Any Advice For Copying A Trumpet Valve?

I have a trumpet that uses three identical valves, but one of them is missing. I'm looking to have one of the existing valves copied in bronze-impregnated stainless steel. I can hone it and have it nickel plated to get the smooth finish I'll need. Problems are:

1) I have no scanner and no autocad abilities.
2) If it ends up being over $75, it's not worth it.
3) The design is rather complex, with a hollow tube of around .750 inches that has three curved passageways moving through it, each of around .450 inch diameter. There is no access to the inside of the piston, since a plug has been hard-soldered into the base.

Is there any chance of my getting this done with the parameters stated above?

The valves look pretty much like the picture below, but without the complex brass shape on the top. I would only need the silver piston section:

The steel prints are tricky as the thermal processes make parts prone to warp and shrinkage. Additionally the material is quite hard, machining and grinding can be tough. Also one bad print and you are out of budget. I'd get a proper replacement, save yourself the headaches. -S

As shea design says, you will never get it right.
It will either not go in or leak.

If you can't buy them then 3D printing would be a good option. If you can buy them for around that price then just buy them since 3D printing and the CAD work would probably be about three times that price. Also, as mentioned you could run into a can of worms with Shapeways' steel. In polished brass, they would come out perfect, however, the cost would go to something like five to six times your budget.

Another thing I noticed is they have a coating on them. Looks like it might be babbitt alloy or something like that to help them conform to the bore well enough to be airtight. If that is the case you'd be dealing with very low tolerance numbers and so you'd need to have it made a little larger and then turned down on a lathe to get them exactly the correct diameter, which would mean hiring a machinist and that would raise the price to probably something like eight times your budget.

On the other hand, you might be able to get this created in CAD by someone skilled in 3D modeling and 3D printed in Shapeways' polished Strong and Flexible Plastic for maybe something like half your budget. If you wanted to try that route you could post a thread here and get some quotes from 3D modelers. You can also directly contact people skilled in 3D modeling here.

Wait. I was just looking at your image again and those are not identical. The holes are rotated and also positioned linearly along the cylinder at different positions. That would make it very difficult to know what your missing valve is supposed to be like.

What ? How did you guys see the picture that Steve attached ? I can't see the picture so that I can't tell Steve whether it's possible to make it in $75.

He linked the image from blogspot.com, here, http://2.bp.blogspot.com/-9EG9FmNwu...SsY5E2RI/s1600/new+stainless+steel+valves.jpg

And here's the Google image search on it. https://www.google.com/search?tbs=s...Gax-agD9zCHFfWXPVtAulrcE_1OUeJwB7drzQIV4-Dx0Q

Hi Steve.So this is the part what you want to make? After it's printed out. Do you know how to assemble this part with the brass shape on the top?This part is quite sample for me.But I didn't estimate how much does it cost to print.

Hi All,

In response to your many comments (thanks!!!) here's more information:

Frozenrain--Yes. That is the part I need. The other parts are easy to fabricate.

Universebecoming--These were just an image to show what a trumpet piston looks like. Mine are indeed identical. The coating on the ones in the picture is monel. I would be honing them down to undersize and having them nickel plated, then honed again. And no, originals can't be purchased anymore. My $75 price was based on the value of the completed horn, minus the original purchase price and the cost of plating and machining. I don't think plastic would work. I've never tried, but plastic trumpet valves are still in their infancy, and so far they haven't held up to the tolerances needed when actually used in playing situations. Most companies that make plastic trumpets (Tromba) are still using nickel-plated brass pistons, but one or two are using plastic pistons.

So now I'm intrigued. I believe the first two posts are correct, and it wouldn't be possible to print bronze valves that would fit the tolerances and be economical. If I were to use plastic and have three valves made, how would that work?

Are tolerances and polish of finished product better on plastic parts?
Is there a plastic available that is hard and solvent-resistant?
Could the part be made a few thousandths of an inch oversized and machined down to a good fit?
Is the plastic stable in different temperatures, or would it expand in warmer temperatures?
Any problem with running a plastic piston inside of a brass cylinder?
What would it cost to have someone do the CAD modeling based on one of the existing valves?
How much might the actual printed valves cost once the CAD work was done?

Thanks