hey, i've got an above avg. drill press and a cross slide vise.

I was thinking of picking up a set of cheap end mills and playing around with it. My question is at what kind of speeds do I need to run the drill press for a given end mill ? 1/4" ? 3/16" ? etc
I'm sure there are books and charts that tell this kind of thing but I've never run across one before ...

and how big an end mill could I use before it'd be too much for
a drill press ? I'd imagine not very big given the overall sturdiness of a mill compared to a drill press.

- jack

Depends on what you are milling, what your end mill is made of and if you are using coolant. How fast you go depends on how many teeth are on the mill. There are formulas for that stuff. Can't remember any right now tho.

Do yourself a big favor and purchase a copy of the Machinist's Handbook. It contains all the charts and equations you need in a very well-structured book.
It's one of the handiest tools I have in the shop.

Yes, the RPM is dependent on what type and size cutter, and material you are using. And with the set-up you are using, you may want to conventional mill.

RPM = (4 x SFM) / cutter diameter

SFM examples:
CRS = 100
HRS = 80

what am I milling: regular old mild steel

what is my end mill made out of: whatever this cheap Harbor Freight set is made out of: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=44603

am i using fluid: no

- jack

Originally posted by morpheus
what am I milling: regular old mild steel

what is my end mill made out of: whatever this cheap Harbor Freight set is made out of: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=44603

am i using fluid: no

- jack

The end mill is probably High Speed Steel.

Mild steel = 1020 CRS, so use 100 for Surface Feet per Minute (SFM)

That will get you in the ballpark.

edit: Here's a quick calculating reference I just found to help.......

http://www.carbidedepot.com/formulas-milling.htm

Originally posted by Kurtastrophe
Do yourself a big favor and purchase a copy of the Machinist's Handbook. It contains all the charts and equations you need in a very well-structured book.
It's one of the handiest tools I have in the shop.


A friend has this book. I'll borrow it from him. thanks.


RPM = (4 x SFM) / cutter diameter

SFM examples:
CRS = 100
HRS = 80 [/B]

what is CRS and HRS ?

any recommendations on how big an end mill i can run in my drill press ?

- jack

Originally posted by Kurtastrophe


The end mill is probably High Speed Steel.

Mild steel = 1020 CRS, so use 100 for Surface Feet per Minute (SFM)

That will get you in the ballpark.

Sweet ! thanks Kurt :D

- jack

The way you figure out what rpm to spin the tool is (cutting speed in feet per minute times 4 devided by the dia. of the cutter) This will get you in the ball park for what rpm to spin. The cutting speed is diferent for what material you use and what type of cutter you use. so you will need a chart for the cutting speeds or a machinests hand book.

so, using the formula from above:

RPM = (4 x SFM) / cutter diameter

given that
SFM = 100
cutter diameter = .375 (3/8")

rpm = (4x100)/.375 = ~1067


for 1/2" cutter
rpm = (4x100)/.5 = 800

that formula works opposite the way I would think, the larger the cutter diameter the faster it should turn
:confused:

- jack

Originally posted by morpheus
so, using the formula from above:

RPM = (4 x SFM) / cutter diameter

given that
SFM = 100
cutter diameter = .375 (3/8")

rpm = (4x100)/.375 = ~1067


for 1/2" cutter
rpm = (4x100)/.5 = 800

that formula works opposite the way I would think, the larger the cutter diameter the slower it should turn
:confused:

- jack

You've got it right Jack........

1/2" = 800 RPM
3/8"(smaller dia.) = 1067 RPM
:D

is there a more advanced formula for how many teeth the cutter has like is mentioned above ?

- jack

well after you get your rpm's you need to figure your feed rate. That formula is IPM (inches per minute)=RPM x recommended chip load per tooth x # of teeth. This won't really mean squat to you though.

I'd have reservations about using a drill press for a mil though. The amount of slop in the spindle is most likely going to ruin several parts and expensive endmills. Most likely it will destroy your spindle on the press also, but hey give it a try and tell us how it worked.

You could always find one of these at a local auction for less than $1000 though

you paid less than a grand for that what kind of mill is it?

You want to chuck up an end mill in a drill press?
Jacobs chuck wasn't designed for side loads, just vertical loads.
You may ruin the chuck.

Originally posted by doctor_G
You want to chuck up an end mill in a drill press?
Jacobs chuck wasn't designed for side loads, just vertical loads.
You may ruin the chuck.

not to mention all the bearings and shafts above the chuck, I don't know, but if it was my drill press, I'd be damn careful, they were never designed for that. At least go slow (if I remember right feed rate is a maximium if you go slower it's less stress on the machine)

chad

Personally I wouldn't even bother and just save up for a mill. I did try it and bent a spindle shaft within a couple of days of using it. Once you have a drill press apart it's pretty easy to see why they are not good for milling. You might have better luck than me though.

I tried it and it did not work worth a crap and I have a decent drill press.

My father bought a Bridgeport milling machine from a factory that was upgrading to new equipment. I believe it was about $3k. I think you may be able to find a deal like that anywhere. Only trouble is they are real heavy.

You can get them all day long here in the machine shop capitol of the US for $1000. Yup, they're heavy and you need to be wired for 3 phase or get a converter. Then you need to buy another $1000 worth of tooling and you can do most of the junk that we need to accomplish.

Easy

Just find a job at a machine shop sweeping the floors at night!

Then you'll have access to all kinds of cools toys, er tools.

As for milling you also have to take into account depth of cut. I haven't used that table in my handbook since trade school 8 years ago. Like it was stated above, it gets you in the ball park. Sooner or later you'll get a feel for how fast you can run stuff with out chatter or burning up an end mill.

The funnest thing too do though is rigid tapping :D

Rigig tapping = SCARY the fist time :p

What is "rigid tapping"?

CNC machines that have synchronized spindle speed and feed rate can tap holes with out the use of axial compensation type tooling. Thus allowing you to tap holes in a very rapid manner. Its scary cause the machine is so fast, and the tool is moving very close to the work piece. (and in to it) Tooling is expensive and it can be very easy to crash. Small typos can cost thousands of dollars.


brook