Roughing end mill question.

[finsruskw]

Just received my 1st roughing end mill and have a question about its use.
Are these meant to be used more on the side instead of the end?
Reason I ask is I have two 11" pieces of 1.5 x 1" stock that need a slice .75"x.5" deep taken off the length of each for my son's log splitter project. These will ride under the top lip of the "I" beam rail and the wedge plate will be bolted to them. I already have the holes drilled.

I have one done that I did with a conventional end mill taking approx 3/8" x .015/.020 deep cuts but it seemed to take forever and generated a lot of heat at a slow feed rate using that stinky tap magic crap.
I am hoping the rougher will speed things up considerably. I do realize the finish cuts will have to be done w/a regular end mill though.

Tips on the use of a rougher would be appreciated

 

[Cadillac]

Yes with a rougher you should be using the side to make use of the corncob effect.
When I made my first splitter carriage I did the same where I milled the slot for the carriage to ride along the Ibeam. Found that using a flat plate then 1/4 or 1/2 material and stacking it to make the profile was ALOT easier and just as strong.
Did you plan on bolting or welding the pieces your doing?

 

[finsruskw]

He is going to bolt it together.
I offered to tap them for 1/2" bolts be he said just drill 1/2"

 

[Cadillac]

The easy way of going about it is have your top plate then a filler strip the thickness of the top of your ibeam. Then a wider piece to run the bottom side of the ibeam. Drill holes in the stack and done. No milling necessary really.

 

[mikey]

What kind of material are you cutting? What is the diameter of the rougher? Is the rougher HSS or carbide? Is the rougher fine or coarse pitch?

Answer these questions and I can give you more info on speeds and feeds based on how much axial and radial depth of cut you wish to use.

 

[finsruskw]

Just mild steel I believe.
Las came over yesterday and used it and turned out the second piece in less that 1/2 the time it took me to do the first one.
Don't know and speeds and DOC he was taking but it sure didn't take long!
1/2" rougher is all I know and he was able to go the full depth on each pass and it left a good enough finish that he was happy with without switching to a conventional bit.
Chips were all nice and silver too!

 

[mikey]

It will still be helpful to go through how to determine your cutting conditions on a manual machine because it applies to any end mill, rougher or otherwise. I am attaching the Niagara Cutter guide for mild steel below.

First thing to understand is that there are two depths of cut for peripheral milling: Axial and Radial. The former is how much of the cutter length you intend to use; this maxes at 1.5 x the diameter of the cutter. Radial depth is the fractional depth of the cutter diameter you need to use. While this is a rough estimate, it is actually quite useful.

For slot cutting, you obviously only have Axial depth to consider.

Next, note that the cutting speeds for roughing end mills are about 20% faster than finishing end mills and the coating also has an impact.

The way you use this info is to determine how big a Axial and Radial depth of cut you need and find the appropriate SFM recommendation and use that to calculate your RPM. Feeds are tabulated below the SFM chart. Find your cutter diameter and calculate your feed per tooth base on how much of the cutter diameter you're using.

For example, if you were using an uncoated 1/2" rougher and wanted to take a 0.25" deep radial depth of cut (dia./2), your sfm would be 144sfm. So, 144x3.82/0.5 = 1100rpm. Your feed would be 0.002" X however many flutes you have on the end mill. If feeding manually, by feel, feed fast enough to feel a slight resistance to the feed; this will be faster than you think.

Give this a try.