Using 80/20

Graphite Dave

Dave Orton
One method of building structures inside a Sprinter is to use 80/20 (www.8020.net) or Futura Industries (www.tslots.com) or other brands of aluminum extrusions. The extrusions are cut to length and then bolted together. Welding or woodworking skills are not required. Hand tools, a wood cutting (3450 rpm) chop saw and a drill press are the only shop tools required. The extrusions can be purchased 1" square, 1 1/2" square or in metric dimensions. I used 1 1/2" square from Futura Industries. The extrusions are available as one slot, two slot, three slot or slotted on all 4 sides. The slots are designed to accept a 5/16-18NC carriage bolt head. The slot is designed to provide a vibration proof bolted connection. While extrusions are not cheap, their ease of use makes up for the cost.

I used a non-ferrous 10" saw blade from Skarpaz part # NF1080N. It has 80 teeth, .095 plate, .125 kerf, and a bore of 5/8". The tooth style is N5TCG. The blade is expensive @ $128.50 but gives machined like cuts. Aluminum cuts like wood. 80/20 has many choices for connectors. I did not use any of their fancy connectors that require the end of the extrusion to be machined. I bought 1 1/2" x 3/16" aluminum angle, 2" x 3/16" aluminum angle and 1 1/2" x 3/16" flat for the connectors. Just cut them to the length required in chop saw and drilled the bolt holes. I did use a lot of the 80/20 "90 deg. inside corner connector" part # 3368 to get a rigid corner connection in some places. The open area between the extrusions was filled with 3/8" (5/16" actual) plywood. The plywood is inset 1/8" from the face of the extrusion. I glued the plywood to 3/4" x 1 1/16" x 10" wood blocks bolted to side of extrusion. Finished panel can still be removed if you have access to back side. Where I wanted easily removed panels I made up 1 1/2" square x 3/16" thick aluminum plates that bolt to the 1/4-20NC tapped holes in the 80/20 corner connector. 9/32" hole countersunk for flat head machine screw to bolt plate to corner connector and a 5/16-18NC tapped hole to bolt the plywood to the plate. The 1/4" tapped hole in corner connector is too close to the plywood edge and caused plywood to delaminate at edge so I added 5/16" hole further from the plywood edge. I used button head SS screws to bolt plywood to structure.

All structures were designed using a CAD program before fabrication was started. Bolting the structures to the Sprinter interior sides and ceiling was a bit tricky since nothing is square with the floor. I finally worked out a solution using angle connectors that compensated for the out of square surfaces. Details of what I built will be posted as they are completed under posts titled Orton DIY - ???. I have now completed the floor and some of the structures and most of the design. Thought this fabrication method would be of interest to other DIY's.
 

Aqua Puttana

Poly - Thread Finder
I had a welding shop I work with buy some for me, I have a surplus dealer that has aluminum and there is a metals dealer. Call a welding shop and ask where they buy aluminum.
I'd think local is the way to go too. Should that not work out McMaster-Carr and Grainger carries it. At the least their listing gives material specs to perhaps use for a local order. Have fun. vic


http://www.mcmaster.com/#aluminum-angles/=etfpya

http://www.grainger.com/Grainger/ww...e&op=search&Ntt=aluminum+angle&N=0&sst=subset
 

Graphite Dave

Dave Orton
Just reread my original post. Did not install the plywood panels as described in first post. Instead I bolted a 3/16" x 1 1/2" x 2 1/2" aluminum flatbar to the back of the 80/20. Flatbar is has a 11/32" hole drilled 1/2" from the one end and a 5/16-18NC hole tapped 1/2" from other end. The two plastic spacers are a 3/8" thick and a 1/2" thick and are 1" diameter. That insets the 1/2" panel about 1/8". Panels look better inset than flush. The bolts are 2" long 5/16-18NC socket head button cap screws. A flat washer is under screw head. Long bolts make it easy to start the bolt into the tapped hole.
 

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ajm3s

Member
I have been reading all your posts and will be using 8020 in some strategic locations.

Have you considered just inserting the panels into the channel? You can rabbet the thick panels to fit the 3/8"? width slot in the 15 series structure. This will lock the panel in-place, however to remove the panel you must remove a structural element. Just thinking out loud.

I am in the process, of working out a design approach, and am seriously considering using 1517-LS for corners to toilet/shower enclosure, floor to ceiling. This will provide a nice soft, yet sturdy edge which protrudes out (into the center aisle) relative to adjoining cabinets, yet to be designed. It also adds a stylish element, as I can see in your work.

Keep up the excellent work!

Al
 

Graphite Dave

Dave Orton
You can put the panel in the slot but then it is not removable for access. I want everything to come apart. In my case I am using the panel to hold the battery in place on one side and on the other side I want access to my heater radiator/fan. The slot is closer to 5/16" wide. Another problem for me was the inside corner brackets would show. The panels will rattle unless you use the rubber insert that they sell to take up the slop. I did put some 1/4" plywood in the slots on the bottom of my overhead cabinets. I then put a 1/4" piece of plywood on top of the 80/20 for the cabinet bottom. I have lights mounted under the cabinets so use the space between the plywood in the slot and the cabinet floor to run the wiring. Since I could not get the Futura guy to send me the rubber insert, I just filled the gap in the slot with silicone from above before I installed the cabinet floor. I thought about using the 1517 but decided not to because I wanted to be able to load a carriage bolt into the ends of the horizontal runs. I use a female eyebolt with the carriage bolt to make a tiedown that I can move anywhere on the 80/20. My van has to be able to be used to haul cargo. I remove the table/bed support so the back end can carry whatever.
 

Graphite Dave

Dave Orton
The five 80/20 (T-Slot) structures are finally completed. Two rear wheelwell boxes, two overhead cabinets and a refrigerator/microwave/shower/portapotty enclosure. Thought it might be helpful to review what I have learned and a couple of wouldhave/shouldhave/couldhaves. 80/20 is the right choice for conversions. I would definitely use it again.

Comments:

1. 1 1/2" sq. 2/3/4 slot 1515lite worked well. I would use the lightest (1515-LS) if I did another conversion. All structures were very rigid. Wheelwell boxes were bolted to the floor and the Sprinter wall at 3 places. The overhead cabinets were bolted to the wall at 3 places and hung from roof ribs in two places. The refrig./shower enclosure was bolted to the floor, at the side and one from roof rib.

2. Using carriage bolts is the preferred attachment method. Makes the most rigid connection and utilizes the deformation of the extrusion to provide vibration resistant connections.

3. Making your own connections out of 2 x2 x 3/16" angle, 1 1/2" x 1 1/2" x 3/16 angle and 1 1/2" x 3/16" aluminum flatbar is easy to do. No need to buy connectors from 80/20 for most joints.

4. I did not thermally isolate the 80/20 from the Sprinter body. I have found that the aluminum extrusions are good conductors of heat. (surprise surprise) I should have used wood between the 80/20 and the Sprinter body at each attachment point. Would have been easy to do with 1 1/2" sq. wood blocks or 3/8" plywood. Picture is attached.

5. The easiest method of bolting the extrusions to the angled Sprinter walls/ribs is to use an angle bolted to the Sprinter. The structure is then bolted to the other leg of the angle. The angle can be rotated to compensate for the angled walls and ribs.

6. I needed to shorten one piece of 80/20 1/8" after it was installed. Used a 4 1/2" angle grinder with a Jisco type 27 80 grit flap disc. Was easy to do.

7. The only 80/20 connector I used was the "90 degree inside corner connector" part # 3368. I would only use these where I have a panel and do not want the ends of a connector showing. Vibration loosens the set screws. The joint is not as strong as an angle or flatbar connection. Use Loctite if they are used.

8. Next time I will use the "standard end fastener" part # 3380 instead of the "90 degree inside corner connector" where possible. I did not use them but should have.

9. I also would use the "drop-in T slot studs" part #'s 3293,3297 and 3297 in more places. I started using them at the end of the assembly and should have used them more.

10. You need to be careful to think of where you need to load a carriage bolt before the ends are blocked. If you do not then the " T slot studs" will work.

11. 80/20 with slots exposed can have tiedowns inserted anywhere you want in the extrusion slot using the "T bolts".

12. 1/2" plywood works well for panels. I inset the plywood 1/8" from face of 80/20. Insetting the panel hides the end grain of the plywood. I used 3/16" x 1 1/2" tapped flatbar bolted to the back of the 80/20 to attach panels. If you use a 2" long screw, you can see the hole to start the screw.

13. I was surprised how many places I bolted stuff to the 80/20. I bolted duplex plug plates,lantern tiedowns, battery hold downs, handles etc. in many places. 80/20 is neat stuff.

14. Used drop in nuts part # 3311 where I needed a tapped hole in the slot. They are a pain to use in a vertical slot. I bolted the 1/2" plywood seats to the 80/20 with 3/4" long flathead screws.

15. Tapped center end holes in extrusions to attach 1/2" plywood cabinet ends. The panels were bolted on so I have access. On the rear of the wheelwell boxes I used male knobs to make panels easy to remove. I store a lantern behind the panel on the right side and an extension cord behind the panel on the left side.

16. 80/20 worked well to frame the 1 1/2" thick floor. Gives tiedown slots and allows insulation and utility runs. Notched bottom of the 80/20 where I needed cords to cross the 80/20.

17. Used 1/4" plywood in the 80/20 slot for the overhead cabinets. Used silicone caulking to prevent plywood from rattling. Cabinet floor was also 1/4" plywood that sits on top of the 80/20. The gap between the two pieces of plywood is used for wiring for LED lights mounted under cabinets.

18. 2 x 2 x 3/16" angle connectors are required at 90 degree joints if carriage bolts are used. If you use 1 1/2" angles you can not get the nuts on the bolts.

19. Used serrated flange nuts on all connections.

20. 1 1/2" width of 80/20 allows me to add 1 1/2" of rigid insulation around the refrigerator to reduce amp load.

21. I preferred the look of the smooth surface 80/20 compared to 80/20 with lines on surface.

21. You can add handles part # 2061 easily to the face of the 80/20.

Hope this helps others who use 80/20. I think it works well in this application, was within my skill set and the finished product looks good. I would definitely use it again if I build another conversion. The cost is offset by how well it works.
 

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Graphite Dave

Dave Orton
Another thought. Next time I would cut the angles 1 1/4" long instead of 1 1/2". That way you would not be concerned with the angle overlapping the edge of the 80/20. Cuts would not need to be as accurate.
 

d_bertko

New member
Dave,

Could you give me your thoughts about using 1x2 instead of 1.5x1.5 product?

I have some chair-bed structures in mind with the longest span only 30".

I figure the verticals don't matter much since compressive strength is strong but the horizontals would benefit from the 2" depth to minimize deflection. About a third less weight/foot than the 1.5" stuff. (Haven't looked at any deflection tables yet.)

No one would build a house out of square wood stock since it would be too wasteful for the horizontal components. Furniture has some different loads but the principle is the same. If I had some experience I would be better able to minimize weight/enhance grace.

Do you think the connection simplicity of using all 1.5" sq stock outweighs the weight savings and other benefits?

My Reese atv ramps that I used in my design impressed me with their high 650lb capacity rating and low 12.5lb weight per section. Aluminum ain't cheap so it was interesting to see all the hollow boxes and copious welds. I'm guessing robots don't care too much about how many welds they have to make.
Dan
 

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Graphite Dave

Dave Orton
I have not looked at the deflection tables but would suspect the 1" x 2" has less deflection than the sq. 1 1/2" with the same load if the 2" is in the correct direction. Obviously the amout of load determines what will work. If it is for a chair for people, I suspect the 1" sq. would also work. Even if the 30" span deflects, what would that hurt?
 

d_bertko

New member
I have not looked at the deflection tables but would suspect the 1" x 2" has less deflection than the sq. 1 1/2" with the same load if the 2" is in the correct direction. Obviously the amout of load determines what will work. If it is for a chair for people, I suspect the 1" sq. would also work. Even if the 30" span deflects, what would that hurt?
Thanks for the reply.

I thought I'd do my homework after my post but we are an Apple-only household and the 80/20 deflection calculator is apparently a Windows-only tool. Those cross-sections are way too complex to compute otherwise.

Am I missing anything subtle about connecting rectangles in 3 dimensions rather than square sections? I did figure on making many of the simple connectors myself since 80/20 is quite pricey there.

Dan
 

Graphite Dave

Dave Orton
I looked in the Futura Industries catalog where they have graphs for maximum loads. For 200 lbs load on a simply supported beam (load in center with supports at ends of beam) the graphs show:

1" x 2" in one direction maximum length = 20"
1" x 2" in other direction = 40"
1 1/2" sq. light = 30"

Maybe a real engineer out there can explain the relationship between deflection and the moment of inertia of an extrusion. If I remember right the deflection is related to the moment of inertia. The moment of inertia's are listed for each extrusion in the catalog. You should be able to use the MI to compare the relative deflections of each extrusion. It was 50 years ago when I last did a calculation.

The connections are up to you. Can not help unless I know what you are building.
 

d_bertko

New member
The Futura pdf was very helpful.

If I use the TS1020 1x2 in the strong orientation and support my 30" span at both ends it will support a concentrated load in the center of around 500 lbs for a .1" deflection in the center.

I'll note that the span length gets cubed in the calculation so a 65" span would deflect about 1" under that same load.

(Derived from the Tslots catalog deflection page at Futura if others need to plug in some numbers.)

Just what I needed. Sounds like the 1x2 will support Santa with a pretty big kid in his lap.

Dan
 

Geek

New member
I'm finding the weak link in my 80/20's strength is rotational twist.

I'm having to re-enforce my bench horizontal lengths as the bed bridge I'm spanning across the middle is actually twisting the 80/20 at the attachment points due to the leverage.

currently one side of my platform rests on verticals and there is no issue, but the hinges I'm using for the swing panel bolt into the horizontal. The hinges are super strong.. the actual 15 series 80/20 is twisting.

Trying to make it clearer.. it is twisting at the arrows:


Easy solution.. I'll just run a brace on the backside opposite each hinge.

In this photo you can see the hinges I have.. and behind them the re-enforcement plates I'm going to use to stop the twisting:


Hope this helps :cheers:
 
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Geek

New member
Could you give me your thoughts about using 1x2 instead of 1.5x1.5 product?
Dan
Are you referring to this?



I'm using it as my wall mounts. It is super strong along the 2" span but not so much on the 1" .. if there is any chance it could have longitudinal flex I'd be careful. I don't find it is any lighter than the 1.5 x 1.5 ..it might actually be a tad heavier per foot because the "back wall" of it is so thick.

 

Graphite Dave

Dave Orton
Tools required to build 80/20 structures:

1. Chop saw designed for wood with aluminum cutting blade.

2. Drill press.

3. Sander for deburring parts.

4. Hand tapping machine. I had trouble tapping plates straight so bought machine from Grizzly.com for $82.95. Works great.
 

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d_bertko

New member
Are you referring to this?



I'm using it as my wall mounts. It is super strong along the 2" span but not so much on the 1" .. if there is any chance it could have longitudinal flex I'd be careful. I don't find it is any lighter than the 1.5 x 1.5 ..it might actually be a tad heavier per foot because the "back wall" of it is so thick.

Geek,

I'm not referring to the wall-attachment extrusions. I think that stuff need only be .5" deep in many cases. Heavy loads should probably get transferred to the floor instead. Otherwise you might put a lot of torsional stress on that skinny sheet metal Sprinter wall. Not to mention that anything deeper than you need wastes space, weight, and $$$.

I could not tell from your pix what extrusion series you are using. Is the depth really a full inch? It looked like the .75" would do the job.

My application was for general use instead of wall-aided. So using 1x2 or 1x3 or even 1x4 extrusions make more sense than square 1x1, 1.5x1.5 or 2x2 series if you know that the greatest expected loads will be on one axis. Think skyscraper I-beams or 2x10 residential joists.

The choice of extrusions is certainly complicated by their attachment utility. That Erector-set flexibility costs a lot of extra metal for the same engineered strength of simpler box or other shapes.

The 80/20 is a lot of fun to prototype with but no mfr would use it for quantity production. Lots of weight could be saved using dedicated engineered and probably welded extrusions.

I can appreciate that the 80/20 folks serves an audience that are not production-optimizers. A niche market for their product and they charge accordingly.

Dan
 

Aqua Puttana

Poly - Thread Finder
I'm finding the weak link in my 80/20's strength is rotational twist.
...

Hope this helps :cheers:
Unless there are attached components which will be damaged by the twisting or deflection as a practical matter it isn't generally a concern.

I've used structural grade aluminum similar to Unistrut in shape/design for boat dollies and multiple boat trailer racks among other things. When I first noticed the twisting of the pieces in some applications I thought I might need to add structure. Turns out the structural grade aluminum stuff is very resilient so it wasn't ever an issue. I should think the material of construction for the stuff y'all are using is of similar grade. The 80/20 looks very nice by the way.

Unless you are loading up the furniture with really heavy possessions and bouncing down the road, a bit of deflection is not a concern. Then again, I don't generally do calculations on my designs as some people do. Have fun. vic
 

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