Milling Issues???

[Kroll]

Guys I am three for three,what I mean I have use my mill three times and three times I have runt three end mills.Yes the end mills are cheap ones from All Indus. but I figure they would last little longer.What I am I doing wrong,I figure I would learn along the way but I don't have that many end mills.So looking at the spanner wrench that I made for my collet blocks I just wanted to mill the edge down which is only 3/8 thick so taking small passes and I runt that end mill so I called this project complete at the expense of one end mill.So moving on to my next project which is a shars axa tool holder that I wanted to make little wider till I order couple XL's.So started with new end mill which I believe is 1/2 so I set the rpm to 920 if I figure it right.Not knowing how much of a cut I just made several passes removing .010 with each pass,and I see the slitter of metal coming off with each pass.Guys I am hand feeding this no power feed yet but I was taking it easy so maybe to easy?Well after several good passes the slitters of metal were not coming off anymore so I took a measurement.Made a pass and remove nothing.I know its hard to answer this question but .010 per pass at full depth of the tool holder which is maybe 5/8 does not seem like a lot nor was the mill sounding like it was straining any.Should I have feed faster or take deeper cuts which each pass was conventional them moving back was climb pass.I just don't see what doing wrong but what ever it is I need to stop.But stop what?

 

[Latinrascalrg1]

Sounds maybe like you are trying to use cheap endmills to cut Hardened steel. Either anneal the parts you are trying to mill or look into a better tool thats gonna probably need to be carbide but im not sure on what cuts what better.
Or better, yet listen to what Bob said in the post below.

 

[Bob Korves]

First, use a feed and speed calculator, at least at first. Here is a whole bunch of free choices:

milling speed and feed calculator - Google Search

You were turning your end mill about twice as fast as it should have been, assuming HSS. As a new user, you really need to check and use this information because you do not know what to expect.
Second, take real cuts, you should be making real chips, and feeling some amount of resistance feedback as you turn the crank. The feed and speed charts will help with that, too.
Third. use the ends of the end mill as little as possible. The sides should be doing most of the work, and where possible, use the sides farther from the end of the cutter, where they normally get less usage. You want the cutter to be ALL worn out when you can say you are done with it, not just one chip or dullness at the corners. For the work I saw, I would be using a 4 flute end mill, which would have 4 flutes working for you, twice as many. The feed rate needs to be half as much when you have twice as many flutes.
Last, remember what works and what does not, and try to repeat what works and avoid what does not in the future.
If you keep working at it, you will improve rapidly, and will soon know by the feel, sounds, and vibration when you have it right and when you have it wrong, and you will know which direction you should adjust your settings to.
Practice (and paying attention) will make you a journeyman.

 

[pontiac428]

There are some dark chips in and along with your "slitters", especially in the first picture. The "slitters" are coming off of your flutes, and the black curlies are coming off of your mill face. You were running a little quick, so it's possible you burnt and dulled the face of your mill (can't tell from the photo, but China mills are going to teach you a lot about frustration). A golden to rose colored chip is right in the sweet spot, but blue to black is way too hot. When you see that, it's time to back off the RPM and try again. I've cut a few tool holders and find they are a mixed bag- some are hard, some not so much. You may have found a hard one. Aside from my usual about USA made end mills, I use 2-flutes for aluminum because it needs lots of chip clearance. Whenever working with hard material, go for the 4-flute first.

 

[ericc]

The steel is hard, rpm is too fast, tools are possibly low quality. I had a very similar experience to you. I ended up making a homemade end mill out of a hand ground US made cobalt lathe bit and fed it very slowly, since it was a single tooth cutter. It did the job, but did require sharpening after cutting one slot.

 

[Kroll]

Bigger chips were from the spanner wrench that I was trying to mill just a good nice looking edge which was about month ago.Thanks guys I now know I should have use the 4 flute and now know that I should have save the two flute for my tramming gage project.I need to make some bigger chips and not slitters that golden to rose color.When doing the spanner wrench the chips were blue and black,and going to use the Little Machine Shop calculator see how it goes.I was thinking that since the holder was Shars and not aloris it would have been just plain steel.Lots of good info

 

[Kroll]

End Mills,the set of end mills I knew were cheap and good for me to learn on.Say if I was going to move up a notch in quality and just purchase one end mill say a 1/2.What should I look for that would work for a weekender whos only a hobbyist want to just mill for personal projects?

 

[cjtoombs]

Those shars toolholders are harder than supermans kneecap, at least the ones I've gotten. I second the speed and feed advice given above.

 

[brino]

Or better, yet listen to what Bob said in the post below.

Okay, that reads like a spooky prediction, but I guess it is October, so carry on.....;^)

So started with new end mill which I believe is 1/2 so I set the rpm to 920 if I figure it right.

That sounds a little fast. Based on the chart on my shop door, I'd run it about 600 rpm based on 80 sfpm and HSS tool cutting mild steel.

However....is it mild steel? Does it file easily?
You may need to adjust it based on material and cutter types.
If it is hard, try a carbide end mill.

There is nothing like practice to learn this stuff

-brino

EDIT: maybe start with aluminum and the move to known mild steel.....

 

[Kroll]

Well guys I tried another endmill 3/8 and using chart on LMS and hard steel which put me a 380rpm it cut couple passes so guessing it is harden steel but thank you brino, tomorrow will give it the file test just for the giggles and grins reason.No carbide tip so just going to order myself couple AXA XL's