wsmeyer
08-27-2013, 06:28 PM
At our SoCal meetup a few weekends ago, Hieu (sillieidiot) was nice enough to let us borrow his fender rolling tool. Unfortunately, as soon as I started to use it it self destructed on me. Returning a tool broken is not cool so I volunteered to fix it and while doing so it became obvious that the way it was designed and made, they simply won't survive a lot of use so I did a couple extra things to hopefully strengthen it enough to last.
One of the problems was due to misuse. Myself and others attached it onto the car using the lug bolts. THIS SHOULD NOT BE DONE. Because it is designed to work on either 4 or 5 lug cars, two pairs of the holes at 9 and 3 o'clock are so close together that the conical shape of our lug bolts will deform the metal between the holes causing the tool to loosen itself during normal use. This then causes the whole mounting surface where it attaches to the car to bend and curl, and at least in his case, crack the welds, and the more you use it, the worse it gets. I did not take pictures before I pressed it back flat and re-welded it but here's an after pic:
http://www.zhpmafia.com/forums/attachment.php?attachmentid=10171&d=1377613875
I had some extra time so I flipped it over and ground the side that mounts to the car perfectly flat. Not really necessary but it looks cool:
http://www.zhpmafia.com/forums/attachment.php?attachmentid=10172&d=1377613887
This is the actual part that self destructed:
http://www.zhpmafia.com/forums/attachment.php?attachmentid=10173&d=1377613894
This is the shaft that exerts all the pressure on the roller that actually rolls the fender lip. I have no idea why they designed it with just a 12mm bolt and washer attaching it. It will last a few uses but eventually the threads will give out and it will look just like this one. Re-threading that to 7/16:
10177
took care of the threads but now will be slightly weaker than the original 12mm bolt. To prevent that from self destructing again I did what they should have done:
10178
Milled out a larger surface area and fit a thrust bearing on it.
Next up is the way they attached it to the tool:
10179
There's two problems with this. That center part needs to rotate, which means you can't tighten the socket head screw completely, and it's never a good design to have things rotating on the threads of screws. This is the kind of thing that really annoys me as there is no cost difference between screws that are threaded all the way and those that have a shoulder:
10180
Now you can tighten the screws completely and it will rotate on the shoulders instead of the threads:
10181
And here's the roller assembled back together better than new and should last through plenty of uses:
One of the problems was due to misuse. Myself and others attached it onto the car using the lug bolts. THIS SHOULD NOT BE DONE. Because it is designed to work on either 4 or 5 lug cars, two pairs of the holes at 9 and 3 o'clock are so close together that the conical shape of our lug bolts will deform the metal between the holes causing the tool to loosen itself during normal use. This then causes the whole mounting surface where it attaches to the car to bend and curl, and at least in his case, crack the welds, and the more you use it, the worse it gets. I did not take pictures before I pressed it back flat and re-welded it but here's an after pic:
http://www.zhpmafia.com/forums/attachment.php?attachmentid=10171&d=1377613875
I had some extra time so I flipped it over and ground the side that mounts to the car perfectly flat. Not really necessary but it looks cool:
http://www.zhpmafia.com/forums/attachment.php?attachmentid=10172&d=1377613887
This is the actual part that self destructed:
http://www.zhpmafia.com/forums/attachment.php?attachmentid=10173&d=1377613894
This is the shaft that exerts all the pressure on the roller that actually rolls the fender lip. I have no idea why they designed it with just a 12mm bolt and washer attaching it. It will last a few uses but eventually the threads will give out and it will look just like this one. Re-threading that to 7/16:
10177
took care of the threads but now will be slightly weaker than the original 12mm bolt. To prevent that from self destructing again I did what they should have done:
10178
Milled out a larger surface area and fit a thrust bearing on it.
Next up is the way they attached it to the tool:
10179
There's two problems with this. That center part needs to rotate, which means you can't tighten the socket head screw completely, and it's never a good design to have things rotating on the threads of screws. This is the kind of thing that really annoys me as there is no cost difference between screws that are threaded all the way and those that have a shoulder:
10180
Now you can tighten the screws completely and it will rotate on the shoulders instead of the threads:
10181
And here's the roller assembled back together better than new and should last through plenty of uses: