Rack Building Basics — Eyelets
It’s been a long time since I’ve posted a Rack Building Basics entry, but I still have some in the queue.
Today’s photo series is about making the eyelets that connect the rack to the fork or frame. There are a couple of ways of doing this, but this series focuses on doing it with brazed in tabs made of flat stock. This is similar to how dropouts are made.
The first step is making a slot in the end of the tube for the tab. I draw the slot and then use a hacksaw and a thin file to make it:
Now we need to cut a piece of flat stock to fit. I purchased 3′ of 1″ wide 4130 which is perfect for this purpose. You only need to make a single cut. I use the tubing as a gauge to how wide it should be.
The tab is the same width as the tubing:
Brazing just the tab in is probably strong enough. Note that I filed the end of the tube to slope the tubing towards the tab:
I like to fill the whole end of the tube with a “plug” of brass. To do this you heat the whole end of the tube and draw the brass around below the tab. I’d do a few tests first and cut them apart to see how well you do at pulling the brass in. It is a bit hard to see in this photo, but the whole end of the tube has brass in it.
After removing the flux I doa little work with a round file (12″ round which is about 10mm or 3/8″ in diameter) to make a nice clean scallop. The tab has also been bent to match the angle needed for this rack:
A bolt hole is drilled and a file is used to ease off the edges:
A final photo showing where this tab is used on the rack. It connects the stays to the fork blades:
At the start of the entry I mentioned that there are other alternatives. A nice and easy one is to braze a piece of tubing perpendicular to the stay and run the bolt through it.5/16 x 0.035 tubing is a nice fit for an M5 bolt. This is an especially good idea if you need a spacer to clear part of the fork blade. In this example the tubing is extended on the inside so that the rack can clear the fork blade even if the fenders aren’t installed. This is from the first rack that I built:
Another option is to simply flatten the tubing in a vise and drill a hole through it. I think that this looks a little less refined, but it is strong. Sorry, I don’t have any photos of this approach.
Alex,
I see by the condition of the flux of the post brazed tab that you”ve gotten the heat control down.
Nice work!
I”ve spent a lot of time looking at the eyelets in “Golden Age” and also at the photos on the Rene Herse web site. It seems that the sheet stock was usually wider than the tube stock. Makes me wonder why. I like the cleaner look of having it the same width, though.
What thickness of sheet stock are you using?
Thank you Alex, for the clear and well-illustrated explanation. Concerning the “horizontal tube” type of tab, it seems like it would be stronger than using spacers in a similar application. Long bolts used with spacers to attach front racks to fender eyelets on the rear of fork ends always look to me like they could break off at the eyelet. Justin
Mike — I”m using 3/32″ flat stock (or it might be 1/8″).
Tabs wider than the tube are probably stronger because you get a fillet on the inside and outside of the tube. I prefer the look without the wider tab though, and I think that it is plenty strong without doing that.
Justin — I prefer the look with an integrated spacer instead of additional ones too.
Perhaps we need a post covering non-90° mitered joints and the mitering of a porteur rack’’s v shaped stay. I think I know how to do it but I”d rather read about it here first.
Serge — That is the last one that I have planned. I took some photos showing how I used to do it, but Alistair taught me a faster method. I want to practice the faster method a bit before posting about it.
I”m between rack projects at the moment, so it may be a month or two before I get there. My current project is building a canti boss brazing fixture.
Could you tell me what the two methods are? I”d about to start practicing brazing again. I”ve only done 90° joints. does it involve the tubemiter patterns?