Well, I’ll keep the design in mind when I work on a “retrofitters” design.
Let’s make a list of sticking points where my version of your design is different than your version.
And let’s keep in mind that both designs are really yours at this point. My design was this monstrosity which required even more parts cut using the temp frame than the original design and which yall rightly (and very kindly) pointed out could be improved on:
At this point we are really really close to the same design:
There are three differences
These arms are different:
I haven’t proposed a solution for that yet, and I think this design works well.
This central bracing is different and the anti-racking braces are different. I really like the ani-racking bracing there. How are the ends of the central brace joined to the vertical 2x4s?
The way the cross brace is moved out from the frame is different.
This is the one I feel the most strongly about. When I tested the different methods I tested the arm with a second 2x4 on top of it which added quite a bit of strength. When I tested it as shown above I felt a little play. I also worry that the user gets to define what a 90 degree angle is here which could result in a difference from one side to the other while the bolt method uses only the factory edges so all you have to do is torque it down really tight and it will be square with no play at all
if you have 3/4 ply, 1/2 wasteboard, 1/2 workpiece you are 1/4 clearance to the bottom bar
3.5" Blocks flat against the legs
If we go back to a solid front beam, this changes
How do we ensure the builder drills perpendicularly into the 2x4? Is this a reasonable concern?
Great question! The nice thing about the bolts is that is that it doesn’t matter. The bolt is only there to pull the two parts together, the factory surfaces of the wood provide the 90 degree reference. I think in the instructions we would recommend using a drill bit at least one size larger than the bolt. I drilled all my holes freehand without using any guides or making much effort to drill straight.
Do other people have issues with the sled running into the bottom bar? If it’s just me I’m happy to go back to it and just modify mine
I’ve not had a need to cut through the bottom of a piece of plywood yet so it has yet to be a problem for me.
I start running into issues when the very bottom of the sled gets to the bottom of the sheet so 9 inches from the bottom, do you see that?
I’ll have to do diagrams to demo, but I disagree
I hardly ever run low on the sheet because my vacuum hose is fairly stiff and it can get in the way. I probably never ran to a point its a problem. Also, my sheets extend out over the lip… 3/4inch ply + 1/2 spoilboard + 3/4inch ply… all with some warpage So the beam doesn’t interfere if I did run it low.
The bolt and factory faces make sure the top beam is parallel to the leg, but not that it’s level
We have been looking at this in different ways, my concerns have been for the vertical movement while @bar has beed looking at the angle of the top beam and distance from the leg
Well, if its bolted, a drilling guide can make sure it goes in perpendicularly and you can use the appropriate size drill bit to make the hole. It could be sized so that the top of the guide is flush with the top of the front leg. That way its dead center, at the correct height, and perpendicular to the face…
I put a piece of 1x4 behind my 3/4" plywood to bring the surface even with the surface of the bottom bar.
If people are worried about bolted timber connections rotating (short or long term) then just insert a timber connector washer between the pieces (this a washer which has the edge cut and bent up in alternate directions) i.e. one of these!
Incidentally they increase the strength of the bolted connection many fold.
I had never heard of those before! Thank you!
How are those of you using top bar frames attaching the loose end of the chain?
A hook screwed into the face of the beam.