One 5 millimeter carbide end-mill later

[Norppu]

I have been learning to use the milling attachment in my lathe. It actually works but it has some serious limitations.
The rigidity is no more a problem. The setup is actually very stable and there was no vibrations around. Having a VFD helps to set the correct speed. As I do not have a power feed for cross-slide I feeded by hand. Actually there is a nice feedback available and after a while I realized that one should apply constant pressure rather than constant speed.
Cross slide backslash is a problem. The backslash, however small, will snap the mill and/or spoil the work. Climb-milling is definitely NOT the way to go. So with this milling setup one has to be aware of cutting directions and never gamble with backslash. One end-mill later I now know how easy it is to snap an carbide end-mill.

Today I made some space in my workshop. A lot of electronics junk had to go. These have been sitting in my workshop the last 20 years and I assume they would continue to do that the next 20 years. Created some hassle in the recycle station today ...


My first real milling item was a replacement for way-wiper covers. The original way cover was made of some very brittle plastic. The new ones are made of some mystery metal from my junk-metal-pile. The material is NOT aluminum. Tomorrow I make the covers for the other side. These have an interesting slot for the way.

 

[Bob Korves]

I recommend you try using HSS tools while you are learning, and perhaps all the time if the machine is not tight and rigid. Carbide end mills are too expensive to break them all the time while getting little gain from them. Carbide is only really needed on hard metals. I rarely use carbide, and I have a mill much more rigid than yours, and work on harder and tougher materials regularly. If you are breaking end mills, something is wrong. More rpm usually helps with carbide, but the feed still needs to be enough for real, solid chips, not dust or foil.

 

[chips&more]

I have a BP and stay away from solid carbide end mills. I like the 6 and 8 flute cobalt or HSS stuff. I have a 1/2" 8 flute cobalt that is still good after a couple of years of strong use...Dave

 

[Norppu]

It is amazing what one can find in Frankfurt flea market. I bought a box full of diverse end-mills. Some are used and some are not. What this box did not have was HSS end-mills. All are carbide. The box weighted about 2 kilograms and the lady asked all 20 euros for it. So I have quite some carbide end-mills.

Broken carbide end mill is not a total loss. I will use those to create brazed cutting tools. I have made a few and the carbide used in end-mills brazes really well.

I will try out the HSS end-mill. It is probably sharper and does not generate as much cutting forces which is good in my case.

 

[Bob Korves]

I will try out the HSS end-mill. It is probably sharper and does not generate as much cutting forces which is good in my case.

HSS is mostly softer than carbide. That means it does get dull if you don't use it correctly. It also means that it is less brittle, so if it is used correctly it will usually not break. The cutting forces are the same for the same size tool in the same material, using an equally sharp end mill. Learn to use the correct speeds and feeds and learn from and pay attention to the feedback the cutter, the machine, and the work is giving you. Learn the simple formulas for speeds and feeds to start the job, then adjust as necessary as the work progresses.