fatbillybob

Wow! great posts guys. Here are some of my comments: 1) There is a radial side load issue at least with my cheap chinese mill. It was never ment for a large endmill like a preferred 1.75" unit. Also, the cheapest endmill of its type so far in that size is about $250 bucks. So if you have a big machine then milling this size is no problem. It is pushing limits with my machine 2) my tube is stout 1.75" 0.120 and or 0.95 wall. 3) Speed is not a problem but feeds are slow with an endmill. I have done similar tasks with new endmills and I am surprised at how long it takes to mill something out. 4) to use an endmill you logistally need to draw a fishmouth shape that is needed. Cut the tube then fishmouth on the mill. Lots of steps. 5) Kurt, when you used the plasma cutter what is the trick to getting the plasma to blow though the metal and leave littel slag? The slag is as hard to grind as the metal. The outside slag is not so hard but the slag in the tube is a bitch! What am I doing wrong? 6) If the low buck notcher and chomp 120 wall it sounds like the easiest way to get close cuts and then grind the rest away for that single node joint. I like John's idea the best but I do like the quick slices I can do with a plasma cutter.

On a side note just saw "american hotrod" TV show. The guys were making a rollbar. What a joke. They made it from three pieces of tube and welded the three pieces! When they grind off all the welds and paint it you can't tell how substandard it is. Amazing perople get paid for that kind of work.

Geo

Yeah, I've seen them build a couple of rollbars/cages now. They need to stick to show cars. What a bunch of monkeys.

kurt M

I think you might be using sub standard grinding wheels if you are having a problem grind the slag off. I can cut an entire 90 deg fishmouth in 1.75/0.120 in about 2 min with just the angle grinder.
To save time and grinding wheels I use the plasma to hog out 90% of the metal I need to remove and then grind the end to fit. Again, low/tech and not production/repeat as needed type of method but for one off type jobs it works.

At least the 3 part bar is metal. There is a co that sells PVC roll bar kits. You cut and install PVC pipe and fittings and then wrap everything in roll bar foam to hide the plastic pipe. The same co. also sells a kit that makes you NA Honda sound like it has a turbo under the hood. It hooks to the linkage and makes a recorded turbo whine as you hit the throttle.

RedlineMan

Hey;

As a point of reference, it takes me less than 10 seconds to notch a tube with my LowBuck. The downside is that you can't do much past 10 degrees without grinding anyway. I have a 2hp 12" bench grinder for that! I still use the LowBuck A LOT. Worth every penny!!

Actually, those PVC roll bars may make a lot of sense for fools running around on the street doing the bling thing. Man, I hate even saying that word. It is a lot better to bounce your head off that than a steel tube if you get in a wreck while flying over an open tressel bridge during a race.