mm alloy side/riser blocks, the Y axis bearings bolt on the top of these
- 50mm thick plus 25mm alloy plate between the Y-axis bearings and the gantry.
- 25mm thick plate for the X and Z axis plates, Z axis will be stiffened with ribs bolted to the edges down the track.
- Mildsteel welded gantry, filled with epoxy and sand mixed at 25-30% by weight.

Bearings:
- THK SHS25 rails and blocks for the X and Y axis
- THK SHS20 rails and bearings for the Z axis
- THK BIF2005 ground ballscrews for the X and Y axis
- THK DIK1605 ground ballscrew for the Z

Spindle:
- Jainken JGH-105-2.2 - 4 pole, 400-800Hz, 10,000-24,000 rpm, ER20 - we chose 4 pole unit for the extra torque.
- Fuling 3.7kW DB600-3R6G-2 VFD

Electronics:
- OMC Stepper online, nema24, 24HP39-5004S, 495oz.in stepper motors for Z and X axis
- 2 x 24HS32-4004S, 339oz.in, nema23 motors for the Y axis
- DM556T drivers for all axis
- Meanwell 48V, 24V,12V and 5V powersupplies
- UCCNC + an AXBB-e controller
- LAPP Kabel Olflex Classic 100CY shielded cable for the steppers and spindle. - 4x1.5mm2. I found some copper saddle clamps in the plumbing section of the local hardware store which clamp around the braided shield perfectly. Hopefully I don't get any inference issues!
- BEST Tech. GPenny USB MPG wheel. This has worked with UCCNC really wel so far. https://www.aliexpress.com/item/4000288265160.html?spm=a2g0o.order_list.0.0.21ef18 021LoXxU

Tooling:
- GSTOOL, BAP400R 50mm cutter and carbide inserts. This works very well so far (in my dad Kingrich knee mill), will be interesting to see if it can run in the jainken spindle. https://www.aliexpress.com/item/1005001343354116.html?spm=a2g0o.order_list.0.0.21e f18021LoXxU
- DGMZNC carbide 3 flute endmills. So far these have worked great. https://www.aliexpress.com/item/33009302932.html?spm=a2g0o.store_pc_allProduct.814 8356.1.13172f0camHre5


The spindle was only dummy-assembled in this photo, hence the strange mounting arrangement.



The gantry has a 75x50x6mm inner RHS tube which has 5 x 3mm laser-cut plates/ribs welded to it. I cut slots in the outer RHS so I could then weld the ribs to the outer tube in the hope that it would help to stiffen the whole assembly. I only really did this because I already had the material lying around and it was basically free. I welded 12x30mm bar to it for the X axis bearings to mount to, plus 12mm plates on the bottom which mount to the alloy Y axis bearing blocks. Then I drilled 25mm holes in the rear and filled it with the epoxy-sand mix as much as possible. Even though I used a round bar and hammered the mix into the voids, it still has some empty cavities in there which I found when drilling the holes. Overall it weighs not far off what I expected and sounds very damp when it tap it. The inside area of the 75x50 tube is still hollow, only the voids between the tubes were filled.
After welding I had it surface ground to give us a nice flat surface for the X axis bearings, then finished it off on Dad's mill.
The little sample of the mix was simply packed into a plastic spray can lid, no vibrating.


The enclosure is made from a 9mm MDF inner layer, 30mm gap filled with wool insulation and a 6mm cement sheet outer layer. The doors are the same but with a 4.5mm and 6mm piece of perspex for the windows. Then the inside is painted with epoxy resin for waterproofing. So far it reduces noise quite a bit. I'll get some dB measurements when the spindle is running. I also have plans to tidy up the windows etc. The sealant underneath the windows looks terrible!



We machined the alloy Y axis blocks together to get them exactly the same hieght, same as the larger 50x650x127 bars.