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Stepper power for autofeed on lathe

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SillyOldDuffer21/10/2019 12:59:30
4779 forum posts
1011 photos

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 Wyatt21/10/2019 14:04:17
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Moderator
16655 forum posts
687 photos
75 articles

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

Gray21/10/2019 15:55:26
1014 forum posts
8 photos
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

SillyOldDuffer21/10/2019 16:56:53
4779 forum posts
1011 photos
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 121/10/2019 19:24:50
915 forum posts
3 photos
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 Grant22/10/2019 19:07:40
56 forum posts
3 photos
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 smiley

Michael Gilligan22/10/2019 21:02:44
avatar
14125 forum posts
614 photos
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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