Hey C&V, I have a real quick question. I'm rebuilding an old townie with my g/f as her first bike project, and i need to replace the rusted 5-speed Mallard freewheel (one i find a tool to remove it!). I have a spare 6 speed Shimano MF-Z012 freewheel I'm hoping I can use. Will this freewheel work with her Sachs Huret Eco rear derailer? All shifting is friction.

Thanks

That should work fine. The 6 speed freewheel should fit the frame fine without having to cold set it(which means spreading the frame). The derailleur should have enough travel to add another cog. You will have to adjust your limit screws to make it work. If you were going to an 8 speed or above you would have issues, but your shifters should be able to handle it also. Friction shifters are very easy to work with. Try this link to get some more info.
https://www.sheldonbrown.com/harris/freewheels.html

That's what I was assuming, but I just wasn't sure if there were any oddities involving the Eco RD's. Thanks for the reply.

Sure, Good luck with the rebuild and as is required in all of the C&V threads- we need pictures. And remember Sheldon Brown's site there is all kinds of cool info there...

oh, pics coming for sure. once the lady is happy with it, of course. she's out polishing the fenders right now, even though they looked fine to me.

<3!

Marry that girl quick...she sounds really cool...