Progress on the Harp Fabricator

3691169051?profile=original3691168970?profile=originalAfter a coupla years of thought and compromises and decisions on how to make a rigid small CNC machine this is what I've come up with.

It will be cast solid aluminum which is the only real solution for the rigidity issue. If you could do it in cast iron it would be perfect. However this seems to me to be the best compromise after a lot of thought and trials. 

This is a moving table design not a moving gantry design.

We plan to make the casting sometime after the 6th of January when I have help from the rest of my team here working on another project. 

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  • Here is the first part! It was perfect until the last pass Mastercam tried to do some kind of scallop on the holes on the finishing pass for some reason I have to figure that out. Tool holding is ER 11 which is max 3/8 tool. I have the vfd set to 7200 RPM I still need to hook the spindle control up to Mach 3.

    I'll do a video as soon as I fine tune the machine I have to hand scrape the ways to get perfect alignment and be able to tighten the gibs fully. It does cut Aluminum and even Steel passed the first test. But I want it perfect before I do a video ; )


  • Nice!

    What did the tool handling end finally look like? 

    (I suspect you will be posting that soon enough)


  • 3702399476?profile=originalFirst cut on the Harp Fabricator!

  • Great to see more progress! I 

    Is it just me or have we (maker community in general) seen the peak of the "Build your own CNC" movement/trend?

    Or has it just been shifted over to the "Buy/Assemble your own 3D Printer" movement/trend?

    Just wondering when Goodwill and other thrift stores are going to start having piles of 3D printers and CNC routers looking for a new home?


  • One more day maybe 2


  • Looking forward to seeing it!

    My Momus has progressed also, but working for a living and the Gotha project has taken much spare time.


  • Nearly finished with the Harp will unveil the final product very soon now! That was a really long project!


  • The third axis is complete and now working on electronics will post some more photo's soon

  • Thanks for the kind words Gary

    You are correct I'm sure a water cooled spindle would be a far better better choice. I'm looking into a ATC based on the 8 Ball system used on the Taig mill for the harp as a simple tool changer design. There are some YouTube videos out there for that design too you might want to look at it.



  • Hi Monroe,

    An interesting point regarding the AC/DC brushed universal motor, but the router currently uses Bosch's dialable speed control with speed/torque sensing and forcing.

    Clearly I could bypass that and directly control the DC/Universal - brushed motor, but then I still have the inherent problem of questionable spindle performance for precision CNC due to the bearings and spacing as well as potential overheating problems and I mainly work in aluminum and G10 fiberglass.

    I think that rather than try to adapt the router, I will try a "good" Chinese (possibly water cooled) VFD spindle if I decide to upgrade my existing DIY CNC router rather than buy a new bigger one.

    I am definitely going to look into the viability of some sort of home brew tool changer in any case, I realize now that there are a lot of ways to go about it, many articles and You Tube videos on line.

    Thank you for your input and I really look forward to seeing how your Harp CNC system works out.



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