Late 40s / Early 50s René Herse tip find

[Jonny69]

Not a lot of progress since the last update. I got a set of early Mafac cantis which I'm 99% sure will fit on the old studs and they've got all their hardware with them. I'll use the original René Herse ones at the front, but that's the missing back ones sorted for now. I've also just committed to an early 49D chainset. These things aren't cheap but it's got 48 and 28 rings so it will look like the originals did.

So as I understand this, the early 49D sets had Stronglight Depose in the oval logo while the later ones had Stronglight Marque Deposee. On the back of the cranks, earlier ones were plain while the later ones had the size stamped on them. My cranks should be the earlier ones. Earlier chainrings had a 122bcd for the inner ring while later ones had an 86bcd to accommodate a smaller triple inner. I think mine have TA chainrings with the later, smaller bcd, but they look like the earlier 49D chainrings rather than the later star shaped ones. But as long as they polish up, that's better for me because I want to maintain the 20-tooth jump that the original René Herse chainset had.

Early 49D: https://velobase.com/ViewComponent.aspx?ID=F9B6EA13-202E-4616-8C78-720A5CB39FBC&Enum=115&AbsPos=26

Later 49D: https://velobase.com/ViewComponent.aspx?ID=201AC3DA-4C28-4B72-903E-623584E07D7B&Enum=115&AbsPos=27

So fingers crossed the threads and tapers are all ok when they turn up.

 

[Jonny69]

Cranks are here. Absolutely filthy but I think they’re just what I was looking for.

 

[Jonny69]

I brought them into work to check the pedal threads since the pedals were here. All good and French which is, uh, good.

Side by side with the RH cranks, you can see how similar they are both in size and look.

 

[Nabeaquam]

I clean stuff like this with detergent and then rub them with aluminum foil and a polishing compound. Then power felt wheel and compound, if it’s not to your liking after the foil. I almost always stop after foil polish.

 

[Jonny69]

I clean stuff like this with detergent and then rub them with aluminum foil and a polishing compound. Then power felt wheel and compound, if it’s not to your liking after the foil. I almost always stop after foil polish.

I won’t hit the cranks with alu foil because it’ll scratch them up and wear the details down. This is just mud (it’s not even greasy) so it’ll just need some hot soapy water and effort followed by a light polish. I don’t want them perfect either, it’ll look out of place on this bike!

 

[Woz]

Liking how this is progressing

The Stronglight is a triple, compared to the original double RH.

Will there be enough throw on that extremely early one-of-kind handmade RH front mech or will you remove a ring?

It does look a great match. I'm sure it will clean up how you want it too. Cursed French pedal threads too

 

[Jonny69]

@Woz I’m going to take the 44 off and just use the 48 and 28. The rings just stack up on these - the 44 and 28 both use the same holes. That’s exactly what I was looking for because I didn’t want an unused set of holes on view.

 

[Jonny69]

I’ve been busy scrubbing the cranks with a green scourer and hot soapy water. They’ve cleaned up quite nicely. Decided a quick mock-up was in order:



I’ll have to cut the chainring bolts down but that’s what it’s going to look like as a double. I’ll give them a quick going over with metal polish and that’s them done.

I mentioned above that I got some Mafac cantis to take the place of the missing rear cantis on the bike. This is them:



So they’re not a perfect match, but they’re close and they’re French. Most important is I think they’ll fit on the existing studs. Trial fit needed.

 

[Jonny69]

Spectacularly slow progress on this, but some progress is better than no progress. Or something like that. As the saying goes.

I cut down the chainring bolts on Friday. This was sort-of straightforward. I say sort-of, because the thread is sort-of M5 but not. My plan was to stick a bit of M5 threaded rod in the chuck on the saw and wind all the nuts on to the same place so I could cut them all the same length. Bog standard M5 is usually 0.8mm pitch but these seem to be 0.9mm, so they wound on a certain amount and stuck. No worries, because I just tightened them up against the side of the chuck before the thread locked up and parted them off like that. Probably should have just taken a picture, then I wouldn’t have had to try and explain it in a very long paragraph which probably makes little sense. Anyway, this is what I got: all cut down to about 7.5mm but most importantly all of them the same.



Then I needed to countersink them slightly to clear the underside of the screw heads. This is where it got frustrating. These damn things were spectacularly hard and my countersink would not cut them. Can’t remember if it’s a Dormer or a Hertel multi-flute countersink, but it did not want to cut these things! So the actual countersunk edge was more of an oily mashed rub than a clean cut, and that meant the top of the thread needed chasing because it was slightly burred over. Only real way I could think to do that was to try and start a new thread entry point with an M5 tap and stop turning before I cut into the existing thread. That was basically successful but did leave the top of the thread quite tight. However, nothing that couldn’t be fixed by copious amounts of oil and working the screws in and out a couple of times.

So all this was quite a lot of work considering I could have just bought some double chainring bolts on eBay for £5 or so, but I don’t really work like that so here we are. And here’s what it looks like:



I didn’t want those modern Allen hex outers on view, so they went on the back leaving the nice plain steel screw heads on the front. That’s exactly what I wanted it to look like.



On the subject of progress, I’ve got the day off tomorrow as time in lieu and I’m fully intending to use it as bike time. Got two rebuilds to do but there should be plenty of time for offering stuff up and checking everything fits.

 

[Woz]

..... if the mountain won't come to Mohamed and all that .....

I've understood that bolts etc. and compatibility of this old stuff is a nightmare. Dimensions and fixtures are all over the place and evolving.

This was a modification on a 70s Stronglight AL ring to fit a 50s Solida or Stronglight steel cotter-pin crank.