I just finished the majority of the design process on the table for my MPCNC build (printing parts currently). I have a few design choices to solidify (see questions at the end of this post) before I start making part detail and assembly drawings. As designed currently the top is 3’-0” x 4’-0” overall.
I might go a little large in the longer dimension. My main goal with this CNC is to build guitars, and for most designs that would be plenty… but I don’t think it would be long enough for a through-neck Flying V or Explorer type guitar, or a through-neck bass.
The frame utilizes standard construction 2x4’s (with 4x4’s) for the legs. The surface of the lower shelf and the base layer of the top are 3/4” MDF, with removable 1” MDF top sections as a resurface-able, easily replaceable spoil board.
This design (currently) utilizes Rockler T-Tracks as well as a grid of 3/8”-16 threaded inserts for clamping/mounting provisions for stock. Pending the following T-Track question I might go with 1/4”-20 threaded inserts for the sake of continuity.
Obviously there is a perimeter inside of the gantry rails that is inaccessible by the cutting edge of the spindle of the MPCNC, but realistically how much should I plan for? Let’s say hypothetically that the center axes of the rails are a 3’-0” x 4’-0” rectangle, what should I expect for a realistic usable cutting area?
Additionally, does anyone have experience with T-Track? It seems like Rockler is the most common variety used, and they have large variety of interesting clamps and accessories… but I would really prefer using a track that uses standardized hex bolts (pennies for 1/4”-20 bolts vs $5-ish for Rockler’s proprietary T-Bolts). My trepidation about going that route is that I don’t want to lose out on the variety of clamps and accessories that Rockler have. Are there comparable tools and accessories out there for 1/4”-20 T-Track?
I have always thought super strut is an amazing option if you can get it locally. It is at every hardware store in my neck of the woods and super cheap comparatively. It was what I wanted to build the CNC out of and it was sitting next to the conduit and that is how that happened.
I try to stay away for that sort of size question. Yes it will “work” But it was designed for a 6"-18" work area. I have some blurbs on the specs page, the size page, and the FAQ’s about this.
I understand wanting one dimension long for necks, but why 3’ the other way?
Unfortunately my official answer is more along the lines of 2 build would be better, one for bodies and one for necks, maybe even one lowrider and one MPCNC. You can share your board between builds in minutes to cut down on costs.
You can literally shave hours off a job with a smaller build. Time vs money.
If you’re asking how big the cut area is with tubes that are 4’ long, there is a calculator linked on the parts page.
The cheap TTrack on amazon or alibaba is way cheaper than rockler. You can also buy ‘toilet bolts’ which are used to attach a toilet to the floor. They are also cheap.
The low rider is meant to be for bigger builds like this, but it’s a little harder for learning. If this is your first CNC, I would suggest building something more like a 16"x16" work area and then getting good at understanding what works and what doesn’t then either buy longer tubes for the mpcnc or also buy a low rider.
You can extend the work area a little. If you leave one side clear, you can work on one half, with the other half sticking out, then flip it. The trick is to also mill some holes for dowels to make the alignment right for the second half.
I think the biggest challenge with guitars is the depth. You’ll need a long bit and a lot of rigidity in Z. There have been some guitar builds on mpcnc though, and I am no luthier.
I do have some CNC experience, not a pro but not a total beginner either.
You’re probably right though… I can do bolt on necks for now. I’m not married to the idea of neck-through instruments at this stage. That can be goal for another day.
I guess my concern with the Lowrider is the amount of Z-travel available. Correct me if I’m wrong but I was under the impression that it was mostly for paneling. If it has enough available Z-travel for a Les Paul style guitar (I’m guessing around 3.5”, but I don’t have my LP available right now to measure) then I might look into that as well.
I really was just estimating on the size I would need. 3’-0” really is probably overkill for the width. I think I will take a trip out to my practice space to measure some instruments to get a more realistic set of dimensions.
Thank you for your responses. They’re very appreciated. ?
I think for the most part you would really want to do a flip. machine half, flip machine the other half. That way you only need half the machine height and you can shape both side.
I’m pretty sure you can build it much longer without any problem, just spend a bit more money on some thick/stiff chromoly tubes and you’ll be good to go. I wouldn’t worry about flex, with proper tubes this just isn’t a concern. But you clearly can’t go for the random, coat hanging kind of stuff.
Your table design is solid, so that’s good, you don’t want it wobbling around. I agree with Ryan on the fact that is makes more sense to flip the guitar in order to mill half of the height, that’s much better and it seems to be how most people are doing it anyways. It’s trickier to do it at first and you need your machine to be dead square, but after a bit of practice it will be just fine.
I wouldn’t worry much about that kind of size, if I were you I’d do it as long as a guitar needs to be and try to reduce the width to the minimum needed. You’ll be cutting wood, not aluminum, and a guitar needs a lot of manual finishing anyways, so that’s fine. My advice is to concentrate all your efforts in getting this as square as possible, that will matter.
As for the lost build space, it will depend on the diameter of your router. I’d say that you lose around 15 cm on each axis, but I don’t have my machine next to me right now so I can’t tell you for sure.
4T-Track - Good news for you. The Rockler T Track uses standard 1/4-20 hex bolts. If you use the 5/16 hold downs you will need to use the expensive custom bolts or as someone mentions toilet bolts.
