Rack Termination
 

Hi, this is a framebuilder thread yet I think would be appropriate to ask about building a pannier rack ( or is there another dedicated thread on this somewhere?). Looking for an operational term in metalworking to describe how many rack manufacturers terminate their racks at the point where they are designed to meet and attach to the frame. It looks to me like the alloy rod end is heated, then fed into a stamping machine that simultaneously compresses the rod to a flat shape on both sides while punching a hole through it. Is there a name given to this operation?

Drawing (thinning) and drifting (punching a hole). These are forging/smithing terms. So you can refer to the ends as drawn and drifted.

Rack tabs/eyes are what I usually use. Basically a mini drop out slotted and filled into the rack tube ends. I've got a bunch of differing styles I've bought over the years. Flattening and piercing remind me of a Huffy, not a hand crafted product. Andy

it has been pretty common for racks to be made with the ends of tubes to be pressed together with a hole drilled for the bolt. I was thinking about doing this for a decaleur, which doesn't take much load. With a little practice, you could crush the ends of a tube with a vise or even just a hammer. I feel like the manufacturers don't use heat, I wouldn't

For racks, I braze in a flat piece of metal for the attachment points.

I couldn't find a closeup picture of the end of the rod treatment I mentioned but this picture comes close. In this case they ran the finished ends to an adapter plate (which I think is a good idea). Looks like a crimped end, then drilled for a fastener. Andy, include a link to the tabs you reference SVP. I'm going to take a picture of a no-name steel rack I've got to show the dropout attachment points and how they are fabricated.

https://cimg8.ibsrv.net/gimg/bikefor...0acd706a0a.jpg

you can see on the non-drive-side rack attachment that the ends of the tubes are just crimped. It's unlikely that they are sealed in any way. Probably done in a hydraulic press.

here are some rack tabs, I usually just make mine since I want them to be stainless https://framebuildersupply.com/produ...and-3-8-tubing
Also these MS2007 - steel Rack lug 5 mm hole
LLewellyn makes some nice socketed rack lugs
Llewellyn Rack Boss Kit-1 set (4 pcs) Articulated bosses SS :: Llewellyn Frame Parts :: Nova Cycles Supply Inc.

potentially make a filler piece , that can go in the tube as its squeezed in the vise,
and then you have 3 thicknesses of metal at that point the one you made + the tube wall thicknesses


made myself some rack struts on my last touring bike frame build . use 1/2" square tube.

bottle braze-ons for the rack , a tab of 1/8" steel for the frame end,
folded down one side of the square when I brazed it up,,

A rigid connection.. to my Bruce Gordon Racks..

https://cimg9.ibsrv.net/gimg/bikefor...232ef15139.jpg
https://cimg0.ibsrv.net/gimg/bikefor...703e041142.jpg
https://cimg1.ibsrv.net/gimg/bikefor...8711221b0c.jpg
Yep, that steel rack lug is what I had in mind. Here is an old steel rack taken off that Maruishi. It is fabricated from tubing and has some form of steel rack lug tacked in there. The alloy example is tubing too, crimped out then drilled. That one is a Racktime.

Lets' have a looksee Bob!

I don't have any ready photos of a rack eye/tab but here's a link to Compass Bikes who do supply some. https://www.compasscycle.com/product...framebuilding/ Andy