Grid Jig "Fold"

[mikey]

when i was thinking about Phil’s grid jig design ( Grid Jig "Koi" ), another idea came into my head.

design principles:

• should be impossible for a beginner to mess up
• should be easy for beginners to make using standardized fabrication processes

the idea is for two pieces of right-angled metal, with holes drilled at the appropriate positions on one face, with the hole-y faces separated by 40mm (the size of a beam), and a flat piece at the bottom, which together creates a channel for the proto beam to go between.

like Phil’s notched strip jig, the jig is used to hold the wood in position under the drill , using an initial hole (on the side) connected to the jig with a bolt. the procedure is similar: put the bolt in, drill, take the bolt out, move the beam forward one hole, repeat.

i do feel like this design could be made with sheet metal (something i’d like to learn how to do, as sheet metal fabrication is more available than CNC machine fabrication here in New Zealand) and standard bolts.

i started a GitHub repo to create 2d dxf files for the sheet metal fabrication and 3d stl files to see what the final product should look like: GitHub - villagekit/gridjig-fold

[HonkyTonkRobot]

I’m not quite sure I understand from the GitHub. Is the angle bracket, clamped to the 40mm beam, while the holes are drilled through equally spaced holes?

I do like the idea behind the design principles. My gears are starting to move.

[mikey]

Is the angle bracket, clamped to the 40mm beam, while the holes are drilled through equally spaced holes?

here’s a drawing that might help:

there’s two “fold” folded sheets and one “table” flat sheet. the "fold"s connect to the “table” to create a channel for a beam to go in, with equally spaced holes.

i did this as multiple sheets instead of one folded sheet, because i wasn’t sure if the radius of the folds would match the corner radius of the beam. also this way, you could use this for aluminium or steel beams which have no corner radius.

[mikey]

after the above idea, i did have another idea using folded sheet metal, which i never shared.

the idea:

• beam is held inside a folded sheet metal channel, using something similar to above
• a 3d printed drill press mount attaches to the channel at each hole location, moving from hole location to hole location
• once the drill press mount is attached, you drill the beam down and up at that hole location

[HonkyTonkRobot]

Both of these are really interesting, With the second one with the 3d printed drill press mount:

1. is the beam in the jig free from the drill press table, and you use the 3d printed mount with the pins to align each hole?

Or

2. is it a jig that goes into a hand drill that helps with the proper locating and drilling?

[mikey]

is the beam in the jig free from the drill press table, and you use the 3d printed mount with the pins to align each hole?

i guess my drawings miss this: the beam should be secured to the channel, probably with some initial beam hole on the side and a bolt across the channel sides (via the beam hole).

is it a jig that goes into a hand drill that helps with the proper locating and drilling?

so to clarify, the jig is two parts:

1. a channel, made from folded sheet metal, that securely holds the beam
2. a portable mini drill press, made from a combo of 3d printed stuff and a standard electric drill, that can be placed into slots that align with grid hole positions.

in case the “portable mini drill press” doesn’t make sense, look at this as an example of what i mean: Printables

now imagine that, but has a way to securely sit in preset slots on the channel.

so the channel holds the beam, you put the portable drill press in a slot, you press down to drill a hole, you move the portable drill press to the next slot, press down, and so on.

[HonkyTonkRobot]

Yea, this feels more reliable to me having the hand drill “Drill press”

Is there a way to account for variation in Beam thickness.

for example how do you ensure the drill press is centered if your beams are 42mm instead of 40mm or is there the expectation that the beams are a perfect 40mm?

[Rongomai_Bailey]

Was wondering about how to simplify the jig. Thought is to reduce to only two custom parts.

mount plate - tapped holes for mounting a plunge router. [8mm plate steel ]
notched angle steel - notched at 40mm [4-6mm laser cut steel]

The 8mm slot on the 4040 v-slot would accepts the drill mounting plate.
This setup will make sure the drill bit is perpendicular to the beam and at a fixed distance.

There would be a V-pointed screw to fit into the notches of the angle steel or a folded V could be designed into the router mount.