Physics of lathe

Energy vs work is always a fun adventure. Google is your friend. ;)

Tom
 
Other than the link which Vacuum posted before I did, I don't have any insight on this thread.
Regardless, I will be following the thread closely.

Daryl
MN
 
Funny you should bring this up. If you look at the history of thermodynamics, Count Rumford (Benjamin Thompson) originally developed the concept of the calorie while watching cannon barrels being bored during the Napoleonic wars. So this issue has been studied from the very beginning of the science.
 
There is a fair amount of data on this subject all over the place.

Look in areas of old where discussion of HSS tooling is involved send forming the tool shape.

Seem to recall much discussion on Relationships between angles and energy etc.
 
Interesting video. Watching the metal in the chip being swaged it is easy to appreciate why there is heat generated in the cutting action.
 
CluelessNewB said:
Slow Motion Youtube Video of Chip Formation.

Click to expand...
I would like very much to have a printed copy of this explanation. It is very interesting as I have had simular thoughts but to a lesser degree of sufistacation. Now it's time to reoil my framulator buchings!
 
Dave Paine said:
If you want to experience the energy of cutting material, clamp a piece of wood on a bench and use a hand plane starting with a very thin shaving, then increase the depth of the blade and keep making cuts.

Cutting wood does not generate a lot of heat but you will experience the energy to cut thicker shavings, especially if the wood is dense.
Click to expand...
Actually, it does generate heat, just not enough to be noticed.

For example, if you were planing an oak board, using 20 lbs of force and moving at a half a foot per second, power required would be 20lbs x .5 ft/sec or .018 hp or 13 watts. For a 1 ft. pass, this would be 26 watt-sec. or 26 j. Oak has a specific heat of about 2 j./g-ºC so we would expect a temperature rise of 13 ºC/g. A 1ft by 1/16" by 2" shaving has a volume of 1.5 of cu. in. or 25 cc. and, at a density of .7g/cc., a mass of 17g. This would be less than 1ºC temperature rise in the shaving. Also, at least part of the energy would go to increasing the temperature of the board.

I know from experience, the shavings coming off my power planer, my router, and my power hand planer are warm when they hit my skin, implying a minimum temperature rise of around 10ºC.
 
OK, I do understand some of this but please explain how 12L14 machines like cheese and 4140 is tough and I can't take anywhere the cut I do with `12L14. I know it's leaded but it's almost as strong and and it case hardens as well as anything. Then there is 1144 or Stressproof, no welding but the chips behave themselves. ???
 
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