Need some help from the auto-rotating monitor experts...

[Le Chuck]

So here's a question, how do I get the shaft through the bearing?  Or better yet, how do I get the bearing on the shaft?  I've got a 3/4" OD Keyed shaft and a 3/4" Bore Pillow block bearing.  I can kind of get the edge of the shaft into it and if I push it goes in but not very far.  All jokes aside does anyone have any good ways of how to insert the shaft say a foot or two into the bearings?

Should go easily. Is your collar fully loosened?

[kahlid74]

The collar is fully loosened.  I got the 3/4" bore 6" diameter pulley on it just fine but the pillow lock bearings are just kind of being a pain in the butt.  I'm also not really pushing it all that far down it because I don't want to put it fully on until I have a test base assembled.  So yeah, still not really going on.

[DNA Dan]

It only takes 1/64th or less of an inch to make this an issue. I would take some superfine steel wool and work the rod lenghtwise. Wipe it down with mineral spirits and give it another go. If that doesn't work, use some super fine 4000 grit sandpaper and wetsand the rod lengthwise. Again, wipe with mineral spirits and try again.

Another possibility is the rod is slightly bowed at the point where it gets stuck. Not much you can do but shrink and smooth out the sides.

You could also try freezing the rod and taking a blowtorch to the bearing.

Whatever you do, make sure there isn't any shavings or dust from the rod when you try to press it in. Although small, they will build up and make matters worse with such a tight fit.

[Le Chuck]

The collar is fully loosened.  I got the 3/4" bore 6" diameter pulley on it just fine but the pillow lock bearings are just kind of being a pain in the butt.  I'm also not really pushing it all that far down it because I don't want to put it fully on until I have a test base assembled.  So yeah, still not really going on.

That sucks then.  I had to ask, I can't tell you how many times for me it's been something simple like that.  +1 to a light sanding and lube. 

[DNA Dan]

Where did you get the shaft from? Where did you get the pillow block from?

Might be a good idea to take some calipers to the ID and OD to see which one is off, then send the company an email.

[TopJimmyCooks]

What these guys are saying makes sense - something very common with rod stock is that its deformed where sheared/cut or possibly banged/dropped at the ends.  I would make sure you've got a slight bevel at the ends or use a straightedge to see if you have any bend or deformity.  you can get a good enough dial caliper at a hardware store to tell you whether one or the other diameter is wrong.  Get a $20 metal one rather than a $10 plastic one. 

good suggestions all.  make sure you know what's up before you do what i did one time:  laid the bearing over a hole in my drill press table, tapped in a recalcitrant bar with my BFH and surprise, didn't spin worth a crap.  That was a $2 bearing though, I think you've got something worth a little more $ to worry about. 

[kahlid74]

Thanks for all the suggestions guys!  The rod and bearings were from different places so it's entirely possible one is on and one is off.   I'll see what I can do.  Had the afternoon off so came home early and just finished the base.  I'm thinking it will hold a 30Lbs 42" TV just fine but we'll see once we mount it.

[darthpaul]

Do you think 6 seconds is too long for a rotation switch? The pololu linear actuators are nice because they have built in potentiometers for feedback if used with the JRK modules. Plus they're ~30% off right now.

I don't think this is a negative, I think seeing a monitor rotate is cool and should be played up. DaOld Mans MRotate has the ability to play a sound, when my monitor rotates, I'm playing the the Star Destroyer alarm sound.

[darthpaul]

I'm telling you, that robot marketplace has some really good products for the mechanicals. Check out the sprocket section. Lots of custom sizes. (I am in no way affiliated with them, just stoked I found them!)

For future reference for anyone, this is where I picked up my gears for my rotating control panels.https://sdp-si.com/eStore/

[kahlid74]

So I wound up building a prototype this last week/weekend.  My friend came over and we mounted the 42" LED TV to it.  It spun like a dream and the weight held fine on two pillow block bearings with 3/4" Keyed shaft.  We then tested the pulley's and like everyone said, at about 90% the pulleys started to slip, which is what my friend said they would do.  I kind of figured they would but I like trying stuff too.

So he was thinking timing belts, I was thinking gears.  The challenge is the weight of the TV pulls the rod just enough where the gears would lose contact, but it's enough to "autotension" a timing belt.  So the next challenge is finding pulley's that are built for timing belts and have an 8mm bore and a 3/4" bore.

I took a bunch of pictures so I'll start a new thread in the Project announcement area and post it all there so we stop clogging up Nitz original thread with my antics.

My big challenge now is this cab or my Battletech VR 3.0 pod.  Fudge, I just don't have enough time.

[nitz]

And back to the original thread topic again.

I've got another question: how do I connect the limit switches? I think I know how to do it, but there are some pins on the motor controller where I'm supposed to wire it to...do I need some kind of connector here? I hope not 'cause I was all psyched to work on this today and it would suck to get delayed while I wait for that to show up in the mail.

Please advise...and remember to really spell it out for me.

[darthpaul]

I know this was probably the wrong thing to do but I just soldered the wires to the pins but if you are using DaOld Man's Mrotate plug-in, the limit switches get connected to the printer port's parallel cable.

[TopJimmyCooks]

Pololu board needs .10" molex connectors.  or you can bend the pins and solder to them. 

[nitz]

Thanks for the quick and helpful responses.

I'll likely go the molex connector route since I may be able to harvest some from an old power supply, plus I haven't soldered in forever and don't own a soldering iron.

[DNA Dan]

See my reply #29 "For the limit switches, I actually bought connectors from pololu for this so I could plug into the board easily. Check out --> http://www.pololu.com/catalog/product/1901 they even make the wires precrimped if you don't want to spend the extra time making your own http://www.pololu.com/catalog/category/72  If you have to solder any joints, just make sure they are well taped, shrink wrapped, etc. You can also install a connector in there, but I typically prefer to have a solid wire with only connections on the ends. "

I don't know what molex connection you're thinking of on a power supply, but these are super tiny connections; .10"

[nitz]

Thanks, this thread has gotten so long I guess I forgot about that post.

I actually did find a couple of the tiny molex connections on an old power supply and tried them out with some cherry switches. Worked great! It's not the prettiest or tidiest solution, but meh, when everything's inside the cab no one will see it anyway so I'm just gonna go with it.

Now to slap together some wood, lazy susan bearing, and my monitor...

[kahlid74]

Thanks, this thread has gotten so long I guess I forgot about that post.

I actually did find a couple of the tiny molex connections on an old power supply and tried them out with some cherry switches. Worked great! It's not the prettiest or tidiest solution, but meh, when everything's inside the cab no one will see it anyway so I'm just gonna go with it.

Now to slap together some wood, lazy susan bearing, and my monitor...

The cherry switches are an ingenious way to incorporate limit switches.  Very cool.

[darthpaul]

Just another option from DaOld Man

[kahlid74]

Just another option from DaOld Man

That arm assembly looks super elaborate.  Is that cheaper than a Rod/Bearings/Stepper motor process?

[DNA Dan]

Well since the linear actuator has already been done, I guess I won't be going that route. It does look complex.

[Le Chuck]

Well since the linear actuator has already been done, I guess I won't be going that route. It does look complex.

Not to be outdone DNA Dan's next rotation build uses a Star Wars Science Force Trainer hack to enable brainwave acutation of an electro-magnet zero friction hover mounted CRT monitor.  A nice side effect is his ability to... these are not the droids we're for... move along. 

[kahlid74]

Well since the linear actuator has already been done, I guess I won't be going that route. It does look complex.

Not to be outdone DNA Dan's next rotation build uses a Star Wars Science Force Trainer hack to enable brainwave actuation of an electro-magnet zero friction hover mounted CRT monitor.  A nice side effect is his ability to... these are not the droids we're for... move along. 

Don't forget that he will also incorporate a Neuro-Helmet into the mix so that his emotions can drive the rate of rotation.

[DaOld Man]

Well since the linear actuator has already been done, I guess I won't be going that route. It does look complex.

I really dont see where it is complex. (Or at least what I have done).
My rig is about as simple as you can get.
It has two pine 2X4's with a hole bored in the center of each. In the holes it has 3 brass bushings for bearings, and for a shaft it has a 3/8" round stock (bar). Add two more 2X4 blocks to properly space the other two 2x4s.
The only thing that might be complicated is the welding.
The lever arm (crank) I used was thrown together in about 10 minutes using discarded parts at work. (I had to weld it at work, since I dont have a welder. I didnt even take my time and weld it right, plus Im not a good welder.). I just used an old wrench that went to a worn out power tool (similar to a router collet wrench), and welded it to a nut. I then bored a hole through the nut and the shaft so a locking bolt could pass through both.
I did it quick and dirty because this is only a test. The test did work, so now Im in the market for a factory made crank, not sure what it will be yet, I may have to make another one out of key stock material.
The other perhaps complex part is the plate that attaches the monitor to the shaft. I had to weld it to the shaft
too.
This 2X4 rig was originally for a stepper, and I tried two different kinds, which explains all the strange cutouts in the 2X4's. (The steppers I tried did not work).
I may have to build another rig to document step by step how to do it.
The actuator I used is pretty simple too. Electrically, its just a DC motor. No special pulse drive needed.
The limit switch set up on this rig is also left over from the stepper trial. I used a special half gear on the first stepper I used. When it didnt work, I used that half gear to make the overtravel limits. I had to used a brass bushing to attach that half gear to the shaft. Im loosing that too, so even less complex.
My first goal on this setup was to use a stepper motor so I could exactly position the monitor through software. (Nice dream, but not truly necessary, my first rotator used limit switches and once you get the limit switches set, stop positions dont change on it.)
My second goal was to make it simple. (Trust me there is not much simplicity to a stepper drive and software.)
My third goal was to do it cheap, so others on a tight budget wouldnt be driven away.
When my steppers failed me, I shelved the rig until i saw DarthPauls project and how he used that actuator.
I thought, "you know that might work on my 2X4 rig".

Now as far as it already been done, dont let that distract you. The rotating monitor idea was here a long time before I was, so it had been "done before" when I got the urge.

Im looking forward to see what you guys come up with.
Keep the faith (and the good work) and some day everyone will be turning their monitor automatically, easily, and cheaply.

[DNA Dan]

Actually I am hoping for a complete single sheet of black glass that IS the monitor. Emulation would be able to be drawn in any direction with animated bezels and whatnot... I am hoping this whole rotation thing is a stop gap measure. Besides in another 5+ years there will be no more 4:3 ratios left.

DaOld Man, Really great job on the actuator! I love seeing what you come up with.

Nitz, are you rotating yet?