School Mass Production

[slausonm]

Hello, I'm new to this site. Thought I would share the mandolin project that I am in the middle of. My brother built one a few years ago and he got me started. I am a flute player and have a degree in band instrument repair. I also have a degree in technology education and teach Engineering classes.I don't play Mandolin. The project is part of a manufacturing class. My students will be doing a Mandolin building project as a mass production. In the past, we have built lap steel guitars and fender style electric guitar bodies. The goal is to build 30 mandolins so that the students will each have one when we are done. There will be some left over that I will sell...hopefully.

Here is one of 4 prototypes I built. http://img.photobucket.com/albums/0803/slausonm/100_1431.jpg

Here is a link to a thickness sander I built for the project. http://www.youtube.com/watch?v=goOm0EomstA

So far the sides are rough cut to size and need to be sanded to thickness. About 20 of the blanks for the backs are glued up.

Materials: Mostly Walnut backs, sides and necks. For some variety there will be some maple necks and backs as well as some Hickory sides and necks. The tops are Engelman spruce.

My prototype has a truss rod I made but I think the mass production will not.

This should be an interesting project. The students have very little woodworking skills and will be learning CNC machining as we go along. We have a small CNC mill that the tail piece will be machined on. We have a homemade CNC router that the necks will be made on(Hopefully) and a laser engraver that will rough cut the tops and back as well as lightly engrave the locations for the bracing. The laser will cut the sound holes as well. Since we are making every part except the tuners and strings cost is pretty low.

OK, so when we get done I hope to show off some very nice instruments, or there will be a discount sale on some very expensive fire wood.

BTW, Thank you for the information on this site it has been very helpful.

Matt

[JEStanek]

Welcome and good luck with the project. Please use this thread to post photos of the instruments, tools, and participants as you go along. You can use the Classifieds (http://www.mandolincafe.com/cgi-bin/classifieds/classifieds.cgi?add_item_button=on)for sales if that's the direction you decide to go in.

Jamie

[EdHanrahan]

Wow, nice project! Why wasn't I a student when...


My prototype has a truss rod I made but I think the mass production will not.

You might want to consider a carbon-fiber reinforcement for longievity.
http://www.stewmac.com/shop/Truss_rods/Carbon_fiber/Carbon_Fiber_Neck_Rods.html?tab=Instructions#detai ls

Much simpler than a truss rod, and you'd only need the 1/8 x 3/8. I suspect that each could be cut to half length, covering 2 mandos. Just a thought!

[slausonm]

Welcome and good luck with the project. Please use this thread to post photos of the instruments, tools, and participants as you go along. You can use the Classifieds (http://www.mandolincafe.com/cgi-bin/classifieds/classifieds.cgi?add_item_button=on)for sales if that's the direction you decide to go in.

Jamie

Thanks Jamie,
I will post pictures or links as I go along. Just be aware that the goal is to teach CNC machining and mass production. Mandolins are just a fun thing to build. Hopefully they will be playable and sound good. We also plan to do a concert with our string teacher's students playing the instruments. Gotta get moving on the project. The initial review from the string teacher on the prototype is that it plays very well. She is a friend, but I don't think she was just being nice.:mandosmiley:

[slausonm]

Wow, nice project! Why wasn't I a student when...



You might want to consider a carbon-fiber reinforcement for longievity.
http://www.stewmac.com/shop/Truss_rods/Carbon_fiber/Carbon_Fiber_Neck_Rods.html?tab=Instructions#detai ls

Much simpler than a truss rod, and you'd only need the 1/8 x 3/8. I suspect that each could be cut to half length, covering 2 mandos. Just a thought!

Ed, I've thought long and hard about the truss rod issue. The neck is a bolt on, so if it needs resetting and repair later on it could be done. I am weighing the benefits and problems of producing the extra parts and or buying carbon fibre. Right now the cost per instrument is down to about $30-40 in materials not counting the tuners and strings. The added cost of a homemade metal truss rod will be about $5.00 and it will also add a lot of manufacturing time.

FYI they didn't have this stuff when I was in school either, I'm 48. I'm just trying to make a dry subject like writing CNC code a bit more fun.

Matt

[delsbrother]

Are the necks bolt-on like Fenders, or bolt-on like Webers?

Are you writing the code by hand, or are you using software (e.g. MasterCAM)?

Do you have photos of your previous classes' work? I'm curious as to how you did the CNC guitar bodies. Did you CNC the necks too?

[slausonm]

The first instrument project we did was lapsteels. It was done on my first home built router. Last year we did guitar bodies. They were built on router #2. Bodies were modeled and code was generated in Edgecam. Students learn basic coding G00, G01, G02, G03, M06, M03...about 20 codes and how to use them including speeds and feeds. They learn to do this before they generate it with software. Again, the goal is to teach cnc coding and not to create luthiers, so we cheated and bought necks for the fenders. I do repair work for a local music store that treats me right. The video of the fender was done for a prototype. The kids guitars had the pickup and control pockets machined in the typical fender places, but the body shapes were their own.


Fender body http://www.youtube.com/watch?v=n1dLIgBVK3g

lapsteel body http://www.youtube.com/watch?v=xXhg1b9It0g

[man dough nollij]

That's a great idea, and a cool way to get mandolins into the hands of kids. Did you do the design yourself? The thickness sander is very cool. Not being a woodworker myself, my first thought was that if you were just taking a little off, wouldn't it have a tendency to act as a high speed board launcher? :confused:

[Bill Snyder]

It is turning against the material as you feed it. It would launch it if you turned loose of the material. Commercial sanders generally have a feed belt.

[slausonm]

That's a great idea, and a cool way to get mandolins into the hands of kids. Did you do the design yourself? The thickness sander is very cool. Not being a woodworker myself, my first thought was that if you were just taking a little off, wouldn't it have a tendency to act as a high speed board launcher? :confused:

Yes! if you send the board in from the wrong side. The cool thing is that to feed the board you are pushing against the sander so as soon as you stop pushing the board stays put because there is nothing for the sander to throw. With that said, I probably should label the enter and exit sides.

[delsbrother]

Can you post a picture of the back/neck joint?

[slausonm]

If you look at my sander video, you can see the neck joint in the picture of the prototype parts. I don't have one apart to take pictures.

[delsbrother]

Ah, sorry, missed that. So the kids write the code to do the neck surface carving as well, or just the joint? How many tool changes, jigs/fixtures are required?

Are you doing stuff like this?

[slausonm]

My router is not a production machine like the one in the video. It cost me about $2000 to build. The builder in the video has more tied up into fixtures than I have in my machine. Right now tool changing is done manually, so as few as possible, to answer your question.

The kids will do a combination of hand work and CNC. I have not worked it all out yet, but the joint for the neck will probably be cut by hand (non cnc) and the countour for the neck shape on the cnc.