Where to read about endmills?

I've been cutting/grinding for a little while now, and I've just been following the steps that I've been taught by the guy teaching me. However, after reading up on some endmills, I'm thinking that there's room to improve on the ability of these endmills, for example, using a different helix depending on whether you're roughing or finishing, or the material type.

I'm just looking to learn as much as possible, so I have the information, and so I can possibly help the company.

Can anyone point me in the right direction?

I really want to focus on our main job here, which is an inconel part where we experience a lot of chatter.

Chatter will increase when the primary relief angle is too great. I find that brand new endmills will sometimes chatter badly until they've been 'run in' a bit, if they can survive at all. I believe that feeding at a high feed rate may help alleviate this, because a high feed effectively lowers the relief clearance as the chip is formed. But if you are machining a tough material where such a high feed rate is not possible, then the only practical way to reduce the effective relief clearance is to grind less clearance at the cutting edge.

I've only ground endmills in a very crude tool and cutter grinder, and basically setting the clearance was/is a crapshoot done by eyeball. Need to be able to check the relief you're grinding on the tool while it is being sharpened.

Very interesting, and you may have hit on something. Whenever we make new tools from blanks, they chatter like hell and are incredibly loud. Once we regrind them though, 95% of the time they sound much better. A full sized endmill (on this job) almost always sounds terrible.

I run Ancas for cutting/grinding, and the primary angle we use is 7° on the face and OD, and the secondary angle is 25°.

Yes, try maybe 5 degree primary.

I once took the time to resharpen the blades of an adjustable hand reamer, to reduce the clearance so it would ream without chatter. That tool cut like a dream afterwards. So I know 'factory' doesn't mean 'correct'.

GoneFishing said:

I've been cutting/grinding for a little while now, and I've just been following the steps that I've been taught by the guy teaching me. However, after reading up on some endmills, I'm thinking that there's room to improve on the ability of these endmills, for example, using a different helix depending on whether you're roughing or finishing, or the material type.

I'm just looking to learn as much as possible, so I have the information, and so I can possibly help the company.

Can anyone point me in the right direction?

I really want to focus on our main job here, which is an inconel part where we experience a lot of chatter.

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end mill catalogs offer a lot of info. try
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Catalogs & Brochures (PDF Format) - Dataflute
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many tool resharpening places now use cnc grinders and many, they tell computer the end mill size and type and it auto sets the proper angles. so end mill has less of the chatter issue when end mill new. sharpened properly there is no difference between new and resharpened end mills. obviously why they want to resharpen a lot of end mills that are they same size and type so they dont have to keep resetting the resharpening setup
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my experience if resharpening service using cnc grinders they are usually resharpened better.

Easy enough to try fast helix cutters for you needs.
http://www.harveytool.com/prod/High-Helix-End-Mills-for-Aluminum-Alloys---45--Helix---Square_61.aspx

Everything counts even the size of your machine and fixtures.. so not just the cutter..
Cincinnati #2 free down load manual good for methods but not much on theory.

It is very difficult to OD grind end mills with not having the very
best equipment.. The smallest wobble on the holding device will make a poor cutter.

Had one friend who finish ground end mills ODs between centers with back spinning the last of the OD. Then he ran the primary OD clearance to a hair land...then adding the secondary..Claimed that the best end mill he ever tried..and yes most end mills are sharp at the OD with clearance coming to the very edge.

He cut off the center and finished the cutting end sharpening after the OD was done.

Theory only goes so far, and is not always right, trying out different end mills and building up your direct experience will teach you far more. Have your tried any of the multi flute end mills? Like 5-10 flutes and HSM paths. I have found them to be absolutely mind boggling compared to the 2-4 flute end mills that I was used to. You do have to use them differently but WOW they are good. Don't forget to experiment with the tool holders, both type and projection from spindle. The tool holder can make about as much difference as the end mill.

To answer your question though browse what the different end mill manufacturers have available. Just don't take it as gospel and never let theory keep you from trying something new that goes against that theory.