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Location: 3961 East Bayshore Road, Palo Alto, CA MAP

Volunteer days are back, in a new format! They're the second and fourth Saturdays, on a smaller scale. See our Eventbrite site at bikex.eventbrite.com for details and to RSVP. Grab your spot and join in on the wrenching for good! See the event calendar for more events and volunteer days.

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Ever find the limit screws of your derailleur or centering screws of your brake hard to adjust with your Phillips (+) screwdriver? If you've ever volunteered at BikeX over the last 28 years, we're confident that's a big "YES!"

At BikeX, we pride ourselves on having the right tool for the job, but sometimes we find we're missing the right tool for an unusual project. Usually, it's because of newer technologies that aren't quite commonplace in our shop. For example, we don't always have the right hydraulic bleed kit for the latest disc brakes, nor all the Campagnolo EPS connection tools. Just last month, we bought our first hydraulic hose cutter and barb driver. But screwdrivers? We have plenty. Twenty-eight years' worth, to be sure. But are they the right ones?

Turns out, as recently-featured volunteer Michael Khaw recalled on a volunteer email thread, he struggled to remove a screw from a Shimano shifter because he didn't have the right tool at home or at the shop. "How do you deal with a too-tight JIS screw without a JIS driver?" he asked the group. Our resourceful, loyal volunteers, as always, had creative, ingenious solutions, using bodyweight, bar clamps and chemicals.

Yet three questions popped into my mind:

  1. What's the difference between Phillips and JIS screws?
  2. Which components feature JIS screws?
  3. And most importantly, why the heck don't we have the right tool for these screws? 

I did some quick reading. This diagram posted by Charles Postis on Flickr might do the best job in illustrating the differences in design between JIS (Japanese Industrial Standards) and Phillips screws and associated screwdrivers:

JIS-vs-phillips-screws

It's subtle, and hard to tell with the naked eye, even with two screwdrivers side-by-side, but the Phillips screwdriver has a gentle radius between each of the four "blades" and has a blunter point. 

Subtle differences: Our new JIS-compatible screwdriver on the left, and well-loved Park Tool Phillips screwdriver on the right.
Subtle differences: Our new Vessel JIS-compatible screwdriver on the left, and well-loved Park Tool Phillips screwdriver on the right.

This video, even though it doesn't feature a bicycle, has an excellent demonstration as to why knowing that type of screw you have, and what tool you need, matters. Jump to 2:30 if you can't spare the four minutes:

After a bit more reading and a quick look at common bike components, I noticed that "JIS screws" are nearly everywhere on components from Japanese manufacturer Shimano. How can you tell? Typically JIS screws have a small dot on the screw. But they're also easy to tell because your Phillips screwdriver, even the nice ones made by Park Tools for bicycles that we have at our tables, don't seem to fit well, and easily slip out under torque ("cam out") and end up damaging and rounding out the cross pattern of the screw head. That's why adjusting limit screws, centering brakes and removing shifter caps can be so difficult without the proper driver. 

Michael found a JIS screw holding a Shimano Rapidfire shifter cap, but a quick look at two bikes near me confirmed JIS screws on a Shimano 9-speed Deore XT rear derailleur, and a set of Shimano cantilever brakes. 

The right tool for the job is important! Shimano derailleur limit screws feature a dimple that confirms they're JIS, but now show damage from a Phillips screwdriver
The right tool for the job is important! Shimano derailleur limit screws and the B-screw feature a dimple that confirms they're JIS, but they already show damage from a mechanic using a Phillips screwdriver.

On the larger screws, found on brakes and derailleurs, you might see a dimple on the screw that indicates it's a JIS screw. But on the tiny ones, like the ones found holding Shimano shifter covers, there may not be a dimple.

Shimano cantilever and v-brakes often feature JIS screws for centering
Shimano cantilever and v-brakes often feature JIS screws for centering

It turns out in 30+ years of working on bikes, the difference between JIS and Phillips screws had escaped me, and had done the same to even the most senior and experienced of our BikeX volunteers. We often say we learn something new every day at BikeX, and sometimes that new knowledge takes a few decades to sink in! 

Thankfully, there are two easy solutions: Building awareness (thus this article), and having the right tool for the job. Now I'm pleased to announce every worktable has a Vessel size #1 JIS screw-compatible screwdriver, and our yellow and purple ("the cave") tables also have new Park DSD-2 #2 JIS-compatible screwdrivers. Give them a test on a JIS screw. You'll immediately notice the difference in grip, and regret all the times you suffered without the right tool. 

A Vessel Megadora #1 JIS screwdriver awaits mechanics at each worktable
A Vessel Megadora #1 JIS-compatible screwdriver awaits mechanics at each worktable
We've got two Park DSD-2 JIS-compatible screwdrivers, and should have more #2 coming.
We've got two Park DSD-2 JIS-compatible screwdrivers, and should have more coming.

This all begs the question: when to use a JIS-compatible screwdriver and when to use the standard Phillips? The good news is that JIS-compatible screwdrivers work great with Phillips screws, but the reverse isn't true, as every mechanic has suffered through in our shop. Perhaps if you've got a true Phillips screw on a plastic-threaded clamp, a Phillips screwdriver could be safer, as its design might "cam out" under torque before plastic threads are stripped under too much torque. Yet you could argue that because most volunteers need to adjust limit screws and brake centering screws regularly, JIS screwdrivers should replace the Phillips screwdrivers on each work table. That hasn't happened, yet, but if you have to pick just one, think three letters. (Or if the screw is also slotted, at least grab a flathead screwdriver if you don't have a JIS-compatible screwdriver.)

Note, for the tool standards geeks: While I use the term "JIS-compatible screwdriver," these days there is no such thing as a "JIS screwdriver" as Japanese Industrial Standards no longer have a screwdriver spec, and DIN 5260-PH/ISO 8763-1 has taken its place as the screwdriver standard to use with JIS screws. If you're going shopping, a Vessel Megadora JIS-compatible screwdriver in the +1 and +2 sizes should do the trick. 

If you're one of our volunteers returning to shop events, please use the screwdrivers! Sorry it's taken us so long to get them.  I also plan to stock a few for sale in the shop, and stock more of the tables with #2 sizes soon. 

Hopefully, with proper use of the new screwdrivers, we'll see fewer rounded screws on bikes in the future, and smoother adjustments of those Shimano components. 

Thanks for reading!