# 2 flute vs 4 flute cutters



## Mikesal (Jan 17, 2017)

I've owned machine shop equipment for years, but never had any formal training.  I just received a set of mill cutters & some are 2 flute & others 4 flute.  What type of cutting jobs is a 2 flute tool good for?  I'm from the "more is better" school.
thanks
Mike Sal


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## Mark_f (Jan 17, 2017)

I prefer 4 flute for cutting steel. I use 2 flute also but at a slower speed. Either one is good on aluminum.


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## RJSakowski (Jan 17, 2017)

Two flute allows for better chip evacuation.


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## David S (Jan 17, 2017)

Also when I look at my collection of two and four flute.  My two flute are centre cutting where as my four flute are not.  So depending on what you are doing it could be a consideration if you intend to plunge cut.

David


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## mmcmdl (Jan 17, 2017)

Use a 3 flute for cutting keyways . They won't overcut when pushed .


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## Ulma Doctor (Jan 17, 2017)

2 flutes for soft materials, at moderate to rapid feed rates
4 for harder materials, at slower feed rates


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## Professor64 (Jan 17, 2017)

I like to use 2 flute for narrow slots such as keways for better chip evacuation especially in stainless steel.4 flute for machining aluminum and mild steel for better surface finish.4 flute in narrow pockets and slots will tend to jam chips and ruin finish and possibly break the cutter. Just my 2 cents.---Glenn


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## T Bredehoft (Jan 17, 2017)

I use two flute end mills when cutting a slot, when both sides are cut at one pass.

Four flute cutters under the same conditions will 'walk' sideways, when one flute is in the lead, it's pushing the flute behind it into the side wall, so it will not cut to size. I use a four flute end mill to cut on one side only. 

Having said that, when cutting a slot to a specific width I use a two flute smaller than the slot and make finish passes to get the slot to size.


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## Mikesal (Jan 17, 2017)

Thanks for all the tips.  Tom, are you a studebaker guy?  I have a few myself....'50 champ the oldest, '70 Avanti the newest.
Mike Sal


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## T Bredehoft (Jan 18, 2017)

Hi Mike, yeah I bought the one shown Jan 6, 1959, restored it about 15 years ago. Also have and drive daily a '55 Land Cruiser with the original start-in-first transmission and a '63 full flow 289. My first was a '50 LC, in '55. Wish I still had it.


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## Mikesal (Jan 20, 2017)

Tom,
I have a '55 president state sedan in the shop right now.  Power steering, power brakes, power windows.  I've got the nose off it now to rebuild the suspension & replace the rusty fenders.  Besides the Studebakers I've got a '54 Kaiser & a '26 model T.
Mike S


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## bfd (Jan 26, 2017)

most of us don't always have a choice as to how many flute end mills we use like many other tools there are better uses and reasons to use them. if that's what you have use it. it might be slower give a worse finish but it will still get the job done. a lot of tooling avail. is based on production needs and reasons. are you doing production? bill


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## Mikesal (Jan 26, 2017)

No, no production.  I make a lot of "one off" parts for different projects (like replica ww2 vehicles).  I needed a new 9/16 cutter & the package I ordered came with both 2 & 4 flutes.  As most of my cutters are a mix of everything, I was just curious as to the best or preferred times to use a 2 flute tool.  I didn't want to waist it on normal stuff if it had a particular special use or characteristic that it should be saved for.
thanks,
Mike Sal


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## bfd (Jan 26, 2017)

ok then use what you have 2 flute tend to be rougher on the machines more chip load per rev. not that it would really hurt the machine slower feed rate. the rule of thumb I used to teach my apprentices is .001" laod per tooth so you don't rub the endmill dull. bill


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