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Tomzhere
12-18-2003, 11:06 AM
I use a 2" x 1/4" x 1/2" HSS side milling cutter in a 1/2" shank arbor in my router. Scary looking thing. Could do serious damage if it got loose. The router speed is about 27K RPM.

I could easily make a new arbor out of some 8620 material that I have laying around. I can also get my hands on 4140 material too.

My question is: 8620 is pretty soft stuff. Can I safely do this? I should mention that this tool is used to take .040 max off of hardwood shafts when spinning in a lathe. Not much load on the tool unless I run into something unexpected. http://bbs.homeshopmachinist.net//frown.gif

Or should I run out and buy another hardended and true router arbors. They don't cost that much.

Tom

wierdscience
12-18-2003, 11:40 AM
I have run insert carbide endmills with a cut down shank in my 3hp Makita for years with no problems,but I do use a speed control on anything bigger than 1-1/4" in diameter because it starts to burn most things anyway,for a 2" dia. in hardwood I would slow it down to about 15,000 or so.The speed controls can be had for about $30.00 USD
As for the arbor question I would buy one,most of the commercial ones are centerless ground and straight.I would be worried more about this than what type steel.If you were to make one see if you can find 4140-b7,its already heat treated and stress relieved.

Tomzhere
12-18-2003, 12:02 PM
Thanks wierd! I guess that was my worry. I know if I make myself it it won't be as true as a centerless ground commercial arbor and I was just wondering what a small error in runout would have on the 8620 turning at that RPM. I think I will go out and get another one. I lost mine a day ot two ago and have not found it yet.