post blast, pre paint

Dom's bike back from the local sandblaster. I'll have to keep it somewhere warm and dry until it hits the painters: freshly blasted steel rusts like a mofo.



the whole frame...



head tube...



top tube...



lower head lug and fork crown...



brake bridge...



bottom bracket and bridge....

Hopefully the next shot has it with some paint on it.

And now for something completely different...

Making some stainless ring-bolts for rock-climbing applications.



30 odd lengths of 316 stainless, cut to length and then a section of texture added with the angle grinder....



... and half a dozen deep notches added to the end of the shaft to provide maximum adhesion for the glue without compromising the strength of the rest of the bolt.




The bender, in all its junkyard glory. The square table thingy pivots on some big bearings, and the thick bit of steel rod in the middle is the former around which the rings bend.




The finished product. All of the bending is done cold, and there is quite a bit of spring in the steel, which means it is impossible to close the ring up completely, so once all the bending...




...is done and all of the rings are ready for welding...



...they go into the next step, which is a little hydraulic press made from an old car jack I found at the rubbish dump. The ring goes into a little slot and then after a few pumps on the jack handle, the ring closes up enough to weld.




Tack weld done in the hydraulic press holds the ring shut until I can do the full pass...




with the TIG welder and some 316 filler rod. There is one final step - to pickle the rings in an acid solution to remove the oxide scale and restore their corrosion resistance. It's hideously toxic though and I'll wait until I've finished the whole process before I do it. But that's the process in a nutshell.

And last of all, the chainstay brace.

All mitered up, and snug against the squared off points of the bottom bracket lug.



And from another angle...



This chainstay brace was brought to you by Coopers Stout. You can see the frame - toasty flux and all - cooling in the vice.



From now on, the work is largely cosmetic - cleaning up around the bottom bracket, tapping the threads in the BB and generally cleaning up around the edges - aka shorelines - of the lugs. But basically, you could whack some wheels and a groupset on this thing and ride it now.

Adding the final touches...

First the braze-on stop for the rear derailleur cable. Obviously it's running on the underside of the drive-side chainstay. First I cleaned up the chainstay with some fine sandpaper to get it nice and clean...



...then fluxed it up and put a tiny blob of silver filler onto the tube...



...then put the clean, fluxed stop on top of the silver, weighted it down with my 'brazing finger' and gently sweated it with the torch until the whole thing came up to temperature and the silver flowed neatly around the cable stop.



Hard to see with the flux still in place, but it's got a neat radiused fillet of silver around it, blending with the tube nicely.



Next, the rear brake bridge. I'm sure there are simple and fast ways of doing this, but I didn't want to take the risk of buggering it up as (a) it's my last brake bridge of this type and (b) the closer I get to finishing this frame the less I want to mess anything up. So I scribed some lines on the bridge - same distance from the edge on each side - and used the lines to ensure that I kept both sides of the bridge even as I was trimming it to length. I would file it down with a round file and then smooth out the filed scallop with a grinding stone I'd dressed to be the same diameter as the seat stay.



Because of the curved nature of the bridge, I had to have some way of knowing when the brake hole was at the correct height, so I ran a piece of tape across it to give me a reference.



And after a lot of patient filing and grinding, this was the result: a very neat tight fit with no gaps. Should braze up very nicely indeed.



And below, the finished bridge, ready to go in. I'll braze this in tonight, which just leaves the chainstay bridge till it's all finished.



Edit:

The next day, post clean-up...



And the brake bridge. As I was doing all of the mitering to get this to fit I was cursing the design of the bridge and it's v-shaped profile. Compared to a straight bridge it's a pain in the arse to fit. But all faults were forgiven once I soaked the flux off. All of the effort in getting a tight miter paid off and it looks fantastic. Will definitely use these again.

Just a quick update. Stole some time this afternoon to work on cleaning up the seatstay to rear dropout join. I said some while back that you do these by adding an excess of brass and then carefully filing and shaping it back to a smooth joint. I do the front and back of the join first, filing the brass an steel tab of the dropout down to a nice smooth transition, and then I hit the sides of the join with a sanding drum to get a concave face at the bottom of the stay.



It's a ridiculous amount of work for such a tiny joint. I'm sure with better brazing and heat control I could get the work required down a bit but for the moment it's a real time soak.



A while ago I posted a pic of a frame I made for myself last winter. It's been off to the blaster's to get sandblasted and I'm just giving it the once-over before getting it painted. I used a wishbone read stay on this one. You can see where the seatstays join into the Y-shaped yoke and where the single tube continues up to the back of the seat cluster. Looks cool, but I'm not in a hurry to do another one.