WGB 

I have a set of Maillard Professional 700 (large flange) hubs. These are the ones with a black plastic dust cap. Per Velobase they only came in 22, 32 and 36 spoke counts but I can say that Velobase is missing some info and they also came in 40 spoke counts as I have one before me. I got this set from Bertinjim and he had a extra set of NOS cones for them.




These are almost mint but must have been mounted at some point because NDS rear cone is pitted. It appears someone torqued down that one side. That cone is pitted along the line where it would have pinched the bearings. It looks better after being cleaned of all grease but pitting is noticeable.




I have the backup set of cones. They are NOS but clearly larger than the ones currently mounted. The one below on the right is a replacement cone. It threads perfectly onto the axle. The replacements are simply too wide to fit through the hole of the plastic dust cap. Per Velobase there were several versions of the Maillard 700, Professional with the only the first version having the black plastic dust caps so perhaps Maillard used a different size dust cap or cone on the later versions. Bertinjim suggested that I carefully widen the diameter of the hole to allow passage of the larger diameter replacement cone through the plastic dust cap.



I measured the diameter of the two cones. The older/original is 16.98mm





The newer/replacement is 17.67mm so the difference is .69mm.





Before I permanently modify the plastic dust cap (and possibly wreck it) I wanted to ask if anyone knew of a source for the 16.98mm cones? Does anyone know of other brands of cones (Shimano, Campagnolo, etc) which are the same 16.98mm diameter?

I can probably drill through the dust cap to widen the hole with a drill set for a very, very slow speed. Alternatively I can use a file and pull very slowly to prevent tearing.

Photo below was copied from the Velobase site simply to show the plastic dust cap.




The last option is the use of an abrasive on the old cone (such as fine grit sand paper) in an attempt to polish the cones smooth while spinning the cone on a drill. I don't know if these old cones have only surfaces which are case hardened or if they are fully case hardened. I would try to follow polishing up with heating the cone red hot with a torch and then dropping in oil.

oneclick 

I'd put the new cones on an axle and chuck it up in a lathe and grind them smaller.

But you don't need a lathe to do that.

Got a bench grinder?
Make a bit to mount an inch or two to the inner side of the wheel, a bit with a corner cut out or arranged to make a biggish L. Hardwood, aluminium, anything will do, it's just a prop to help hold your axle (with the cone mounted on it) against the grinding wheel. A big bolt with a pair of nuts and a "fender" washer will do.

The top surface of the bottom leg has to be at the correct height so that when you place one end the axle-with-mounted-cone on it, the cone will contact the wheel.
The wheel-side of the vertical leg has to be at the correct distance so that when you place the axle-with-mounted-cone on it, you an adjust the contact by moving the free end.

Put your gloves and glasses on, start the grinder, place the axle-etcetera on the L, hook one finger (on the side of the mount AWAY from the wheel) over the end of the axle to hold it in the corner of the L.
Bring the cone close enough to the wheel that it starts contacting, and as it grinds allow it to rotate - control the rotation and contact with the free end. Be careful, of course.

It's pretty easy to get a smooth round surface this way - not likely precise or smooth enough to be a bearing surface, but fine for a dust-seal.

If the L is mounted just the right distance away right the cone's outer surface will be cylindrical.
If you don't have a bench grinder you can use another kind of grinder, adapting your mount to suit.

Follows rule number <n>: If the substitute part doesn't fit the original, modify IT, not the original.

Here's an example - not a cone, but a 15mm socket. I needed a thin-wall one to get at a cotterless crank bolt. This is an old tool, and when freshly made the surface was smoother, rust and use have left their marks.
As well, you can see the marks left by the grinding process - each contact bounced the socket away a tiny bit - look a the chrome on the side and you can see wee little dots in lines. I played with the mount angles to get a curved surface. The dots add up, the surface subtracts.




Here's an end look so you can see how concentric it is - sorry for the focus:

juvela

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Hello WGB,

There are two generations/periods for the Maillard 700 (actually manufactured by Etablissements Perrin).




Your set is the G1/Mk.I as launched in 1973.

It may be that the replacement cones you have are for the G2/Mk.II version.

One person who could shine some illumination on your question is member Chas. verktyg

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steve sumner

I would modify the dust cap b4 I'd ever start grinding on the cones.
I remember BITD that those cones had an extra small outer dia. and
no other brand or even other models of Maillard would fit. replacements
were unobtainium even when the hubs were in production. enlarge the
dustcaps and any number of cones will then fit.

dddd

The good news here is that these appear to be standard-threaded, not the later hub's special fine-thread as also used on
Maillard-built Edco and Roval hubs.

Also fortunate that 17mm is a most-common cone OD! Keep looking if you have a co-op or other local parts source.

The OD could easily be ground down by hand on a bench grinder, letting the axle turn freely as the grinding takes place will keep the OD round and concentric.

Most efforts at re-grinding bearing cones don't go so well. so proceed with caution and precision. If the metal appears displaced/deformed along the ball track, then the cone is one of Maillard's infamous soft ones and can be re-used as is or perhaps lightly re-ground.
I don't do this myself but others have done it with reported success.

By all means leave some slight free-play in the axle adjustment, since the axle compresses measurably as the QR lever is flipped.
Most cones that fail are from having no clearance and end up severely loaded in use from such over-tightness.