JonnyHK 

Something I've 3d printed for a friend is some bottom bracket clamping parts to help him when he is repairing or repainting frames.

Basically a number of different sized top hats that take a 10mm threaded rod so you can clamp the frame more easily (you need two of each size).

Free to share https://www.thingiverse.com/thing:4671416

guy153

Nice but I think they might go a bit melty if you were repairing the frame!

Cynikal 

If you want to hold your frame by the BB and use heat, these will do the trick.

BBBS Bottom Bracket Buddy System - Peacock Groove

duanedr 

These make no sense to me. Were these an initial attempt at 3d printing? Is your friend building in carbon? The problems i see are soft material wearing out fast and not taking as much clamping force as metal. 3d printing this very simple part would probably take longer than machining it from steel or aluminum. And having a bar running through it, ensures that the user will be fumbling around trying to manage the 3 pieces. Making them out of metal and adding magnets and a lip to the backside so they stick to the vice as it opens and closes will make these really useful tools. Maybe making them cones so they self-center would also be good.

unterhausen

magnets, a lip, and less protrusion into the shell would make these a lot more useful. Even in plastic.

bulgie 

The Peacock Groove ones linked to above are even more sensible, with their lip that catches the top of the vise jaw. I saw them and had to have them! They're on their way to me now. Thanks Cynikal !

Mark B in Seattle

JonnyHK 

Not if you are repairing another area or if you aren't using heat.

They solved his problem. Most of his work is renovation, so just holding the bike steady so he has a free hand seems to be what he wanted.

He doesn't have access to a lathe (nor do I) so this was a very quick and cost effective solution.

I could probably find a way to insert magnets now that it has been suggested.
I didn't think a cone shape would work with the 3d prints - too much point load on a fairly weak material. Easier to make multiple sizes.

unterhausen

it's much better to have a cylinder than a cone, although I didn't see anyone suggesting that.

I think they would be useful, but the lip on the big end would reduce a lot of frustration. Although that would mean a lot more support material to remove, I guess
Probably could achieve the same thing by having a bolt hole off-center

Cynikal 

Always happy to support a small builder and enable someone's addictions. They are on my list as well. Need a disk brake jig first.

duanedr 

Got it. Proof in the pudding and mother of invention team up for the win again!

Yes, i see your point regarding a cone with 3d printing - i was thinking in metal. This thread has me thinking i'll make a set of cones with a lip and magnet. I made a set a few years ago with a lip and the lip is game changing. I made them for BSA shell and need them for T47.

Thanks for sharing!

unterhausen

I don't understand why you would make a cone. A cone can tilt quite a bit. Stepped cylinders are a much better idea. For all practical purposes, you just need T47 and BSA.

Andrew R Stewart 

And I've been using small squares of 1/4" plate to sandwich BB shells for years. Where have I been?

I do have a couple of printed plastic dummy headsets that are very nice when mocking up or traveling with the fork in place. Andy

unterhausen

In 45 years of building, I have never really been tempted to hold a bike by the bb, what does that help with?

bulgie 

It's how I spread the dropouts, like when someone wants to go to a wider hub (repair/mods, not so much for framebuilding). Back when I had access to an alignment table that held the BB shell, I still found the vise method quicker than using the table. Now that I don't have a table, the vise method is my only choice.

At Davidson I modified a vise, making tall jaws that were thick brass and taller than even a tandem eccentric BB shell, so I could grip any BB and get full purchase on the faces. Had to remove the cast-iron projection below the jaw-mounting bolts, that the original jaws sat on top of. Downside, now any really major hammering from above was only being held by the bolts in shear, and friction. But this was not a vise for hammering, we had other vises for that. So it was a full-time soft/smooth jaw vise, but still pretty good for general use. I miss that vise.

Mark B in Seattle

duanedr 

Yes, I see your point. As always with framebuilding, individual processes are different. I'm just thinking that if the angle of the cone would be at an appropriate angle to accept any BB diameter within a reasonable depth (1"-1.5") and be of a sufficient hardness that it doesn't hang up as the BB is tightened in the vise, it would be better than a stepped cylinder. This assumes that a stepped/shelved outer end was part of the design. This shelved outer end would interface with the vise jaws and hold the BB shell perpendicular to the jaw as it closes, It would then be a matter of holding the frame in the left hand with the BB 'roughly' in line with the cones and tightening the vise with the right hand to secure it.

I clamp frames like this when doing rear end alignment/widening work as well as fillet finish work, braze on work, HT reaming work, etc.

I happen to have a chunk of bar that will work so I think i'll try to make something and I will post pictures.