Keyrings keep breaking

Heya

Still really new to glowforge and I have been having some issues with the keyrings I am making, the circle cut out area keeps breaking!

I am using 5.5mm thick oak for the keyrings and am attaching the split ring straight to the charm.

I have left a 3 mm border around the hole cutout and this is where they are breaking, I can see tha this would be a weak point as it sticks out but can’t figure out a way to fix the issue without changing the shape of the whole design.

If any one has any advice on what I can do to stop this but ideally keep the awesome shapes that would be greatly appreciated.

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The only thing I can think of is hardwood is far more fragile than plywood. You just said “oak”, so I don’t know which you are using, but oak plywood would be stronger than oak hardwood.

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One thing I learned long before Glowforge is that sharp points focus the stress. If you made those points the same radius as the hole it would not be a total solution but a big step to one. The choice of oak would be a point as well if you are going to use oak. Good white oak has a much denser structure than the more common red oak.

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Can you show us a picture of a broken one? That way we aren’t guessing at where the break is happening and can give better suggestions?

This it what I relearned about rings:

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Your keychains have a very porus grain structure. This is going to cause a lot of potential stress fractures. I’d highly recommend either 1: switching wood or 2: if you’re set on using that wood seal with a few layers of ether CA glue, thick polyurethane, or a few layers of lacur. Any of these will fill in the voids and give some extra backing

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You could also put in a metal rivet or eyelet.

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Thats a great tip! I will definitely have a look at that on my future designs

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Here is an example of one of the broken ones. I have tried using the medium and thick prograde plywoods from GF and then have been using some oak hard wood from 908 ltd and then finishing it with danish oil

Here is the wood I have been using Solid Wood Sheets, Oak

Ah, I didn’t realise that. I can email the company I got the oak from and see if it is white or red oak - it just says oak sourced from France on their website.

The grain of hardwood is a weak spot that tends to split, so I’d change the direction of the grain so it’s running vertical. Combine that with a beefed up hole, and it might work. I still think it’s going to be prone to breaking though, and I’d suggest switching to plywood. (The sandwiched layers of plywood is much stronger.)

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I have tried with the thick proofgrade ply and had breakages with that also, is it worth finding a different supplier of thick ply? not sure how the GF ones compare with others.

You can try, but the keychain hole has to withstand a lot of torque when in regular use, and I’ve never had any survive a long time on my daily keychain, even with plywood. I resorted to layering the wood with a thin layer of acrylic on the back for stability. (Or you could sandwich it between wood.) You could also try draftboard (aka MDF), and it might hold up better since there is no weak grain. But I get that it wood (pun intended :stuck_out_tongue: ) be a very different look than you have here.

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I think you are on to something. The thick plywood (at least in the PG) is not MDF core, so I it would not be quite as strong. I think the MDF (or Draftboard) would provide more strength.

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I usually just add either 9mm or 12mm jump rings on my keychains. Every time I try just putting the keyrings through, whether wood or acrylic, I break the hole. Jump rings make it easy.

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Try the medium instead of thick, it has a different core as @bill.m.davis mentions.

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Oh yeah, good point; I use jump rings too, and they really help.

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And for those already broken you might make a few of these with the tips apart by just under the thickness of the pendant
hanger-2
:grin:

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I will try out the jump rings as I have not used them before :+1:

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What are peoples thoughts on using Bamboo for the keyrings? Or as they are pressed strips would that be a weak point?