🌞 New Stock Frame Design 🌞

[mooselake]

I have a smaller version of the same set.

Think it’s time to clean up the Mooselab annex.

[madgrizzle]

@bar

There is no bottom brace

I await more details with breathless anticipation

[dlang]

@bar

There is no bottom brace

I would really like to remove it because I find it prevents me from fully using the the bottom few inches of the sheet when the sled runs into it. Instead the sheet being cut would rest on those braces which protrude from the front (the same distance as the bottom bar used to protrude). We will need to find a new system to attach the bungee, but that shouldn’t be too difficult.

given how bottom-heavy the sled is, I wouldn’t expect that you can go beyond the bottom of the sheet without having some support there. I’ve been viewing it that with the appropriate size wasteboard you can make your workpiece flush with the bottom support, and I consider it just fine to run the bit down into the bottom support if that’s what it takes to make the cut right (after you do it enough that it’s hard to position the workpiece, you unfasten the bottom rail and replace it for $6)

[dlang]

no bottom brace means that the chain supports have to be hung from the backer board.

I was really hoping to make it so that that board had no structural meaning. Instead of having it and a separate wasteboard, you could just use it as the wasteboard for most cuts, and replace it when you chew it up too much (while it’s there, it can provide support against racking, it doesn’t even require screws, just glue some blocks to the wasteboard against the side rails in the corners)

[madgrizzle]

@dlang

I consider it just fine to run the bit down into the bottom support if that’s what it takes to make the cut right

You could put the brace on the backside of the legs if you really don’t like it up front. Just makes it a further reach for the stretchy string anchor point.

[dlang]

@dlang

@bar

There is no bottom brace

I would really like to remove it because I find it prevents me from fully using the the bottom few inches of the sheet when the sled runs into it. Instead the sheet being cut would rest on those braces which protrude from the front (the same distance as the bottom bar used to protrude). We will need to find a new system to attach the bungee, but that shouldn’t be too difficult.

given how bottom-heavy the sled is, I wouldn’t expect that you can go beyond the bottom of the sheet without having some support there. I’ve been viewing it that with the appropriate size wasteboard you can make your workpiece flush with the bottom support, and I consider it just fine to run the bit down into the bottom support if that’s what it takes to make the cut right (after you do it enough that it’s hard to position the workpiece, you unfasten the bottom rail and replace it for $6)

This brings up an issue we should test.

@bar (or anywone else), can you hang a 3/4 plywood on your machine and then change the machine dimensions so that they extend about 5" wider than your machine in all dimensions, then under manual control (so you can recover from problems), run the sled all the way off the sides, top, and bottom of the machine (say move the bit 1" off the edge) and see how unstable the sled is in various places.

I will predict that:

1. there are no problems off the top
2. the sled starts tilting away from the wood well before the bit gets to the bottom of the bottom guide (once the CG gets below the support, I expect fairly significant problems)

I don’t know what will happen on the sides. I could see the sled want to start to rotate around the Y axis as the CG passes the edge, I could also see the chain to the far side preventing this from happening (although, this may depend on which triangulation kit you are using, the top metal kit would resist this more than the ring kit)

[Keith]

@madgrizzle

Just makes it a further reach for the stretchy string anchor point.

this can be compensated with a couple of stub pieces of 2x4 screwed into the bottom support behind the legs. One would probably want a 9 or 10 foot bottom beam to get it outside of the working area

[bar]

@dlang

I can get to about here before the sled starts to rotate under:

I actually cut out the center of my lower brace to let me more easily use the bottom part of the plywood.

In theory using an backer of appropriate thickness could make it so that the bottom brace would be an asset instead of a liability, but it’s been my experience that the lumber is never exactly the right thickness and the bottom brace usually leaves a noticeable mark on my cuts if the sled hits it.

I would vote that if we decide we really need a 10’ run for the stretchy string to attach to we do this

@madgrizzle

put the brace on the backside of the legs if you really don’t like it up front.

Or

@Keith

this can be compensated with a couple of stub pieces of 2x4 screwed into the bottom support behind the legs.

I agree with the goal of making the plywood not structural. I think that being able to take it on or off, or maybe not even requiring someone to buy it could be a big improvement.

So given the goals of 1) not impeding the sled at the bottom of the work area 2) not using the plywood as a structural support…how do we want to do the lower arms?

[bar]

The more I’m thinking about it the more I really like @madgrizzle’s idea of putting it on the back of the legs.

That way we would not use the backer plywood at all and it could even be optional which is an exciting thought. The legs would be very stable on their own with braces at the top and bottom. It seems like an excessive amount of wood to use just to support the little bungee cords, but when you think of it as making the back plywood sheet optional it makes sense

[madgrizzle]

Well, here in North Florida, my unconditioned shed does a number on plywood and if I don’t have a means to clamp it down to something completely flat, my cuts will be all messed up. For me, having a very flat backboard (i.e., braced) is important. So, having a back brace on the backside of the legs, at a minimum, allows me to add another 2x4 to the front of it (making it flush with the front face of the legs) so I can screw my backboard into it and straighten it out. 2x4’s are cheap, perfect plywood cuts are priceless… messed up plywood cuts are pricey.

[dlang]

@madgrizzle

Well, here in North Florida, my unconditioned shed does a number on plywood and if I don’t have a means to clamp it down to something completely flat, my cuts will be all messed up. For me, having a very flat backboard (i.e., braced) is important. So, having a back brace on the backside of the legs, at a minimum, allows me to add another 2x4 to the front of it (making it flush with the front face of the legs) so I can screw my backboard into it and straighten it out. 2x4’s are cheap, perfect plywood cuts are priceless… messed up plywood cuts are pricey.

the design has two cross braces, you can add vertical bars between them pretty easily

[dlang]

@dlang

I can get to about here before the sled starts to rotate under:

what about top and sides?

In theory using an backer of appropriate thickness could make it so that the
bottom brace would be an asset instead of a liability, but it’s been my
experience that the lumber is never exactly the right thickness and the bottom
brace usually leaves a noticeable mark on my cuts if the sled hits it.

well, if the wasteboard makes everything taller, then it shouldn’t be a probelm

I would vote that if we decide we really need a 10’ run for the stretchy string to attach to we do this

@madgrizzle

put the brace on the backside of the legs if you really don’t like it up front.

Or

@Keith

this can be compensated with a couple of stub pieces of 2x4 screwed into the bottom support behind the legs.

I agree with the goal of making the plywood not structural. I think that being
able to take it on or off, or maybe not even requiring someone to buy it could
be a big improvement.

So given the goals of 1) not impeding the sled at the bottom of the work area
2) not using the plywood as a structural support…how do we want to do the
lower arms?

I’ll point out the idea I posted:

Chain take-up idea that would completely
eliminate the need to have the stretchy cord go down to the bottom.

Until we do something like that, stub arms screwed to the back of the legs will
work (and they may not need to be quite as low??, less of a trip hazard)

I’ll look at tweaking the alternate 3 cad to match these things

[blurfl]

@dlang

Chain take-up idea that would completely eliminate the need to have the stretchy cord go down to the bottom

Where would the bungee tensioner attach to the frame? The discs are out even with the sprockets, wouldn’t that put the bungee out there as well?

[dlang]

@blurfl

@dlang

Chain take-up idea that would completely eliminate the need to have the stretchy cord go down to the bottom

Where would the bungee tensioner attach to the frame? The discs are out even with the sprockets, wouldn’t that put the bungee out there as well?

I would have it go horizontally to attach to the top beam somewhere. In any case, it is well back from where the chains are

that was a quick diagram to show the idea, I was thinking that a bolt through the stack to a 2x4 hanging from the top beam could hold them in place (very low loads

[Joshua]

It seems like the recent designs aren’t leveraging the self assembling nature of the original Maslow. A few pieces of ply wood cut from a temporary Maslow would go a long way to help alignment and rigidity

[dlang]

@Joshua

It seems like the recent designs aren’t leveraging the self assembling nature of the original Maslow. A few pieces of ply wood cut from a temporary Maslow would go a long way to help alignment and rigidity

but avoiding having to build a temporary Maslow is such a huge win.

Adding one or two diagonal braces across the back will give a lot of stiffness (for those who really don’t want plywood as part of the structure)

[Joshua]

There are just so many design freedoms when you can include CNC cut parts. Cutting and screwing all those 2x4’s isn’t a small job

[dlang]

cutting all the 2x4 parts isn’t a small job, true, but they are all simple, square cuts.

Other than anti-racking work, where would it be better to have a CNC cut part than a 2x part?

Is the advantage of this worth someone having to build a temporary frame (and what would that temporary frame look like) just to cut the plywood parts?

This all stick frame is not as pretty as the original Maslow, but it should go together a LOT faster and result in a better machine. If there are things that you then want to CNC (like a very precise sled), then they can be done on this frame rather than having to build one frame, cut some things, and then build the real machine.

[dlang]

Ok, here is alternate 3 modified to match what @bar posted above, our discussion of the chain guides, make sure the angle is really 10 degrees (it was more like 5 in recent posts) and a couple of cross-braces (since this can be used without a plywood wasteboard attached).

This given enough height to use either a unistrut or a 2x4 and still fit through a door, we probably could afford to loose an inch of height, or raise the bottom support an inch or so (it’s only 9.5" off the ground, not much room for bricks or dust collection if you are really trying to cut all the way to the bottom)

Size	Type	Quantity
120	top beam	1
91	2x4	1
82	2x4	2
73	2x4	2
63	2x4	2
45	2x4	2
25	2x4	2
20	2x4	4
12	2x4	2
10	2x4	2
3.5	2x4	6

[madgrizzle]

You could just about build the entire thing flat on the ground if you used bolts for the back leg and front-to-back brace. Everything in red could be in built with it flat. That would make for easy instructions.

Might be best to build it face down and not attach the top beam and attach the two diagonals instead (to prevent racking as you move it). Or build it face down, flip it and then install the top beam. So many options.

Just throwing this out there for people that like a collapsible frame, but if the top beam structure was bolted to the front leg with two bolts, one could be removed and the other could be left as a pivot point to drop the top beam down to rest on the front of the frame.