Flycutters: help to understand 3 different types

Well I was assuming Ron would be machining it in the supplied annealed condition which it is usually sold in.

Hello Again,

Yeeha ! I got a reflection in Aluminium ! Chuffed !!!

Rong Fu 30 Round Column Mill 2HP Motor

Aluminium Block Unknown type of Aluminium, Plenty of WD40 whilst cutting.

400 rpm approx 2.5"diameter cut 8 seconds per 2.5mm so = 80 seconds/inch = 0.75" per minute approx 0.001" doc - thats extremely slow feeds/speeds comparted to Jason's . WIll do some variations to better understand things.

Shortened the stickout to approx 0.5" (and yes I was getting chatter on the long stickout and shorter radius curve on tool - some interesting patterns & could hear it squeal). Need to do something about those 2 nuts before shortening stickout further.

Re-ground the tool to a much flatter curve as suggested by Jason.

Wasn't able to get as nice a finish on black bar - although it looks horribly corrugated it is actually quite smooth to the touch - cannot feel the corrugations with fingertips - do the corrugations indicate I am feeding too quickly ? Haven't quite got a reflection on the black bar.

Nevertheless, this is the best finish I have ever achieved on my mill with both black bar and aluminium. Think I just need to play around a bit and better understand speeds feeds and grinds.

Will try the "conventional" flycutter next.

Many thanks for all of the help/tips/photos in this thread.

Hey Ron Laden,

I cannot figure out which part of your cutter contacts the work and cuts it, your bottom edge looks almost horizontal to me.

Thanks Again,

Bill

I thought the same on looking at the pic. I'd want to back off the bottom edge to give it a bit of trail clearance angle and prevent the trapping of bits of swarf against previously-cut surface. But then the flycutters I use in the lathe are very much less rigid.

When fitted to an ARC flycutter body their toolbits give about 5deg clearance. And that is what I used for that photo posted yesterday.

It does look like that in the previous picture but the picture below shows the angle with the tip touching the surface of the work piece. It is shallow and this is the standard ARC tool (unmodified) fitted to the seat which I put in at 20 degrees. I could mod the cutter or it would be simple to add another 5 degrees to the seat but I,m not inclined too as it flycuts just fine, I had no issues with swarf.

Ah, yes, thanks - that's what I'd do. I smooth the point rad with a medium India oilstone and usually get a shiny finish, like on the fishes in my album or the valve face here:-

**LINK**

I had a go at cutting the silver steel with the HSS bit, it cut it ok and didnt struggle but I didnt manage a decent finish, it was not that bad but not as I would want. I tried various speeds and feeds and was only taking light cuts but I gave up and changed over to a carbide tip, wound the speed up and it transformed it as you would expect.