Introduction: Mobile Teaching Cart
Most teachers don't have much room to work with in their classroom. Some don't even HAVE classrooms and are basically mobile all day, floating around the school with a bunch of stuff. There are plenty of retail products out there intended for that purpose. Mostly metal with plastic bins and rails. They range anywhere from around $60 all the way up to $600 or so.
I decided to see if I could replicate one of the high-dollar ones to see how much it'd cost to build something similar. I ended up coming in at just under half the amount for something that should work fairly similar. If you've got some of these bits and pieces around, then that just makes it cheaper for you!
please note: some photos are taken in different locations. A lot of it was cut/test fit in one location and moved later to my place since I don't have a table saw :P
painter's tape + dry erase marker (or sharpie)
power drill + a bit wide enough for your screws
table miter saw
wooden drill block (basically scrap wood you can drill into)
Ikea Trofast containers - medium and small bins (the 9'' and 4'' deep ones)
Evenbrite Aluminium - 3/4'' x 1/2'' x 1/16'' at 36'' long (bought at Home Depot)
Screws (these are just short lil ones)
1'' Schedule 40 PVC pipe -- I bought 8 10' pieces and had leftovers.
(4x) 1-1/4 in. x 1 in. Schedule 40 PVC Reducer Bushing
Formufit PVC accessories (www.formufit.com)
- (4) caster wheels with locking brakes;
- (4) 1-1/4'' caster brake fittings
- (8) elbows
- (18) "T"
- (6) "Y"
- (4) Cross piece (not pictured -- formufit link here: shorturl.at/prtKV)
- (10) "four way"
- (4) 1-1/4'' straight connector
Step 1: Design Step
Fig 1 is what I was attempting to replicate.
Fig 2 is the basic design of what I ended up with
Fig 3 shows some of the alternate designs and options that I was playing around with.
I decided to include a 2'' clearance above each row of bins for two reasons -- first, for any supplies that might be taller than the bin itself; secondly, to provide enough room in case I needed to go back and add a horizontal PVC run between the two vertical sides for structural integrity. Obviously, doing that would eliminate that headroom that I just mentioned, but that might be a small sacrifice to make. This might not be as much of an issue if you use a different rail system (see the next step for thoughts on this).
You'll also notice that the caster assemblies (I call them my frankencasters) are positioned "outside" the rig, rather than directly beneath it like the metal cart. The main reason for this is that the caster fitting that I wanted to use only goes into 1-1/4'' PVC fittings, and if I built the entire rig out of 1-1/4'' it would increase the cost as well as the size/bulk of it. I couldn't figure out a decent way to make that transition. ** If we put it directly beneath the corners it added about 7'' to the height so we would have had to modify the design. Doing it this way with the dog-leg wheels added cost and trouble (in terms of extra fittings and cuts, etc) but reduced the overall height by a few inches. So keep this in mind when you're doing your planning. See the note below as well.
** If you have an Ace Hardware near you, you could look to see if they have something like this: https://www.acehardware.com/departments/plumbing/p... (Schedule 40 1-1/4 in. Slip x 1 in. Dia. Slip PVC Reducing Coupling) -- or buy it online of course. In the time frame that I was building in, these were out of stock (even for ship to home!) so I had to go with my "frankencaster" assembly. NOTE! if you go this route, you may need to get a different caster attachment from Formufit. They make two types so double check!
Step 2: Planning, Part Two
So, for the rails and bins... There are two types of Trofast systems. One is built of wood and is basically just notches cut into the wood that the bins slide into. The other uses a plastic "U" shaped channel that's screwed into the sides of the unit. Sadly, they don't sell the channels by themselves - that would have made it too easy I suppose!
We took a bin with us to Home Depot and looked around. One option was something called Mira Lustre U channel molding at about $11 for 96'' (5/8'' wide); another option was Everbilt aluminium angle, 3/4'' x 1/2'' x 1/16'' at about $4 a piece for a 36'' piece.
In the end we went with Everbilt because it was cheaper and wouldn't require any cutting as we had estimated to build out at about 36'' wide anyway. The downside to this is that the bins aren't as secure or stable compared to the when they're in a channel type system.
If you have room in your budget (~$48 for Everbilt vs ~$66 for the Mira Lustre) and the tools to cut it, the Mira Lustre might not be too bad. The 3/8'' version is slightly too shallow to hold the bins, and the 5/8'' one is slightly too deep, which is probably fine. You do need to keep in mind the overall width of the channels and bin -- together -- when planning out how long to cut your horizontal pieces. That's why I'm mentioning this part BEFORE you cut the PVC!
Step 3: PVC Cut List and Fittings
IMPORTANT NOTE: As you go through the pictures that come along, you may notice that there are drilled holes in the vertical pieces of PVC. IGNORE THIS. Wait until I tell you to drill before you drill! The reason for this is that everything was drilled and assembled in one place, then taken apart to move to another. It will be MUCH... much... much easier if you wait until I tell you. Trust me on this.
second note: You see all the blue bits of painter's tape? This is important too. As I cut, I labeled them with letters so I knew which piece I was holding and where it needed to go. It'll save you time. You may seriously want to consider taking special care with the rails later too.
Fig 1 depicts all the pieces + lengths that I cut for this prototype. Fig 2 just shows you (most of) of the pieces post-cut. Fig 3 is some of the connectors. (I forgot to put down the cross piece for that photo. Bad me.)
(2) A - 10.5''
(2) B - 10.5''
(2) C - 10.5''
** Note - yes I know this basically amounts to 6 10.5'' pieces. Go with me here.
(8)D - 12.5''
(5)E - 12.4'' (less than 10.5'' but more than 10.25'')
(6) I - 7''
(2) J - 24.5''
(12) K - 2.5''
(1) L - 29''
(2)M - 16.5''
(4)N - 10.5''
(6) O - 4.3'' (between 4.25'' and 4.5'')
(4)P - 51''
(6) Q - 10.25''
(2) R - 9 1/8''
(2)S - 47''
(2)T - 21''
(2)U - 28.5''
FITTINGS (Fig 3)
Step 4: Caster Assembly
I told you way back there that the caster assembly got to be a bit of a... frankenstein kind of situation due to the difference in pipe diameter. Here, in Fig 1, you see what I meant.
For each caster assembly you will need, from bottom to top:
(1) Formufit 1-1/4 diameter caster fitting
(1) 1-1/4'' connector (straight piece)
(1) 1-1/4'' x 1" Schedule 40 PVC reducer bushing
(1) 1" pvc, (2.5)'' long (K)
(1) 1'' 90 degree pvc elbow
(1) 1" pvc, (2.5)" long (K)
(not pictured and shows up in Fig 2: (1) Tee fitting)
Fig 2 shows the Tee fitting added to the assembly, and then two bolts through the Tee and elbow fittings to help keep the wheel vertical.
You'll need 4 sets of this abomination.
NOTE: If you didn't read it, go back to see my remark about the other option for this.
Step 5: Build Your Base
You will need:
(4) 3 way fittings
(4) caster assemblies
(4) "T" fittings
(4) 4-way fittings
(4) "I" (7'') PVC
The 3- way fittings go on the outside four corners. The T fittings go on the outside long sides, and the four-ways form the inside long edge between the bumpout and the rail section.
The long side (without bumpout) lays out this way: (3 way) Q (Tee) R (Tee) Q (3 way).
The top and bottom horizontal edges lay out this way: (3 way) E (4 way) i (3 way)
The bumpout edge: (3 way) Q (Tee) R (Tee) Q (3 way)
Internal edge: (3 way) Q (4 way) R (4 way) Q (4 way)
Step 6: Build Up!
Go vertical! This is where the long risers ("P") come in. (Fig 1, 2)
Then add your wheel assemblies - Fig 3-5
Add a K piece to your corners (Fig 3) and put the assembly on top of that K (fig 4).
Fig 5 shows all 4 wheel assemblies in place on the corners, and turned in the proper orientation (I have them all aligned "lengthwise".
Step 7: Up and Up
Fig 1 (continuing to add vertical pieces...)
- "U" goes into the inside of the bumpout, on either side of the "P" pieces.
Fig 2 (building out the bumpout)
"J" goes into the corners above the wheels on the bumpout section. Add a 3-way on top of "J". Stick an "M" piece running parallel to your base. Add a tee fitting, insert the other "M" piece, and the "L" goes into the open leg of the tee fitting. Another 3-way fitting will complete the top. Add "i" pieces in the open horizontal socket on your 3-ways.
Fig 3 (better view of the bumpout and more vertical sections)
Add a Tee fitting on top of the "U" pieces - connect to the bumpout with "i" - and then add T to the top of your Tee fittings.
"S" goes on the outside corners, above the wheel assemblies.
Fig 4 (capping off the risers)
Add a 4- way fitting to the top of your "T" pieces and cross fittings to the top of "P" pieces. A/B/C are similar in length, and go in between to form the top of your rail section, where your wood surface will rest. Do this for both sides!
Step 8: "Above the Line" Top Section
(8) "D" - these are the vertical pieces.
(4) T fitting
(4) elbow fitting
Insert "D" into all the open ports on your fittings. Your elbow fittings go on the outside four corners, and your Tees go on the posts in between. Connect the fittings horizontally with another pair of A/B/C sets; generally, B goes in the middle.
Step 9: Spot Check
This is what I had so far
(I took the photo after I put the side rail on and before I put the bin rails on.)
Step 10: Adding Rails
Remember when I said not to drill until I told you to drill? Here's the time for it.
We took our rail pieces to the belt sander and rounded off the corners where we could, as there was some concern about the edges being bumped into. Then we measured off the distance between the vertical posts and predrilled holes. Note here that we used a scratch-built "u" channel made of wood to raise the metal off the worktop and drill through it using a sturdy drill bit. The reason it's raised is - well, you don't want to drill into your worktop do you? :) If in doubt get one that's made to go through metal. If it can do that, then it can handle the pvc without issue.
I took some painter's tape and began measuring from the bottom up. The black lines indicate where the "bottom" of the rail should be - basically the level that the top/lip of the bin should rest at, roughly speaking. This is with the 2'' headroom (mentioned earlier) factored in.
Then we began screwing them in, starting on the ends and then moving to the internal verticals. (The thinking behind this was if the ends were where they were supposed to be and were level, then we didn't need to mark all the interior verticals, saving some time.) We used a level to make sure everything was level -- you don't want your bins sliding when they're not supposed to! There were a couple spots where the holes in the rails didn't quite land in the right place so we had to redrill or widen out a hole to make sure that the screws would make good contact with PVC. This metal isn't too difficult to drill through, but just measure carefully so you don't have to mess too much with it. Note that we did have a little bit of difficulty on the very ends in making sure we had something to drill into/through - so you should keep that in mind. You might need to shorten the entire structure a little -- either by banging things closer together with the rubber mallet, or by cutting a bit of length off. (Just make sure it's a uniform shortening all around, or you'll have a bad time later.)
You might notice that we have some marked off lines without a corresponding set of rails. One reason was we ran out of rails! We also didn't have enough bins. So that's something for the next round of prototyping.
We also put a metal rail on the top of the bumpout section in order to support the whiteboard.
***NOTE**** if you anticipate needing to take the thing apart for any reason... I recommend, if possible, separating the vertical sections and keeping them assembled as is without removing the rails. If you need to take all the rails off for some reason, take special care to very carefully mark all your rails along with the coordinating points on the PVC so you can put everything back exactly the way it was -- to make sure that all the holes are aligned after all the trouble you went through to drill them all in the first place. Trust me on this. I didn't do that when I took it apart and it took a hell of a lot longer to Tetris everything back into place. With four holes per rail...... yeah. So if you listen to nothing else, pay attention to this.
Step 11: Wood Shelves
These are relatively flimsy temporary shelves. I thought it'd be sturdy enough but I'm not totally satisfied. I'm convinced yet about stepping up to 1/2'' thick wood because that could be too heavy/thick. With the horizontal bars in place, I considered putting a bracket around those pipe sections and screwing them into the wood for stability and support, but I wasn't sure that screws were the best solution. I would have to countersink the head if coming from above, and the wood's not (currently) thick enough for that - if coming from below, it would have to be a REALLY short screw or nip off the excess somehow. So we shelved that discussion (see what I did there) and just dropped the wood into place without securing it to the PVC. We'll go back and play with that and update when we have a "better" solution.
We cut two pieces - 36.5'' by 7'' for the little bump-out section, and 36.5'' by 13'' for the top. We experimented by using a table miter saw to carve out notches on the larger piece before dropping it down into place. It does help prevent the wood from sliding around when moving the cart. The one down below we didn't do notches, and it slides off fairly easily; that's going on my revision list.
Step 12: In Use and Future Plans
Future Prototyping Plans
-- I want to get rings like this ( https://www.amazon.com/gp/product/1604180021/ref=... ) to put onto the side without the whiteboard for pocket charts. Hooks for flip charts or easel pads would also work I think. Make use of the vertical real estate!
-- Considering DIY-ing a bigger whiteboard without the marker tray - it might sit better on the rail. The one in the photos is 24''x36'' and not magnetic. I have one the same size that IS magnetic, but it's cheap and warped.
-- I also want to paint the entire structure, I just haven't decided what color scheme to use yet. Krylon Fusion All-In-One or Rustoleum will probably adhere well to both the wood and metals so there's that.
-- play around with securing the wooden sections, or replacing with something more sturdy and easier to secure.
-- possibly modifying the caster setup using that piece from Ace Hardware that I mentioned.
-- I may need to add some PVC sections horizontally on the shelf section to help keep it from flexing - there's a bit of flex, enough that bins with some weight have some trouble staying in place, or cut down the horizontal bars to make the structure narrower, which may serve the same purpose. (that's the pieces labeled "E")
-- add the last set of rails; buy more Trofast bins and possibly bin lids.
-- I'm considering adding something to the sides of the open section on top, just to keep things from sliding off. Same for the bumpout section. Bungee cord?
-- possibly something to keep the bins from sliding completely off the rails on either end for the same reason as above, though it hasn't happened yet.
Second Prize in the
Classroom Organization Challenge