I finally got my CF dialed in and need to make a bunch of brackets with 3/16 304SS. I have to add bolt hole patterns for 5/16 structural bolts. The actual size I need for bolt clearance is .313”. I made them 0.32” in CAD and will do some testing.. but just to get a reality check - What is the smallest functional bolt hole I can realistically cut in 3/16 SS with a non-high resolution machine torch. It is the HTP torch which uses compatible nozzles with Hypertherm 45 (non-XP model - assuming legacy)
They don’t have to be beautiful, and bolts have about 3/16 flange on them to cover scars from piercing.. Just curious what is the theoretical limit where a real machinist would roll-eyes and recommend a laser, water jet, or mill?
I cut a lot of mild steel, with some aluminum here and there.
I’ve had holes stay within .03” to .05” for a consistent number of cuts before consumables start wearing down. As your consumables wear down, your actual torch flame won’t be as concentrated (nozzle orifice becoming oblong) and your torch height will deviate a bit (hafnium wearing down on the electrode).
When I’ve had some worn consumables, I noticed as much as 0.15” deviation.
This is assuming you’ve actually dialed in your table and figured the correct kerf for your consumables, speed to run holes of that size in that thickness material. I will run something like 50ipm on an M10 bolt hole in 3/16” yet I’ll run 42ipm on something like an M6 bolt hole in that same thickness.