1968 Rear bumper - old topic revisited

[nfrntau]

I just recently had my rear bumper re-chromed. It looks awesome with one exception. Even though I pointed it out to them when I dropped it off they removed the witness line from the top of the bumper.
I called him up and told him about it and he went and got another original bumper out of his stack told me he saw what I was talking about and would make it right.
Friday I went to pick it up and it's flat on top also. I now have two beautiful original bumpers with flat tops. So I went with him to his stack (it's big) of old bumpers and we pulled three other original 67/68 Mustang bumpers and they were flat on top also.

Am I going nuts?
Do any of you have this witness line on your original bumpers?
Is there any mention of this for MCA judging?

I told the chrome guy I would find out something and get back to him, he'll make it right, re-chrome yet another bumper, but I need to figure out what right is and then find it.

 

[Ruppstang]

I am not sure if it is possible to save it if it is what I am thinking of. During the rechroming process they remove the old chrome and small imperfections and unfortunatly the witness line. I went and checked our cars and it was not there. Today I'll look through some old bumpers to see if I can find one. I am a MCA 67-68 gold card judge and I am not aware of any rules regarding a witness line on rear bumpers. It would be a nice detail to presevere. Marty MCA 38812

 

[Mosesatm]

It's difficult to see in a photo but if you look at the gas cap frame reflection you should be able to see how it changes shape in the red circle. That is the point where the rear bumper angles down a degree or two.

 

[sam]

wow.......I'm not sure what the "witness line" really is. Perhaps it's because I am not into the car show judging etc...............but I'd like to know anyway.

 

[gofastguy]

wow.......I'm not sure what the "witness line" really is.

Me neither! But I'm pretty sure our side scoops have them too. I had someone who seemed to know of what he spoke tell me about the ones on the side scoops.

 

[Ruppstang]

Our HCS still has its unrestored rear bumper and I checked it and the witness line is there. But is so very slight that you can hardly feel it when you run you fingers acrossed it. As I said earler I sure it would be lost in the rechroming. For you trying to figure out what a witness line is. It is a line on the top surface of the rear bumper that is about 1 inch in from the back edge and runs the lenth of the top surface. If you have a reproduction or a rechromed bumper it will not be there. Good question nfrntau. Marty MCA 38812

 

[tomcwarren]

Here's a pretty good descripton of what a witness line is WRT molding/joining of parts (figure 27):

http://www.kinetics.com/guide/non_flash/t15.shtml

For the record, I see a witness line just about 1/16th of an inch to the 'rear' of the bolt head on my rear bumper, looking down on it while standing next the the left rear quarter. I'll take a picture later when my wife returns w/the camera.

Tom

 

[sam]

Our HCS still has its unrestored rear bumper and I checked it and the witness line is there. But is so very slight that you can hardly feel it when you run you fingers acrossed it. As I said earler I sure it would be lost in the rechroming. For you trying to figure out what a witness line is. It is a line on the top surface of the rear bumper that is about 1 inch in from the back edge and runs the lenth of the top surface. If you have a reproduction or a rechromed bumper it will not be there. Good question nfrntau. Marty MCA 38812

Gee thank for the explanation. Just when I think I have apretty good handle on the car, I learn something new. Great !