1/2" roughing end mill

I'm in the middle of making some QC tool holders out of steel ,tried using a 1/2" 2flute to cut the slot with not very good results ,the 2 flute did not like it at all . Now I've read kind of inflicting information . My question is ,can I use a 4 flute rougher to cut a slot ?

Sean

Being a rougher you would need to finish the sides anyway. Why not use a 12mm rougher and then finish with a 1/2" 2-flute.

Real question is why did your existing 2-flute not like it? Would need more info on that.

Hi Sean what material are you milling and what machine are you using to mill on. I would rough out with a smaller rougher cutter and then finish with a nice new new sharpe cutter.

David

When you say steel, is it mild steel, leaded, tool steel, gauge plate. Is it going to be hardened. I would use the horizontal on some thing like this it needs just setting up one cut and change the part to do a batch of holders.

David

Edited By David George 1 on 26/05/2018 21:23:47

Thinking about it again if this is the slot for the toolbit you won't get much of an advantage using a rougher on a slot, assuming your mill is not that meaty you may only be able to use 2-3mm DOC which does not make the best use of the serrated sides of a ripper.

Half decent 12mm 2 or 3 flute cutter to get to the bottom and finally wided off with that to get your desired 1/2". Short series will help keep any chatter down and save you paying for length you won't need.

Won't help for this job, but all carbide mills can be bought for £10 on the bay from a UK source. Is it worth getting a new one instead of a poor re-ground one? Could well be cheaper in terms of frustration...

Regards

Richard.

+1, 'steel' covers a huge range of different possibilities and many steels are truly horrible to machine, even if they haven't been heat treated or otherwise hardened.

Motor car bodies are often made from 'Dead Mild Steel', because it's malleable and easy to press and weld. Boron steel is common in the safety critical parts of new cars; it is immensely tough to the point of being a problem to the powerful 'Jaws of Life' hydraulic cutters used to cut accident victims out of a mangled wreck. And many stainless steels are famous for work-hardening.

If you don't know what variety of steel alloy you have there's always a distinct possibility that it won't machine well whatever you do.

Looking at the sparks made when an unknown steel is applied to a grinder can help. See Wikipedia. I've not had much success doing it, but the flowering sparks on the cover of MEW267 look like high-carbon steel to me.  (Not at all clear what's making the sparks - is the picture Photoshopped?)

Dave

Edited By SillyOldDuffer on 27/05/2018 11:15:25

Dave- I wondered about that cover- looked like a flywheel in a 3 jaw while a dremel in toolpost grinds the internal bore...? I didn’t come up with a reason why though... or why the high carbon flywheel...

-Richard

Sorry for off topic...

Edited By RichardN on 27/05/2018 12:09:58

Could the sparks be from where someone is restoring a worn chuck?

Mark, you cheated and read whet it says on the cover. Dremel in a toolpost holder grinding chuck jaws held in position with a spider not a flywheel, maybe people should buy the mag

Even worse paying good money for the mag and then not reading it properly. I plead guilty to this and many, many similar offences!

A 4 flute endmill is not good practice when cutting a slot. In general there is too much swarf to cope with when there are 4 flutes or more. 3 flutes or less is better for slot cutting. If you take lots of small cuts , so in the region of 1 to 1.5mm deep the 4 flute will cut a slot. But in general a slot drill cutter will take about 50% of it's diameter as a depth of cut, like cutting a key way . I never bother with the wavy sided roughing cutters. For a 12mm slot, I would use a 10mm 3 flute end mill/Uni Mill cutter, and then go down it with a nice 12mm cutter. If the size of the slot is important, then using a new or very good condition 10mm cutter , 4 flute or 6 flute and finish the sides of the slot that way with a 1.0X cut off the centre line each way until it is at size. Most carbide cutters are about 0.02 to 0.03mm in diameter undersized anyway.

With tool steels, or steels harder than free machine MS, often the depth of cut is about 1/2 and the feedrate is about 20% less with a surface cutting speed also about 20% less maybe more depending on the steel and the sturdyness of the mill and set up.

Neil

Beware the error in the Wiki reference where it says …

Spark testing is a method of determining the general classification of non-ferrous materials.

The rest is good stuff, especially the diagrams.

Regards,

Sam

Definitely not a Photoshop job. Those old Burnerd chuck jaws were made of some good carbon steel. Captured on a Nikon point-and-shoot camera by yours truly. Took a bit of time to capture the sparks just so, but I had plenty of time while taking tiny fairy cuts with the Dremel under fine feed with chuck rotating at 30rpm or so.

Edited By Hopper on 29/05/2018 02:27:35

The clues is in the big letters spelling out "Cover Story: How To Restore a Worn Chuck".

A Plate is being used to hold the jaws in their operating position while they are lightly ground on the inside.

If you want details, buy a copy!

Neil

An excellent photo Hopper. Having tried to take similar I know catching sparks on camera ain't easy.

My suggestion that the front cover was Photoshopped has me wearing sack-cloth and ashes. No excuses, I looked at the picture and didn't read the words...

SOD, you'll need some of that matching abrasive underwear mentioned in another thread...