This took about two hours to throw together. I bet it would be less if there were instructions so I didnāt have to reference the CAD model for all of the lengths. The through bolts were really easy.
Itās really solid with not much in the way of a tendency to rack. I could certainly push it over if I tried, but itās pretty stable.
@dlang I think you might be right that I need 3 2x4s as spacers. I know weāve worked this all out before and I think I just forgot. I will review in the morning when I am fresh.
Letās compare notes and pictures of the finished versions and talk about what worked and didnāt work about each.
@bar What about your bottom horizontal 10ā 2x4 thatās right above your leg supports. Itās in your CAD image but not your final design? That should help a little.
I believe you are right to highlight this. I would expect high forces to cause deflections. This is why Iām seeking maximum frame stiffness in the directions of those forces.
As I said, Iām not worried about it standing when the wood is new, itās as things age and loosen up that there will be grief.
look at any fence/gate thatās bolted together and hasnāt been touched for years and how they sag
.
One change I think you should adapt from āmyā design is the bottom crossbeam and wings as separate pieces. That gives you a place that you can mount tabs to support the workpiece that you donāt have with a solid beam behind the legs.
As for the skill needed to build the design. Thatās why the main design we have been working on only uses square cuts and why we have the detailed written directions and are doing pictures to go through each step. Itās also why the assembly instruction donāt require any measuring, just using other parts as spacers (including centering the top beam)
well, you can drill pilot holes for screws as well, and they go a lot faster
than the large bolt holes.
But if you were talking about replacing screws with bolts on a 1-1 or even 2-1
(bolts instead of screws diagonal from each other), I wouldnāt be fussing as
much.
But we are replacing 4 screws with a single bolt and counting on the friction to
hold things together forever.
Thatās not nearly as good.
We would be better off with no screws and just glue and clamps compared to a
single bolt.
A single bolt is sufficient to hold each corner of the triangles that are the basis of Barās design. The other bolts that could pivot are prevented from doing so by the plywood portion of the frame. Pretty simple.
This didnāt start as a long postā¦ I tried to whittle it down to the salient points. Everything here is meant with the greatest of respect to all.
From a commercial product standpoint (we all want @bar to stay in business), the more accessible a product is the more likely someone is willing to invest in the product. My opinion is that @barās current design is clearly less daunting than any that have been offered. However (constructive criticism) I know it would not work in my shed. As I have done with the current stock design, I would end up adding a top brace, bottom brace and at least one vertical brace. I have to have something to clamp to in order to make the workpiece flat.
With respect to bolts vs. screws and glue, glue is an immovable joint but I personally think itās easier to assemble using bolts and bolts that loosen over time can be tightened up. @dlang has come up with a clever set of steps to minimize the difficulty in assembling. The downside to glue and screws is that the joints are permanent and thereās no disassembly/collapsing/rebuilding allowed.
With respect to top beam, @barās design causes issues with someone wanting to use unistrut though technically, you could mount the unistrut to the top of the 2x4x10 top beam.
So with all that said, perhaps we give the builder a couple options on the website at the same prominence as the stock design. Let the builder choose what they want or what they are comfortable building:
Stock Design (using hardware provided if they just want a basic design and will check on the tightening of bolts over time)
Option 1: Permanent Frame Design (using screws/glue with ability to use a unistrut-only top beam)
Option 2: Collapsible Design or an All-Unistrut Design
Too many options will lead to decision paralysisā¦ we just need them to feel comfortable they can build something and purchase the kit. Considering the time it takes to get the kit after purchase theyāll have plenty of time to study the options and make a decision on which frame they want to build. Edit: I really hope that comes across as humorous
first off, in re-reading my posts yesterday, i realize there was a tinge of 'but this is going to throw away all the work that I spent all day sunday doing" in my initial reaction, apologies for that.
I created the assembly steps to do everything the default way and then listed options below, Iām going to move the description of the options up to the top, and then flag the differences in the assembly steps.
looking at the two with fresh eyes:
the rear crossmember is not needed if you build the machine and never move it. Itās needed if the rear legs are going to get knocked around (either because you have to move it as-is or you put wheels on it) or if you are going to make them able to fold.
Iāll flag that as optional
the verticals and top crossmember are only needed if you are not going to have a sheet of plywood there all the time (or if you have problems with the plywood warping the way @madgrizzle does)
Iāll flag these as optional
The remaining significant differences in basic shape are:
solid bottom beam vs wings and center bottom crossmember
I think the bottom crossmember is very important.
Iāve had 4x8 sheets of maple plywood warp over time from only being supported by their ends.
The bottom crossmember being flush with the bottom of the workpiece means that we can attach tabs to the bottom of the crossmember to support material thatās not wide enough to rest on the kickers
diagonal braces
This gets into the discussion we were having yesterday about the long-term stability of the machine. If you are going to (semi)permanently attach a sheet of plywood to the front, they arenāt needed long term (but itās useful to add at least one of them to keep everything square until the plywood is attached.
The idea that the plywood isnāt part of the frame, but is instead just a wasteboard (which could be foam instead of plywood) is something I find attractive, and itās really easy to attach them
top beam mount
This is what we were hashing out yesterday, letās leave that as a separate discussion
@bar, what are the lumber lengths you used for your frame? it looks like you have the kickers a bit higher off the ground than the design weāve been working on, and it looks like your legs are a bit taller.
I made the rear legs 5ā long so that you could get both of them out of a single 10ā stick.
I have the top of the kickers 10.5" up the front legs,
I have the front legs 6ā (72") and the resulting machine is really pushing the max height to fit through a door (80" tall and 28" deep)
moving the kickers up will mean needing more height and the result wonāt fit through a door.
one note on the top crossmember, without something of a fixed length at the top, you canāt square up the mcahine. The top bar could be that thing, but then you have to square the machine after you stand it up, and thatās areal pain compared to being able to square it while itās (fairly) flat on the ground because when things are standing up, they donāt stay where you put them, and thereās no easy way to anchor things (put a weight next to the frame to hold it in place)
I had a āwingsā setup on my frame for a while, they were a source of trouble because they were insecure due to the leverage concentrated on the small attachment point. I settled on a 10ā bottom beam and find it more secure.
A beam across the back legs doesnāt add as much stability as bracing them from the aforesaid bottom beam would.
did you just attach the wings to the legs? In this I extend them a bit and also attach them to the crossmember, which adds quite a bit to their strength
I agree itās not as strong as a solid piece of wood, but is this bad enough to have a full length beam and a crossmember in front of it and a couple inches down?
Just to add fuel to the fireā¦ I posted this in another thread that devolved into discussing what to do with the crate of leftover quadrilateral bracketsā¦
Hey, I got a new badge āFirst Oneboxā for that autogenerated link quotebox. Not sure how I did it, but Iāll take it.
Haha we have a bunch of extra brackets, but not enough to send them to everyone
I just donāt like the sled running into it giving me little bumps in my lower cuts. Iām game for having a front cross brace as long as we can put it somewhere the sled wonāt hit it
theyāll have plenty of time to study the options and make a decision on which frame they want to build. Edit: I really hope that comes across as humorous
