# Using the Shars 7/8" insert end mill on a BP



## Jake2465 (Aug 22, 2019)

So, I needed to machine out this piece of aluminum for part of the helicopter project. On hand I had an insert end mill that I got from eBay for the sole purpose of giving me some deep hole machining capability. The stick out needed to be 3" so the collet nut would not end up crashing into the top of the part.

Note: rpm was set to 3000 for both tests.

my first attempt was to use the entire depth of cut that the inserts could give me, which was about 0.350. Then I went down to a 0.100 width of cut and tried to run at 12 inches per minute. The results were not great and I was getting a lot of vibration. So I aborted the run and went back to the drawing board.

I knew the problem was that the mill was not liking that much sideload from a tool with that much stick out, so, the answer was to find a way to reduce the side load and increase the axial load (vertical load). I went from a 0.350 depth of cut, down to a 0.035 depth of cut. I increased the width of cut to 100% of tool width. I increased the feed rate to 60ipm.

metal removal with initial settings that gave me problems:
0.350 depth x 0.100 width x 12 feed = 0.42 ci/min

metal removal with modified settings:
0.035 depth x 0.875 width x 60 feed = 1.84 ci/min

The results were much better and although this is not really supposed to be the way to run an end mill, it's working well for my applications and that's all that matters. I had to push the mill to 60ipm to eliminate chatter. Once I did that, then it worked out ok. I used mist coolant and lots of it. The mix was Kool mist 77 with water. Spray mist had to be used because the inserts are not nearly as sharp as an end mill flute and chip weld would have been near-instant. I had my air gun handy and good thing too. It started to chatter when recutting chips, so I had to keep blowing the chips out of the hole every few seconds. Should have brought my snorkel gear along.

information on the end mill:

I got it from eBay from that Shars dealer located in Illinois:









						7/8x3/4x4.5" 90° Indexable End Mill APMT Insert 3FL W/Certificate save $82.25 P[  | eBay
					

Shars 7/8x3/4x4.5" 90° Indexable End Mill APMT Insert 3FL W/Certificate New. Shim Screw M2.5 x 6.5 APMT 22 1003 PDER DM YBG202. RAMP MILLING, HELICAL INTERPOLATION MILLING. All types of square shoulder face milling, side milling and full slot milling (shaft end mill) of steels, alloyed steels...



					www.ebay.com
				








I went with this end mill because it had a 3/4" shank, but the diameter of the actual cutter was 7/8". This would eliminate any chance of the tool rubbing on walls.

The only downside is that I found out I had to use their proprietary inserts which were not all bad because their prices were reasonable. I went with these inserts simply because that's what I could find on eBay, although I believe they have some that are actually intended for aluminum:









						ZCC 5PCS APMT 1003 22 PDER YBG202 CARBIDE INSERT FOR ALLOY STAINLESS STEEL !{  | eBay
					

SHARS APMT 22 PDER DM APMT 100308 PDER YBG202 FOR ALLOY STAINLESS STEEL. Insert Grade: YBG202. YBG202 Nano structure nc-TiAlN Coating Grade. Style: APMT. Nano structure nc-TiAln coating process ensures higher tenacity and hardness.



					www.ebay.com


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## JimDawson (Aug 22, 2019)

Here are the aluminum inserts https://www.shars.com/catalogsearch/result/index/?cat=431&q=APKT&to_be_used_on=aluminum


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## Jake2465 (Aug 22, 2019)

Ill have to try those out and see how they do


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## mksj (Aug 22, 2019)

Wanted to verify you are doing climb cutting as opposed to conventional milling. Per Jim's recommendation use aluminum specific inserts makes a big difference. APMT you are using is for stainless, so not optimal for aluminum. Usually there is more information as speeds and feeds for a particular cutter head and insert, but what you are doing looks conservative. On the inserts, my read is you can use APKT which are very common but according to the holder information they only say compatible with ZCC inserts which is strange.

FYI, I use the Minicut Wave endmills, something along the lines of the 930PM-2440 has a 4" DOC and typically in aluminum I can do a 1" with a DOC 0.3" or greater at 3200 RPM around 12+ IPM. I use these for rapid material removal and deeper cuts, 3/4-1" size endmills. The wall cuts are also very clean.


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## Jake2465 (Aug 22, 2019)

mksj said:


> Wanted to verify you are doing climb cutting as opposed to conventional milling


Yes, that is correct. I am using climb milling.



mksj said:


> according to the holder information they only say compatible with ZCC inserts which is strange.


Strange indeed. I ordered other inserts and had to send them back because they would not fit. I ended up just going with those inserts I purchased.

I do need the correct inserts for sure. Normally, I use ALU-Power end mills from YG1 whenever I need to cut aluminum. They have performed very well and I was able to maximize the power my mill could give me and hit around 6 ci^3in/min. It was throwing a little rooster tail of aluminum and that made me happy. I took a swig of sweet tea and chomped on my burger while watching that mill get with the program. Life was good that day.

Anyway, this is my first time dealing with some deep hole stuff. The only tool I had on hand that could do it is said Shars insert mill. But, I believe for Low HP mills, regular carbide end mills cannot be beat in performance with their sharp gound edges and higher helix angles. The only rub is that the end mills that get that large in size start to really cost come coin.


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## Jake2465 (Sep 1, 2019)

I looked up the inserts on the Shars website and I noticed that they were not the 1003 series inserts. I ended up ordering these other inserts from eBay since they explicitly stated that they were 1003. 









						APET 1003 APKT 1003 for milling Aluminum  | eBay
					

THIS IS AN ANSI STANDARD PVD MULTILAYER COATED INSERT FOR MILLING ALUMINUM AND PLASTIC. THIS INSERT FITS ALL ISO/ANSI STANDARD HOLDERS FOR APKT, APET & APPT INSERTS. THIS IS OUR BEST MILLING INSERT YET.



					www.ebay.com
				




I hope those work out.


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## jbolt (Sep 18, 2019)

They are pricy but I use solid carbide reduced shank end mills from Maritool for deep hole/pocket finish work. Roughing is done with corncob roughing end mills after pre drilling as much as possible. Good chip clearing is esential for finishing.

Sent from my SM-G955U using Tapatalk


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## Jake2465 (Sep 18, 2019)

I was just talking to Jim about insert end mills and I think the consensus was that it's hard to get a knee mill to behave well with those things. Helix geometry is just not optimal. My mill only weighs about 3000lbs and uses the little quick-change 30 taper Erickson holders.

I have had good success with using a big 1.5" indexable end mill as a face mill. Good finishes and such. But, once I try sideloading the tool, the mill starts to complain and I noticed that the quick-change system seems to not be real fond of high amplitude vibration. I've had the big spanner nut start to work itself loose before when I tried running an indexable T-slot cutter for 5/8" T slot nuts. It vibrated like hell and I started to hear a pitch change mid-cut and hit the E-stop. sure enough, the nut loosened up and was thinking about dropping the tool holder out of its quill.

After this thread kicked off, I did go and research some of the end mills. Unfortunately for me, most of them were a bit out of my budget since I do not have any immediate work to perform that can offset the cost. I ended up bidding on this new carbide end mill from eBay and picked it up for about $60 bucks. I figure if I use it for aluminum, then it should last a very long time.  This one is from a company in CA called "Promax", model # 109-04846. It is a 3/4" three flute with a 3-1/4" LOC.


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## Jake2465 (Sep 18, 2019)

jbolt said:


> Roughing is done with corncob roughing end mills



How do those run in terms of noise and performance? Also, I have heard others say that odd-numbered flutes tend to vibrate less. I am not sure if that means they vibrate considerably less or marginally less, lol.


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## jbolt (Sep 19, 2019)

Jake2465 said:


> How do those run in terms of noise and performance? Also, I have heard others say that odd-numbered flutes tend to vibrate less. I am not sure if that means they vibrate considerably less or marginally less, lol.


Roughers are amazingly efficient at removing a lot of material quickly. I can't say I ever recall experiencing any unusual vibration with one.


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## mksj (Sep 19, 2019)

I have a few Promax ZRN coated end mills for aluminum, they work very nicely. Most of my aluminum end mills are 3 flute, they run much smoother than 2 flute ones on my manual mills. I use 5 or 6 flute roughers in aluminum, primarily a 7/8" and it will quickly remove an amazing amount of material without fowling. As mentioned, the Minicut wave end mills are kind of a fine rougher with the finish of a standard endmill. The ones I use are usually the polished 3 flute with the wave cutting edge, nice performance at an affordable price. Just picked up four new 5/8" ones for $70.


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## Jake2465 (Sep 19, 2019)

mksj said:


> I have a few Promax ZRN coated end mills for aluminum


Do you think the wavy features give them better performance?


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## mksj (Sep 19, 2019)

I do find that the wave edge breaks up the chips and are less likely to load up then my standard 3Fl high helix end mills. The can take fairly high feed rates, but I am (maybe too) conservative when milling. The Minicut end mills are made from high cobalt powdered metal, and are designated as roughers but give a very decent finish. I had picked up some 3/4 and 7/8" Minicuts 930P end mills years ago, they get a lot of use for deep cuts and they have held up well. When I do not need to remove a lot of material I typically use 1/2" 3Fl high helix carbide from Promax and Hanita, they last a long time (unless I drop it ).


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## Jake2465 (Sep 19, 2019)

Do carbide end mills basically not wear out on aluminum? I've probably cut a couple cubic feet on my alu power end mill and it still seems really sharp.


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## JimDawson (Sep 19, 2019)

Jake2465 said:


> Do carbide end mills basically not wear out on aluminum? I've probably cut a couple cubic feet on my alu power end mill and it still seems really sharp.



Under ideal conditions they do seem to last a long time.  Correct feeds & speeds, and flood coolant.  We normally break them before we wear them out.


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## Jake2465 (Sep 19, 2019)

JimDawson said:


> Under ideal conditions they do seem to last a long time. Correct feeds & speeds, and flood coolant. We normally break them before we wear them out.


Sounds right.


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## davidpbest (Sep 19, 2019)

mksj said:


> Minicut wave end mills are kind of a fine rougher with the finish of a standard endmill. The ones I use are usually the polished 3 flute with the wave cutting edge, nice performance at an affordable price. Just picked up four new 5/8" ones for $70.



Mark, where do you buy your Minicut end mills?


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## mksj (Sep 19, 2019)

Typically I buy mine on eBay, just a matter of timing and keeping an eye out for specific ones, and/or those sold in lots. Just wait for the price I want to pay and often make an offer for less. On both the cobalt powdered metal and carbide I break a tip before I wear them out, and even those with a chipped tooth, I still use them for rough cutting and they work well enough. Only exception with wearing out an end mill in aluminum has been with really gummy alloys and it literally fuses into the flutes. I use air and no flood coolant, just local paint brush for lube.


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## jbolt (Sep 20, 2019)

mksj said:


> Only exception with wearing out an end mill in aluminum has been with really gummy alloys and it literally fuses into the flutes. I use air and no flood coolant, just local paint brush for lube.


Ah yes, I have some not so fond memories of my early flood coolant system failing in the middle of a CNC part run while milling some 5052 bar stock. Was quite amazing to watch the fully gummed cutter literally plow through the stock without breaking.


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