Bultaco Sherpa 340 sidecases

[bobsemail]

The best way for aftermarket is to make a cad 3d model and make permenent mold castings. The tooling would cost about $12,000 US Dollars per side compared to $40,000 + per side. This method is the most cost effective method up to 10,000 parts. The permenent mold casting is gravity filled instead of forced injected with a plunger like a die casting. The perment mold would have much less porosity (high degree of pressure tightness) and higher strenth than a die casting or sand casting. Vacuum impregnation might not be required for the clutch cover. It's also possible to build a family tool for around $18,000 but I would not do that because the magneto cover would sell like hot cakes or they could mess up the mold. Cost would be under $20.00 each including machining and polishing.

If you just needed one part you could do it in your garage like this.

http://virtualindian.org/3techcasting.htm

[pschrauber]

The best way for aftermarket is to make a cad 3d model and make permenent mold castings. The tooling would cost about $12,000 US Dollars per side compared to $40,000 + per side. This method is the most cost effective method up to 10,000 parts. The permenent mold casting is gravity filled instead of forced injected with a plunger like a die casting. The perment mold would have much less porosity (high degree of pressure tightness) and higher strenth than a die casting or sand casting. Vacuum impregnation might not be required for the clutch cover. It's also possible to build a family tool for around $18,000 but I would not do that because the magneto cover would sell like hot cakes or they could mess up the mold. Cost would be under $20.00 each including machining and polishing.

If you just needed one part you could do it in your garage like this.

http://virtualindian.org/3techcasting.htm

Thank You for Your posting,

as already mentioned from You and me too the costs are to high for just 10 or 20 cases each side.

The costs for a die cast are too high. So I tried a sand casting, which should have been done by a company that is specialiced in casting prototypes for the german car industry, Volkswagen and Audi, the quality is very good, they use a special aluminium alloy that is very strong also if not casted under pressure. Also the Volkswagen group cannot effort a diecast form for each protyp they need. But the problem is the shrinking of the metal when the case is casted and it cools down, (about 4% in each direction)

The side cases have a tricky form and that makes it difficult to calculate and produce a positive form. These costs making a 3D model crop the model and then the milling of a casting mould for each side would cost around 4000

[old trials fanatic]

So what do we do long term ? I would assume most of us have repaired cases on our bikes. At some point this will probably be the straw that breaks the camels back and stops us using the bike.

Long term prospects not looking good

[bobsemail]

Another option would be to get a manufacturing company to take a lot of points on a cordinate measuring machine and then have an Engineering college make a CAD model (there is a shell type tool in the CAD systems to make the model bigger to allow for shrinkage). They can then print a sand castable 3D model. Take to a sand casting company and make the casting. You still would have to have it machined. I'll take a look at my new 199B when it pick it up. Below is a pretty cool do it youself prototyping method. Might be more appropriate for like side panels or headlight plastic. Also we use some urathanes that have a much higher yeild strength than these materials (just keep your feet on the pegs and you wont have any problems!).

http://www.alumilite.com/HowTos/MoldingSteeringWheel.cfm

[pschrauber]

Another option would be to get a manufacturing company to take a lot of points on a cordinate measuring machine and then have an Engineering college make a CAD model (there is a shell type tool in the CAD systems to make the model bigger to allow for shrinkage). They can then print a sand castable 3D model. Take to a sand casting company and make the casting. You still would have to have it machined. I'll take a look at my new 199B when it pick it up. Below is a pretty cool do it youself prototyping method. Might be more appropriate for like side panels or headlight plastic. Also we use some urathanes that have a much higher yeild strength than these materials (just keep your feet on the pegs and you wont have any problems!).

http://www.alumilite.com/HowTos/MoldingSteeringWheel.cfm

Sounds nice and great too, after my casting sidecases in aluminium medly.

I bought a pair of used sidecases the other original one's that are damaged i have now sended to a special company that will repair them, (very expensive).

But if You get replicas out of plastic and they work, (don't forget the kicker, the clutch and the gearing locations on both sides). I am surly one of the first that will buy a pair of you. Just send me an PM when got any good results.

[slowrider]

I know this is an old post, but has anyone ever looked at 3D modeling?