Wooden Eiffel - TriLap joints

Hi Folks

I've working away this week on building some wooden Gridbeam parts - I now have 8 grid beams, However I suspect that the drilling will not be accurate enough to build a good frame with (I'm waiting for some bolts to come via EBay to check this out). It seems that I have spent a lot of time building a pillar drill and drilling out the gridbeam without get a good system. Its a bit frustrating!!

However I think the idea of trilap joints is good - I'm going to have another go - but this time only going to predrill the holes that I need and I'm only going to drill one half of each joint. I can then use wood screws to joint everything together and it will not matter if some of the holes are ~1mm out of true.

I'm building a chair for my daughter first before a RepStrap frame - but will keep you posted on this thread.

Cheers

CS

Grid beam, Tri Lap joint. This sort of thing?

From here: [www.gridbeam.co.uk]

Yup that the stuff

-- can be made out of wood or metal beams - the idea behind Eiffel is that the machine is capable of making its own beam's - but I'm making a 'strap so I've got to make the first generation of beam's

CS

Good choice, I think. I also started one but am still building a rustyspoon huxley. May finish it at a later date.

From Desktop

The beams are 12" long pieces of ready made trim purchased at Lowes. They are actually 11/16x11/16x12" each.

And my holes didn't line up very well either. ~0.5 mm off on several using my cheap Harbor Freight drillpress.

Even though the pieces are small the frame is really strong and has zero movement when racked side to side. Could probably stand on it, but won't!

Arvin

Just got the bolts - surprisingly at least one joint works!! Tomorrow I will start building it up a bit more......

CS

I've tried to build up a a basic cube and as I thought the acuracy of the holes that I've made with my home made pillar drill are not accurate enough, three out of the four top joints worked OK but I've not been able to get the fourth joint to work.

As I've said its back to plan B - where I only predrill some of the holes and use wood screws to join to the blind wood.

...more later.

CS

Folks

After a bit of moving round I did get my basic cube made and I've learnt a bit. I've double spaced my holes to save drilling, but if you do that you have to alternative down each side otherwise you'll not be able to make trijoints. I've make my hole wrong so don't copy my beam - I make one up right at some point and post a pic.

Was surprised how well it when together considering how sloppy my workman ship was!!

Its been very use having a physical model to work with while I work out how to make my daughters chair which will use the same wood dimensions, but I'm only drilling the holes that I need.

CS

Edited 2 time(s). Last edit at 08/03/2011 03:09PM by currystomper.

Here is a link to the prototype gridbeam wooden Eiffel

[reprap.org]

The plan is to play with the form of the structure until I'm happy, then rebuild it using the same technique as my daughter gridbeam chair

Edited 1 time(s). Last edit at 08/29/2011 04:06PM by currystomper.