gugie 

While I dream of someday investing in a Di-Acro, I've been getting along with a $10 Harbor Freight 3 tube diameter for over 60 racks and dozens of decaleurs for several years now. When I bought it I figured it was a starter tool, to be upgraded later on, fully expecting it to break after a dozen uses. It's been holding on for 7 years now! For larger bends I use DIY wood "pulleys". There are some tricks to using these tools that I've figured out over time.

I mostly work in stainless steel to avoid the cost and hassle of chrome plating, but recently made a rack out of 3/8" CrMo with this bender. It's damn hard to bend with my litle $10 tool, but I'm just barely able to do it. Note that this bender makes as tight a bend as a given tubing diameter can take. You can search for "tubing minimum bend radius" for rules of thumb, as well as engineering analysis of why this is so.

I've got a box full of scrap while learning how to use my meager tools. Measure once, cut twice, buy more material...

Jim, neat idea to use that quick release pin! Bag ejection on bumpy roads is a real thing.

Schlafen

That is such a clean setup. I wish I knew clamping the fork blades like that was an option before I had canti posts brazed onto my Peugeot.

Piff 

Beautiful rack, and inspirational. I hope to make a similar rack for my road bike within the next couple years.

Is it possible to talk a little about how you made the fork clamps? Thanks.

bulgie 

Well, whether it's really an option depends on your luck finding someone willing to make it. I doubt Jim is offering to sell these (Jim,please correct me if that's wrong).

Most other builders will be put off by the challenge of making those clamps, which are clamping to the blade where it's still oval and tapering. I expect that is very finicky work, unless Jim has some shortcut. It definitely can't be done without the builder having your fork in his hands, because every fork will be slightly different at that point.

I would caution any wannabee rack builders to go a more standard way for your first few racks, don't try Jim's way until you have achieved mastery!

merziac

It would also be notable to understand the reasoning for doing it this way despite the challenge, maybe @Portlandjim will expound on it for us.

Its been interesting to see other builders have an epiphany while looking at mine and we're talking serious, long respected ones.

Schlafen

I can make clamps, not identical, but ...clamps. My fork has quite thin and flexible blades, I very much love how it rides, but I was worried the fork blades would be damaged long term by the extra load applied in a flexible part of the fork.

My frame and fork have been PC'd recently, now they need re-doing

Portlandjim

I am not going to make any Merz racks for sale these days! When I designed the Specialized Expedition bike, 1983 or so, I really wanted to offer this bike with serious touring racks. As Mark mentioned above, bicycle frames are not the same even within the same batch of frame/forks with the same size. There is no way to do this in a production setting for a price that any customers would accept. My racks with these clamps are equal in strength and stiffness to brazing the racks onto the frame and fork. Plus, this method allows the option of easily removing the racks for transport on an airplane or just riding the bike without racks. The other problem with trying to sell them on a production bike​, even with an inferior mounting method​, they still cost ​t​oo much, both for materials and labor. In the end I gave up, Blackburn racks were so cheap and worked OK for most riders. My racks will hold up if you want to ride around the world, and are night and day better than Blackburn racks (or any racks!)

. Check out this story from Bicycle World, it mentions my racks.

Mark is correct in his comments about the clamps. I figured out the taper of the fork tubing, this is tricky as the tube is also flattened. Then I made the tube that goes around the fork tube out of thick tubing, the inner and outer are taped using my CNC lathe. This tube is ovalized to match the fork at the mounting location. The threaded barrels are brazed on to this tube using a fixture to ensure that they are postioned correctly, then each clamp is slit using a saw in my milling machine. Getting these clamps onto the rack struts in the correct position is done off the fork in this case, the fork was painted which meant on brazing with the clamps in position is out. All this work has to be done as a one off, it's very time consuming.

repechage

I viewed that clamping method and saw labor hours, a not economical amount, milling with a digital path can of course help but still has to be programmed.
I looked at those keenly to see how an almost as strong, visually simpler way could be fashioned, might be possible, maybe not.

HelpSingularity 

nkk

What a beautiful rack!
But those fork clamps are the bomb, absolutely sublime.
Way to go!

repechage

With the Legend of Turbo Cotton tires.

repechage

that is a one man workshop definitely, OSHA would faint. Marvel at the motor reduction of the turning apparatus on the wall.
this shop has great natural light as the roof is glass, used to fill the space of the light and air shaft of the surrounding building.
C.N.C. Also had a space similar, also in Paris.

Portlandjim

I have the HB bag mounting parts for 3 bikes ready for the plating shop. I've decided to use Electroless Nickel Plating, with a glass bead blasted base. All 3 of the handlebar decaleur mounts are different, because the stems are different. The one in the middle clamps onto the bars, I'm using a Cinelli 1R stem so no clamp bolt. The one with a stud is for a 1A stem, the other one is for my Singer. These decaleur parts are fiendishly difficult to make, at least the way I did them is! The small "U" shaped tube thing mounts onto a Merz front rack, this allows the French style handlebar bag to be mounted.

repechage

Detailed parts. No economies of scale there other than task memory

Portlandjim

The pin and receiver tolerance is a killer, diameter (ID and OD), the spacing distance and parallelism on both parts. Because these parts are brazed, they don't stay where they should be after they cool. There is zero market for these parts in any case. Every bicycle is different, with a different stem position and design. Almost a requirement that to be any good they must be one off custom designs. One reason those old "constructeur" bicycles cost so much.

bulgie 

Speaking of finicky designs I wouldn't want to have to mass-produce, here's mine, made to fit a '50s French bike:



Because it attaches to both the front and the back end of the bar-clamp bolt, it's triangulated = very stiff and strong.

The part that bolts to the bag is from a Berthoud decaleur. But I didn't like that way they used a solid-steel pin, the full length of the bag, to join it to the stem-side piece. (solid steel = heavy!)
So I drilled it out to fit a 3/16" thinwall stainless steel tube to replace the solid pin. It fits more snugly than the Berthoud pin too, reducing the slop. Berthouds flop around a little and even rattle on washboard; mine has no noticeable slop while riding. On mine, the SS tube has a springy flare at the end that snaps into place, no other retention needed. The Berthoud needs a spit-ring or safety-pin, which you have to remove and then keep track of (not lose) while the bag is off.


This all started because someone gave me a Berthoud decaleur for free. Fixing the things I didn't like about it ended up being more work than just making my own decaleur frm scratch. The only Berthoud parts left are the two tubes that bolt to the back of the bag. But now that it's done, I do like it.

Next I'd like to make a Routens-style, like the one Jamie Swan made for himself. Simpler and easier to make, but also pretty excellent in use.

Mark B

Portlandjim

I got my front bag parts back from the plating shop on Monday. I decided to use electroless nickel plating, with a fine grit blasted prep. The color has a brown tint, it's not going to be confused with chrome plating. The reason I went with this finish was mostly because it is very thin, I chose the coating to be 0.0002". The pins need to fit into the receiver with no binding if the bag is to be removed without issues. It turns out that this plating is very slippery, the pins go in and out perfectly. Chrome plating builds up on the edges and can change the fit on threads. It's also very expensive, especially if you choose a first class shop. Electroless nickel is not cheap either, but it's less than chrome. It's also very good for resisting rust. This Decaluer is made for a Cinelli 1A stem. Pressing the blue button lets the 2 balls to move inside the pin, allowing the bag to be easily lifted upward. The "U" shaped tube that the detent pin goes in has been machined before it's bent, so that the detent balls open without any up and down play. The alignment of all these parts must be close to perfect, not easy to do for brazed assemblies.

tiger1964 

Lovely work, and that from someone with a major aversion to racks & bags on my bikes.

So, do you do your own plating? Is that practical in a non-commercial application?

There is one chrome shop within a sane drive of me and, if it closes, I could see that being a problem.

Portlandjim

Electroless nickel plating is not something for the home tinkerer to tackle. One can purchase DYI electroplating kits, I just found this source for example: https://caswellplating.com/electropl...ting-kits.html

I don't want anything to do with working with toxic chemicals myself. Chrome plating in California will be gone early next year from what I've heard. It's so expensive now, it really doesn't make sense to chrome plate bicycle parts. It's almost always less expensive to just purchase NOS or nice used parts. Jim Merz

repechage

My nextdoor neighbor just got back a set of trim rings for a 1960’s Lancia.

chrome will still be around next year but at this point the end is near. 1/2027 is by reference when time is up.

what it means if not delayed by courts, items to be plated will have to be shipped out of state.

chrome is already being phased out in the Auto Industry. If one looks around, very little being used now, stainless, aluminum are the current bright work elements. Badging will probably be the last to go.