I was checking the size of the "cone" (if that's what it would be called in this case) on the I-Motion internal hub on my new bike using a vernier caliper, in particular this one, and I realized... why not just use such a caliper as an adjustable cone wrench? The jaws are a little thinner than those on the Park wrenches I have now, but it seems like this would get the job done for the average guy overhauling his hubs every so often... I would just hold the cone with the calipers, holding the adjusting wheel to keep the jaws clamped, and then turn the locknut with another wrench.

What do you think?

It might work. I made an adjustable cone wrench by grinding down the jaws of an 8 inch adjustable wrench from one side until only about 2.5 mm of thickness was left. I started with a good quality wrench so there was no slop in the jaws. I ground slowly so I did not overheat the steel and cooled often. I finished it by hand with an oilstone. The wrench cost about $9. It took about an hour of my time. I have been very pleased with the results. (I posted this shortly after I joined BF in March 07 and included a photo. Try searching with my handle.)

The photo of my homemade cone wrench is at #18 in this thread.

Or go buy a Park DCW series for $5-6 and not have the jaws spring?

+1

Dedicated tool > multi-purpose tool.

Doesn't seem like the calipers would be strong enough...what would keep the jaws from spreading?

Except when your one dedicated tool too short.

What a horrible thing to do to a precision measuring device.

That's what I was thinking too. You have to tighten the lock nut against the cone pretty hard to keep the whole assembly from coming loose. I'd think that much force would be pretty hard on the vernier and may diminish it's accuracy.

Agreed, altho it's certainly not a Starrett, Mitutoyo, etc. ( it's an inexpensive $10 ), used as a cone wrench it might not retain much in the way of accuracy . Also, as Retrogrouch mentioned, there is more force required in the cone/locknut interface than a caliper could possibly handle. Get yourself supplied with the proper tools and be done with it.

True, it may not be a high dollar one but it would do most hobby applications. I saw a guy use his 1" micrometer for a welding clamp.

I like to use my micrometer to tighten my pedals. And I use a precision inch-pound torque wrench to whack the bolt on a stuck quill stem too. Works great, although I'm still wondering why the seat post on my old Columbus SLX frame measured out at 23.7. Maybe that's why the seat binder bolt snapped off even though it was well below correct torque.

Perhaps it would work once or twice before ripping apart under the torque. I don't know. But calipers are made for measuring things. Do you hope to use it for measuring things after you've used it as a cone wrench? That cheap caliper does a reasonable job for measuring millimeters. But I assure you it won't after you use it as a cone wrench.

Just buy the cone wrench.

It would not even work the first time. Neither the jaws nor the locking screw up to the torques involved. Just because it LOOKS like a pipe wrench doesn't mean it'll perform like one.

Not many people know how to properly use a vernier caliper anyway!
I found one in my drawer a couple weeks ago and had to do a little head scratching. It'd been about 35 years since I'd last used it. Don't really feel like converting 237/256 of an inch! to decimal when I can use my dial caliper or mic. I seldom use the mic to be honest!

Yeah, you got me there, as are those mentioning the torque issues as well.

Use the right tool for the job.

I'd rather be short a cone wrench than a caliper

I fashioned a cone wrench using a rotatory-tool with a cut-off wheel. Basically making one cut horizontally for the thickness and a cut vertically to complete the cut.
I used 4 cut-off wheels doing it, going slowly and dipping the wrench in water to keep it cool. Total time to make this wrench was about half an hour.
I am very skilled with a rotatory-tool, so those with less experience using a rotatory-tool may use more cut-off wheels and take a bit longer to do the job.
It may help if the wrench is but in a vice when making the cuts. I didn't do this but I don't recommend this be done and always wear safety glasses when using a rotatory-tool.
It's a long story why I did this but it is done and now I have a nice strong 14mm cone wrench.

100209_1715a.jpg This is the best photo of the wrench I could get

I hate vernier calipers. I need a magnifying glass to read the stinken vernier scale, I need to check and double check my reading to make sure it is correct, and then the vernier is only good to 2 or 3 mils resolution.

Dial and digital calipers are huge improvements over verniers. Go ahead and use the vernier as a wrench. That is about all it is good for.

That's what bifocals are for. Do you really need better than 2 or 3 mils resolution for bike stuff?

So you used $10 worth of tools to create a $5 tool?

I'm a total tool geek.What you propose is just abuse.I even calibrate my tire pressure gauges.