Smartphone app for beginner

[WCraig]

Hi:

I found a couple of old threads on this subject but nothing since 2015. Since apps come and go fairly often, I'd like to ask what people are using now. I've only got a lathe at this point. I'd prefer something that makes it simple to select an appropriate rpm given the material (brass, aluminum, mild steel, ...) and a diameter. Well, also between carbide and HSS, I suppose.

I'm on iOS but I expect most such apps are on both major platforms now.

Craig

 

[SamI]

This one seems to work pretty good

On a more serious note though, on a manual lathe I prefer to go by feel instead of looking anything up. I take an educated guess, take a cut then adjust accordingly based on chips, surface finish, what mood I'm in etc. After a few cuts I’ll take a look at the tool tip and see if there’s any wear or built up edge and adjust accordingly.

You'll probably find that if you use carbide tooling then on smaller diameter work the speeds will be faster than your lathe can go.

 

[WCraig]

"take an educated guess" ... but that's the thing, I'm a complete noobie. I'd like something that gives me some guidance while I gain experience. I don't have a mentor. My phone is always in my pocket. I'm hoping it can help.

Regarding carbide, I've read multiple times that it "needs" much higher surface speeds than HSS. What goes wrong at slower speeds?

My understanding is that "optimum" cutting speed is basically about factory floor efficiency. IOW, run as fast as possible while leaving a good surface finish and not ruining the tool too quickly. It is not a big deal to me if something that could be done in 5 minutes takes me 10 minutes. Or even 20 minutes.

Take facing cuts on the lathe. As the tool moves to the centre of the work, the cutting speed drops. To zero, at the very centre. Regardless of HSS or carbide. Doesn't that mean that carbide is just fine cutting at slower speeds?

Trying to understand...

Craig

 

[Cadillac]

Carbide usually doesn’t have a razors edge let say. You need more infeed pressure than a hss tool. Coating on carbide add another layer over the edge making it not as sharp also. Carbide works good it’s just more temperamental with speeds and feed. Reason hss is good for a hobbiest is you can buy tool blanks and grind any shape you need and can cut about 90% that’s out there.

 

[rwm]

I just do it in my head. SPFM is 1/4 of the RPM x diameter in inches. I do have a little chart posted with recommended SPFM for various material.
If you are trying to figure the RPM just take SPFM x 4 and divide by diameter.
I hate pulling out my shiny Pixel when my hands are covered in cutting oil! Stop texting me!

Robert

EDIT:
I just had an awesome thought...If you had Alexa in your shop, could you verbally ask her for speeds and feeds? I don't have her but maybe someone will let us know! That will clearly be the future- a shop assistant that you can talk to.

Robert

 

[RJSakowski]

Just great! I already have a back seat driver that I can talk to. Now I need/want one for my shop?

 

[RJSakowski]

Seriously though, I have two Android apps on my smart phone.

One called "Lathe Calculator" by Dark Zero which will calculate x axis equivalent for compound movement at various angles, knurling diameter, spindle speed vs. surface feed, and thread depth for metric and UN threads. The second is "FS Wizard" for the mill which inputs all kinds of parameters and gives rpm, width of cut and depth of cut.

Truthfully, I don't use either.

 

[homebrewed]

I don't have a DRO setup, so my most-often-used "app" is an old HP11 calculator. My lathe dials indicate actual movement so I do a lot of divide-by-2-ing when shooting for a specific diameter. Any old 4-banger calculator would suffice but the HP11 isn't used for much of anything else these days. So the first response to the OP actually is pretty reasonable, even if it was offered in jest .

 

[francist]

I built my own "app" using an Apple Numbers spreadsheet. Not quite as foolproof as a real bona-fide app, but it does work nicely enough. I also incorporated a belt shift diagram to output the proper pulley sheaves to use for the displayed RPM/SFM. Naturally this is machine specific, in my case the Atlas 618. The user has the choice of Material, Tooling (HSS or Carbide), and Work Diameter.

In retrospect I find these types of things are useful at the beginning, but as others have pointed out I now just go by feel most of the time. Maybe that's lazy or maybe I'm just not demanding enough of the finished product, but that's how it's worked out. I still have my "app" if I want to check a material I haven't used before, but again, after a while you get kind of used to that too. It was useful at the beginning though to get the feel of the machine and find some baselines.

-frank

 

[WCraig]

I built my own "app" using an Apple Numbers spreadsheet. Not quite as foolproof as a real bona-fide app, but it does work nicely enough. I also incorporated a belt shift diagram to output the proper pulley sheaves to use for the displayed RPM/SFM. Naturally this is machine specific, in my case the Atlas 618. The user has the choice of Material, Tooling (HSS or Carbide), and Work Diameter.

In retrospect I find these types of things are useful at the beginning, but as others have pointed out I now just go by feel most of the time. Maybe that's lazy or maybe I'm just not demanding enough of the finished product, but that's how it's worked out. I still have my "app" if I want to check a material I haven't used before, but again, after a while you get kind of used to that too. It was useful at the beginning though to get the feel of the machine and find some baselines.

-frank

View attachment 278389

Hey! I'm just beginning. I have a 618. And Numbers. Could you send me a copy? ctreleaven at cogeco.ca.

Thanks in advance,

Craig