Could possibly print it and acetone gas smooth it out, you can get a super glossy and smooth finish that way. Most up printers are ~120mm build area or something like that though, wouldn't be able to make something 210 in size. Maybe on a reprap (if the thing works long enough ;P)
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Or you could just print the part itself (possibly in interlocking sections) and then use that to make a plaster cast mould.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Could ya sculpt the shape out of plasticine…then cast it in silicone then cast it in fiberglass/ kevlar or something simlar….why can't ya just make if from metal?
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Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Ok, I should stop being secretive with the project, I want to make a carbon fibre trombone(s). Very traditionally they are only made from brass, rarely stainless steel, and after my studying the tooling for making the part above out of brass would be rediculous and explains why my own american made trombone is so bad. There is a company making plastic trombones, but plastic is soft and dulls the ring from the bell. I have found one carbon fibre trumpet in the world and it is considered to be the shiz, but it only has the bell and flare made from CF, the rest is brass, and it is considered too hard to make by the (traditional) manufacture and won't be repeated.
My research shows it would be a lot cheaper for me to make a CF trombone over a brass version and I have a lot of non-traditional features I want to add. So it's what I want to do instead of working for other people.

Miles's idea sounds the best to me. I can actually afford to start playing with that idea. But it might be easier to make the tuning slide first rather than the neck tube.

Interesting concept - wouldn't the slide need to have a metal lining for smoothness and reliability? There is a ton (perhaps too much?) info out there if you Google 'mould making'

Would it be possible to use a piece of plastic tube filled with something stiff to make the original part to be moulded? If you can find the right tube and fill it with sand (to stop it collapsing or kinking in the bend and stiff wire (to hold the shape) then you should get an evenly curved U section
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Yeah good idea Daniel and a cool niche market to target…..could ya just dismantle a real trombone then cast that in silicone for a mould?…..or go real low tech and could you put a mould release on the trombone itself and cast the carbon fibre on the trombone itself?…..don't really know anything about carbon fibre…but i take it you can laminate it in layers like fibreglass?…..If you could put the carbon fibre in a lathe and smooth it that way…..then you might be able to get parts that move inside each other like on a brass instrument.

edit ...yeah here is a guy making it look easy
https://www.youtube.com/watch?v=Ybyh6Q9MBgE
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Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Well I only own one trombone and I'm not about to take a blow torch to it. It has a few dents that would need to me bang out and there is a lot of lacquer missing, so it would need polishing and coating. It is also a small bore bone and I would prefer a larger bore. The other issue is there are a lot of parts, more than I think is needed. Plus I would probably cry if I had to cut up a trombone.

The main slide isn't too big an issue. There is 0.5mm clearance for most of its length, with a 100mm long 0.2mm step at the end. My trombone actually has rust on the slide at the step and is still slick. The tuning slide needs to be tighter, but the slide is only 65mm long. The plastic pBones use a glass fibre slide.

Perhaps the thing to do is start with the easy bits and progress to the harder parts as you gain experience. Are you planning to make everything yourself or to use commercial CF tube for the straight parts?

Feel free to call me a tone-deaf idiot, but is there any reason the tube has to round rather than square?
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

I can't use comercial tube because bore of the tubes are unusual (0.547"). Round tube and sweeping curves form better standing waves.

I would suggest as you want a hollow tube you will need a male mold.
Trying to lay up a long tube from the inside would be almost impossible.

If you don't care too much about strength (IE you don't need super light and super strong) that you would print up a male part (or copy an existing part but watch out for shrinkage), then cast a 2 part mold off that. Then cast up a wax part out of that mold.

You want a low temp wax, most of the CF resins don't like high temps.

Then lay up the outside of the wax part, perhaps vac-bag it (not being able to use a thermosetting resin will limit your options some) and watch out for it warping.

Then when you have a finished part you can melt the wax out and you just need to smooth the outside, I'm guessing some sort of resin dip would do the job for you.



If you did want the ultimate in strength then you want to basically repeat the above process but use something like woods metal for the blank, then get it filament wound. The issue you would have would be the complexity of the wind, so you would likely need to DIY the winder, re-purposing a 4 or 5 axis mill would probably do the job for you. But it might be worth talking to commercial winders some of the new machines are pretty good in the number of axies they can do. Do be sitting down when you ask for a price on a one off though ;->
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Mechanical engineers build weapons, civil engineers build targets

Need some opinions on this thought,

So i keep having to lathe hardened material, which is too hard for the hss or cobalt blanks. I have some carbides and home made holders that work sweet, but the spindle occasionally stalls out on account of the v belt drive, and that almost always results in the tips breaking off.

I'm going to make a new tensioner so i can really heap some tension on the v belt, but i need something better. Doing a large timing belt drive direct from a chunky motor would be best, plus it would let me dial in the exact rpm neccessary which can be handy for getting the finish right.

A fat AC motor and VFD is the obvious choice, but there isn't a great deal of room to mount it in. So i was kinda thinking of a DC motor, maybe a magmotor, etek or maybe even a giant hobbyking brushless which would alleviate the need for a VFD. Reckon they would be powerful enough?

Alternately, maybe grabbing one of these and a 10:1 belt reduction would be nice?

http://www.ebay.com.au/itm/WATER-COOLED-SPINDLE-MOTOR-2-2KW-INVERTER-VFD-2-2KW-VARIABLE-FREQUENCY-DRIVE-o-/121224070249

Thoughts?
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Those spindles really only like running at high speed, I'm thinking 24KRPM belt drive isn't going to be toooo happy lol.

Going up in size of the motor shouldn't be *too* much bigger and AC and DC should be in the same ballpark in terms of size for power.

Doing it DC would work, but the hard part would be driving it, your 1/2HP AC motor is going to push 2Kw or more in peaks, so you need to get drive electrics that'll handle that.

we have a 3/4 HP (I think) with matching VFD on our lathe and it works well ;->

If you are doing lots of really hard stuff, have you looked at ceramic cutters?
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Mechanical engineers build weapons, civil engineers build targets

After machining a few V belt pulleys, I am really not happy with the degree scale on the lathe's compound slide - its tiny and probably very inaccurate. Is there a sneaky way to set the compound angle accurately using extra tools / gauges?
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Didn't see this D: But have thought about this a few times.

Easiest way to do it accurately seems to be taking a test cut on a superfluous piece of aluminium, then measuring off of that and adjusting as appropriate.

Otherwise maybe you could setup a dial indicator and measure the deflection over distance of the compound then work out the angle based on that.

With a 10mm range dial indicator one could probably get the V belt angles set like that. Might have to give it a try myself! haha
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

I think adding another, larger degree scale and zero that during installation could solve the issue.

On my lathe I zero'd the arrow that indicates 0° , and added another arrow on the measured 90° mark. This gives me a wider range of compound angles.

The markings on the lathe itself are accurate enough for most of the jobs I do, and for the jobs needing more accuracy, I'll farm the job out.
My el cheapo chinese lathe just isn't up to that kind of tasks.