What end mill to buy?

Solid or indexable carbide. These steels can easily work-harden and carbides are a must.

Work-hardening is an interesting process where you go from milling away merrily to destroyed HSS end mills in matter of few seconds. As steel hardens, it dulls the mill, which hardens the steel even more which ...you get the picture.

Enco, MSC have quite a variety, including some reasonably-priced imports of decent quality.

Depending on power of yer mill, sizes vary from 1/4 to 1" .

If you're just starting and have decent power in yer mill, don't overlook "corncob" cobalt roughers for hogging metal away. Again, be carefuls with steels that can work harden on you.

Another good thing to have is indexable face mill . I prefer ones with at least 3 inserts.

Alex wrote:

So cheap import end mills are OK. I thought I saw some posts saying that cheap import end mills are not that cheap considering that they last much less than quality mills.

rashid111 wrote:

There are very few materials that cannot be cut successfully with HSS, and neither of these materials fall into that category.

True. But that's more a function of the method than the material. Keeping a good feed with a responsible speed (you can almost always go a bit slower with HSS to extend edge life) and lots of coolant is crucial.

I certainly advocate carbide use for turning (once the operator is proficient with HSS!) because it is reasonably priced (brazed toolbits and insert holders). Indexable facemills are a great idea, but I think carbide endmills and indexable endmills (especially) are generally unnecessary for the HSM, given their cost.

Naturally if you're doing a *lot* of this type of work, carbide endmills will certainly be a benefit.

Solid carbide endmills can be had below 1/16". We use solid or brazed carbide endmills which are about 2"+ diameter with 6"+ cutting length at work (30+HP machines). I'm not saying you'll be able to use the full range of what's available, but they are available in virtually any size HSS is.

The corncob roughing mills are an excellent idea. One thing, I've found that it's surprisingly easy to break them because you expect to be feeding them (quite a bit) harder - something to be aware of. For any serious roughing work, they are typically a minimum requirement. Finishing endmills (what one thinks of as a standard endmill) are certainly prone to dulling after removing a comparatively small amount of material, especially in tougher steels.

That is fantastic advice. Depending on the type of work you do, indexable facemills are the most used tool on the rack. Squaring up stock, sizing prismatic parts, etc. The more flutes, the faster the feed *and* the less chatter you'll get as it's easier to get at least two teeth in the cut at all times. Once you only have one flute/tooth in the cut, you'll get a hammering effect as the cutter body is under intermittent load.

HTH.

Regards,

Robin

Alex, The advise from the other responders is very sound. However, carbide inserts use minimal edge relief and with stainless, the extra relief offered by M 42 (8% cobalt) drastically reduces drag heat, as the material is "sticky". Also, if you don't have a high HP mill at your disposal, you may find that cobalt tooling is a better choice, as it reduces required power. As a tip, sacrifice cut depth for feed speed. It is important to keep the tool edge below the cut suface and any work hardening that might occur. Steve

You've left out the most important part of the equation. What machine are you using?

If it's a little table top unit, carbide may never work well for you. You MUST have a rigid machine and set up to use carbide.

I am using a Millrite vertical Mill with 1 H.P. is it rigid enough for carbide?

Yes, assuming its in good condition. Thats a stout stubbly little bastard.

Gunner

Political Correctness

A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

What would be the max end mill diameter that can be used on 1 H.P. machine? I want to remove more metal in a single pass but I suspect bigger end mill can stall my motor.

Based on what little I know..Id have to say your utter absolute top end is going to be a 5/8th 2 flute or corncob endmill. But this is something I dont know much about. When I last had a small miller , I recall running .50 with no issues

Gunner

Political Correctness

A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

Oh..I should mention..that is largely based on full diamter cut and no more than 1/2 diameter deep.

Gunner

Political Correctness

A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.