I may not understand the assembly but here are a few things to consider: Steel pins can be pressed into undersize brass holes, the interference fit needs to be pretty good. Drills do not make round holes but end mills do. A temperature differential between the hole and the pin changes the pressure needed to assemble the parts. John Ferrell 6241 Phillippi Rd Julian NC 27283 Phone: (336)685-9606 johnferrell@earthlink.net http://DixieNC.US NSRCA 479 AMA 4190 W8CCW "My Competition is Not My Enemy" ----- Original Message ----- From: "Mike Hord" To: Sent: Friday, January 23, 2004 9:52 AM Subject: [OT:] Securing a steel pin in brass > Okay, this is tricky to explain, but I'll try. The important bit is the > fourth paragraph, so you can skip the first bit if it's too poorly > explained to make sense. > > Imagine two brass cylinders, 4mm in diameter, one 2mm in height > and the other 10mm in height. Now stack them vertically, aligned > along their central axis. Drill a hole in the center, and pass a small > screw through the hole in the 2mm piece and thread it into the > hole on the 10mm piece. > > Now drill three holes spaced equally around the screw, and put a > steel drill bit with the flutes removed in two of them. The result > is that when you turn the screw, it pulls the 2mm piece towards > the 10mm piece a little at a time, with the drill bits sliding down > into the 10mm piece and affixed to the 2mm piece. > > Here's the problem: how do you join the steel bits to the brass? > Right now we use super glue, which is okay, but since they really > need to be sterile, it would be nice to autoclave them, which > means temperatures up to 150-170 degrees C, and superglue > doesn't generally like that. > > Solder won't join to the steel. Any other ideas? > > Mike H. > > _________________________________________________________________ > Get a FREE online virus check for your PC here, from McAfee. > http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963 > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics