fly cutter wear

You also appear to be cutting at a larger diameter, can you reduce it?

Neil

As I mentioned in another thread this is one of the inserts I use on my Fly cutter. The insert is for turning aluminium on a lathe but works fine on the mill. I haven’t chipped one yet but I obviously don't take deep cuts. I have a larger insert for use on steel or just a plain HSS tool piece.

with a low speed of only 250 rpm and a cutting speed of 100 feet per min ,the max radius of cut using HSS tools is only about 3/4 of an inch, tool wear is due to using too high a cutting speed, If speed cannot be reduced then carbide is the answer, the older style carbide cutters with the carbide brazed to a steel shank produces quite good results,better than using screwed on inserts ,the brazed shank is more rigid.

That sounds reasonable in theory but in practice there seem to be an awful lot of folks out there using inserts in fly cutters to good effect so I think your “better results” comment may not stand up. I’ve had excellent results using inserts. These guys certainly seem to be getting a good enough finish as well:

**LINK**

Posted by Martin Connelly on 25/09/2020 11:00:34:

The temptation to go too fast is always there.

Martin C

On a couple of occasions I’ve done this on purpose and got a very nice surface texture with the right type of tool grind!

I made on based on the suburban linked above using tnmg inserts. Admittedly it's on the larger side for a hobby mill but I get a decent looking finish with it. Experemented a bit with the inserts and it seems the best finish I had with larger tip radius inserts.