MI59 Double Cut

Discussion in 'Luthier's Corner' started by fretman_2, Jan 12, 2017.

  1. fretman_2

    fretman_2 Senior Member

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    Starting a new build and taking the MI59 concept into double cut territory. Got some old cypress from a demolished house that'll go into the first body...

    Concept drawing...

    [​IMG]

    Cypress...

    [​IMG]

    Stay tuned as I'll use my homebrew CNC machine as much as possible on this build.
     
    Last edited by a moderator: Apr 23, 2017
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  2. pshupe

    pshupe Senior Member

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    I like it. I think all the curves go well together, with a possible exception of the "f" hole. You may want to add a bit more curvature to that. It's a very cool design though. The double cut totally changes the feel of the guitar. Looking forward to how it goes with the new CNC.

    Cheers Peter.
     
  3. Marty M.

    Marty M. Senior Member

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    This is probably the most action the MI59 has seen in decades...LOL.
     
  4. ricky1918

    ricky1918 Senior Member

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    nice design! Subscribed, can't wait to see your CNC!
     
  5. fretman_2

    fretman_2 Senior Member

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    LOL...for sure Marty. Nice to dust off an old design and give it new life!

     
  6. fretman_2

    fretman_2 Senior Member

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    Cool...I'll give it my best shot!

     
  7. fretman_2

    fretman_2 Senior Member

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    This is the first guitar body done on my DIY CNC machine. The wood is cypress from an old hunting and fishing camp. I'm told it's from old growth trees. The body is a double cut version of my MI59 design. Some particulars...1/4" spiral upcut bit, 60ipm feed, step down 0.05", step over 40%. Step down and step over were too conservative...gonna increase both of those as it took about an hour and 45 minutes to cut out the body. Much of that time was pocketing work. I'll also give Fusion360 a try instead of MakerCAM.

    I trammed (right word?) the top of the body blank with a 1/2" bit. You can see some ridges where the bit isn't 100% parallel with the spoil board, but it's nearly perfect. I can't feel the ridges when I run my finger across. I feel good about that because I've done no shimming what so ever. It's pretty square as first constructed.

    [​IMG]

    After tramming, I ran the blank through my thickness planner to get both side parallel.

    [​IMG]

    Various stages of pocketing for controls, pickups, and neck.

    [​IMG]

    [​IMG]

    [​IMG]

    Finally, just about complete with the body. I didn't cut all the way through on the outline as I didn't want to have the bit cutting through 1.75" of wood.. I took it to my band saw, and will finish up that little bit with a pattern following bit on my router table.

    [​IMG]

    I'll post some pics as I do the neck...

    I still have some tweaks to do on the machine...I've started installing homing switches, and I still need to construct new spindle clamps...also dust collection. Having dust collection will actually save me some time as I'll be able to do other things while the body is being cut rather than staying close by to have chips and dust vacuumed up.
     
    Last edited by a moderator: Apr 23, 2017
  8. pshupe

    pshupe Senior Member

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    Looks good. Surfaced would be the term I would use but that could be just me. ;-) I use the same method to flatten my spoil board. It's great if you don't have a big enough jointer or thickness planer.

    I just started using Fusion 360. It's pretty cool and I bet extremely quick once you get the hang of it. I whipped up this on the weekend.
    [​IMG]

    rendered
    [​IMG]

    It's a design for a friend's guitar. It took me a while but I just opened Fusion 360 on the weekend and watched a few you tube videos. All design so far. Once I finish this body I will look at the CAM options, which from initial looks, they seem to be very nice.

    Yeah that DOC is really slight. The bits can cut full diameter, usually, but I generally cut that in half. So a 1/4" bit should easily cut 1/8" depth of cut. You might want to use a larger diameter bit for large pockets. I use 3/8" for most smaller pockets then 1/2" for chambering a full body. It sure decreases overall machining time when you get all that stuff dialed in. Your depth of cut alone is costing you more than 50% of your machining time. If you use 3/8" diameter bit with 50% DOC and even 50% stepover, you should be able to get that time down to about 20 mins. It's gonna depend how much torque / load you want to put on your spindle and machine but those specs should be very conservative.

    Cheers Peter.
     
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  9. fretman_2

    fretman_2 Senior Member

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    Wow Peter...that's fantastic! I've just now begun to used Fusion360. Been trying to understand how to do a 3D guitar neck! Really...I don't have to do the whole neck in 3D...just the part that actually has the profile. I can blend the rest in by hand.

    BTW...what YouTube vids did you watch??

     
  10. pshupe

    pshupe Senior Member

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    I just googled it and came up with Lars Christensen's videos. I think these, or alike, are a must. I would start with some flat stuff first then go to the carved.

    Here is his page - https://www.youtube.com/user/cadcamstuff/videos

    I'm still watching his videos. Lots of tips on how to be faster. I haven't gotten to any non-flat planes yet. I only have to figure out a sloped plane then I can look at CAM in Fusion. It looks much better than my current software.

    Cheers Peter.
     
  11. fretman_2

    fretman_2 Senior Member

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    Cool...thanks for the info Peter!!!


     
  12. Marty M.

    Marty M. Senior Member

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    That looks good. Hey, just something to consider to speed up the process. I don't use a 3d program except for carving necks, tops, and contours because of all the extra travel that seems to be involved. If you do 2.5 D for all routs and perimeter, it really moves along faster. My top speed is about 50 IPS. I use CAMBAM for each individual rout and then assemble all the individual programs into one in Notepad.
     
  13. pshupe

    pshupe Senior Member

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    Hey MartyM - I would imagine all those toolpaths are 2d only. Pockets and profiles. I agree about the 3d. I use Vectric software right now for toolpaths and while the 2d is OK to good, the 3d is horrendous because I have the cheap 3d version and you have to surface the whole piece even though you only want a little chunk.

    Cheers Peter.
     
  14. fretman_2

    fretman_2 Senior Member

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    Yea...all my tool paths were 2D. I'd only consider Fusion360 for the adaptive clearing, but now that I've read more about it, it may not be any faster. The advantage with adaptive clearing is that more of the tool is in contact with the work piece, extending tool life.

    I used 60ipm to cut out the body, but used 80ipm to level the top. Is CAMBAM a program that has to be purchased?

     
  15. emoney

    emoney Senior Member

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    I'll be curious about that Cypress and how it turns out. I've always worried it would be
    "gummy" for lack of a better word. We have lots of Cypress around here, and it was a huge
    product for use in building homes way back in the day because Termites hate it, I understand.
    In Florida, we grow our termites big enough to give names and have saddles, btw.
    I've got a really long beam of the stuff just sitting in the corner of the shop that came out
    of my barn but haven't decided what its going to be used for. Keep us posted!

    Oh, and the CnC looks great. Come down here and build me one next.
     
  16. fretman_2

    fretman_2 Senior Member

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    Yes...it is gummy. All of the dust kind of clumped together. I'm sure in the short run it'll be ok. I really don't think that working with it will be all that different than building a pine body.

    Thanks for the kind words about the CNC machine. I wish I had time to build another machine...would be happy to do it. It's difficult to reach a balance between gigs ($$) and building guitars/CNC machines!

     
  17. Marty M.

    Marty M. Senior Member

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    From the flashcut website:

    Working in two and a half dimensions (2.5D) means you are cutting a part that has multiple flat features at varying depths. During a 2 ½ D cutting process, the Z axis positions itself to a depth where the X and Y axes interpolate to cut a feature. The Z axis then retracts so the X and Y axes can move to the start point of the next feature, which may be cut at a different Z depth than the last feature. Most simple CAM programs deal with 2.5D parts.
     
  18. fretman_2

    fretman_2 Senior Member

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    Here's my first attempt at a rendering in Fusion360...

    [​IMG]
     
    Last edited by a moderator: Apr 23, 2017
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  19. fretman_2

    fretman_2 Senior Member

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    Ahh...so the pockets can vary in depth...

     
  20. pshupe

    pshupe Senior Member

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    Hey MartyM - Sorry I thought 2.5d was when you had an object that had machined areas on perpendicular faces. You would flip the object 90 degrees on the bed and cut the other face.

    fretman2 - Not sure what you mean about varying depths? In my software I pick a 2d line and tell it to cut a certain depth. If there are pockets of different depths I have to make another tool path for that cut. Although if the bit is the same it will merge all the tool paths into one and cut at once instead of having to loaded different paths for the same bit.

    What my software does not do is combine machining as I have just described with 3d contour machining or any plane that is not at 90 degrees from the bit. I have had to move the work piece to do something small like an angled neck pocket.

    Regards Peter.
     

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