Phil_gretz

I'll need help from your collective wisdom here. I have a 1980s Sugino crankset that I've removed for cleaning and polishing. Four of the five chainring bolts have slotted nuts on the backside, the kind where you can put a large screwdriver in to hold the nut still while you loosen the bolt with a 5mm hex wrench.

The last one has some sort of replacement nut, which is a smooth circle. No slot to hold it. In fact, because the flange is only about 1.5mm thick, there's nothing really to grab. Both bolt and nut spin when I attempt to loosen it. I'd prefer not to mar the nut or the inner chainring by trying to clamp its edge - or something equally ham-handed.

Has anyone dealt with this before? What would you try?

Thanks in advance.

Phil G.

dsbrantjr

I wouldn't worry about saving the nut; it doesn't seem to be working very well and they are cheap to replace. First, I'd put a drop of penetrating oil on the threads to lube things up. Then I'd take either a Dremel disc or an Xacto or jeweler's saw and make a slot in the nut to hold it. Then remove it the usual way and toss it. You might even be able to hold it with a long-nosed plier with one jaw inside the nut and the other catching the edge. The chainring should be fine if you are careful; hold it in a padded vise so you don't mar it and will have both hands free.

bradtx

Phil, Not exactly the same problem, but I had to use a jeweler's screwdriver as a wedge under the screw to remove the nut with an under the crankarm screw.

Brad

Ex Pres 

If this non-standard fastener still consists of a female "sleeve" that inserts inside the crankarm and ring holes, then hold the end you can grab, and drill from the other with a bit the size of the male (threaded) part.

You don't have to drill out the sleeve (and risk damage), you're just trying to release it.

Phil_gretz

I have a Dremel and a cutting wheel, as well as a good magnifying headset, so should be able to do this. I may be able to re-use the nut, too, if the slot is clean. Thanks!

HillRider

I'd make saving the nut the lowest priority as replacements are cheap and easy to find. Slot the nut with the Dremel and a cut-off wheel and remove it using the regular wide screwdriver or chainring nut tool.

dsbrantjr

Whether you buy new (as little as $5/set) or re-use what you've got, don't forget to grease the threads when you reassemble it. I use Tef-Gel on all of my dissimilar metal joints, especially down low where exposure to road salt is likely. The Shimano TL-FC20/21 tools are very handy for holding the nuts from spinning.

FBinNY 

Since you don't like this nut anyway, here's an easy solution with zero risk of dinging the chainring.

you'll need a power drill with a 3/8" or larger countersink. Hold the front bolt with an Allen key and countersink the nut from the back a millimeter or two until the flange separates, Then slide the screw and nut out the front.