Tech tip - Tired of rounding out Phillips screw heads?

Andrew337
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Andrew337
Edited Date/Time 11/2/2015 3:08pm
Up until recently I had always cursed the manufacturers under my breath for using Phillips screws that seemed to be made of moon cheese. I had no idea that all this time I had been using American/European standard Phillips drivers on Japanese Industrial Standard (JIS) screws. The normal Phillips screwdrivers are close, but not quite right. The fillet between the blades is a larger radius than JIS (along with some other subtle differences) so it won't properly engage the fastener. I just got some proper JIS screwdrivers in the mail (Vessel Megadoras), tried them out, and now I feel like an idiot for all these years not knowing I was using the wrong tool. Perfect fit, the driver no longer tries to cam out and damage the fastener.

Just thought I would share, it doesn't seem to be common knowledge. Maybe it will save someone some frustration.



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Markopolo400
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Markopolo400 10/20/2015 12:06pm
10/20/2015 12:06pm Edited Date/Time 10/20/2015 12:06pm
I didn't know there were two different kinds, thanks for sharing.

But...Impact driver...Done Smile
gpnewhouse 10/20/2015 2:19pm
10/20/2015 2:19pm
Never knew there was two types, thanks for sharing that. I'm currently on rebuilding a Honda at the minute and keep facing the seized bolt/screw problem so this should help.
harescrambled 10/20/2015 10:48pm
10/20/2015 10:48pm
Now that's an interesting post. Never had a clue there was a difference. That would explain most of the stripped case screws, etc...that I've seen over the years
captmoto
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captmoto 10/21/2015 10:08am
10/21/2015 10:08am
I've pointed this out a couple times but not as a main topic. Look closely at the screw heads. You will see a small dot stamped in them. That indicates JIS.

The Shop

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Beast666
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Beast666 10/21/2015 10:44am
10/21/2015 10:44am
If you happen to have a JIS Phillips head start to cam out, take a drift punch about the same diameter as the Phillips cross and indent the cross with a couple of taps then use your impact driver it will come out unless the screw is cross threaded of seized due to dissimilar metal corrosion.

Also look for ACR Phillips bits as they have ribs to give you added bite on the cross.
Bruce372
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Bruce372 10/21/2015 3:50pm
10/21/2015 3:50pm Edited Date/Time 10/21/2015 3:50pm
I round them, cut a slot with a hack saw and then replace with Allens lol
Team Ideal
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Team Ideal 10/21/2015 6:35pm
10/21/2015 6:35pm
Interesting, going to be investing in a couple of those. I found out a couple years ago to use a Snap On to loosen and an elcheapo to tighten. Snap On phillips is hands down the best out there, wonder if they make a JIS style?
Cancerman
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Cancerman 10/22/2015 3:29pm
10/22/2015 3:29pm
As I was building my RM500AF I found most of the CR500 bolts had the same problem, so I bought a polished bolt kit on eBay for $30. Problem solved.

mb
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mb 10/22/2015 9:20pm
10/22/2015 9:20pm
Been rounding out the screw heads for years. My dad used to work at a motorcycle shop back in the '70's. Look in his toolbox to find an old wooden handle Honda screwdriver. JIS, fits like a glove. Thanks dad! Smile
.kyle
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.kyle 10/23/2015 3:21am
10/23/2015 3:21am
I don't know if you have the same in USA, but here in the UK we have Pozi Drive screws which have an added feature to prevent rounding.
MaxPower
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MaxPower 10/23/2015 4:42am
10/23/2015 4:42am
For the longest time i had thought float bowl screws were made of Japanese scrap metal. I figured what the little dot on tbe screw head meant a few years ago. Its not our fault, it's not like you see different choices of screw drivers for sale other than the #1,#2abs #3 bit sizes. 8mm head fasteners are the best thing to happen to dirt bikes
Falcon
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Falcon 10/23/2015 11:07am
10/23/2015 11:07am
Max, I feel your pain. For a while, I'd go buy extra float bowl screws just so I could work on the carb, because I knew I'd have to destroy the old ones getting them out.
AHRMA361 10/26/2015 1:37pm
10/26/2015 1:37pm
I use the Vessel JIS screwdrivers. Heavy weight and extremely well made. You won't regret your purchase.
Barrettp
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Barrettp 10/27/2015 5:04am
10/27/2015 5:04am
Witte screwdrivers are pretty good, made in Germany. I bought a set for $30 from Home Depot
Team Ideal
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Team Ideal 10/27/2015 5:56am
10/27/2015 5:56am
AHRMA361 wrote:
I use the Vessel JIS screwdrivers. Heavy weight and extremely well made. You won't regret your purchase.
good to hear, I ordered some yesterday
Micahdogg
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Micahdogg 10/27/2015 7:17am
10/27/2015 7:17am Edited Date/Time 10/27/2015 7:21am
In my opinion, the problem is when the screw driver slips. That's when you trash the head. Its not a problem of the soft metal, or the slight difference of bit type.

When I attack carb bowl screws I use a 1/4 drive ratchet, a 1/4 inch SAE socket, and I put my bit in the socket. That way I can palm the ratchet and really drive the bit into the head of the screw. If you push into the screw with that kind of force -and- turn you will get so much more leverage than holding a screw driver. 9 outta 10 times you'll bust the screw loose.

I use this method on reservoir cap screws and any other small screw that you don't want to trash. You can then reinstall them with a regular screwdriver
Andrew337
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Andrew337 10/27/2015 9:10am
10/27/2015 9:10am
Micahdogg wrote:
In my opinion, the problem is when the screw driver slips. That's when you trash the head. Its not a problem of the soft metal, or...
In my opinion, the problem is when the screw driver slips. That's when you trash the head. Its not a problem of the soft metal, or the slight difference of bit type.

When I attack carb bowl screws I use a 1/4 drive ratchet, a 1/4 inch SAE socket, and I put my bit in the socket. That way I can palm the ratchet and really drive the bit into the head of the screw. If you push into the screw with that kind of force -and- turn you will get so much more leverage than holding a screw driver. 9 outta 10 times you'll bust the screw loose.

I use this method on reservoir cap screws and any other small screw that you don't want to trash. You can then reinstall them with a regular screwdriver
You're right, the problem IS when the screwdriver slips (it "cams" out of the head), but the only reason it slips is because it doesn't fit properly. I'm going to assume you've never tried a JIS driver in those screw heads. They don't slip, they don't cam out when you turn. Feels like using a hex key in a socket head cap screw, or a Torx, you only have to apply torque and minimal axial force. The tip design, while subtle, makes a big difference.

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Micahdogg
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Micahdogg 10/27/2015 9:28am
10/27/2015 9:28am
No I haven't and I wasn't aware of JIS, thanks for the heads up on that. I will probably add some of those to my arsenal now thanks to your post. I have several different bits though and I usually find one that fits good, then tap it into the screw head with a small ball peen hammer just to make sure it has a good bite. Then use the socket and ratchet and presto. I've trashed out enough of those buggers along the years to find out the hard way.

Also for trashed screws, you can usually hammer the heads flat again, then hammer a bit into it, then hammer the head flat, then hammer the bit, etc... and clean them up to be usable again.
Rdubs19
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Rdubs19 10/27/2015 4:36pm
10/27/2015 4:36pm
Extremely useful info, thanks a ton OP.
captmoto
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captmoto 10/27/2015 9:54pm
10/27/2015 9:54pm
Barrettp wrote:
Witte screwdrivers are pretty good, made in Germany. I bought a set for $30 from Home Depot
They look like great tools but I don't see where they are JIS drivers.
Barrettp
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Barrettp 10/28/2015 6:24am
10/28/2015 6:24am
captmoto wrote:
They look like great tools but I don't see where they are JIS drivers.
I'm not sure if they make jis or not. Just a suggestion for good screwdrivers that won't strip everything
lumpy790
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lumpy790 10/28/2015 11:37am
10/28/2015 11:37am
that is what they use on deck screws.
Vegas
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Vegas 11/2/2015 3:08pm
11/2/2015 3:08pm Edited Date/Time 11/2/2015 3:08pm
Micahdogg wrote:
No I haven't and I wasn't aware of JIS, thanks for the heads up on that. I will probably add some of those to my arsenal...
No I haven't and I wasn't aware of JIS, thanks for the heads up on that. I will probably add some of those to my arsenal now thanks to your post. I have several different bits though and I usually find one that fits good, then tap it into the screw head with a small ball peen hammer just to make sure it has a good bite. Then use the socket and ratchet and presto. I've trashed out enough of those buggers along the years to find out the hard way.

Also for trashed screws, you can usually hammer the heads flat again, then hammer a bit into it, then hammer the head flat, then hammer the bit, etc... and clean them up to be usable again.
That is great advice for already stripped screw heads. My little trick is with a magnetic tipped screwdriver I pick up a good bit of steel grinder dust from the shop floor and then put the screwdriver in the stripped screw head (works with allen heads too) and that'll usually help take up the play on any rounded corners on the stripped screw head.

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