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Educate me about end mills

I'm a part-time knifemaker with a mini mill. Mostly I use it for drilling & tapping but occasionally need to ruin, er, machine a piece with its regular milling capabilities. This can involve end cutting or side cutting.

Over the years I've collected a variety of end mills, mostly from sets, all center cutting, 2-flute and 4-flute (I understand the difference), single end and double end. Must have 2 or 3 dozen of these in different sizes, all dull.

In fact, they seem to go dull incredibly fast, although they cut fine when brand new. Might be my technique, might be the mini mill (not rigid enough), might be I'm not holding my mouth right. Might also be because they are the cheapest end mills available so they can be sold in sets for $35 or so.

So I'm looking to buy some quality end mills -- just straight, center cutting mills, in basic sizes 1/8" 3/16" 1/4" 3/8" 1/2" etc. And I want them to last a little longer than the sets I've been buying.

I've got the MSC Big Book in front of me, and there's a bewildering arrays of brands, styles, materials, coatings, functions, and I presume quality. So I just don't know where to start in making a decision about which one(s) to buy. My budget is not unlimited so I can't afford to experiment with tooling that won't do the job.

I am cutting mostly annealed carbon steels, stainless, damascus, titanium, German silver and lots of softer stuff for scales and embellishments. Most of this is just light cuts to straighten out an edge or make multiple identical pieces. Shallow slots. I've used the mill to cut the flats on hunting knives, taking 0.005" off at a time. Even some freehand stuff for inlays. The rest of it is probably as varied as the stuff you guys do.

If any of you have any recommendations, I'd be grateful for them, and any other advice about end mills you'd care to share.

-Frank

Reply to
Frank Warner
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Fantastic knives Frank.

Dennis

Reply to
TwoGuns

I use M-42 end mills now, and haven't bought any plain HSS in years. The additional price is very little, the greater wear resistance is remarkable. For 1/8" size I use solid carbide, I can get these for $3-4 on eBay. The no-name HSS Chinese stuff is junk.

Especially on stainless, don't make very shallow cuts or allow the cutter to progress too slowly across the part. Either causes work hardeneing, and the workpiece becomes harder than the tool. That's when the burnout of the cutter happens. You have to keep up an aggressive feed to prevent that.

Jon

Reply to
Jon Elson

Are you cutting dry? It sounds so to me. Using coolant will help greatly. What I use is a Noga sprayer with Rustlick WS-5050 soluable oil:

Despite MSC's photo, the one gallon size comes in a reasonable container.

I buy used endmills locally. It's a good way to start.

These are very different materials, and require different techniques, especially the stainless and titanium. You need to get a book on machining and read about these materials. For instance, stainless needs slow speed, high torque, heavy pressure, and lots of black sulfur oil.

Joe Gwinn

Reply to
Joseph Gwinn

Thanks for asking this question -- after looking at the links Gunner gave I now understand why I lose an end mill every time I try to cut steel.

Next time I'll try for more patience.

Does lubrication and/or coolant help?

Reply to
Tim Wescott

On Feb 15, 11:08=A0pm, Tim Wescott wrote: =2E..

I made up a spreadsheet chart of cutting speeds for my mill with the 6 belt settings and spindle speeds for rows and common tool diameters for columns. When the usual 600 RPM isn't appropriate it's easy to look up the nearest speed and find its belt setting.

Motor Head RPM .125 .250 .500 ... Low Lg 600 20 39 79 Low Med 350 11 23 46

600 RPM gives ~80 FPM on a 1/2" end mill, which has worked well for me on all but hardened steel where I'd use carbide anyway.

Name-brand USA HSS end mills stay sharp a long time with a little cutting oil brushed on whenever the smoke disappears. The cheap blue- tube ones seem to require much lower speed or they dull very quickly in steel, so I save them for aluminum.

Jim Wilkins

Reply to
Jim Wilkins

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