Hi everyone. I have recently ran into an old band mate who I havn't talked to for about ten years, turns out he is now a machinist. I told him that I had a few spring guns that I wanted to make guides and top hats for and he said he would be glad to help me with anything I needed. I was thinking about investing in a lathe, but this is much cheaper and it gives us an excuse to get together and have a "jam" sesion. My question is: What is the best material to make these guides and top hats out of? He told me that it didn't matter how hard the material was, he can cut anything. Opinions please?
Getting serious, I've had good luck with bearing bronze (the hard variety, I believe it is ASTM43, but not quite sure) for the guides and stainless steel 316 for the top hats.
If your friend can really cut anything, it would be interesting to make tungsten carbide guides and top hats, smooth as glass, hard as diamond, unbreakable, max performance and very little maintenance. IDEAL!
Hey Hector, thanks for the suggestions. I'm going to see what is available to me this weekend and maybe get started on some parts. Thanks again. Mulby.
Tungsten carbide is very breakable, just as diamonds are. I've seen quite a few tungsten carbide cutters chipped or broken from being given the wrong amount of feed. While being very strong and durable, like cast iron it will break when it reaches its limit. Reminds me of glass breaking in a way...
Mulby, I just ordered a monolith spring from JM so I may need to barter with you to get a guide made up. As far tugsten for a guide I think the cost would be a little crazy wouldn't it? I think the rass alloy trick from above would be the way to go.
It is a phenomenon, as you so well have noticed, where the TC shatters like glass, obsidian, flint or other hard materials.
Conchoidal fracturing is a result of point pressure. If you have ever knapped a flint arrowhead you know the pressure point process.
Ideally, in a spring guide and in a Top Hat there are no pressure points, all stresses are evenly distributed. The bottom of the spring has been forged square and ground even, the inside has been relieved and there should be no pressure points.
A tool breaking from too much feed is breaking because the point pressure went through the roof and heat also accumulated in that same point, it is a combination of heat and pressure in a single point what breaks those tools. Now a question for you: In the same situations would a HSS (Mo-Van) tool break before or after the TC tool has broken?
I see your point. Sort of like deciding if glass breaks or shatters. The harder the material the easier it is to fracture through any imperfections in the structure. I would always choose tungsten carbide for any cutter, I just have to respect its weaknesses and be prepared to cater to them to get the full benefits of its superior performance. I even use reloading dies with tungsten carbide inserts. No lubrication, and smooth operating!!!