Control Center for Lathe

[Jonesy]

I've got a VFD to run the motor on my lathe and it's got a display that can be configured to show either freq in hz, motor rpm, or another rpm based on the motor rpm and a multiplier / divider, so that can be the rpm of the lathe.

I thought that sounded ok but my son has decided I need more than this as I'm getting older and not the sharpest tool in the box!!

Actually, it was me that asked my son for his input as I would like the machine rpm displayed, but there is a 3 step pulley and back gears. That's 6 ratios and the inverter does not cater for this.

What he's come up with is a little more than that.

The finished article will be a control panel and display on the housing in which the inverter will live, with a rotary control to adjust the speed, a button panel to select the ratio, and another rotary control to dial in the diameter of the work. The display will show the selected gear and ratio option, the resultant machine rpm, the work diameter and the surface speed.

I know this is all not really needed but he enjoys projects like this and who am I to say no?

[Doozer]

I know tachometers can be purchased
with a magnetic pickup that can directly
read spindle RPM. Maybe this would
simplify things.

-D

[oxford]

I know this is all not really needed but he enjoys projects like this and who am I to say no?

Good for him if he enjoys the projects. It sounds like all of the display output will have to rely on some kind of user input. I don’t see how the display is going to know what pulley step you are on without you putting that input in.

Im with Doozer, out a direct reading tach on the spindle with a readout display.

[Jonesy]

Yeah I suggested a tacho but he over-ruled me.

User input is pressing a button or scrolling to select the gear / pulley ratio (not sure which it'll be), and then turning a dial (which will probably be an encoder) to dial in the diameter.

Oh, and pressing the start button and adjusting the speed.

All this is just so cheap to do nowadays. Way over my head but he enjoys these projects.

Had to get him to do all the inverter VFD setting up last weekend. I stopped after the first page of the instructions. I think it's a combination of the grey matter eroding and eyesight going south. Just can't seem to absorb information like I used to. Even with glasses, although I can focus my eyes I cannot focus my mind when trying to scan over instructions to find the relevent sections and bypass the drivel. End up just staring out of the window.

My inverter manual has hundreds of pages. It amazes me that I used to understand this stuff. I used to teach electronics at college FFS! Seems so long ago.

[oxford]

Yeah I suggested a tacho but he over-ruled me.

User input is pressing a button or scrolling to select the gear / pulley ratio (not sure which it'll be), and then turning a dial (which will probably be an encoder) to dial in the diameter.

Oh, and pressing the start button and adjusting the speed.

Just seems like a solution looking for a problem. If it works for you, that’s all that matters.

[MaxHeadRoom]

What is the make/model of the VFD?

[David Powell]

Encourage the Lad, buy him his own outfit, get him into our hobby ! Regards David Powell

[CalM]

I've got several machines powered on VFDs. 2 Lathes, 2 Grinders, A vertical band saw, and a pair of press drills.

I like to display HERTZ! that way I can better judge how happy the motor is ;-)

Actual spindle rpm is never critical, the cut will demonstrate that. I pick a suitable spindle "speed" based on gear ratio etc, then fine tune rpms with the VFD.

Both lathes are entirely operated via the apron controls and a 10k pot Well worth the effort to wire into the machine controls, and not have "another thing to pay attention to".

[Doozer]

Why do you care about SFM on a manual lathe ?????
I don't.
Not even on any of my manual machines.
If you can't tell by what the chips look like,
you better take your tools and go home.

-D

[Fasttrack]

Jeez - tough crowd.

I think it sounds great. Is it necessary? Well my wife would argue that a lathe isn't necessary, to say nothing of lathe accessories. So it's all a matter of perspective. It sounds like your son wants to do something nice for his old man and he wants a bit of a challenge. Good for him! And good for you. I'm excited to see the finished article.

[Jonesy]

Some funny replies... thanks! Much appreciated.

I worry about letting my son loose on my tools. If he gets hurt my wife will kill me.

He's a bit of a clever-clogs having previously built 2 3D printers from scratch (and scraps) and a CNC, and all the control systems amongst other things. He really enjoys these sort of projects. This particular one is a fill-in.

It may well be a solution looking for a problem, but it's a fun one for us.

Not for you? Never mind.... you'll get over it.

Oh... and the vfd is a Nordac 500.

Why do you care about SFM on a manual lathe ????? I don't.

If you can't tell by what the chips look like, you better take your tools and go home.

-D

Why do you care about SFM on a manual lathe ????? I don't. Good for you.

If you can't tell by what the chips look like, you better take your tools and go home. I am home.

[Doozer]

Dude, it is my sarcastic humor.
Really.

-D

[Jonesy]

Dude, it is my sarcastic humor.
Really.

-D

Right back at ya, dude.

[The Metal Butcher]

Some funny replies... thanks! Much appreciated.

I worry about letting my son loose on my tools. If he gets hurt my wife will kill me.

He's a bit of a clever-clogs having previously built 2 3D printers from scratch (and scraps) and a CNC, and all the control systems amongst other things. He really enjoys these sort of projects. This particular one is a fill-in.

Sounds like your son is either a child prodigy or too old to have his folks bossing him around, eh? Kids who build CNCs from scratch are probably smart enough not stick his limbs where they don't belong...? Plenty of dumb kids running these things during the industrial revolution. They lived. Mostly.

[Bob Engelhardt]

There's a similarity to the one that I made:


Inputs for FPM, stock diameter, and all the pulley settings. A (long) PDF write here:
https://drive.google.com/file/d/1RVR...ew?usp=sharing

He might get an idea or 2 from mine, function wise, even if he uses Arduino or somesuch.