# Need New End  Mills For My G0704



## outsider347 (Sep 8, 2016)

I've used up moat of my cheep/china end mills and looking to buy some better tooling. I use my 704 manually  on mild steel mostly & looking to replace standard sizes. 
Suggestions appreciated
tks
ed


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## JimDawson (Sep 8, 2016)

I recommend keeping a stock of the cheap endmills for utility use.  I find that the China endmills work almost as well as the good HSS stuff but some are not sharpened correctly.  I buy the Harbor Freight sets with the 20% off coupons.  I also use solid carbide and carbide tipped router bits, normally 1/2 inch shank where possible.  Then I also buy solid carbide end mills, normally in 1/2 and 3/8 inch sizes.

Enco and MSC are the best for mail order.  Last I looked, the Enco web site was still working.  https://www.use-enco.com/


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## Subwayrocket (Sep 9, 2016)

Keep an eye on Flea bay for NOS , new old stock M42 end mills . They go cheaper because they're not carbide but they do good in steel and will cut stainless .  And if you need drills, Drill Hog USA sells M42 drills at a good price.


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## outsider347 (Sep 9, 2016)

Will do subwayrocket.
Jim. How do you decide which to use?  quality carbide?   cheepo utility hss

If I spend the $$ for carbide What would be the benefits with using on my little 0704?

Tks Gents
ed


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## Charles Spencer (Sep 9, 2016)

Even if you get some better tooling I'd still keep some Chinese end mills around.  For under $7 you can't go wrong. 

http://www.banggood.com/5pcs-468101...r-HSS-Straight-Shank-Drill-Bits-p-995505.html

I use these whenever I want to spare my American made end mills.


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## JimDawson (Sep 9, 2016)

outsider347 said:


> How do you decide which to use? quality carbide? cheepo utility hss



For rough/non-critical work I am most likely to grab cheap HSS.  For fine finishing and profiling parts I am most likely to use carbide.  And of course for tool steels and stainless I normally use carbide.  This is not to say that you can't do accurate work with cheap end mills, but the carbides stay sharp longer.  I have a few good HSS end mills, but normally don't buy any but aluminum cutting types in longer lengths because I work in a lot of aluminum.



outsider347 said:


> If I spend the $$ for carbide What would be the benefits with using on my little 0704?



In thinking about this a bit, carbide may not be appropriate for your machine.  Carbide requires rigid setups and minimal backlash to prevent breakage.  Carbide tools are much less forgiving the HSS.  Try a 1/4 inch solid carbide router bit in your machine and see how it reacts, available at you local hardware store for about $20  Router bits have a slightly different geometry than end mills, and the web is a bit smaller, but still work well.


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## Subwayrocket (Sep 9, 2016)

The M42 is a lot less likely to break than carbide, and cheaper ...a buddy of mine who does home milling and runs a cnc for a living suggested against carbide for me for that reason .
I do have a few shars indexable end mills that take carbide inserts. Both the indexed carbide and M42 worked well in stainless and steels . The inserts can be found cheap on ebay .
Good luck Ed !


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## outsider347 (Sep 9, 2016)

Tks Charles Can't go wrong at that $$$
Tks subwayrocket. makes sense to me
Flute question.
I've been using 2 flute style....because I really don't know why

2 Flute--  application?
3  "             "              ?
4   "            "              ?
5                                 ?
6                                ?


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## JR49 (Sep 9, 2016)

Charles Spencer said:


> Even if you get some better tooling I'd still keep some Chinese end mills around.  For under $7 you can't go wrong.
> 
> http://www.banggood.com/5pcs-468101...r-HSS-Straight-Shank-Drill-Bits-p-995505.html
> 
> I use these whenever I want to spare my American made end mills.



    Charles, the end mills you linked to are very tempting, but they are metric sizes.  Do you have metric collets for them or do the close fractional sizes  work?  On a side note--I lived about 25 miles north of you (Fitchburg, Ma.) till I was 27 hated the winters, been in Ca. ever since.   Thanks JR49


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## JR49 (Sep 9, 2016)

outsider347 said:


> Tks Charles Can't go wrong at that $$$
> Tks subwayrocket. makes sense to me
> Flute question.
> I've been using 2 flute style....because I really don't know why
> ...



Great question, Outsider, as a newbie, I thought "2 flute for aluminum- 4 flute for steel" .  But just yesterday, I needed to cut some 1/4" slots in a 2" dia. steel pipe and wanted to plunge into it, only had a 2 flute center cutting end mill in 1/4", so I used that, and it worked very well!  Maybe, some of the "pros" could help us newbies  out with a Flute Application Post.  Happy Machining,  JR49


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## Doubleeboy (Sep 9, 2016)

2 flute gives more room for chips, but with half the cutting teeth of 4 flute your feed would need to be cut in half compared to four flute.   If you are going to mill aluminum do not use 4 flute Tin coated endmills, you will very likely have chip weld that is near impossible to remove.  I like uncoated 2 flute for aluminum or if you have rigid machine you can you 3 flute hi helix in carbide and really go to town, but the mistakes cost $20 plus.  CDCO has some half decent end mills in M2AL that cut pretty good about the same as the interstate branded ones I use to get from Enco.

cheers
michael


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## JimDawson (Sep 9, 2016)

JR49 said:


> Great question, Outsider, as a newbie, I thought "2 flute for aluminum- 4 flute for steel" . But just yesterday, I needed to cut some 1/4" slots in a 2" dia. steel pipe and wanted to plunge into it, only had a 2 flute center cutting end mill in 1/4", so I used that, and it worked very well! Maybe, some of the "pros" could help us newbies out with a Flute Application Post. Happy Machining, JR49



"2 flute for aluminum- 4 flute for steel" is correct in most cases....except for slots or keyways, then use a 2 flute.  So you grabbed the correct end mill for the job.  The 4 flute will pull sideways and oversize the slot, where the 2 flute won't (as much)

Also I generally drill a pilot hole where possible so the end mill does not have to center cut.  For a 1/4 inch slot, I would drill about a 0.200 pilot hole.  The geometry of an endmill is not correct for plunging (drilling) and that should be avoided where possible, even using a center cutting one.

On smaller machines, >4 flute endmills require a feed rate that taxes the feed to keep the chip load up.  It is best to stick with 2, 3, or 4 flute.  More endmills are destroyed by too slow of a feed rate than anything else.  The too slow means the endmill is rubbing rather than cutting, especially true when conventional cutting rather than climb cutting.


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## mikey (Sep 9, 2016)

Doubleeboy said:


> 2 flute gives more room for chips, but with half the cutting teeth of 4 flute your feed would need to be cut in half compared to four flute.   If you are going to mill aluminum do not use 4 flute Tin coated endmills, you will very likely have chip weld that is near impossible to remove.  I like uncoated 2 flute for aluminum or if you have rigid machine you can you 3 flute hi helix in carbide and really go to town, but the mistakes cost $20 plus.  CDCO has some half decent end mills in M2AL that cut pretty good about the same as the interstate branded ones I use to get from Enco.
> 
> cheers
> michael



I agree with Mike re number of flutes. I like/use 3 flute HSS fine roughing and Hi-Helix finishing end mills from Greenfield in aluminum. The high helix pulls the chips out of the cut and the three flutes gives a nice finish, all at max speeds. I have used them on my Sherline and RF-31 mills and they cut great. You will find that a 3-flute end mill will leave a much better finish in most materials, albeit at lower feeds than with 2-flute cutters. 

I tend to use 2-flute cutters in steel/stainless, mainly to get the chips out of the cut to keep cutting temps as low as possible. As in all cutting operations, the heat is mainly in the chip so clearing them, especially with materials that work harden, is a good thing. In general, the more flutes you use the better the finish, the lower the feeds and the more coolant helps.

4-flute cutters tend to come out for finishing cuts in ferrous stuff. Most of the time I use roughing end mills to get close and use the standard end mills for finishing.

Solid carbide is most useful to me for deep cuts. The stiffness of the material reduces flex and this matters when you need a clean vertical edge on a thick part.


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## outsider347 (Sep 9, 2016)

Thank You Gents for the great lesson....so much to (I don't) know
ed


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## Charles Spencer (Sep 9, 2016)

JR49 said:


> Charles, the end mills you linked to are very tempting, but they are metric sizes. Do you have metric collets for them or do the close fractional sizes work?



I just use them in my fractional collets.  Haven't had any problem.


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## mikey (Sep 9, 2016)

I wanted to add that HSS is fine for most materials but cobalt is even better - holds an edge longer, especially in more abrasive or harder materials; tool steels and stainless come to mind. Carbide doesn't add much other than stiffness but mostly because I can't get over 3K rpm on my machines. If I could then carbide would be more useful to me. 

The number of flutes matters but the depths of cut relative to the size of the end mill when slotting or edge cutting is just as important, the reason being that this determines your speeds and feeds. The deeper your cut the slower your speeds and feeds. Niagra Cutter used to have a wonderful guide that gave this info by each major material group. I just looked and cannot find it as their website has been "updated" ... change is not always good. I'll see if I have a pdf of that info and will post it if I can find it.


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## mikey (Sep 9, 2016)

Found them. I tried to post them to this thread but while I could upload them to the draft copy of this post I could not insert them into the body of the post. I will ask admin for help.

Heh, heh, wouldn't you know it - it posted after all. Hope you find this useful.


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## Subwayrocket (Sep 9, 2016)

If you go looking on eBay/Amazon , be aware the the term cobalt is often used loosely by sellers who don't know what they have. Make sure they specifically say M42 or it could be just coated or anything in between . M42 is usually not much more in price .  T15 works well too , if you can find it.


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## Splat (Sep 12, 2016)

Subwayrocket said:


> If you go looking on eBay/Amazon , be aware the the term cobalt is often used loosely by sellers who don't know what they have. Make sure they specifically say M42 or it could be just coated or anything in between . M42 is usually not much more in price .  T15 works well too , if you can find it.



Definitely! I found this out the hard way. Questions are your friends.


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## Ironken (Jan 25, 2017)

Subwayrocket said:


> Keep an eye on Flea bay for NOS , new old stock M42 end mills . They go cheaper because they're not carbide but they do good in steel and will cut stainless .  And if you need drills, Drill Hog USA sells M42 drills at a good price.


Diggging up an old thread here.....I ordered drills from Drill Hog USA. Their customer service is A+ and quality is excellant!


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## Subwayrocket (Jan 25, 2017)

Ironken said:


> I ordered drills from Drill Hog USA. Their customer service is A+ and quality is excellant!


Yeah that guy is real good to deal with . He is a little flexible on price sometimes too .


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## Ed ke6bnl (Jan 25, 2017)

just received my step bit from drill hog and had to make a hole in a tab for my buggie and so far I am impressed, I will see how it stands up. Was an ebay purchase with lifetime warranty.


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