Metal spinning

[Buffalowed Bill]

I have several friends looking for a thin brass taillight housing for a 1931-32 Studebaker. After some bird dogging, the piece has been allusive. The housing is not round so spinning may not be the proper term for the process. Is there a source for this type of service?

Bill 

[keiser31]

1 hour ago, Buffalowed Bill said:

I have several friends looking for a thin brass taillight housing for a 1931-32 Studebaker. After some bird dogging, the piece has been allusive. The housing is not round so spinning may not be the proper term for the process. Is there a source for this type of service?

Bill 

Best thing to do is post photos of one so people know what to look for. Someone on this forum may have one.

[Gary_Ash]

Bill:  The originals were probably stamped steel, but stamping tooling is expensive now, like $10K-$50K.  For a few parts - or only one - your best bet may be to have it drawn in CAD on a computer, 3D printed, then cast in silicon bronze and chrome plated.  Your can farm out most of the steps, but getting the 3D CAD drawing done will be the hard part if you can't do it yourself.  It would help if the Studebaker National Museum has an original drawing of the part - call Andy Beckman.  My 1929-40 Chassis Parts Catalog  for 8 cylinder cars shows several oval shaped lights for 1931-32.  Photos and part numbers will help a lot.

 

Here is a part that I drew on the computer, 3D printed at home, had investment cast in silicon bronze at a local foundry, and then chrome plated.  They used to say, "Good, fast, cheap - pick any two".  Now I say, "Pick one".

 

Spinning works for round parts, not so much for other shapes.  Hydroforming can work if you can find a shop to do it, but again the tooling is not cheap but better than stamping.

 

[John_Mereness]

Gorgeous part, but please order up some slotted head screws  

[Buffalowed Bill]

John, thanks, a point well taken. Since you just posted a picture I won't have to. In the past finding this part has, proved to be problematic. I'm not saying that they aren't out there, just that they are hard to find. One of the problems has been that the cars came stock with a single taillight. There was an optional right side light available as an accessory. Many of the owners want to add the right side light for safety sake and looks. Thirty years ago when I restored my 80R, I couldn't find a decent one. It hasn't gotten any easier, even with eBay. With the pent up demand, I thought I would try to find out what the options might be.

 

Thanks Gary. So size must matter with these. In other words, the same part didn't transfer from model to model? I am aware that the ovaloid headlights were used on some of the smaller models. That indicates to me that the shape may have been translated to the taillight-is this correct. The cars that used the acorn style headlight, I guess would have used another style taillight, correct? 

 

Great looking part! I seems like what you did would allow for multiple copies. How would that relate to the lost wax process? Is using an original part for a pattern an option?

 

Bill

[Gary_Ash]

Bill:  Do you have a copy of the original drawing for the taillight housing?  The Studebaker National Museum may have it; ask Andy Beckman.  My 1929-40 Parts Catalog shows p/n171750 for the tail lamp body for models 70/80/90 in 1931 but p/n 254687W for models 71/91 in 1932.  [Is W the code for a plated part?]  From that, a CAD drawing can be made for a cast replica.  It's possible to take dimensions from an original part.  Of course, even a thin-wall casting will have thicker walls and weigh more than a stamped steel part but the outer dimensions can remain the same.  With proper attention to foundry practice, even cast walls can be pretty thin, say 1/16 inch or so.  The fuel filler assembly pictured above was not a thin-wall design.  It's 4" diameter x 3" high, weighs 2.8 lbs.  Oh, and John Mereness:  yes, I put some Phillips screws in temporarily to hold it together, but will find some proper slotted head screws, probably fillister heads.

 

From the CAD drawing, a file can be generated for 3D printing.  A 3D print in PLA plastic can be used just like wax in a lost wax investment casting process.  The PLA melts and burns away when the plaster mold is heated to 1100 °F before the molten bronze is poured in.  For multiple copies, just 3D print more PLA patterns.  When there are only a few copies to be made and the printing time is a few hours each, this works OK.  For some parts, a silicone rubber female mold can be made from the 3D printed part and multiple wax patterns made from that.  I'm currently having four rear view mirrors, left side, made for 1941 Commanders and Presidents, since the '41 Commander I bought recently doesn't have an outside mirror and the remains of the late Jay Fisher's inventory yielded only a right side version with a swan neck, not as pictured in the 1941 accessories brochure.  Earlier, I had a bunch of carb throttle arms cast by printing one plastic part and the foundry made wax replicas before casting.  A photo below shows the PLA plastic master in the lower right corner with some of the as-cast parts; later they got drilled, tapped, and bright zinc plated.

[lump]

Gary Ash....Impressive! Wish I had greater skills on the computer! 

[studerex]

I found one at Hershey this year and one last year.  Both gone now.  They do show up.  Lionel had them made in a bronze casting.  I seen a few and they look ok but were heavy.  I think John McCall ended up with the patterns.  

[Rusty_OToole]

If they are thin sheet steel it may be possible to form the shape using a steel or hardwood mold to stretch mild steel tubing then turn the edges over by hand. Visit a muffler shop and see how they can stretch an exhaust pipe end to make an adapter.