I actually started with these as they were the easiest to make and were also the smallest so I just about had enough wood to make a new part if I messed up. A luxury that I didn’t have for the main frame of the bike!
All 3 layers of wood have the grain running along the length of the stays. This is perfect for developing the strength and stiffness in the stays but I’m worried about what happens when I drill a great big hole for the bottom bracket and then put a big force perpendicular to the grain. I don’t much fancy my bottom bracket dropping out on the road! So, I’ve reinforced around the BB by putting 2 layers of 175gsm fibreglass tape with the strands running perpendicular to the grain inbetween each sheet of wood. This gives me 4 layers per stay. I don’t know whether this will be enough but I plan to put more reinforcement in the main bike frame so the combination of the 2 should hopefully be ok. When wetting out the fibreglass with epoxy make sure it goes completely see through to avoid any dry patches in the joint.
Head tube, part of set tube and bottom bracket from the donor bike cut to size and welds filed down. I’ve deliberately left the surface fairly rough to give a decent key for the glue to bond to when I glue them into the frame. I didn’t drill any holes in the seat tube as the seat post is such a close fit into the tube I thought I’d probably end up with either a jammed seat or a seat post that wouldn’t fit in the frame if I tried to do anything to the tube.
Swiss cheese head tube? I used a hand drill to pepper the head tube with holes to lighten it. All the forces will go throught the solid bearing mounts at the ends of the tube and into the wooden frame so I’m not too bothered about weakening it in the centre. I’m undecided as to whether I think the holes will increase or decrease the strength of the glue joint when it gets fixed into the frame. It feels like it should give it a bit of a mechanical key to grip on to but there is also a smaller surface area of tube for the glue to bond to… any ideas? Oh, and the lip that you can see at the ends of the tube was just a feature of the donor bike. Nothing that i’ve done. Although, i’m going to use it to wrap more fibreglass tape around the head tube to tie it into the frame.
A couple of shots showing the internal cable guide. It’s made from some 8mm aluminium tube that I picked up at Homebase. I wanted some plastic tube but couldn’t find any so this had to make do. I just bent it by hand with a little help from a vice and it’s big enough for the brake outer to slide through.
Drop outs cut from 6mm aluminium sheet ready to be glued and screwed into the stays
Brake bridge cut from 6mm aluminium sheet and slotted and glued into the seat stays