Hidden Hinge Clearance

Hidden Hinge Clearance

I finally got my hidden hinge working as previously I was having problems with it fouling just before the second stop.

I’m not good at imagining things in 3 dimensions, especially when they are moving. I’d posted a couple pictures on a forum site and someone helpfully suggested moving the hinge inwards. I was convinced this would work, so I mocked it up. It did work – well sort of. Everything that was fouling now cleared, but unfortunately as the door opened, the front edge of the door also moved forward in an arch. It now fouled the bonnet side.

Therefore I went old school. I put the hinge and door back to their original position and cranked up the disc cutter.Hidden Hinge Clearance
It looked a mess, but with this slot everything cleared. Now all I had to do was make it look OK.

Modified Recess

I widened the hinge recess and added a curved recess so the bottom edge of the door would clear.

Hidden Hinge Clearance
If I was starting over, I wouldn’t make the A pillar quite this shape, but I’m not doing that now. Only a couple areas would change as a lot of the lumps and bumps are deliberate as they are surfaces for the door rubber to compress against.

This is the door closed. I rounded the bottom edge of the sill to match the door curve.

Hidden Hinge ClearanceThis is it open nearly 80 degrees. You can see the curved edge of the door now tucks into the enlarged recess. Even with the door opening this wide, there is still 5mm clearance.

Hidden Hinge Clearance

Strengthening the A Pillar

In the process of doing the modifications, I added some hidden 3mm plate to the rear of the hinges. These plates added local strength, but now the flex was hard to spot because it was distributed over the whole height of the pillar. All these plates had done was move the flex elsewhere, so more strengthening was needed. If I didn’t take a different reinforcement route, stress fractures would appear.

Without a door as leverage, getting the hinges past their stops, takes some force. They are made from 3mm plate yet when you open the hinges, using a vice and pliers, you can see flex around where the pliers grip.
A lot of force!

I added four dimple die strengthening plates. Although very simple and light, these plates make the A pillar rock solid. Originally when tapping it, it sounded like a kettle drum. Now the sound’s dead, plus they are only tack welded. It definitely needed these plates. – So much so, I might add two more.

Hidden Hinge Clearance
Now I’ve got all the shapes as I want them and everything working, the next big job is to make it’s twin. Hopefully, although there’s going to be an awful lot of measuring, I won’t keep re-making every piece.