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End mill leaving a line in the middle

jmx66

Active Member
Active Member
#1
I have this carbide endmill and it leaves a line in the middle of the work. Is there anything that can be done about it?
 

ddickey

H-M Supporter - Premium Content
H-M Supporter-Premium
#3
That's also happened to me and never knew why. What I ended up doing is taking three cutting passes instead of two and it seemed to help. No idea why.
 

rgray

Active User
H-M Supporter-Premium
#4
One of the cutting edges is lower (longer)in the center ??? Relieve it and the line will go away. Just my guess, it's 3:00 am so possible I'm not awake fully.
 

British Steel

Active User
Active Member
#5
Is it a groove or a ridge? If it's a groove then Russ probably has it, the centre-cutting edge has a pip that you could take off with a diamond lap, if it's a ridge... Ye cannae change the laws of Physics (or Geometry), Cap'n! and I can't see how that could happen...

Dave H. (the other one)
 

4gsr

Global Moderator
Staff member
H-M Supporter-Premium
#6
Take you your flat file and draw file the surface little, with a very light force and smooth out the ridge and you should be good!
 

Bob Korves

H-M Supporter - Premium Content
H-M Supporter-Premium
#7
From the patterns of the cutter's path, it just about has to be a pip sticking out in the middle of the end mill. A round or similarly shaped diamond Dremel tool would make quick work of it.
 

Wreck™Wreck

Active User
H-M Supporter-Premium
#11
In 30 years working in the business I have never seen a milling machine that will not leave visual artifacts at the bottom of a pocket made with an end mill regardless of the cost of the tool or machine, what the human eye can see is well beyond sub-micron levels of surface finish, you can't feel it and you can't easily measure it but it is easily seen. End mills are hollow ground on the end for this reason, the edges cut and you are not dragging the not cutting part across the work. I suspect that very low end tool manufacturers/marketers do not do this. Buy an $80.00 tool and do the same job then report back and let us know how it worked.