Filed In: Process

Father/Daughter Project - Part 5

November 29, 2019   |   Chris Blandford

Moving on to the chainstays.

Steps for today:

…
3. Tab Dropouts; Slot Chainstays
4. Braze Dropouts to Chainstays
5. Finish Chainstay Ends
...

Before I dive in, one thing to note. For the first couple frames I made I did things one step at a time, with a sort of process tunnel vision. Now, however, I tend to do things whenever it makes most sense in the overall build. An example of this is with the chainstays. Previously, I would’ve brazed the front triangle together before even touching a chainstay or dropout. Now, however, I work on these as separate sub-assemblies of a larger whole, prepping everything in anticipation of finally joining stuff together.

Anyway. I begin by laying my chainstays on top of my overview drawing. I include the tire, chainring(s), and crankarm in these drawings, and check that the chainstay will clear all three. I also check that the outer diameter of the dropout end isn’t wider than the tab on the dropout. It’s a bit of a balancing act to choose the most appropriate chainstay (to this point I’ve only bought pre-formed stays--I haven’t bent my own) and get it ideally positioned. Once satisfied, I trim the dropout end of the stay to length and rough-cut the BB ends to length. Then I lay the chainstays on my surface plate and run a straightedge across their tops, scribing a “top” line onto both.

Tool note: I use my Anvil fork jig as a makeshift chainstay jig. A while back, I made a crude little adapter that fits in the steerer tube holder of this jig. It holds the BB ends of the chainstays in place while I work on them, kinda like a crappy chainstay mitering fixture. (I miter out of the fixture, but the jig is helpful for getting everything in its place.) I use the fork rake measurement and a little math as a makeshift BB drop/rise indicator.

Next, I put a tab on the dropout. For chainstays, I’ve been making these 8-10mm deep. I check the internal diameter of the small end of the trimmed chainstay, and take off an equal amount of material from each side of the dropout (hacksaw first, then files), so that the tab fits into the stay.

Filed In: Process

Father/Daughter Project - Part 4

November 25, 2019   |   Chris Blandford

Ok, enough of the planning and ordering. Off we go. I’m going to start with the Daughter bike, and--as such--have set aside the Father bike’s materials for now.

To this point, I’ve always started with my bicycles’ frames. So, same here.

Steps for today:

1. Clean and Inspect Main Tubes
2. Miter Front Triangle
...

First, I clean the head, seat, top (though not in this case), and down tubes, inside and out. For this, I use 80 grit emery cloth (shoe shine style) and 91% isopropyl alcohol.

Filed In: Process

Father/Daughter Project - Part 3

November 22, 2019   |   Chris Blandford

Time to play connect the dots.

To this point, I’ve been designing my bicycles based--largely--on the published geometry charts of brands and builders that I respect. I don’t have the riding experience to have justifiable opinions about much of anything. So, I build to match models that look interesting to me, adjusting here-or-there for fit and whatnot.

Given that a kid's bike has all sorts of odd things going on (and given that nobody publishes dimensions for these little bikes) I decided that--for the Daughter Bike--I’d just go ahead and pick up a stock model to have on hand. (Sorry if that’s cheating.) On Wednesday I purchased a 16” Cleary Hedgehog from Clever Cycles here in Portland. This would’ve been the model I’d bought if I wasn’t planning to build Mathilda a bike. Yesterday I stripped the frame (see Nerdnote A) and took measurements, plugging them into BikeCAD as I went along.