PDA

View Full Version : Got a Mill, Need Advice



Northboundtrain
04-20-2006, 04:37 PM
I've been on the hunt for a mill for just about a year now. At times, I've considered just buying an import, but I've always postponed the purchase because that's not what I really want. The other day I was scrolling craigslist and "holy @#&%!!!" there's the mill I've always wanted, a Clausing 8520, ten minutes from my house.

Needless to say, It now resides in my little shop. They guy gave me some HSS bits with it. He never worked steel, just aluminum and plastic. I'm really eager to start playing with it, but I'm not sure what bits to get. I tried out one of the HSS bits on some steel and it works okay if I go real light and slow. I've got lots of carbide router bits for wood. Can I use these on steel? How about brass or aluminum? Also, where can I get info on the right spindle speeds and feed rates for various bits and materials? If I need to go out and buy some end mills, what's a good starter set?

Thanks

J Tiers
04-20-2006, 04:42 PM
Get a shop text, like the Audels or similar, prefereably from the 60's or so. That will give setup, speed etc info.

For end mills, basically what you need.... although I have lately become very fond of "roughing" end mills for cutting material fast with no strain.

Alistair Hosie
04-20-2006, 04:45 PM
First of congratulations northbound well done I hope you have many years of service and fun from your new toy.The dreams we all have when we built our workshops I remember during that period well.I was hardly ever able to get to sleep thinking it would never get finished then one day it's there.However as you will realise the mill is just the beginning you will as the rest of us did become seriously addicted to the best hobby around keep well Alistair

Schutzhund
04-20-2006, 04:46 PM
http://www.frets.com/FRETSPages/Machining/QuickTricks/RouterBit/routerbit.html

http://www.frets.com/FRETSPages/Machining/QuickTricks/RouterBit/routerbit.jpg

CCWKen
04-20-2006, 07:15 PM
I've used router bits on aluminum but I don't know if I'd try it on steel. Although the carbide is probably C3, the cross section of most router bits is pretty small and have few flutes. I'd dig down and get the right tooling.

Congrats on the new mill!

Scishopguy
04-21-2006, 12:03 AM
Congratulations on your good fortune. It is hard to find exactly what you want in machinery. You will need to get some reference books. Any version of Machinery's Handbook will give you your speeds and feeds. These are a starting point and you will want to adjust up or down as the material dictates. You can use router bits in the mill providing that you are working with wood, plastic, aluminum, or a similar material. The cutting geometry is not the same as it is on end mills and they won't last long on anything harder. The carbide is the softer and more wear resistant grade. If you are not familiar with milling operations get a book on basic machining. There are some things that you don't want to do with a mill of this type. Climb cutting, when the rotation of the cutter pulls the work into its feed direction, is dangerous in steel and deep or heavy cuts in aluminum. It will cause the cutter to overload due to the slack in the lead screw of the table and will most likely break the cutter and mess up your laundry. Hydraulic feed machines, like the Cincinnati Hydrotel are good in either direction but there is no lead screw there to have slack. Most mills, even in new condition, have about fifteen thousandths of slack in the lead screws unless it is a CNC and has ball lead screws. Get some good reference books and take it easy until you get the feel of it and that mill will make you happy for the rest of your life.

Jim (KB4IVH)

Happiness is a floor full of chips!!!

david_r
04-21-2006, 02:09 AM
Check this chart.
http://ase.tufts.edu/mechanical/shop/feeds.htm
To figure RPM on your mill, take the SFM x 4/dia

I.e. 3/8"" HSS endmill in steel at 100 SFM
100 x 4/0.375=1067 RPM

Then drop down to the closest RPM on your mill.

HTRN
04-21-2006, 07:26 AM
I've been on the hunt for a mill for just about a year now. At times, I've considered just buying an import, but I've always postponed the purchase because that's not what I really want. The other day I was scrolling craigslist and "holy @#&%!!!" there's the mill I've always wanted, a Clausing 8520, ten minutes from my house.

The guy who sold it to you wouldn't happen to be an old guy in or near Sayreville NJ, would he?


HTRN

Alistair Hosie
04-21-2006, 03:58 PM
Hey Jim said
Happiness is a floor full of chips!!!
everytime I see your posts I think of chipshopguy mmmmm chips(french fries to you American boys) :DAlistair