Crank ring bolts - what tool to get on the back side
 

I've noticed that the crank rings on my Shimano Golden Arrow crank appear to be a bit loose. I got them as tight as I could when I assembled the crank originally, but I don't have a screw driver with a flat head wide enough to span both sides of the notches for the back-side nut. Thus it was very difficult to get a lot of torque on the bolt to cinch it down tight. Any handy ideas? I've thought about putting a butter knife blade in a vice and put the backside bolt on that and see if that works - but not sure how well that will go over.

There are specific tools made just for this use called chainring nut spanners or chainring nut screwdrivers. They hold the nut from rotating while you tighten the bolt with an Allan key. any LBS or mailorder bike supplier has them. Bike Tools Etc. lists several models and they are all under $5.

Your butterknife technique will work in a pinch.

The butter knife (or really really wide, perhaps sharpened screwdriver) technique works fine. The tool is mainly just a convenience thing for bike shops where time is money, though it is useful. Prooly though, next time you have to buy something from your lbs, bring your crank and ask for them to tighten you up right quick. They'll probably not mind.

Suppose I'll pull the crank this weekend and give it a go. I've been down to the LBS enough in the last few days they probably wouldn't mind giving it a good once over for me.

You need one of these:

Double-check your toolbox if you've ever bought an assortment of tools at one time... this is one of those cheap tools they like to sneak into tool assortments so that they can turn a 26-piece-set into a 27-piece-set and look like a better deal. I was surprised to discover I had one when I needed one.

don't think I'm that lucky (my mini tool kit is burried right now under a ton of stuff from today's build) but there may be something around simular enough to make it work.

Mine's a screwdriver-with-a-spike design; I know I'd noticed it before but not known what it was for ;)

Those little flat spanners won't work if the nut is really difficult to tighten as they tend to pop out of the slots. I've got both Sugino and Campy versions and neither is real useful. The screwdriver-type is much more effective.

Well, I expect you're right - but how would you deal with this?

Well, I'd start with a good quality 8 mm or 5/16" drill bit......

I'd take out the bolt, put a little grease on the threads and under the head, and try again. If that didn't work, I'd take the granny "off" (but not actually take the crank off) and see if that gave me enough access to the nut.

What you have is a spoke driver for rapid pretensioning the spokes on a wheel that you are building. The "spike" drives the blades up when the spoke reaches a certain depth. This allows you to quickly pretension all the spokes to an even starting point. Nice second application. I might try mine for the chain ring tightening.

Not necessarilly. Chainring nut tools are often made in the wide-blade-screwdriver-with-a-spike form. The spike keeps the driver from slipping off sideways while you tighten the bolt. I have a Performance house-brand chainring nut driver in exactly that configuration.

OK. Nice to know that its possible. I am sure size matters in this case. I tried to see if the pretensioner worked and it was too small. Thanks.