Any DB CAD Drawings? or CNC Resources?

[gbaker]

Does anyone have knowledge of available 3-D CAD drawings of DB parts that would be suitable to produce CAM G-code for a CNC routing machine? I am mostly interested in the plates.

I would also be interested in the G code itself.

Any discussion appreciated.

Thanks.

[powerbass]

I have contemplated this idea and made a few posts about the process. I haven't seen any cad drawings for DB. I have spoken to a CNC owner about making me some though. I don't have direct experience w/CAD, I worked in a busy high end custom furniture shop that employed a CAD designer/drawer so I have seen the process and worked w/the drawings. Plotting in the shape of a plate in autocad etc would probably be very time consuming and expensive if you paid a designer. If you planned on making thousands of tops it would pay back. The other option is some CNC machines have a scanning capacity. This process works by placing an object on the CNC bed, the router head has a special tip that gently touches the object, moving up/down and forward in very small increments. This process makes a digital file that then can be used to mill an exact duplicate shape. The scanning process can take a very long time for a large object. Since a bass is symmetrical R/L you could scan just 1 side of a plate and flip it to create the full picture. There may be a quicker process for more expensive machines - it's all about how much you want to spend. James Candino on TB seems pretty knowledgable about bass construction and CNC. If you need a CNC person I have a contact though someone local is better since you could spend time w/them

[gbaker]

Thanks Powerbass. I read your posts over in the "Kit Bass" thread but didn't want to hijack it.

[RCWilliams]

there are soft ware packages which can take measurements from digital photos with a target of known size in the picture also there are new 3d scanners on the market as well as diy types tat are supposed to work fairly well.

I suspect that any one who spent thousands of dollars developing geometry and gcode for cnc production isn't going to want to give it away. if you can get a good point cloud from a 3d scan and a good outline revers engineering should not be too hard.

[robobass]

Originally Posted by RCWilliams

I suspect that any one who spent thousands of dollars developing geometry and gcode for cnc production isn't going to want to give it away. if you can get a good point cloud from a 3d scan and a good outline revers engineering should not be too hard.

+1. If I was looking to have some custom CNC plates made I'd probably try to contact someone like Shen first.

In other threads it was discussed the cost of the machines, slow scanning and cutting time, and learning curve. All of this is improving at like the rate of Moore's law. Here is a company in Germany which makes a very professional machine for about 13k which is plenty big to do bass tops and can cut through wood at 10 meters/minute. They sell A violin sized version for about 1.3k. Also, software is getting cheaper and much more user friendly. The point is that in a few years you will see very capable machines in most small woodshops and even in hobbyist's garages. I don't know if this is a good thing for luthiery overall, but it's coming, like it or not. One thing I look forward to is the explosion of cool and crazy experimental designs we will start seeing.

[powerbass]

I started making furniture before CAD and CNC so I watched the initial development in the furniture field. The machines and CAD process started out very cost prohibitive, now many shops have CNC and CAD drawing is standard practice. Even though the machines and process have gotten better and cheaper a machine to carve a bass top would be a substantial investment. With woodworking equipment the larger, heavier the better, big powerful motors can handle hours of production. Entry level machines are lighter duty using routers instead of powerful cutting heads. I would look around in your area for a CNC shop/woodworking company. The scanning method I mentioned in the above post seems archaic (I saw this machine scan a 2' x2' panel that took several days to complete). There is probably a lazer/light scanning process similar to a desk top scanner that would scan an object in a fraction of the time. As for not liking CNC or CAD, it is really nice having a full size CAD drawing that is accurate to a thousand of an inch. Once you had the scan you can create a mold for a plywood top or carve solid wood. Keep us posted

[powerbass]

On a different note here is a vid about how carbon fiber cello's are made, notice how the tops are done http://www.youtube.com/watch?v=J_gI3...eature=related

[gbaker]

Originally Posted by powerbass

On a different note here is a vid about how carbon fiber cello's are made, notice how the tops are done http://www.youtube.com/watch?v=J_gI3...eature=related

Very interesting PB, thanks.

I am looking into a small CNC router maybe 28"x48" but have decided the CAD part needs to come first.

[powerbass]

You might want to post over on the bass guitar luthier's corner Forum on TB. CNC is utilized extensively for slab bass bodies and necks. I am not positive but I think google sketchup software is CAD compatible

[vejesse]

I admit I haven't looked into CNC wood routing at all, But I would think that if you want to get into this kind of work, then learning how to draw and generate your own toolpaths and G code would be something you would want to handle yourself. Do you have CNC machining experience? Would someone else handle the CAD/CAM software and run the machine? The drawing/toolpath generation is the easy part compared to actually making good parts.

[james condino]

If you are really, really serious about building a LOT of plates, then cnc makes great sense. If you are just a casual builder, then you need to ask yourself what are my priorities: Do I like working with wood and building things and is that where I find purpose and peace of mind, or have I never really built anything and am afraid of the traditional processes, so I'll stick with my computer and work out some of the challenges digitally.

On the safe side of things, I probably spend a total of approx. 25 hours to hand carve a spruce top, and then probably close to the same for the purfling and the bassbar; maybee more. Are you willing to spend upwards of several hundred hours to learn all of the software, get all of the CAD file details worked out, and make a few mock ups just to get one approximate top plate that you'll still probably spend 50+ hours on getting the fine details for your first build???

Have you ever actually carved a fine billet of spruce by hand using very well sharpened simple tools that fit the shape of your hand and body such that the grace of your posture and body position comes out in the subtle curves of an arch or a recurve that is almost sexual in its beauty??? Have you ever sat next to a CNC machine for 8 straight hours while it felt like your teeth were rattling out from the noise and vibrations until you wanted to scream at something or someone until you exploded because you couldn't take it anymore, day in and out for months at a time???

I've done both, and can comfortably say that hand carving the spruce is probably my most favorite task in all of my lutherie related activities. To paraphrase my good friend and mentor, classical guitar builder Eugene Clark, " Why would I ever need to take up yoga or fly fishing, when I can stay right here in my kitchen and carve beautiful spruce by hand..."


On the lucky days, I carve by hand; others, I use some pretty nice technology for the first 90%. I'll actually be meeting with an excellent luthier and cnc specialist next week to get a double bass plate and some F5 mandolin plates scanned in preparation for duplicating them. For me, I'd rather hand carve the initial prototype, have that scanned, make a cnc duplicate, and then make any adjustments both by hand and digitally if possible. Probably the most important thing to remeber is that a cnc carver may make nice arches and a great one will even cut your purf channel, but you won't know anything about the tone, the deflection, the wood differences, or any other of the many important aspects that make up the nuances and details; you'll be more like a production dork in the world's slowest and most inefficient bass factory....

Here is a recent image of a beautiful piece of maple, European pearwood purfling, a delicate hand, and one of Christopher Laarman's amazing finger planes at work on my recycled western red cedar bench...

j.

[robobass]

Originally Posted by james condino

...Have you ever sat next to a CNC machine for 8 straight hours while it felt like your teeth were rattling out from the noise and vibrations until you wanted to scream at something or someone until you exploded because you couldn't take it anymore, day in and out for months at a time??? ..

Yeah, the noise issue is definitely a big consideration. My old Bridgeport actually made a pleasant and almost musical sound as the I-beams of my loft building took up the vibration, but there are few things louder and more unpleasant than a CNC router. You really need to have it in a separate room if you want to preserve your sanity and your hearing. Working with hand tools by contrast is a wonderfully pleasant way to spend one's workdays!

[drurb]

Originally Posted by james condino

Have you ever actually carved a fine billet of spruce by hand using very well sharpened simple tools that fit the shape of your hand and body such that the grace of your posture and body position comes out in the subtle curves of an arch or a recurve that is almost sexual in its beauty???

Wow! Wonderful writing and imagery. Your love and devotion for the art sure comes through. Please let me know when the book is coming out.

[james condino]

Funny you should ask- there are actually two books in the works right now. You can also find my ramblings in Fine Woodworking, regularly in American Lutherie, and I just recently gave up a regular column in Mandolin Magazine.

As a little sidetrack, I've been at this for over 3 decades now. For me, the work environment has a huge effect on how I do things. If I'm in a dark, poorly lit underground room, the work comes up pretty gothic looking. If I use too much large loud equipment, it starts to get a bit erratic and I notice an impatience to it- as if to say I've gotta get away from all this racket. If I do it by hand in a slow, patient process using a fine tool that I built or like the Larrman plane shown above ( I waited ten years for that to be custom made for me! I think they are one of the most beautiful and functional tools made.), I really feel that it has a strong effect on the outcome. I'm at peace, visually and functionally the tool is a joy to carve with, and the resulting curves and flow in the workpiece reflect it.

I fully understand production requirements and trying to compete on a larger market scale. For those things, a cnc is pretty much a must have item. The biggest thing that I learned when I worked for one of the mid sized custom guitar factories is that although they originally made outstanding works of design and function, by the time I came along ten years later, their #1 operational goal was working like crazy people- 20 guys making 40+ instruments a week, because they were paying $28,000 a month in interest on all of that fancy machinery BEFORE they could make payroll, pay the electric bill, or anything else. That skews a persons approach and motivation pretty heavily.

Last month I paid $75 a plate to have Dave Smith cnc some F5 mandolin back plates for me, along with a couple of other folks who I'm trying to see if their work can integrate into my setup. Dave's got a small Iso Techno machine that probably cost around $25k to get running. The trouble for me is that I understand and know that this machinery could be used for incredibly precise work, yet every time I've tested someone else's carvings, they come out closer to a high grade rough carving rather than an precision crafted work. When I run the numbers, it makes a lot more sense to outsource the actual machine time than to have it here on site and become a machine manager and not so much a luthier. The technology has a lot to offer, but I think that the real change that you'll begin to see soon is the ability to have multiple sources to rent time on their machines, rather than everyone having their own, much the same way you can now send off your prototype design to a computer chip manufacturer and three weeks later it comes back working or when you need to run some gigantic number crunching, so you rent a microsecond of time on a supercomputer.

I also know from experience that it is a LOT easier to sell a $500 part than a $5000 instrument, so there is an opening for someone to become a specialist carving for other people ( again, possibly to pay for that big expensive machine....)...
j.

[Jake deVilliers]

Originally Posted by james condino

If you are really, really serious about building a LOT of plates, then cnc makes great sense. If you are just a casual builder, then you need to ask yourself what are my priorities: Do I like working with wood and building things and is that where I find purpose and peace of mind, or have I never really built anything and am afraid of the traditional processes, so I'll stick with my computer and work out some of the challenges digitally.

On the safe side of things, I probably spend a total of approx. 25 hours to hand carve a spruce top, and then probably close to the same for the purfling and the bassbar; maybee more. Are you willing to spend upwards of several hundred hours to learn all of the software, get all of the CAD file details worked out, and make a few mock ups just to get one approximate top plate that you'll still probably spend 50+ hours on getting the fine details for your first build???

Have you ever actually carved a fine billet of spruce by hand using very well sharpened simple tools that fit the shape of your hand and body such that the grace of your posture and body position comes out in the subtle curves of an arch or a recurve that is almost sexual in its beauty??? Have you ever sat next to a CNC machine for 8 straight hours while it felt like your teeth were rattling out from the noise and vibrations until you wanted to scream at something or someone until you exploded because you couldn't take it anymore, day in and out for months at a time???

I've done both, and can comfortably say that hand carving the spruce is probably my most favorite task in all of my lutherie related activities. To paraphrase my good friend and mentor, classical guitar builder Eugene Clark, " Why would I ever need to take up yoga or fly fishing, when I can stay right here in my kitchen and carve beautiful spruce by hand..."


On the lucky days, I carve by hand; others, I use some pretty nice technology for the first 90%. I'll actually be meeting with an excellent luthier and cnc specialist next week to get a double bass plate and some F5 mandolin plates scanned in preparation for duplicating them. For me, I'd rather hand carve the initial prototype, have that scanned, make a cnc duplicate, and then make any adjustments both by hand and digitally if possible. Probably the most important thing to remeber is that a cnc carver may make nice arches and a great one will even cut your purf channel, but you won't know anything about the tone, the deflection, the wood differences, or any other of the many important aspects that make up the nuances and details; you'll be more like a production dork in the world's slowest and most inefficient bass factory....

Here is a recent image of a beautiful piece of maple, European pearwood purfling, a delicate hand, and one of Christopher Laarman's amazing finger planes at work on my recycled western red cedar bench...

j.

Well put James! One of the things I love about what I do is the preponderance of time spent using hand tools. I can hear the birds outside or the trains going through the village.

I fail to understand why people want to acquire a whole new skill set when a little out-sourcing to a tradesman with the appropriate tools and experience gets the job done with speed and accuracy.

[powerbass]

Have you ever actually carved a fine billet of spruce by hand using very well sharpened simple tools that fit the shape of your hand and body such that the grace of your posture and body position comes out in the subtle curves of an arch or a recurve that is almost sexual in its beauty??? Have you ever sat next to a CNC machine for 8 straight hours while it felt like your teeth were rattling out from the noise and vibrations until you wanted to scream at something or someone until you exploded because you couldn't take it anymore, day in and out for months at a time???

This is beautiful writing James. I can appreciate both these scenarios. I have some low level hearing damage from too much time spent in the machine room - I would get nasty headaches from the compression on my skull from hearing protectors, a respirator and safety glasses. I have also spent months hand shaping furniture parts with finely sharpened hand tools. I agree with your view of how to use CNC. There are shops out there that have invested significant resources to make them work. For the average luthier why take all this on? The place that CNC would make sense is for roughing out the plate blanks. Roughing out by hand is time consuming and mostly hard work. As much as I love using hand tools I could see having a top plate being roughed out to within a reasonable tolerance then finishing the graduating by hand.

[DerHoggz]

I'm fairly good at CAD, and I am also learning to use my school's CNC router (4'x8') and had a similar idea. Imagine a top carved from this stuff:

[gbaker]

Originally Posted by Jake deVilliers

Well put James! One of the things I love about what I do is the preponderance of time spent using hand tools. I can hear the birds outside or the trains going through the village.

I fail to understand why people want to acquire a whole new skill set when a little out-sourcing to a tradesman with the appropriate tools and experience gets the job done with speed and accuracy.

Jake, I understand your comment along with James's. I rather expected the thread to wain philosophic and that is fine.

My question was not about whether it is more pleasant to carve or to program or to do tool design and setup. All require skill, knowledge and a measure of perseverance. I could spend the time to carve a top, or learn CAD, or build a machine. I also know that for a single top, carving is the most efficient probably most pleasant path. However, even the strong proponents of carving have expressed a reduced level of enjoyment in carving a maple back. Maybe there is opportunity, a market for roughing out backs and then why not tops.

I may not have made my objectives clear, I mainly asked about resources. My first objective is to check resources, cost and price points and then decide what (else) I want to do with my shop. If I were to set up a small-shop CNC router, which I may, I would want it to be big enough to produce a bass plate. I am looking for resources, then I will decide if there is opportunity.

And yes, I have found some services available. I was corresponding with a Chinese manufacturer about a carved spruce top to replace a damaged ply top on an old German bass. He was very reasonable, under $200 for M&L plus shipping. However communication was difficult, the spruce and accuracy unknown and what if it didn't work out? So I opted out.

I have a very good friend that has a full CNC machine shop who is also a OT fiddle player. He has cut wood and composite tops for a guitar manufacturer and made jigs and fixtures for a fiddle maker. He would probably rout a bass top for me for free if I asked him to. But whether a given top could be produced for a reasonable price considering shop and big-machine overhead is a different matter.

So I was (still am) looking for resources, mostly the software side - CAD drawings, CAM g-code. I appreciate all the comments offered.

[gbaker]

Originally Posted by powerbass

You might want to post over on the bass guitar luthier's corner Forum on TB. CNC is utilized extensively for slab bass bodies and necks. I am not positive but I think google sketchup software is CAD compatible

I'll do that PB, thanks.

[RCWilliams]

setting up a cnc , generating the geometry and tool paths to rough out a top are not cheap. I suppose if you used the same approach that is used on most plywood basses I have seen... same arch, different outline, it would be possible to make a generic bass plate top or back, the problem is every arch does not fit every outline and then there's the graduation. every one has a different concept of what makes the right arch and the right grads.

one question is do you want a plate with a finished edge, FF's, purfling chanel and within .1mm or so of the final shape, or do you want a generalized roughed in plate with no outline, no rough grad, etc. either one is achievable.

here is a picture of a test plate run out of junk wood. from here it becomes very important for the ribs and form to be precise.