The procedure worked fairly well. The main problem I had was melting plastic caused by the heat generated by the Dremmel tool. Just from experience in working with both the old and new Miyata plastics, my gut feeling is that the old Miyata saddle plastic would not melt as easily as the new Miyata plastic does. Don’t have any factual evidence to base this on, just a gut feeling.
Great photos and an excellent idea, Bruce. And you are certainly qualified to have a gut feeling. How many seats have you converted now? It seems like you have posted three versions with each becoming more straightforward.
Thanks. I’ll probably use this technique when I do my first self-made airseat. I have a really cheap Dremel, which doesn’t spin very fast (I didn’t want the expensive one because I didn’t think I’d use it much). How tough is it to cut through those bolts?
Did you replace them with new bolts when you were done? If so, how do you get the new bolts to not spin?
For anyone who hasn’t done this yet, it might be worth mentioning that the domes (which are hollow) on these nuts are actually pretty thin metal. A couple of the domes just snapped off by themselves when I was putting my new Miyata seat on the uni I found in the trash. http://www.unicyclist.com/gallery/Xmas-in-July
So hold onto that Dremel tool carefully: the cutting wheel is going to go through the dome quickly.
Last-minute thought: You might be able to sink away some of the heat while cutting the slot by clamping a Vise-grip (locking pliers) onto the nut.
Mr. Harper shared once that 1/4-20 or 24 carriage bolts fit the square holes in the metal plate perfectly and shouldn’t spin, much better than the undersized 6mm that come with the seat. I found it to be so and am using the 1/4" bolts from now on. The plastic holes are a different story though and require the bent rod or other solution to hold steady.
Rick,
Great idea about the heat sink. Should’ve thought about that from my old soldering days. I’ll give it a try. Another thought is to do a wet cut. It won’t hurt to get the vinal cover wet but would make for a messy job. Just have to be careful when using a dremmel tool that is plugged into the wall.
I certainly do have a lot of gut to feel…
I think I’ve probably done 7 or 8 seats now, both the old and new style combined for quite a few of the kids in our club. I have another two in progress in the workshop. If we all keep up on this, maybe our collective voices will eventually be heard in the Miyata headquarters in Japan.
I don’t have the tools or the confidence to bend a threaded rod like that - although that looks like the best solution. I think I might try some epoxy or those grippy toothed washers or a combination of the two to keep the replacement bolts from spinning.
I think the biggest thing that bothers me about this whole cheapening of the Miyata saddles is that the price is still the same. If miyata is making cheaper saddles, then they should make the saddles cheaper.
Bend the rods, Nick. You need a hammer, a vice, a hacksaw, a file, and a length of 1/4-20 threaded rod. It is easy to cut to length with the hacksaw. The ends are easy to chamfer with a file. It will bend easily and accurately against the vice jaws. It’s cheap and it WILL NOT EVER spin.
Your not going to let me get away with a half-ass job, are you? I don’t have a vice, a hacksaw, or a file. Files are cheap, I can use the dremel instead of the hacksaw (and probably the file, too), but the vice is hard. Even if I bought I vice I would have nowhere to mount it in my rented suburban townhouse.
I have an alternative to bending threaded rod. There is a part that you may be able to find at a hardware store that seems to work great. I’ll post pictures tomorrow when I get to the office.