Fact or Fiction Lathe 101

[pepi]

As the new machine quest gathers speed, new questions arise. Figured I would start a central thread where such questions can be ask and us boots learn....


To turn aluminum and obtain a good finish 1500 + rpm is suggested ?

Using carbide tooling again 1500 + rpm suggested ?

Belt driven lathes produce a smoother finish .....?..... as green as I, think that is suspect.



greg

[schor]

when turning you are more interested in surface feet per minute speeds for a particular material and the diameter which you then use to calculate the rpm required

Tom did a good video on that.

[Dr Stan]

Cutting speed, AKA Surface Feet Per Minute, is calculated based on the size of the material/milling cutter and the type of cutter (carbide, etc). Coolant also plays a factor.

SFPM= (Pi X Dia X Rpm) /12 It also depends on the depth/type of cut and the rigidity of the machine/set up.

Download the Machinery Repairman 3 & 2 http://eric.ed.gov/?id=ED203130 and conduct a search in the document for "cutting speed". Page 218 will explain the use of cutting speeds on a lathe. Other pages will help one calculate the appropriate cutting speed for mills, etc. One of these days (you know how that goes) I'll set up a spread sheet to automate the process.

[TomG]

Fiction, fiction, as covered above, fact.

Belt drive lathes do produce a better surface finish because a belt dampens the inherent noise that gears produce. It comes at a price though, belt drive lathes can't generate the torque that a geared head lathe can.

Tom

[Dr Stan]

(10-15-2016, 02:08 PM)TomG Wrote: Fiction, fiction, as covered above, fact.

Belt drive lathes do produce a better surface finish because a belt dampens the inherent noise that gears produce. It comes at a price though, belt drive lathes can't generate the torque that a geared head lathe can.

Tom

As my favorite handy man always said "more power" Tim The Toolman Taylor

[Vinny]

(10-15-2016, 11:27 PM)Dr Stan Wrote: As my favorite handy man always said "more power" Tim The Toolman Taylor

LOL

[TomG]

[the penguin]

Greg,

per our phone conversation last night, I would suggest that for your first carbide tool, that you get a SCLCR-08-3 tool, that uses the CCMT 32.5x series of inserts. There are also boring bars that use the same series of inserts. Little Machine shop, sell the tool and the inserts, Shars, HHIP, Grizzly, CTC (out of Hong Kong, but very good service, EBay (ISI Direct) and many others sell the tools and the inserts.

I believe this is a good basic tool, that will get you started on the path of using carbide on your new lathe.

[pepi]

Excellent advise and will be using it ...... thanks Jack

Steve S, damn good link bookmarked it for more reviews. That 9 minutes was worth two hours of reading .......easily

And Tom ... the clip had volumes of good usable facts that were clear and easily understood.

Thank for the time that went into it...


Stan, took a gander at the .gov link I am sure there is some good reading in there. The 9 minute clip answered questions I had not even thought of. With the tooling suggestions made by Jack and Tom's clip. I feel that I have a real good base, for method and direction.


Thumbs up y'all !
greg

[Hopefuldave]

(10-15-2016, 02:08 PM)TomG Wrote: Fiction, fiction, as covered above, fact.

Belt drive lathes do produce a better surface finish because a belt dampens the inherent noise that gears produce. It comes at a price though, belt drive lathes can't generate the torque that a geared head lathe can.

Tom

Although, some run multiple belts (mine runs 5...) and even those run on a pulley separate from the spindle, on its own bearings... Add an 8:1 backgear (helical, to reduce noise, vibration and "gear marks") and it has all the torque I'll ever need :)

The step from single-phase to 3-phase motors makes a big difference in surface finish too, a bit like the smoothness of a 6-cylinder Vs. a Hardly-Rideable V-twin!

Dave H. (the other one)