>>Sorry about Blender, I used solidworks and it has a nice helical sweep feature Thanks for the info. I need to get away from Blender but I’ve gotten used to it and can’t seem to kick the habit. >> It looks like the brass infused steel on shapeways prints about 3-4 mil >> thicker than the stl so small threads would have to be oversized to work - >> maybe on v2. I thought those looked like Shapeways parts. If you ever do anything with fairly complex geometry I’ve found that by going right to ExOne (Shapeways subcontractor) you get better results for about the same price. ExOne can deliver the parts annealed, which may help with any post-machining as I’ve found the default shapeways SS/Bronze to be a pain to work with. I’m really excited that you are also working with SLS on your igniter and using Arduino for control. Looking forward to hearing more. Best, Graham