Vintage Olds Recording Trumpet Valox Barrel and Valve Guides

prusaprinters

This is a replacement of the 1970's Olds Recording trumpet Valox Barrel and Valve Guides. This is a change from the earlier metal valve barrel before the 70's. These parts are increasingly hard to come by as they are no longer in production. According to some, the original Valox material is claimed to be a type of POM/Delrin/Acetal. Over years of use, it will get worn out with loose alignments. Eventually it needs to be replaced. I have recreated a functional 3D model based on the worn out parts that I have.An excellent guide on how to dismantle the barrel and valve guides are shown in this link. Special thanks to Centex Brass for publishing the guide.POM is notoriously hard to print. As such, alternative materials should be considered. The ideal material needs a number of properties. The following chart will help you decide on the choice of material.Filament Material ComparisonMaterialPrintabilitySelf-LubricatingResists WearResists MoistureResists OilCostigus® iglidur 180OkVery GoodVery GoodGoodGood$$$POMVery HardVery GoodGoodGoodGood$$Nylon PA12OkVery GoodGoodAbsorbs water and expandsGood$$PETGEasyOkOkAbsorbs some waterGood$PLAEasyNoBadBadOk$In short: Do not use PLA. Use at least PETG.As cost is a consideration, I use PETG in this project. If there are more interested without going through the printing trouble, I might consider to pool in together and print it in iglidur 180.Print Parameters:You may use the .step files instead for better resolution. I use OrcaSlicer. - Barrel:Rotate 90 degrees. Have the guide rails face up. (See Photo)Ironing: All top surfacesIroning Pattern: ConcentricInfill: 100%Infill Pattern: ConcentricSupport: YesNozzle: 0.4mmLine width: 0.42mm- Valve Guide (2.5mm or 2.8mm):Infill: 100%Infill Pattern: ConcentricSupport: YesAvoid seams on slot (See Photo, red area indicating seams to avoid)Post Processing:Remove all stringing and debris.Shave off blobs that may affect the smoothness and alignment.Test fit on the valve before attaching the alignment pin on the Barrel. Remove any debris blocking the inner stem.Condition the fit of the valve guides by moving repeatedly across the barrel.Sand the barrel if needed. Do clean it to prevent abrasives entering the valve casing.Assembly:Follow this guide to dismantle the barrel and valve guide.Carefully transfer the alignment pin onto the Barrel. Try not to scratch the parts with a piler. Insert the spring, valve guide onto the Barrel.Insert through the stem, making sure the alignment pin is seated in.Screw the rest of the stem to secure the Barrel.Lubricate the contacts points between the barrel and valve guides with standard trumpet valve oil.Additional Notes:I have included two different valve guide clearances. You may use the 2.5mm version with 0.2mm clearance on self lubricating materials. This gives the least rotational play. Use the larger 2.8mm version for 0.5mm clearance if the material used is not ideal at the expense of some rotational play.The original alignment pin holes on the barrel are quite tight fitting with thin walls. It may be difficult to get it right due to the small clearances.If I'm not wrong, the Olds Super Star trumpet is also using this type of barrel and valve guides. However, I do not have one to test on.