Darth Lefty 

As I mentioned in another couple threads, my wife got me a Calfee DIY bamboo kit for Christmas. It's probably premature since it hasn't even shipped yet, but I figured I'd start a build thread to keep myself going. I was interested in the kit from the time of the Kickstarter, and I watched all the build videos... but at the time we didn't have the budget. I was really disappointed both that I couldn't buy in, and that it didn't fund. I was happy when the kit came up for order on their website. But I still put it off until SWMBO gave her blessing. I bought the 29er kit in size medium, along with the plan and some small parts. The kit contains the bamboo and several major fittings (BB shell, dropouts, head tube, an insert for the seat tube).

This being my first effort at a bike frame, and the first major hobby project for me in a while, I intend to build it up just according to plan. The kit makes a very conventional MTB, with 135mm QR and disk brake. I did have a list of things I wanted to try. Colored cast wrap was the only thing specific to the basic idea of a bamboo bike. I wanted to try a thru axle, longer slacker frame, 27.5+ tires, Boost spacing, all the latest stuff. But all this isn't really included in the kit's design, and I can save it for a second effort of my own design if the first one works out ok.

I haven't sprung for the jig or the tool kit. For mitering, I figure I'll borrow use of a drill press and hole saws, or just file it by hand as Canaboo suggested in the Kickstarter thread. The jig is a bunch of hardware store plumbing and I think I can recreate it without too much cost.

I'll post up photos when the kit arrives. I don't know when I might start building. My family is about to add kids 2&3 at once, and one part of me thinks that I'll be able to work on it during the work outage. I was able to work on and build up a bike during kid 1. But the other part of me remembers the extent of the effort required for kid 1 and approximately doubling it, in addition to kid 1 being 2-1/2yo now. Will I even survive, much less play with a hobby?

Darth Lefty 

According to FedEx, the package has been delivered. It took just one business day because I'm only a couple hundred miles from Calfee. But it also took eleven emails - so far, could there be more? Five from Calfee and six from FedEx. I guess Calfee has all the notifications turned on. I suppose this makes sense for someone anxious about their custom carbon fiber tandem, but for a box of heavy-duty toasted veggies, it does seem like overkill!

Darth Lefty 

The contents of the box. Check it out, curved chain stays! They look creased so I guess they were formed this way as they were dried, not grown this way. The cast wrap was packed in sort of like packing material... just lots of little clever ideas like that throughout the project. I was curious how the design would handle fork travel as the ad copy for the plan said it would handle all common lengths. It has different "pages" for each travel that tape over the head tube area of the plan. That adds even more adaptability if you moved those pages around. The fittings are all aluminum, not that weight is going to matter... the downtube is like a baseball bat!


Untitled by Darth Lefty, on Flickr

squirtdad

Funny Calfee provides JB weld

Darth Lefty 

I watched the videos today and took some notes about the jig and tools. I chose the 44mm head tube, which means I'll need a 1-7/8 hole saw. These exist, but individually, they don't come in hole saw sets. I think that the smaller head tube could have used a 1-1/2 hole saw, which is the same size as all the other miter cuts. The bottom bracket tube is 68mm wide. It has a score around one side so you can remember which is left and right... though I didn't determine which yet! The head tube, BB shell, and seat insert are all knurled.

Canaboo

Nicholson half round rasp and coarse sandpaper stuck to a tube of the same size as your metal pieces is a better plan.

Darth Lefty 

The Calfee jig puts the frame centerline at 101 mm in the air... or four inches. I stopped by the home improvement store with the kit's hardware in my pocket. I started in the tools, but their selection of rasps was pretty crappy, so then I went over to the plumbing section.

The bottom bracket shell sits over the outer diameter of a threaded 3/4" fitting and the fitting has a hex that the shell will rest on. I had a hard time doing math while wrestling the 2yo, however, and so I didn't get it up to exactly the right altitude, need to go back and get a different stackup.

The seat post shell fits over a 3/4" pipe nicely (3/4" pipe is 1.05 inches, 27.2 mm seat post is 1.07 inches).

I was looking for a similar trick with the head tube... But I stopped there since kiddo was bored with playing with pipe fittings and needed lunch and nap. The seat tube and BB shell will get me through first blood on the bamboo. I looked it up just now and the OD of a threaded 1-1/2 PVC fitting should be 1.72, which should do the trick.

helixbikes

Thanks for posting this! I'm patiently awaiting the 29er kit from Calfee, and look forward to following your adventure. One of the biggest frustrations - and fun parts of this build - is the lack of information about it so far. Good luck with the build!

helixbikes

First question: what is the BB situation like? English, BB92, or something else?

Darth Lefty 

@helixbikes it's Swiss... just kidding! English, 68mm.

I got my rasp, a 4-in-1 8in rough and Nicholson brand just like Canaboo said. Got it at Ace because Ace is a hardware store and not a home improvement store and I'm realizing there is a difference. Still, it was the only rough one they had - all the others were bastard cut or smooth cut. I'd have preferred a long one with a handle.
https://www.nicholsontool.com/files/r...-and-file.html

I got another couple of fittings but still not happy. I figured a thread/thread coupling would work but the ones at Ace had full length ribs and no hex at all. So I got a thread/slip fitting but it's too small dia on the slip end and it sits too high on the union. The shoulder of the fitting needs to be at 67mm which is just lower than the BB shell itself, you can see that the new stack on the left is too high and the right stack is too low. It would be easy with slip fittings but the NPT threads give a lot of adjustability. Still, it needs to be reasonably close to begin with. Will try back at Lowes or Home Depot to see if their fittings have slightly different ribs


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etw

Very cool idea. Keep posted on progress. Part of me would love to tackle this kind of project, but I also fear being over my head and ending up with a pile of random pieces of bamboo sitting in my basement, not knowing what to do with it. Maybe you will inspire me.

Canaboo

You won't get far with that rasp. You need the half round pattern makers one. Order one online if you can't find one locally.

Darth Lefty 

@Canaboo You keep giving me new search keywords

https://www.toolsforworkingwood.com/...ality%20Issues.

Canaboo

Good quality is hard to find. For the amount you are likely to be using it even a sub par one will get the job done.


You can just use the floor sanding sandpaper from Home Depot stuck to dowels or pipe for the finished miter. You can remove the bulk of the material by just cutting a shallow v and then rounding it out.

Darth Lefty 

Before I spend fifty or a hundred bucks on a handmade file I'm going to go through my late grandad's jumbled box of old tools and see if there's anything in there that will do the trick. That reminds me, I need to make sure my tetanus shot is up to date.

Darth Lefty 

I'm home due to a daycare snafu, and kiddo is napping.

The seat tube is a few inches longer than needed, giving some extra material to practice mitering.

This is a program that calculates a pattern for mitering. Enter a very small thickness for a close fit, otherwise it calculates per the inner diameter of the cut tube for a close welding fit (explained further down the page).
Tube Coping Calculator

Let's see if it will do the attachment. This is not a real angle on this bike, just a rough guess at the head and down tubes for demonstration purposes.

Darth Lefty 

Some photos. Grandad's tools were just as I remembered, a diesel-smelling clutter of small hardware and little homemade metalworking tools interspersed with Copenhagen tobacco cans containing electrical tape and other little containers. This is only a small sample. There are a ton of little files, but nothing really for woodworking, which fits my memory of his hobbies. He probably made this toolbox.


Untitled by Darth Lefty, on Flickr

Then a couple of the miter pattern in action. It doesn't perfectly work because the tube isn't really cylindrical, it's conical, bigger at the nodes. I relieved the back side of the pattern a little by making little cuts in it. Canaboo is right, the going is slow with this dinky rasp that allows only 3" strokes. It's not impossible, but to do ten of them I think I'll find another way.



Untitled by Darth Lefty, on Flickr Untitled by Darth Lefty, on Flickr

Canaboo

Notch it more aggressively closer to your line. The seat tube is the easiest one to do. It's the only one that is just a straight up notch with no angle to the miter. Your seat tube/tt may also be close to this.

Darth Lefty 

And as they rode, Arthur said, I have no sword. No force, said Merlin, hereby is a sword that shall be yours, an I may. So they rode till they came to a lake, the which was a fair water and broad, and in the midst of the lake Arthur was ware of an arm clothed in white samite, that held a fair sword in that hand. Lo! said Merlin, yonder is that sword that I spake of.

The 10 in Nicholson rasp cost about $45 with the handle at Woodcrafters. Oh my God, is that ever a candy store. Don't go in there unless you have zero extra money beyond what you're buying. The handle is threaded like a die and the threads grab the tang as you screw it in. This is new to me, every other file handle I've ever seen was just pounded-on, and coming loose.

Near miss shown on index finger... Old scar from 20yo accident with a hobby knife, too. Perhaps I should be wearing gloves. Apropos of that, I did find out today that I had a tetanus shot about a year ago. My wife had me get a TDAP, for the P on the end, not the T at the start. I had just forgotten. With the babies nearly here, I needed to check.


Untitled by Darth Lefty, on Flickr

This went very quickly. It would have gone quicker yet if I'd had the tube in a vise instead of sitting on it on the steps of my deck. The bamboo is hard as heck. I bet it's as strong as any other bike I've got, except maybe the tandem, but I'm not going to go around the garage smashing seat tubes to test my theory! I've got no doubt that there's enough strength here for the tubing, as long as my joinery turns out ok. It's not perfect with some daylight showing through, but good enough for a first practice shot. With the wrap-and-sand for finish, the real cut should go great.



Untitled by Darth Lefty, on Flickr
Untitled by Darth Lefty, on Flickr

Canaboo

You'll be able to close that up quickly with the sandpaper. Make sure you align the miter so that your seat tube quirks are front to back rather than side to side. Looks like you've a got a slight bend that will match the wheel curvature.

Darth Lefty 

That's what Mr. Calfee does in his video. Thanks for following along, you've been very encouraging

Abe_Froman

I want to build a frame now

Darth Lefty 

No progress report, but some notes. Mountain bike tires usually have their max width on the casing somewhere but they also have a shoulder at the edge of the knobs and their cross section is sort of lightbulb-shaped. This frame does not have any cross members to worry about at the OD of the tire and of course the stays get further apart as they go back, so this is the place to worry about clearance. Surly and Schwalbe both helpfully have dimensions for their tires at this location. The shoulder for both 27.5+ Dirt Wizard and for various Schwalbe 29er x 2.3 (60-622) is around 345mm from hub center. For 29er tires the shoulder is up to about 62mm and for 27.5+ it's 75mm or more. And then of course it needs some clearance - which is why most of those 27.5 plus tires will fit in a 29er frame with some close clearances. There are some tires listed as 27.5x3 that are really 3" (both WTB and Schwalbe have both 2.8" and 3" tires). There are some that are listed at 3" but are really more like 27.5x2.8. The Dirt Wizard seems to fall into the latter family.

Looking at my stays, I'm thinking the limiting factor will be not the curved chain stays but the straight seat stays. They sit a bit wider by the hub because the upper part is bolted on the outside of the dropout, but up at the seat tube they go together pretty closely. They're about 1.5" apart at the top and 6" apart at the hub. They might be a little bent at the nodes. Will it be enough, even for the 29er?

Canaboo

You can set them as wide as possible on your seat tube and/or bend them slightly with a heat gun to gain clearance.


Bamboo plasticises readily with dry heat.

Darth Lefty 

Notes continued.

The fitting that I'm using for a base of my jig stands is called a reducer bushing. It's about the size of a MTB tire, and a similar, modified part is what the Calfee jig uses for a MTB tire fit check.

I checked my seat stays. One of them has a very slight bend at the node. The other one is kind of weird - on one side of the node it's straight, but on the other it's bowed, and yet the bow curves out and back in to put the end of it still in line.

I don't think 27.5+ tires will be possible unless the stays get bent, or replaced with bent ones like the chain stays.