Trying to do it per the plan which includes oversized hole.
I have been working on a slightly different concept in that:
It’s supposed to be a half Maslow (I intend to bring the panels already cut in half from the store).
It’s a box or sandwich construction with internal reinforcements which will make it very sturdy.
Wood sections are tall and narrow to separate front and back panels and avoid using excessive material. Panel thickness is half what would be normal to use in a one panel only construction but the same mass of material will work in a much more efficient way in terms of strength.
Openings on panels are mainly to cut some parts out of the panels (and I like the looks of it).
What do you think?
Nice work ! like it.
You really want a solid beam between the motors, that’s where 90% of the forces are
There are triangles in the important places in this design, it might well not need a beam. It would be interesting to measure to see if there is any deflection, easy enough to add later. The openings give many places to clamp stock. The non ply pieces look like they could be 1" stock, reducing cost and weight. It looks like the rear legs could easily be designed to fold flat for storage. I like it a lot
Do take pictures when you build it!
So I ran the tests and here’s the executive summary.
- I find that both designs are incredibly strong. @bar’s design is immovable and with only three screws and without glue set up, I had to apply all the force I could to get a creak out of @dlang’s design. I think tomorrow after the glue dries, it will be immovable as well. I don’t know that glue is needed, I put all I had into it just to get the slightest of movement. There’s no way the sled will exert that much dynamic force onto the joint.
- I love the idea of bolts but I could not for the life of me drill through the edge of the 2x4 and come out on center on the other side. I tried four times and the best I could do with a hand drill is to come out to the left of center on my second attempt. On all the attempts, I straddled the 2x4 with a 2x4 on each side and clamped them together to give me a solid piece to drill into (so it wouldn’t tilt). Left is attempt 2 (which is what I used for the bolt-up), right is attempt 3.
This is what I used to drill through the wood. Maybe not the best choice.
- @dlang’s design went together fairly easily and I used a corner of a sheet of plywood to square make sure I was square prior to driving the screws through to the leg. The gorilla glue I used was quite tacky and I had to tap pieces in place. After the screws were driven, I checked for square again and it looked like it moved just a little, but the edges still felt good to the fingers.
Prior to screwing:
- I drilled a perfect hole through the edge of the 2x4 using my drill press. It was actually quite pleasurable whereas, to be honest, I got frustrated with the hand drill. I think if I had bought a more expensive drill bit (a full length auger rather than a speed bore) the results might have turned out better, but I can’t say for sure.
And now I’ve got to go watch Paw Patrol with my “eldest” twin…
Maybe others can try to drill on edge and see how they do.
That pretty much matches what I expected.
I don’t think a different bit would help a lot, it’s just hard to drill a really straight hole with a hand drill
Can you try to check with a square to see how accurate you ended up?
The ability to unbolt and respace the top beam when cutting something much thicker/thinner than normal makes me keen on the bolts, so trying to think of ways the make this hole straighter in case it does turn out to be key.
For similar jobs in the past I have had good results by marking the centre on both sides, and drilling 70% through from both sides, in this way the entry/exit points line up, and the second drilling naturally tries to take the easier path set by the first. The bolt should not have too much trouble going through, especially if using a slightly oversize bit. My instinct suggests that this should result in half the error seen when going all the way through from just one side.
The other option is to mark both sides of a scrap piece (perhaps a 2*4 in the 2 inch dimension) and keep trying until you get a reasonably accurate one, then hold or clamp that piece against the actual beam as a guide.
Using both approaches together would be even better.
to make the depth adjustable, get a 2’ length of unistrut, cut it in half.
drill through the short 2x4s in two places (drill from the top, it doesn’t matter if the holes are crooked)
use long bolts to attach the unistrut open end down to the horizontal arms. These bolts can be loosened to move things in and out.
attach the top beam to these two pieces of unistrut (short lag screws through the unistrut into the beam works for wood, simple bolts work well for a unistrut top beam)
use nuts like https://www.homedepot.com/p/Superstrut-3-8-in-Steel-Channel-Spring-Nut-5-Pack-ZA1003-8EG-10/100179881 (available in 1/4, 3/8, and 1/2)
and some sort of washer big enough (these square ones work) https://www.homedepot.com/p/3-8-in-Square-Washer-Gold-Galvanized-5-Pack-ZAB2413-8-10/100343097
The forces aren’t ever directly in the line between the two motors, and with @LuisP’s narrower design, are rarely going to be outside of his triangles. I could see making the top boards in the triangles go to the centerline of the frame, just to be sure. Anything more is probably overkill.
Yes, I was actually already modifying the triangles in the way you suggested.
I think you have good suggestions. I can try tonight to drill from both sides. With an oversized bit, this just might work.
I do think a drill guide would also be an option. I tried using a guide I made by using my drill press to drill through the flat side of a 2x4 block last night, however, when I tried it, it actually made things worse because it wasn’t “clamped” down to the surface (it spun and got stuck on the bit). My back was aching bad at this point so I called it a night. I think a guide that wrapped around the sides (to center-align the hole and stay in place) might work much better… especially if you do 70% or so from both sides. I’ll try to make one tonight to test.
I can’t readily measure the squareness my build of @bar’s design since I didn’t spend alot of energy trying to make sure the holes in the blocks and the ‘top beam’ were centered.
I’ll try again tonight using @matmaxgeds’ “double sided drilling” technique. I’ll also redrill the hole in the top beam so that its the same distance from edge as the bolt is from the leg and I’ll spin the spacers so that they don’t interfere with the square.
It will be near 20 hours of cure time on @dlang’s design glue when i get back out there so I’ll see if I can move it at all. I’ll also pull the screws to see how well it holds.
I think that both designs could benefit from the use of a guide or jig. For @bar’s something to help center the bit the right distance from the end of the piece. For @dlang’s something to keep the pieces square while screwing. Here’s something I sketched in sketchup made from pieces of 2x4. If we’ve spent so much effort on this particular effort/decision because it’s critical, my opinion is to make it fool proof and include a guide/jig in the kit.
Jigs are always awesome, but that is a lot to include in the kit, both in terms of effort to create and fabricate them and in space and weight for shipping.
I agree, but you could ship the critical parts and let the builder construct it with the scraps left over.
For the @bar guide, you can cut the legs with the guide, unscrew it and rearrange the pieces to make a template for the top beam holes as well.
And I’ll point out that in reality, the drilled holes or the screwed in boards don’t have to be perfect… they just have to be the same. So if the same error occurs on both legs/supports, it’s not a problem. (Correct?)
I posit that you could even have the builder construct the guide/jig in its entirety and end up with acceptable results.
@dlang, on step 17, are we drilling through two 2x4’s on edge and is this being done with it up in the air?
- prepare the top beam
clamp the 10" top beam supports with the non-factory end flush to the top of the legs on the outside of the front legs
center the top beam over the end of the top beam supports
drill through the top beam for bolts to the supports
drill pilot holes in the supports if you are using lag bolts
remove the top beam and unclamp the top beam supports
Hi - thinking about the jigs - given that most people building the Maslow will have a router, it wouldn’t be that hard to make a ‘U’ shape jig by routing out a roughly 2 inch wide slot (precise depth or angle not important) in a piece of 2*4 in order to hold it in place, for people who don’t have clamps, or are using a short piece of scrap, or don’t want to nail/screw it temporarily. That might be easier than making a 3 piece jig and could help both designs currently being suggested.
Can you describe how the jig would be used for both designs? It would help me understand what you are proposing.