What causes Built up edge on a reamer?

I have recently had my first troubles with Built Up Edge.
Is it lube failure?
Or a speed and feed issue?
What do you do about it when it rears its ugly head?
Is there a Troubleshooter process?
Thanks

 

Rub copper on the edge. I use an extremely old penny that actually contains copper

 

I cut up a piece of copper water pipe to clean the edges. Some reamers build up, some cutting oil doesn't do the best job. And try pulling the reamer more often. The cutting oil only stays in place for so long.

 

Thanks fella's.
But what causes it????

 

https://www.sandvik.coromant.com/en-gb/products/Pages/how-to-use-reamers.aspx

What causes BUE? The Sandvik library may not be that descriptive as to what actually causes BUE, but provides good troubleshooting advice. There is a whole library available from then and most other top name tooling manufacturers.

Now what causes it......"Vibration", usually from unstable conditions. Altering coolant concentrations, speeds, and feeds can help, solving the stability issues, as making those changes can alter the vibrations that occur during all metal cutting.

 

Thank you very much. The coramant info was quite helpful.

 

Pressure. The edge will roll in the same way the edge on a knife blade rolls.

 

Pressure, heat, friction causes material from the workpiece to stick to the cutting edge, it occurs on all cutting tools as the edge degrades, you can see it occur on this video

 

I'm pretty sure the buildup is just very fine swarf that cements itself to the edge of the reamer from the pressure and heat. I remove it with a machinists scale I keep in my pocket. I don't think it is rollover from the reamer cutting edge, or I'd have no shoulder cutting edge on any of my reamers by now.

I don't get it at all when I use flood coolant. The reamers come out crystal clean.

 

I used to get it when I chambered on a manual lathe with no flush system. The last 7,000 barrels were done on my Haas using a flush system with oil. Pretty much eliminated the problem. The few times it shows up I break it off with my finger nail and then stone the face of the flute using a hard knife edge stone to remove any residual material. I also don't run reamers as long as I used to.

 

Dave,

Damn, that is a pile of barrels. If I may, are you running a rigid setup when holding your reamers? Pm me if you would rather. Thanks Dave.

Paul

 

The largest contributing factor to BUE (built-up edge) on reamers and other cutters is speed. When speeds are too high, BUE forms, heat breaks down the hardness of the cutting edge, etc. When I'm teaching machining, I harp on RPM/speed being too high as being THE primary cause of cutting tool breakdown, especially with HSS tooling.

There are other contributing factors to BUE, especially if we talk about materials other than 4140 or 4xx stainless steels, but speed is the largest factor in barrel steel machining for BUE.

The rule I was taught by senior machinists about reamers (in general, not chamber reamers specifically) is "half the speed, twice the feed" - ie, put the reamer under load, but then halve the RPM from what you'd use for another cutting tool, such as a drill bit.

When I chamber, I'm typically turning at about 90 RPM, using high-sulphur lube and clearing chips every 0.050" to 0.100" of depth.

Rubbing copper on the reamer, and pennies: The year that we changed from actual copper in pennies to copper-flashed zinc was 1982, I think. If you find pennies from before 1982, you've got an actual copper penny. Hang on to them - they're typically worth more than a $0.01 in melt value now.

 

Great advice. I use a chunk of large copper wire i shaped into a screwdriver looking shape

 

I wear out a lot of reamers. A lot. I use Monroe Fluid Tech Astro-Swiss HD LV in a flush system. Good stuff
Depending on diameter I run reamers 250-350 RPM's. Very seldom do I get build up.