Hi, I’m looking for measurements on a 1940 Ford frame. I have been doing a number of rust repairs on the underside of my frame after clamping it to a home made chassis table. Problem is the residual stress in the frame as a result of welding on the underside: when I take out the bolts that hold the front of the frame then the rails drop about an inch. I’d like to have measurements like below in order to be able to judge what are the best spots to relieve the stress. Can you help me please? Kind regards, Chris Sent from my iPhone using H.A.M.B.
You should work from a datum line and measure up or substitute your frame table provided it is level. The lowest part of the frame is parallel to datum line as a reference and other points of reference needs to measure up from that line. Identical reference points on each side should correspond measurement wise to datum line. I worked in collision repair for years and when it came to work on on my 35 Chevy frame I determined that it had previous collision damage that need to be rectified before any other work was undertaken I also did a similar 33/4 Ford frame and similar to my Chevy, chaining down both ends to pots in the concrete and using a hydraulic jack where it was low and slowly pushed the frame back into correct shape and relieving the stress in certain areas with a large hammer and using some heat in other areas. Go a little over where it needs to be and allow frame to spring back slightly until it's where it should be. I did one side at a time and checked lengths and diagonals to ensure that it was square with no torsional twisting. Could I suggest unbolting both front frame horns and leaving the frame in the jig. Make sure that you use some HD bolts/nuts and washers to secure frame in jig. You may only require a hydraulic jack under each frame horn and some slight heat to correct things. Could be that continuous welding put excessive heat into frame causing the distortion. Alternating from side to side with MIG only doing short sections at a time allowing welds to cool before moving onto another area. I fabbed up jigs for my 46 Olds due to substantial frame mods, it's squarer now than when I commenced the work. .
Hi Budget36, Thank you. I know about the Wescott drawings. I have drawn my green lines on one ;-) Regards, Chris
Hi Mgtstumpy, Thank you for you elaborate response. I failed to mention that I had to cut away the entire datum line of my frame. I had to replace it with fresh steel. The datum line looks straight in Wescott diagrams but it isn't on real frames. It has a slight curve and for that reason I can not use the datum line. I decided to make a reference line that is tangent to the frame rails in 2 points that I'm sure of begin correct when the frame is in the jig. I have had to replace almost the entire bottom 2 inches of the outer frame rails from the rear kick up all the way to the front. So now I know that the frame is out of shape but there is likely not a single point that I can heat in order to correct its shape. Currently I have 6 points along each frame rail at more-or-less equal distance that know are correct. If I manage to relieve the stress everywhere then I know the frame is close to the old shape. But I'd like to do one better. For that reason I'm hoping for someone that can help me with the measurements.
Have you considered getting another 40 frame? http://smclassiccars.com/ford/20461...ng-chassis-with-title-coupe-pickup-sedan.html
Hi 19Fordy, Another frame is not an option. I live in The Netherlands. Our law stats that I can not swap frames. Technically I can but then the law states that the identity of the car changes so much that I no longer have a car authentic enough to restore. I will never get a license to drive the car. It is not that bad. I have finished all rust repairs on the outer frame and inner frame and I have learned a great deal during the repair of the frame. But I also learned that I should have recorded the entire shape of the frame rails before starting the repairs.. Now I'm left with only 6 points along each frame rail to check the shape of the rail for correctness..
I have the body off my 41 truck frame. I could measure that for you but I am at work until later this evening. If no one beats me to it I can get those measurements for you.
@cjtwigt I understand that the law is the law.....but it is very difficult for me to comprehend how replacing a chassis with one of like kind is not treated the same as replacing any other part of the vehicle that is damaged or inoperable. Are you absolutely certain it is that difficult (impossible) to replace the bare chassis (frame) while using all the original running gear that comprise a ‘rolling’ or ‘complete’ chassis? Alternatively, could you obtain a correct frame and ‘swap’ individual frame sections [side rails(s) for instance] and just claim it is replacing ‘parts’, not the chassis in its entirety? By the way....I disagree with your statement that the datum line “is not straight, but curved”. I believe the datum line IS a straight line, not a physical thing, sort an imaginary line that serves as a reference to the height of contours above or below the datum reference point. In some technical references I have seem it also referred to as ‘the water line’, serving the same purpose as reference dimension. However, since water self levels, water levels could be usedul in establishing the datum line. Ray
Hnstray is correct about the datum line, in frame repair we would hang gauges on the frame front to rear and establish the datum line with a center indicator. With the datum line you could deturman if the frame was square at all points and if it was high or low at all points. The frame cannot be the datum line and for your purpose doesn't have one. One thing else is a frame that is warped from welding, especially Mig, is difficult to straighten with out cuts and heat. I had a customer who wielded his frame for a 55 Chevy capping the bottom of the rails so they were smooth. He did his work with the frame upside down on stands and made himself a banana. To much heat over the length of the frame made it unusable. Just remember the datum line is what you measure from to establish squareness of the frame. You can pick a point anywhere on the frame and compare it to the other side to see if it measure the same.
I will add that I have seen guys use the floor as a datum line when building a frame, laying it out fist on concrete and building to the layout. Height and squareness are easily measured with plum bob and a tape measure.
This is getting interesting. I'm learning a lot today. Thank you all! Also found out that there are 2 different Wescott diagrams for the 1940 Ford frame: http://www.wescottsauto.com/WebCatalog/Tech/FrameDiagram1935-40.pdf https://www.jalopyjournal.com/forum/threads/wescotts-36-40-ford-frame-dimensions-gospel.1095038/ I checked the 3 3/4 measurement just behind the front axle from what I think is the datum line in the first diagram and fortunately it matches bang on. Unfortunately there are not much other measurements in the diagram. Do you think the first diagram is accurate enough - when zoomed in - to interpolate my own measurements from the datum line in the diagram?
This is not going to be much help. 1. The only item I had that was long enough was a section of pipe. B. The measurements via tape measure are not very accurate and the frame isn't a straight line like the pipe D. Camera angle can effect actual measurement. But I said I would so I did! Never let it be said i didn't follow through. Don't listen to my wife, she makes stuff up! 8 Measurements starting at the front mounting hole, continuing back at each hole. Except for measurement 7, that is from the forward rivet on the X member. #1 #2 #3 #4 #5 #6 #7 #8 I doubt that is much help other than a reference.
Hey Bandit Billy, Thank you very much for the effort! I have some reference now to see if my frame is not too far off. I can see you focused on getting the right camera angle. Beautiful frame you have there. Again, thank you very much for the effort! I really appreciate it. Kind regards, Chris
I think your method would work ok. However you need to indicate an exact starting point for the first "Green Line: from either or both ends then it could be done with a level to insure vertical is correct and careful measuring.
from the bend forwards, it is foreshortened 1/2 and inch thats how it would sit across the bottom = level something like that
Hi Nobby, Thank you! Could you send me the binary file that you used to make the print-out please. Do you know if it is accurate? I only have the inaccurate diagram corresponding to the first of the links below. FYI: These diagrams do not depict the same frame: http://www.wescottsauto.com/WebCatalog/Tech/FrameDiagram1935-40.pdf (this is the inaccurate diagram as it displays the front half of the outer frame rails having a part that is straight in the vertical plane. This is incorrect. There is no straight line in the front half of the outer frame rails in the vertical plane) https://www.jalopyjournal.com/forum/threads/wescotts-36-40-ford-frame-dimensions-gospel.1095038/ (this diagram could be correct as it shows the entire front half of the outer frame rails as curved in the vertical plane)
the pdf is very accurate look at the drawing under your photo the line through the lower spring pockets IS THE datum I have redone the pdf full size and can lay that out and do some full size measurements if you like even in the metric
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