Traditional hobbyist methods of finding where to draw the X

[idrivejunk]

coupe fender : find a position you like on one fender and cut it in . Then make a pattern of the cut out by placing tape all over the fender and over the hole .cut out the tape that is over the hole. cut the tape along the fender to body side as a reference edge . Take the pattern off (carefully ) and lay it upside down on the other fender using reference measurements to bottom of fender and the reference edge . Mark the position of the hole . I would also level the car side to side so you could use a reference guide of a stick or something taped to the trunk at an equal distance from the back of the trunk lid (parallel to trunk edge)to string a plumb bob down to each fender off the sides an equal distance from trunk center line for checking equal distances apart . If you already have one done you could also just remove both fenders and bolt them together at the mounting flanges to make sure you could mark the second one in the same spot . If all else fails just paint it metalflake as it would draw the eye hypnotically away from any minor discrepancy .

I tried the tape pattern when making roll pan ends but it was not successful however that is a valid method which I considered for this. Rear fender mount flanges are horizontal on this build but when making tubs, tacking the edges of them together was one step taken in assuring symmetry of the quarters and fenders in relation to CL.

[idrivejunk]

By the way , I am in no way a professional . I have spent the last 4 years staring at and avoiding any further attempts to make the passenger door on my coupe line up properly.

Had you been able to post images for assistance, we may have been able to help you conquer that.

[idrivejunk]

For me the first part of installing the taillight would be to look at the car from a distance and find the right spot to put. then mock it up and go to the back side and look at it from a distance.  For me the flow is first, next would be to cut it in and make sure it flows as to not have a spot where water could sit when it rains on the car or when its washed.
Similar to chimp on the opposite side but I don't trust the numbers on old cars. Put the template where it should be and step back and make sure it is level. One fender could be rolled differently at the bottom then the other so measuring only gets you in the ball park.

I installed frenched taillights in my 46 multiple times till I found what I thought was a good flow. I have mine in the car about 3" further then most so they run parallel to the trunk line.

$.02

Thats a bargain for two cents. You are right, eyeball first. Of course thats what I did for initial positioning and I think just as most folks find, on a Model A coupe the sweet spot for height is near centered at the level of the trunk gap. As to flow, current status of the revised lamp area is shown on the car's thread. A drain hole hidden under the lamp housing is probably a good idea. The body was constructed with no precipitation considerations however. Not for wet days and intended to be dusted, never washed. Kinda sheltered, show car life is.

[idrivejunk]

I have thought about this problem some over the years.  I have always wondered how they were able to add Quad headlights to cars in the early days of customs and make them the same side to side.

My thoughts would be to build a jig/fixture to hold both of the add ons in place based on the distance and angle I wanted them on the car.  Then attach this fixture to the car temporarily by careful measurement.  I suppose the fixture could also be on stands on a level surface and the vehicle is level with the floor.(everything in the same plane)  Once you have the part you are adding to the car in the position you want it, you build out to the part being added.  The fixture holding the add on could be made of wood or metal.  Our friend Sumner used a building technique like this for his land speed lakester.  He built a lot of the car out of wood and then removed the wood parts and replaced them with metal as the build progressed.  It allowed him to position the major components where they needed to be as he worked.  This gave him a good visual reference also.  I have not built anything this way but I have used some variations of this method.

Just my thoughts  

When I used the big floor based stand up cardboard template for the 51 grille opening, that was a loosely similar method to what you propose. On the 31, with the tail lamp partially submerged in the fender, jigging might get a little complicated but I certainly get the gist of your approach. Seems quite logical to me. Perhaps not always best suited for every occasion or practical in the pro shop but definitely an accurate means which in some circumstances could be the only or best way.

[idrivejunk]

If I understand the 51 fender problem correctly, lining up the lines on the two fenders, I would level the frame, then put one fender where I want/like it, make the line level (parallel with frame) mount the other fender, or mock it up on blocks clamps etc. and simply stretch a string along the feature line on the already mounted fender to line up  the  feature line on the other fender.

Only trouble is every horizontal line must also be at correct height in relation to all other body parts simultaneously. The sketch I posted lists steps in order, which I found effective for establishing that. From running board brackets up. Those are what truly dictates position of the entire body. Where you have suggested string, I use a yardstick and just hold it up there with a level on top then view from a distance which allows the whole truck length to go behind the yardstick.

[idrivejunk]

I tend to go with what looks right rather than what measures right. For instance with a shorter tire, the front wheel looks better move ahead 3/4 to 1" ahead of the original position because most wheel openings are not symmetrical front to rear and if located in the original position when radically lowered it makes it look too far back in the opening. Moving it forward gives it a more aggressive look, like it is straining to move. By the same token the rear axle often looks better moved back because the taller tire in the rear tends to overwhelm the wheel opening. For instance when I do a 41 to 48 Chevy car the wheelbase ends up closer to 118" than the stock 116".

So when doing body modifications I measure, but if it doesn't look right mocked up, I will move it to where it does look right. So many cars are not symmetrical left to right it isn't funny. If the fenders are slightly different in width what looks centered on one side may not look right on the other.

When mounting a body on a prebuilt frame if the front fenders are attached to the body, that has to be taken into account when mounting the body. Get the front fenders right and go from there. I do have a Laser, and I have used it to mount bodies. It impresses the hell out of customers.

The 51 cab ended up about an inch forward from where the chassis manufacturer's mount holes are. Firewall position being the compared reference. In this body design, only inner fenders and hood hinges connect cab to other panels.

Impressing people is not my goal and I don't own a laser level but do agree that walking up to the vehicle and saying this is about where I want this is first. Followed by measuring, rough cutting, mockup, and eyeball. And then correcting to suit eyeball. At that point if a guy is satisfied he can finish. I prefer to find out why measuring didn't work though, and will seek a root cause so that measuring and eyeball have matching results. Because these are six figure builds. To deem a discrepancy between the two insignificant in a critical appearance area is to leave some symmetry on the table in my book so I believe reinvestigation of adjacent areas is called for before moving on. If those all prove out and the issue does not harm asthetics, I'll roll with it due to the nature of old Fords.

If I could just work on post-traditional-rodder era, pre-unibody GM vehicles, I would.    However, all during this century my range of ability necessarily has included "Whatever they give me to fix". That was a big mental leap but I have been successful at meeting customer needs the entire time, as I expect you have.

[idrivejunk]

What Frank typed is spot on for body /fender placement. For items like tail lights exhaust etc I use movable templates. I will take a piece of pattern board (cereal box, shirt board card stock etc) and make a pattern the size and shape of the light then use magnets or tape till the placement is pleasing to the eye. Then I will break out the measuring tools to set the other side. Exhaust placement is similar. A short length of tubing held in place and moved till it looks right.
As Frank stated sometimes the eye is a better tool than measuring do to the "tolerances" found on ancient sheetmetal!

See my replies to Frank and John. It is not uncommon for me to use a cardboard template. An example on the 30 is trunk sides, and on the 51 for placement of the valance slot. Just examples off the top of my head. Measuring and eyeballing work together, thats the common denominator I see in these replies. No one is claiming to use one or the other exclusively. For show cars, in my opinion, the goal should be for the two methods to jive. Eliminating a maximum amount of doubt or speculation. Because many flaws just don't become apparent until the job is at a show or has at least been painted and fully assembled.

[idrivejunk]

Go out in the country and find a stop sign. Wait, that's to build floors.

Here's where I'd probably start with the 1951 Ford pickup:

Level the frame front to rear and side to side. Get two pieces of ABS pipe big enough to not sag across the width of the truck. Cut slots partway through each one at right angles to the lengths. Use a steel rule, saw, or just a scrap of steel to line those slots perfectly. Go to the other end of the pipes, just far enough away to be a little wider than the truck, and cut a similar slot in both pipes at the same time.

Now you have two pipes partially cut through with slots an identical distance apart.

Mount your first front fender. Now, set up your ABS pipes on stands, one just ahead of the truck, one behind, measured off the truck so they're parallel to their respective frame ends. Hang a plumb line on each side of the truck with the line strung through the two slots. Measure off the door frames of the cab, the bed sides, whatever you know is already centered on the frame to make sure the strings are parallel to the frame. Put a Level on the tubes and line levels to make sure your string is perfectly level and at the same height as your character line.

Now you have a sight line the same height all the way around the truck equally distance from the centerline on both sides.

When you're done don't lose that stuff, you can use it for your home wheel alignment.

A good hobbyist approach! Sounds similar to my above-the-body measuring method but I only have one stick of heavy gauge tubing to use. A felt tip dot on the concrete can serve as a placeholder, and measuring a full set of those can reveal damage issues that might otherwise be missed. For my home driveway post-part-replacement toe setting efforts on FWD coupes, I just compare distances between chosen tire tread ribs as reference and have had satisfactory results. Trial and error is the fine tuner on that for me and an extra try has only been needed once, when I went the wrong way. Last time I paid for an alignment was around 2014 after changing front struts. And there I go, following an off topic tangent myself.

[idrivejunk]

Who wants to take a stab at outlining a procedure for assuring that points along the leading edges of these front fenders are symmetrical?

Go!  

[idrivejunk]

OK then, another approach at question asking:

Which statement seems most true to you?

A: No problem exists

B: No solution exists

C: A problem may exist but could be ignored

[enjenjo]

I'm going to go with C I do see some minor problem areas but from my perspective they look minor. And I am not sure the time to correct them is justified. Some times close enough is close enough. But you are most qualified to make that judgement.

As for making a pattern some low tack painters tape laid over the fender in a couple layers could be used to take a shape from one side to be transferred to the other with minimum distortion.

[idrivejunk]

Your thoughts are always appreciated.

For a six figure look, I think locating discrepancies is prudent even if remedies are not. Because the photograher will randomly select the exact angle which looks wrong and pick that shot for the cover according to Murphy's law and I want to avoid that. "We" may not care at this point however. I haven't made twenty an hour since '09 and this is the last show car we will do.

When a guy sees a problem but can't pin down the source, measuring or guessing is whats left before slicing and moving things to see if it looks better. Go two moves deep into that game and you wish you had measured. Leaving things be and hoping nobody notices may be the common and perhaps best solution, however ignorant it may seem to some. The opposite has an equal chance of being truth unfortunately.

I am fairly certain that the felt tip mark on the driver's fender is the result of using a tape or tape and paper pattern. Can probably verify that with a photo. However use of such fails to reference fender location in relation to the rest of the vehicle so that is no help with length, width, or height. Or shape, really. Just surface area and features on that surface. As I see it.

Heres what I had in mind: Level vehicle both ways. Plumb bob  reference points on chassis to floor. Using floor as datum plane like on collision repair rack or chassis building jig, establish chassis CL and mark. Using plumb bob and measuring tool, take comparative measurements. Correct overall length of body, width, then height. As needed.

Then put dots on front fender leading edges at 2" intervals and make corrections as needed to bring all dots of the suspected fender to within a cumulative (adding length, width, and height variations together for each dot) maximum of 1/2" to their mirrored locations on the side chosen as the desired shape.

That sounds reasonable to me.

:?:

[idrivejunk]

https://m.youtube.com/watch?v=eKmRkS1os7k

[kb426]

I have not built any rods to that level that you describe. I would say that on some, the side to side comparison could vary. On most, if the cab or body is square to start and all the panel gaps are equalized, that will cover most of what is visually perceived. I haven't been doing major surgery also. I live in amateur-ville.

[idrivejunk]

If everyone did their own, I'd be out of a job. But doing so certainly simplifies the answer to whether something is done or not. Leave a single stone unturned and thats exactly what will be pointed at first. Or ignored. Theres no way to predict perceptions of otbers and thats a big part of why I post. Without second opinions, I am blind and must turn every stone including boulders to assure that I know what I am putting out. If the owner or boss said it looked good to them, I'd be glad to break pusuit of the sweet spot. Since carving filler is no longer part of my job, my best is all I can do because them that do carve won't take symmetry into consideration. It has to be built in and smooth enough to not be ruined by that. This car may end up looking like one guy did it from the cowl back and another did ahead of cowl.  :oops: