Russian machinists.

[A.K. Boomer]

He said .01mm (dia. reduction).
In his previous videos the reduction was .01-.055mm (more reduction was in stainless steel)

His goal is to increase surface hardness. In one of the older videos he demonstrated surface hardness increase from about 25% (for harder steel) to about 100-250% for softer steels. Stainless steel gained the most.

This is what I thought the main reason for doing it would be - you can get great surface finishes with just machining the part with a nice sharp radius tool,

but the ball/roller method gives similar results to if the part was shot peened - with of course the lack of rough finish,,, it increases the surface hardening and also the skin density of the part itself, great for increasing durability...

[plunger]

This is another Russian machinist and Im fascinated how he drills at 40 seconds in the video. He doesn't even seem to bother with a pilot hole or center drill. I cannot believe how easy he makes it. I tried this with a 32mm drill in a predrilled hole the other day and my drill started spinning in my tailstock to my horror.

[MikeWI]

Couldn't you rig something like a scissors knurler is made to reduce the forces on the lathe?

[dian]

hm, i do it with the edge. so not even sure area is smaller.

[MattiJ]

i burnish to size often. i do it with the bearing race. i dont see any advantage in using the ball.

and yes, for 0.15 mm infeed you need a stout lathe.

I have used also bearing race.
Ball might be better in a way that contact area is smaller and it probably needs less force. Also no need to worry about bearing "shoulder" digging grooves to workpiece. (happen to me once before I rounded/polished the shoulder slightly with bit of abrasive paper)

[dian]

i burnish to size often. i do it with the bearing race. i dont see any advantage in using the ball.

and yes, for 0.15 mm infeed you need a stout lathe.

[macona]

Writing in the 1930s, the late Fred. H. Colvin reported that roller finished cylindrical surfaces had a high grade finish, but the process produced a wavy, out of round finish with micro cracks in the surface when examined under a microscope.
So, what is the difference between roller burnishing as practiced in the 1930s, and roller burnishing 21st century style?

Better steels maybe? Or he just does not know what is happening on the microscopic level.

[CCWKen]

You won't do that on a flimsy lathe. It's just like trying to make Knurls with a push tool. I followed that guy for a long time. Way back when he was on an old lathe in a dark corner of that factory. After he started making YT money, he started making toys and built or bought a new apartment. I kind of "forgot" to go back and look after that period. Just like another machinist we know. The videos just became play-time.

[JRouche]

Stainless steel gained the most.

Pretty much why SS gauls so well.JR

[Richard P Wilson]

Writing in the 1930s, the late Fred. H. Colvin reported that roller finished cylindrical surfaces had a high grade finish, but the process produced a wavy, out of round finish with micro cracks in the surface when examined under a microscope.
So, what is the difference between roller burnishing as practiced in the 1930s, and roller burnishing 21st century style?

[plunger]

He said .01mm (dia. reduction).
In his previous videos the reduction was .01-.055mm (more reduction was in stainless steel)

His goal is to increase surface hardness. In one of the older videos he demonstrated surface hardness increase from about 25% (for harder steel) to about 100-250% for softer steels. Stainless steel gained the most.

How do you know what he said. I cant hold tolerances of .01mm so its not going to be of any help to me.

[MichaelP]

Can someone tell what he is saying at around 4:25 about size reduction?

He said .01mm (dia. reduction).
In his previous videos the reduction was .01-.055mm (more reduction was in stainless steel)

His goal is to increase surface hardness. In one of the older videos he demonstrated surface hardness increase from about 25% (for harder steel) to about 100-250% for softer steels. Stainless steel gained the most.

[JRouche]

Dont we have a new partner here from that neck of the woods?

I hope we are not really serious about someone elses machining ability? Cause I would have to break out a photo of my last job. Horrific at best. JR

[JRouche]

I've learned that Russian machinists is usually a bad idea, just like rushing your proctologist is a bad idea. After all, when they're Finnish, they're Finnish.

Hey! I see what you did there. Cause after all without the Russians Finland woulda been Germanland (for a second). JR

[redlee]

https://cogsdill.com/products/burnishing-tools/

We used burnishing tools at work for valve stems, packing bores, bearing sizes and anywhere a super finish was required.