Heavy Facing Pass on Lathe

I was roughing out a shaft for a reduction gearbox when I realized that it was an inch longer than necessary after I had got it in the chuck and dialed in. Fortunately the lathe is heavy and powerful and I was able to remove the extra material in 4 passes. This video shows one of the passes. The material was 4140 HTSR (hardness about Rc 32), just over 8" diameter. The RPM was 355 and the feed rate was .021"/rev giving an initial metal removal rate of 46 cubic inches per minute. I apologize for the shaky camera. My camera stand wasn't available and I had to hold it by hand. The shower of hot swarf had me dancing around a bit at the beginning.

[vikassm]

One thing I've noticed back when I operated machine shop, older pulley driven lathes seemed to have more 'freewheeling' or flywheel action compared to the gear driven ones, with identical 18" faceplates. Everything was powered by identical 3hp motors too.
Probably because the pulleys were quite large and heavy in order to handle moderate amounts of power, resulting in quite a bit of inertia.
Looking inside the gearbox of circa 1945 lathes, Gears were comparatively tiny, adding little if anything to the flywheel effect. Of course, those geared machines simply ran for years and years requiring a simple oil change once in a while whereas the Pulley driven machines required quite a bit more maintenance. Tension adjustment, cleaning dust off the pulleys, belt change, sanding the pulleys once in a while to restore friction and so on. But, fly-cutting and trepanning on the older Pulley driven lathes was a joy to watch. Amazing surface finish as long as the tool was sharp at half decent speeds and feeds. Weight and inertia did the rest.

[johnkelly]

Came over from Swan Valley Machine Shop's recommendation... Your presentation style is easy to listen to. Subbed here.

[cstewart]

You get you a face gaurd and you gonna be alright, i know how hot these chips be

[captcarlos]

Nice blue chips.
There's a certain pucker value on initial contact when the motor 'acknowledges' the cut.
She sure knew she was a work in' on that facing cut!
And that the mass of that chuck helped maintain the revs initially!!

[Iceking]

WOW! Just plowing through the chips. Great info.
Thank you.

[chrisstephens]

That is the difference between amateurs and professionals, an amateur saves material by spending time and a pro saves time by spending material. I would have used a bandsaw to save all that lovely material, no matter how long it took.😉

[theessexhunter]

In all the years I have been machining I never look at the feed rate dial just the carriage movement speed....Yep that is too fast or slow. Guess it comes from manual milling also the drilling from a tail stock feed is by hand so you get a good feel for the feed rate.

[MiSt_PL]

One word - WOW :O DCLNR does the job :-D

[stevechambers]

Scary. that’s a good lathe what make is it ?👍👍👍👍👍

[outsidescrewball]

Yikes...what a shower of material, as I watched I wondered where you were standing if necessary to disengage ....

[userwl]

At 1.10 sounds like a chip got you Ken... hopefully not on your neck 😲... that's the second worst place after in your ear 😓 I see you using a CNMG insert I've seen bad things happen with them pulling into the job either facing or turning. My last choice of tool.