Stepper power for autofeed on lathe

[Phil GrantParticipant @philgrant54580]

Do all the previous images show as I used the same dropbox link for them all!

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Phil Grant on 20/10/2019 09:59:21:

Do all the previous images show as I used the same dropbox link for them all!

.

No … nothing except the Youtube video

[JourneymanParticipant @journeyman]

Must be an iPad thing all the images show for me (Linux Mint, Firefox).

John

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Journeyman on 20/10/2019 10:07:50:

Must be an iPad thing all the images show for me (Linux Mint, Firefox).

John

.

Thanks, John

MichaelG.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Journeyman on 20/10/2019 10:07:50:

Must be an iPad thing all the images show for me (Linux Mint, Firefox).

John

Not working directly for me on Ubuntu/Firefox. However, I can see the pictures if I right click on the image space and select 'View Image'. (This loads an application to display the image outside the browser, ie independently of the web-site and browser combination.)

Edit: The brilliant theory that follows struck out below is WRONG!  I should have been able to display one of Phil's photos in this post, and it doesn't work…   Back to the Drawing Board in sack cloth and ashes!    

The only peculiarity I can see in Phil's Dropbox links is they all append a query string, query strings being a way of passing extra information to a server. I think it's telling Dropbox that the image is one of many, so that – if called by suitable software like an Image Viewer – Dropbox can download a series of images as from a slide-show magazine. As the forum/browser combo only expects a single image per link, my guess is the extra query parameters are illegal in that context. The Browser expects only one image, not the first of a list.

Assuming my theory is correct, it's not a forum problem. The forum just allows writers to insert links to remote images that are passed unchanged to the readers Browser. It's the writers job to get his external links right! Technically, the missing images are due the readers web Browser not coping with a query string copied innocently by Phil from Dropbox.

However, I think it's easy to fix. An example, with the unwanted query string in bold:

https://www.dropbox.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?dl=1

Removing the ? and everything after seems to create a working link:

https://www.dropbox.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg

Once Phil's posts are locked, links can only be changed by an administrator. Phil can tweak the links when first inserted and while the timed edit window is open.

Dave

 

Edited By SillyOldDuffer on 20/10/2019 11:37:15

[Michael GilliganParticipant @michaelgilligan61133]

Thanks for the extra info. Dave

As I’m sure you realise; it is difficult to ‘right click’ on an iPad …. and the ‘long press’ alternative doesn’t seem to work with Phil’s image frames.

If you could post his dropbox link as text, I can probably get there

… much appreciated

MichaelG.

[Tony Pratt 1Participant @tonypratt1]

I have just completed the first stage of an electronic lead screw build based wholly on the excellent You Tube channel run by Clough42.

All works as intended, fully capable running both metric & imperial feeds/threads on my metric lathe at the touch of a button, only problem is that the Nema24 stepper rated at 4 Nm is only giving 2.3 Nm so slightly underpowered, the supplier refunded the money & let me keep the motor.

Now going to trial for a while then tidy up the mechanical bits & box up the controls.

Tony

[Frances IoMParticipant @francesiom58905]

It would be much easier both now and especially for the future to use the admittedly clunky album feature of this site – Dropbox is a tracker (hence the ‘free’ nature – viewers pay via privacy) + also such ‘free’ sites tend to drop images after a time thus often wrecking the thread (see the mess made when one such site went commercial)

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Tony Pratt 1 on 20/10/2019 12:21:57:

I have just completed the first stage of an electronic lead screw build based wholly on the excellent You Tube channel run by Clough42.

All works as intended […]

.

Looking good, Tony

MichaelG.

[Brian OldfordParticipant @brianoldford70365]

Posted by Tony Pratt 1 on 20/10/2019 12:21:57:

. . . . . . the Nema24 stepper rated at 4 Nm is only giving 2.3 Nm so slightly underpowered, the supplier refunded the money & let me keep the motor.

.. . . . .

Tony

Could you increase the torque by gearing down the motor?

[Brian OldfordParticipant @brianoldford70365]

Posted by Phil Grant on 20/10/2019 09:58:34:

Another go for the images.

All the images are good for me now. PCB looks good. What is the power rating of the resistors you have used?

[Phil GrantParticipant @philgrant54580]

Posted by Frances IoM on 20/10/2019 12:31:33:
It would be much easier both now and especially for the future to use the admittedly clunky album feature of this site – Dropbox is a tracker (hence the 'free' nature – viewers pay via privacy) + also such 'free' sites tend to drop images after a time thus often wrecking the thread (see the mess made when one such site went commercial)

I will have a look at using the album feature.

Although it's the first time I've had issues with Dropbox links on forums

[Phil GrantParticipant @philgrant54580]

Posted by Brian Oldford on 20/10/2019 19:52:21:Posted by Phil Grant on 20/10/2019 09:58:34:

Another go for the images.

All the images are good for me now. PCB looks good. What is the power rating of the resistors you have used?

1/8W to get them small enough.

[Phil GrantParticipant @philgrant54580]

Created a new thread with pictures using the Forum Album method, hope you can now see the images.

[Michael GilliganParticipant @michaelgilligan61133]

Thanks a lot for that, Phil

Your Album images are fine … I am evidently unworthy to view your Dropbox

MichaelG.

[Tony Pratt 1Participant @tonypratt1]

Posted by Brian Oldford on 20/10/2019 19:50:18:

Posted by Tony Pratt 1 on 20/10/2019 12:21:57:

. . . . . . the Nema24 stepper rated at 4 Nm is only giving 2.3 Nm so slightly underpowered, the supplier refunded the money & let me keep the motor.

.. . . . .

Tony

Could you increase the torque by gearing down the motor?

Certainly could, but call me old fashioned if the motor is advertised at 4 Nm I would expect to get that value, I'm now going with a Nema 23 again rated at 4 Nm from 'CNC4U', hopefully it will deliver the quoted power!

Tony

[SillyOldDufferModerator @sillyoldduffer]

Bit of research into how Dropbox manages images has revealed all. Although Dropbox shared links look just like ordinary web image source URLs, they aren't! They actually activate a management layer inside Dropbox that presents the image, as I suggested earlier, as one of many. In consequence Dropbox links can't be embedded successfully in a webpage because Browsers expect a single raw image. To keep the Browser happy it's necessary to bypass Dropbox's management layer.

One solution suggests it can be done changing the query string from, for example,

https://www.dropbox.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?dl=1

to

https://www.dropbox.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?raw=1

Didn't work for me, perhaps because the method is historic. Instead it seems Dropbox now provide direct access to embeddable images by requesting them from a different server. Rather than:

https://www.dropbox.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?dl=1

try

https://dl.dropboxusercontent.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?dl=1

Fingers crossed, that does work. Not sure it's a good way of managing images though. I prefer the forums own Album system for the reasons given by Frances. Although a shade clunky and basic the album avoids many technical issues and is future proof in that it should last at least as long the Forum.

Dave

[Neil WyattModerator @neilwyatt]

Note, Dropbox free isn't intended for image hosting in this way. You could end up exceeding your bandwidth limit if a picture gets displayed a lot with the result your account gets throttled or limited.

Neil

[Gray62Participant @gray62]

Posted by Tony Pratt 1 on 20/10/2019 12:21:57:

All works as intended, fully capable running both metric & imperial feeds/threads on my metric lathe at the touch of a button, only problem is that the Nema24 stepper rated at 4 Nm is only giving 2.3 Nm so slightly underpowered, the supplier refunded the money & let me keep the motor.

Tony, how are you measuring the power of your steppers, I have some I would like to verify before I put them to work.

thanks

Gray

[SillyOldDufferModerator @sillyoldduffer]

Posted by Neil Wyatt on 21/10/2019 14:04:17:

Note, Dropbox free isn't intended for image hosting in this way. You could end up exceeding your bandwidth limit if a picture gets displayed a lot with the result your account gets throttled or limited.

Neil

Good point!

I believe the bandwidth limit on a Free Dropbox account is 10Gb/day. The photo I used as an example is 1.3Mb, so about 8000 downloads of that would do the mischief. (8000 downloads isn't much in web terms.)

Phil needn't panic though : since he started his thread, it's averaged about 260 views per day, quite respectable but not Top of the Pops. Putting the same Dropbox pictures on a busy thread like 'What did you do today' would be more risky, though I think all Dropbox does is send 404 Errors until next day's ration becomes available.

Dave

[Tony Pratt 1Participant @tonypratt1]

Posted by Gray on 21/10/2019 15:55:26:

Posted by Tony Pratt 1 on 20/10/2019 12:21:57:

All works as intended, fully capable running both metric & imperial feeds/threads on my metric lathe at the touch of a button, only problem is that the Nema24 stepper rated at 4 Nm is only giving 2.3 Nm so slightly underpowered, the supplier refunded the money & let me keep the motor.

Tony, how are you measuring the power of your steppers, I have some I would like to verify before I put them to work.

thanks

Gray

I connected a 12" bar/beam to the motor & energised it so the holding torque could be measured. 4 Nm = 2.95 foot lbs so in my estimation I should have been able to load my 12" beam with 2.95 lbs before the motor let go?

There are various You Tube videos showing how to do it but I think the methodology is correct, any 'experts' are welcome to comment, also be aware how the motor is wired will affect the power.

Tony

[Phil GrantParticipant @philgrant54580]

Posted by SillyOldDuffer on 21/10/2019 12:59:30:

Bit of research into how Dropbox manages images has revealed all. Although Dropbox shared links look just like ordinary web image source URLs, they aren't! They actually activate a management layer inside Dropbox that presents the image, as I suggested earlier, as one of many. In consequence Dropbox links can't be embedded successfully in a webpage because Browsers expect a single raw image. To keep the Browser happy it's necessary to bypass Dropbox's management layer.

One solution suggests it can be done changing the query string from, for example,

https://www.dropbox.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?dl=1

to

https://www.dropbox.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?raw=1

Didn't work for me, perhaps because the method is historic. Instead it seems Dropbox now provide direct access to embeddable images by requesting them from a different server. Rather than:

https://www.dropbox.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?dl=1

try

https://dl.dropboxusercontent.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?dl=1

Fingers crossed, that does work. Not sure it's a good way of managing images though. I prefer the forums own Album system for the reasons given by Frances. Although a shade clunky and basic the album avoids many technical issues and is future proof in that it should last at least as long the Forum.

Dave

Thanks for that Dave, you learn something every day

[Michael GilliganParticipant @michaelgilligan61133]

Posted by SillyOldDuffer on 21/10/2019 12:59:30:

[…]

https://dl.dropboxusercontent.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?dl=1

[…]

Fingers crossed, that does work. Not sure it's a good way of managing images though.

.

Just to confirm, Dave …

Yes, that works fine on the iPad

MichaelG.

Edited By Michael Gilligan on 22/10/2019 21:07:06

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