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With the very capable help of Brad Way, together we designed a tailpiece for a custom project. Unfortunately, it is as complicated as it is beautiful. It will require a 5 axis machine to pull it off. I'm looking for someone capable and willing to do a one-off (it would be more, except, and of course, the project is left-handed) piece out of 6061-T6 aluminum, +/-.0025 (.005\") tolerance, and a surface finish super smooth for a subsequent anodized finish. Note that the mating surfaces of the piece do not need to be polished, i.e., the inside of the mounting flange, and the underside of the body.

Suggestions?

All the best,

David D. Berkowitz
Berkowitz Guitars

I hope you got some money set aside for this thing. It sounds like it would be very expensive. Especially if you don't have a cad model.

May I ask why you have to have it done on a 5axis? I know if someone just happens to have one laying around it can make run times a lot shorter and can increase accuracy, but finding someone with a 3 or 4 axis machine will be a lot easier and you could just run 2 operations. Especially for just a 1 off part. It woul be cheaper IMO.

+1 on the multiple setups.

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Jim Watts
http://jameswattsguitars.com

Zeke, its all in Solidworks. I'm exploring some combination techniques employing 3 axis, annealing and bending the part.

Ok solid works just made your life much easier, and cheaper. I think doing it in a couple of stages on a 3 or 4 axis would probably be the way to go. I don't know what the part looks like but if the bend is complicated it may be better to cut rather than bend. Tooling for a special bending fixture would be high dollar. If its a simple 90 degree bend or similar it wouldnt be bad though.

The recommendation from an guitar industry guru was to have Brad flatten the part, have it machined, make a two-part hardwood die, anneal the aluminum and bend it in the vice with the die. The part is designed to mortice into the side of the guitar at a particular point, so it's a very shallow curve, and discontinuous. The guru's point was that folks have been making parts for 100's of years without CNC, and there is no need to do everything by machine.

Well he's right. In a sense. CNC is more accurate and faster in a production setting. I still cut a lot of one offs by hand though. Depending on how complicated it is, it can take longer to program and set up a machine than to cut it by hand. (only issue is a lot of "machinist" today don't know how to work a manual machine)

What's a manual machine?

well, that would be a machine that is operated manually.......like a manual lathe, milling machine, table saw, router, jointer, planer....I can keep going if necessary

Mike

ps....drill press, mortiser, stroke sander, wide belt sander, shaper, gang saw, ....... more?

You mean there are machines that aren't hooked up to a computer, and a human actually has to control it?

How archaic! That's almost like... what's that word?

Craftsmanship?

i suspect that you don't wish display the part on an online forum so as a result opinions are naturally going to be all over the place -although having a picture posted would obviously help a lot.

fwiw an artifact of "design freedom" is lack of concern of how to actually mfg something in the first place. but then again, it is this very same process that fuels innovation to develop new ways to make things. sort of figuring a way out of a self-imposed "design trap" so to speak.

The part could probably be made on a 4 axis mill if it helps. The key part is the 4th axis being the rotary axis which is critical.

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Brad
Avon, OH

See now that makes it much simpler to find a machine and cheaper. The thing that worries me is the fact that the OP has considered bending the part which leads me to believe it is pretty thin which could lead to issues when trying to cut on a 4 axis. Like arie said its hard to know when we are just guessing about the part. Also mr berkowitz mentioned annealing. Would that not defeat the purpose of using 6061 T6, which has been heat treated? If you need the strength annealing reverse the HT in a sense.

Zeke, the heat treating and bending was a recommendation of a very talented, innovative and HIGHLY respected professional member of the community, who has advanced work in metals, carbon fiber, and other materials. If anyone knows how it can be made it would be he. Not at liberty to divulge my source, but suffice it to say he is one of the big dogs. I should add that he saw the drawings.

I'm not saying it won't work I'm just saying you might as well start with 6061-O which is essentially the same but already annealed. I don't see any reason why you would need a tremendous amount of strength in a tailpiece anyhow. Im just trying to save you some trouble and money.

It sounds like you already have some very capable people already available to help you, that said if you cant find a 4 axis mill I have 2 and can quote the part for you. Im not really into doing one off parts so it would probably be cheaper to find someone who does, but it may not be. Some shops these days are really charging a lot more than I think necessary. Anyhow best of luck!

I agree with Zeke. I build airplanes, and we have all sorts of problems with engineers calling out bending T6 material, or welding it for that matter. Once you introduce the stress or heat, you have to anneal it to get the strength back in - end of story. Like Zeke said, if you don't need that much strength (for 300 lbs of tension, you don't) then don't bother using something that is not right for the part - go with T0 and save yourself a lot of potential problems.

Frankly, a tailpiece can't be that big; i'd start with a solid block of aluminum and bandsaw out the rough shape... you could actually stack a bunch of these tailpieces together in a "nest" and save a lot of material - and flip it over and do it on the other side of the block - just like getting two solid necks out of one piece of mahogany/cedar.

Have fun!

depending upon the severity of the bend T6 can be stress relieved after forming and brought back to a T6 temper. depending once again upon the degree of the bend, the loss of strength would generally only be about 5%. part geometry will determine the final processing which could range from a simple 18 hour cycle at 320F to more involved processes where final outcome can be dependent on many, many factors. keep in mind that if the process isn't carefully controlled, grain growth will become something to deal with which will manifest itself in a pebbly appearance to the part and just sanding it smooth will only hide the problem.

Folks, the part is 4.5" long, generally P shaped in cross section, the flange portion is .150 and the head about .375" x .450 tall. It is designed to fit on a section of the lower bout between the apex and the waist, really on the upswing to the apex. So the piece might have a rise of .500" over that 4." It is not that severe a bend. I understand all your skepticism but we're not talking aircraft here, we just need to hold 140lbs of tension. That's it. Furthermore, the person who made the bending recommendation is one of the THE materials and process innovators of the past 25 years of guitar making. I can only think of one other who fits that description in the industry.

Surely someone like that has access to a five-axis machining centers?
Regardless, it sounds like you have it under control. Please post photos when you have it done!

I also would love to see pics when its done! It sounds very very interesting. Im sitting here trying to draw it out in my head
Best of luck and keep us updated.

rhetoric aside, imo it would appear that your designer engineered you into a hole, and your expert bailed you out. this project seems like a slam-dunk. so just do it!

good luck