In hot rod building, one thing inevitably leads to another. While getting ready to bend and cut the ribs for the rear deck it quickly became clear I needed an exact positioning for the rear door jamb (since the two pieces will be tied together). This further necessitated an exact positioning of the front door jamb. And this further necessitated a precise design and placement of the door hinges - something I was figuring on doing about 10 weeks from now. So at this juncture we have to take a little side track into the mystery of door hinges.
After reading a number of hinge related threads here on HR.Com and also some outside sources, I've decided to take a stab at making up my own hinges. After looking at some stock hinges as well as some hidden hinges it seemed to me that the hidden units would be just as easy to make as the visible ones.
Knowing nothing about hinge design, however, I needed some way to graphically look at and design the hinge so that the door would open properly. And this is what I came up with...the official HR.Com Rat Rod Door Hinge Tester. My doors are going to be very straight and simple but I think the tester could work, with some minor alterations, on nearly any door style (front mount or suicide). Note that the tester is to be used as if you are looking from the top of the door straight down toward the ground.
Photo # 1 shows the pieces of the tester cut from heavy stock paper. On the top is the front jamb. The hinge pocket area is shown in black stripes and the exterior body line extending to the front of the car is shown in red. This would be the equivalent of looking down the side of the cowl from the top. I am anticipating making the hinge pocket out of 2x2 square tubing and that is the dimensions I am using for the pocket of my tester.
Next to the top is the door itself, on the left of the piece, shown in red outline and stripes (note: door length is not to scale but the depth,2", is to scale). On the far right of this piece is a duplicate of the hinge pocket area and fits over the top of the pocket shown in the top piece in this photo. The pivot point of the hinge can theoretically be anywhere within this tan area. Just to the left of this tan area you will see a blue strip. This represents the typical gap between the jamb and the door. I have used 1/4" as my design gap.
Next down is the hinge itself - in black. I intend to make the hinge out of 1/4" by 1 1/2" steel and weld it at a right angle as shown. I will also weld a pivot sleeve on the end as shown.
The piece on the bottom of the photo represents the rear door jamb (in green) and the outside body line extending to the rear (in red).
Photo #2 shows the four pieces assembled to represent how they might actually be laid out in the car. Note that we can move the hinge and hinge pivot point anywhere in the tan pivot point area. Then by sticking a pin in the center of the pivot point on the hinge we can "open" our imaginary door and determine if there is any interference with jambs or body lines. We can also determine how far the door edge will swing away from the body line.
Photo #1 By sticking a pin or compass point through the pivot of the hinge were can open and close our door. This photo the door in the "ajar" position. This is the spot most likely to cause problems/contact at the rear door jamb, just as the door is swinging open or closed and also potential problems at the front jamb where the edge of the door can come in contact with the edge of the exterior body line. Although it it not that easy to see in the photo, in real life you can see quite clearly if there is going to be contact at either the front or rear of the door as you swing it open and closed.
Photo #2 shows the door in a fully open position. By moving the hinge around to various spots within the tan area and then sticking a pin through both the hinge and the door piece you can quickly identify hinge placements witch will definitely NOT work as well as those that will. I'll use the tester to determine the pivot point which allows the maximum room for error at both the front and rear.
Since the last budget update of 11/23/04 there have been expenditures for additional steel (tubing for the body skeleton) and bolts/hardware. The expenditures as of 1/02/05 are:
Donor vehicle ('81 Ford F-150)--- $400.00
Steel for chassis and body-------- $638.70
Front Tires, incl mount & bal.------ $141.56
Carrera Coil-overs (fronts)--------- $341.46
4-Bars and rod ends (fnt & rear) --$309.04
Grade 8 bolts and fasteners------- $159.17
Primer/paint (rattle cans)------------$ 23.41
Balance in budget $986.66
Major items remaining:
Body sheet metal (?????)
Lights ($80 est)
Gages ($100 est.)
Gas tank/lines/filter/fittings ($160 est)
Brake lines/fittings/proportioning ($120 est)
Exhaust ($60 est)
Drive shaft ($110)
Trans Cooler ($50)
Radiator Fan & switching ($100)
Looks to me like we'll run somewhere in the neighborhood of $500 over our target budget of $3,000.
Photo #1 shows the bending form (see prior entry showing how this was made) firmly attached to exterior wall of the garage. Since the form is made of 3/4" fiberboard and the ribs we are forming are 1x1, I taped 1/4" of washers behind each screw hole that is used to mount the form to the wall. I clamp the end of the 1x1 to the form at the point where it will eventually be welded to the rear door jamb. The two ugly looking boards sticking up are simply to keep the 1x1 snugged up against the wall to prevent it form getting out of line and possibly twisting.
Photo #2 is a close up of the come-a-long used to bend the 1x1. The end of the come-a-long is attached to a chain which is bolted to the bottom plate on the garage wall with a 1/2" lag bolt 4" long. Seemed to hold just fine.
Photo #3 is a close up of the "notch" cut into the form so that each top rib is started at exactly the same point on the form and is bent at exactly the same length. I used three clamps just to minimize any movement on the end of the 1x1 during bending.
The "come-a-long bend" is only half the story, however. Since I am cold bending the tubing it springs back towards its original shape and has to be further bent to fit snuggly around the form using a pipe bender.
Photo #1 shows the 1x1 rib as it comes off the come-a-long bender. I have taped the edge of the form with black tape so it will show up better in the photograph and give you an idea of how much more bending we need to do with the pipe bender. Note that the bending form has now been taken off the garage wall and moved into my nice warm shop.
Photo# 2 shows the tube in my handy dandy Harbor Freight pipe bender.
Photo # shows the tube length wise in the bender. I used the largest die, for 2" pipe, that came with the set. The square tubing basically self centers on the die and on the two rollers. However, one must check before making each incremental bend to insure that the pipe is remaining relative straight in the bender. If it gets crooked it will put a pretty wicked twist in the pipe (don't ask me how I know or how hard it is to pound out one of those twists).