I know the answer will probably be "not worth it" but I'll ask anyway.

I have replaced sprockets on freewheels, but not in a long time. I just changed my chain, and it skips on only one sprocket. The freewheel is a Shimano 600 (remember them?) 6-speed with a 13-32 range. I don't see any replacements. I might have a replacement sprocket on an unused freewheel.

Is this feasible? I took apart Suntour and Regina freewheels but never Shimano. I assume I'd use two chain whips to get started.

The freewheel is on an old bike, and I cannot use a wider freewheel. A 7-speed freewheel would be wider, correct?

From what I've seen there's little ryhme or reason to freewheel sprocket hub sizes. I've taken a few apart and found that none of the ones I did were compatible other than two Shimano ones of the same era. So by the time you find a freewheel that IS compatible you may as well just spin it on instead of messing around swapping sprockets. The only possible case where this would not work may be with a 7 speed Shimano where the sprockets may be the same size centers.

Often there's "almost" enough room for the 7 speed. If you were to play with the spacers on the axle and shift them around a bit or introduce new spacers you can offset the hub a little more to allow using a 7 speed and then adjust the non drive side spacers to get the overall axle nut spacing back to where it is supposed to be. From there adjust the wheel dish to recenter the rim. As I understand it this is exactly what they did when the makers switched from 6 speed freewheels to 7 speed freewheels so you're certainly not doing anything unusual. It DOES make it so that the drive side axle has more unsupported length and on bikes used for serious trail riding this can lead to bent axles. But if it's more of a grocery errand bike it should be just as fine as all the other 7 speed freewheel bikes in the world....

Good points. And I just found some 6-speed Shimano 14-34 freewheels at very low prices. The trick was to search for 14-34 rather than 14-32. The difference between 32 and 34 is small enough, and I'm not that picky. My chainrings are now 42-52. I live in a hilly area, and I use this bike to haul stuff, so a low lowest gear is handy.

Oops. I spoke too soon. Everyone is out of stock.

I'll see about putting a 7-speed on. Sheldon wrote an article on how the Shimano mega-range freewheel is built with a superior design, so that's not bad. The chainstay stays thick really far back on this bike. It's a 1971 Raleigh Super Course. As it is, it's difficult to put the rear wheel in. But I might manage it. As you said, I'll probably have to add a little spacer to the right side of the axle.

Tom,

if you can get the first one or two threaded sprockets off, you cna check whether the others are threaded or splined. Once you have the model and exactly what you need check at yellow jersey in Madison, Wisc. They keep lots of loose sprockets for building custom freewheels and might have the Shimanos you need. If you ever need Sun Tour Winner series, or Sram freewheel sprockets, I still have a bunch in most but not all sizes.

Thanks, Frank!

I, too, have a few Suntour freewheels and extra sprockets for them, but I've recently decided I don't like them any more. Though mine are Procompe/Perfect, not as nice as Winner.

I would say loose screws but I don't know if they would have something for the Shimano 600.

Try flipping the bad cog over, if it works, you have a new cog.

Ooh, two excellent suggestions!