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IndustryArena Forum > MetalWorking Machines > Shopmaster/Shoptask > Shopmaster Patriot VFD CNC Under CSS
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  1. #1
    Join Date
    Oct 2009

    Shopmaster Patriot VFD CNC Under CSS

    Got around to making a quick and dirty video showing CSS, or Constant Surface Speed on the Patriot

    Shopmaster Patriot CSS - YouTube

    I'll get one of actual chips under CSS up soon.

    Here is the code running in the video.

    G18 G40 G49 G90 G94 G80
    G48 S1000
    G96 S100
    G0 X1.7625 Z0.1
    G0 Z-0.005
    G1 X0.01F5
    G0 Z0.1
    G0 X1.7625
    G0 Z-0.01
    G1 X0
    G0 Z0.1

    Basicly, the normal wizard code for OD facing then, before the M3 to turn the spindle on you insert the G48 with the S command to limit the maximum spindle speed, the insert the G96 and S command to turn on surface speed control and give the desire surface feet per minute. Then before the M5 command to turn off the spindle you do good housekeeping and cancel CSS with the G97 with the S command to set the new spindle speed back down to a reasonable amount.

  2. #2
    Join Date
    Aug 2013

    Re: Shopmaster Patriot VFD CNC Under CSS

    Great video jlm,

    I was more intrigued by your video of the 1045 spline washers you fitted to the top of the quill pulley. Is this primarily to stop the rattle?
    Mine rattles too, looks like a good fix. How did you source the washers?

    Another question, you vid shows your machine running at 2000rpm- out of the box mine won't run anything like that speed- what did you do?

  3. #3
    Join Date
    Oct 2009

    Re: Shopmaster Patriot VFD CNC Under CSS

    I set up the VFD to max at 125hz instead of 75hz. It will go higher, but I'm not sure the spindle bearings are up to it. Once I check the bearing specs, I may take it up higher. I need to run it under a load for an extended period and check it with my heat gun.

  4. #4
    Join Date
    Dec 2007

    Re: Shopmaster Patriot VFD CNC Under CSS

    We recommend a maximum of 120 Hz setting in the VFD.

    If you have loose splines e-mail me and I can send you a file on fixing it easily.

  5. #5
    Join Date
    Aug 2013

    Re: Shopmaster Patriot VFD CNC Under CSS

    JT, thanks that's great.

    My VFD is set on 60Hz so 120 Hz will do all I need from it.
    I've had so many things to learn about that this was way down on my list.

    As for my "loose splines", I just want to be clear that my "problem" is just that the Mill drive is noisy compared to the lathe drive which is really quiet and smooth. The mill drive is no noisier than my pillar drill.

    The rattle clashes with my mechanical sensibilities as I feel that it could cause a wear problem in the longer term- but by no means am I suggesting that it will- its just that it makes me feel that way.
    As I say, its no noisier than my pillar drill and that's lasted fine. Every time I switch that pillar drill on I think "why does it have to rattle so much?"

    If there is a simple fix for the Mill spline I'd be glad to give it a go, especially if its one that others have done so I don't make silly errors.

    JT, I'll send you an email.

  6. #6
    Join Date
    Oct 2009

    Re: Shopmaster Patriot VFD CNC Under CSS

    I spent a fair amount of time chasing down the rattles on mine. Most came from the covers and some tweaking, bending and spacers eliminated them. Another source was the handles and knobs. I removed the axis cranks since I always run CNC under MDI or program and tightened the way lock handles and it runs fairly smoothly now. I do need to tighten the splines just a bit.

    JT, I believe I did use 120hz on the VFD settings.

  7. #7
    Join Date
    Sep 2013

    Re: Shopmaster Patriot VFD CNC Under CSS

    Hi Julian, My handle is Countryguy here on the zone. I do not post much (if any) on this board. I happen to notice the thread on the 1045 spline fix. I think my YouTube vid to JT on how I fixed this is out there? Anyway - to your question- My unit is a 2010 early CNC unit which had chatter when cutting steel. If you can hold the Pulley up top while trying to rotate the R8 spindle back and forth (play or slop) then you may need to address it. JT will send you a Doc on how to repair this w/ a pulley top split and slack removal process. It looked really well done and that is what gave me the idea on a method I could do w/ my home gear. I've cut quite a bit of 1045 steel and this fix remains very tight. BTW - It's nice to see some activity here w/ our 3:1 gear! If you have Q's you can find me on the other site.

    As for the RPM and the setup- I replaced the .75 HP motor w/ a full 2hp WEG aluminum metric frame. Bolted right up. Why- Long story but the VFD went belly up - So it now has a WJ200 3HP Hitachi w/ remote panel. ...and I elected to put in new motor. Yet another learning experience! And don't get me started on 3phase CT and VT values for selecting the right motors. Who knew it was all this complex!! I have a real appreciation for the Industrial Engineer types now.

    I also purchased two new belts and a Tb Woods shiv/pulley and noticed a much smoother spindle setup in high speeds, The TB Woods motor shiv seems really well made and smooth. I also cleaned and polished (as best I could) the top spindle pulley. It was quite pitted and a bit rusty. When I was done it was bright metal and very smooth. I've really enjoyed taking this machine apart , learning and then if I can, making it better incrementally. Been a fun ride. JT has been totally fantastic and always reply's quickly. that is so appreciated when you are a newb!

    What's up of late?
    I just made a small air-grinder pencil adapter to do custom engraving. It's still being worked on and I'm learning all about the engraving tips and feed/speeds with materials like brass, aluminum and steel for small designs. It mounts right onto the lower spindle bracket and 1 of the arms sticking out. (not sure if the new ones have it?).

    Here is a link to my doc for the R8 spindle/spline repair just in case someone wants to review it. The Hobby-Machinist.com - The Friendly Machinist Forum

    ..and a pic of the air-pencil holder project. Still in work, but seems to perform well. The air-pencil can hit 56K rpm! Now that is fly'n !!

    Attachment 253530

    Enjoy and may the chips fly your way. CG.

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