Half Shaft dab?

[Mike Z.]

Having restored several half shafts, driveshafts and suspension parts; I normally would grab the specific year guide (from vendors and my own history examples) and dab and mark inspections accordingly. I was laying awake the other night (you never do that do ya), thinking about the work I wanted to get done in the shop and knew I had some half shafts and a driveshaft to detail for my current "frame-off" project: 70 LS-5. I thought, ya when I am judging-I typically see the green dab on the halfshafts and looking from the rear of the car, where I am laying; the dab is concentrated at a point, then the paint was allowed to run-?down? Then I got to thinking: as we know, the suspension was loaded onto the frame while the frame was up-side-down. So, my question is: when did the inspector dab that green paint and what was it an inspection verification for? Was it prior to the "flip"? or after? If you think about it: if prior, as I believe it would have been (so, any repair could be taken care of before the flip) and if the inspector was standing at the rear of the frame-the paint run down, but when the frame was flipped, it would appear to run UP? I guess it would run down (when flipped) if the inspector was standing from the front side of the car and applied the dab to the front of the shaft-but, I do not think that was the practice. So, what's your opinion or does anyone have any facts to a procedure that would have been followed?
Thanks,
Mike

[Terry M.]

Re: Half Shaft dab?

All of your speculation assUmes the paint daub (whatever it was for) went on at St Louis. Allow me to suggest you broaden your outlook and consider that it went on where the shafts were manufactured. No, I don't know that was the fact, but neither do I know they were applied at St Louis. Absent knowing what they represent, it is hard to contain our speculation.

[Gene M.]

Re: Half Shaft dab?

Mike,
Here is what I can tell ya about the drive shaft as I know it. The green paint dab on the drive shaft and the blue dab on the rear end input yoke are to be align up at assembly. So I would interpret it as done (paint dabs) prior to parts arrival to line for assembly.

As far as half shafts the only ones I believe that had paint marks were for big blocks as they were shot peened in the mid years not sure on later c3's. Understand my knowledge is only inclusive of 68 after that limited........

[Mike Z.]

Re: Half Shaft dab?

Terry, you have a good point. I had assumed the white marks at the yokes were inspection marks for the U-Joints, which very possibly could have been applied at the sub-contractor site; however, the white marks could just as easily been for inspection that the fasteners were torqued or French locks bent over properly, etc-which, would mean they were applied in St. Louis. But, the green dab in the middle of the tub-to me would be inspection that the half-shaft was properly installed, torqued or whatever. Also, if the green dab was applied other than in St. Louis; why would all the dabs be running the same direction (rather than one side running up and the other side running down). We typically see them from the rear running down-I believe now, because all we see are restored-perhaps not quite they would have left the factory. Because the shaft is the same P/N on either side, and if dabs were applied elsewhere; how would they all end up running the same direction, when installed on the car? Are there any "Bow Tie" cars out there that still have decent dabs to learn from?
Mike

[Mike Z.]

Re: Half Shaft dab?

Mike,
Here is what I can tell ya about the drive shaft as I know it. The green paint dab on the drive shaft and the blue dab on the rear end input yoke are to be align up at assembly. So I would interpret it as done (paint dabs) prior to parts arrival to line for assembly. To me: how would these marks be done other than at St. Louis? I mean the green dab on the driveshaft aligns with the blue dab on the rear end input yoke-had to be done in St. Lewis-I really do not think the driveshaft and the rear end member were sub-contracted by the same vendor-maybe, but I don't think so. But, you may have hit on something I was having trouble with: the half shaft dabs painted on the front of the shaft-if the inspector marked the fronts of the halfshafts at the same time he marked the driveshaft-standing just front of the frame cross member, or leaning over one of the side rails; maybe, just maybe it could have been that way. Now, if this was the case: the paint dab would have run down, right? So, what direction would it appear when you flip the frame? UP, when looking from the rear of the car. I am assuming the frame was still inverted when the marks were applied.
As far as half shafts the only ones I believe that had paint marks were for big blocks as they were shot peened in the mid years not sure on later c3's. Understand my knowledge is only inclusive of 68 after that limited........

Thanks for your input,
Mike

[Michael J.]

Re: Half Shaft dab?

The ones I have seen, on '67s, were mostly small dabs, like 1" -2" or so in diameter. I haven't seen any runs, maybe they were just not enough paint? Have you seen runs Mike?

[Edward J.]

Re: Half Shaft dab?

Mike my two cents on the paint dabs or marks anywhere on the car is are only to make some judges happy,As for alot of the judges have enough of a headache trying to judge 4 or possibly more cars in a short time period. And each and every car the paint dabs and marks applied at the factory is different, So you see the point. and its even possible that some cars may not of even had some marks.

Terry please correct me if I have made a era.

[Michael W.]

Re: Half Shaft dab?

I thought the paint dabs on the half shafts were to help the line workers differentiate shotpeened from 'regular' shafts.

[Mike Z.]

Re: Half Shaft dab?

The ones I have seen, on '67s, were mostly small dabs, like 1" -2" or so in diameter. I haven't seen any runs, maybe they were just not enough paint? Have you seen runs Mike?

Yes, most of the half-shafts and driveshafts I have worked on are fairly rust free and although dirty and greasey, the dab is faint, but there. My problem is most are sent into me, so not on the car, and all of the cars I have are already restored, and I failed to take good pics of this detail before they were removed from the cars. So, once they are off the car, there is no way to ID which direction the dab ran (you can switch sides they were originally installed and the dabs runs the opposite direction). I see these dabs re-applied on quality restored cars and I guess this is a pretty small detail in the scope of things-I am just trying to learn how certain procedures were done at the factory, to try and step up my game. The detail I am putting into this 70 is light years ahead of my 66 Duntov Award car that I completed in 99. This is a hobby we have passion for and that passion, I believe leads to the history of the cars, and ultimately the details of the process of manufacturing them. At this time I am leaning toward making my dabs run up (when looking from the rear of the finished car).
Mike

[Tony S.]

Re: Half Shaft dab?

I agree with Gene. In '65, the L78 half shafts were shot peened, a green daub was added (sometimes a white stripe) and then the BB half shafts were covered with a low gloss asphalt type black paint. I think that was done before being installed on the chassis. Different rules apply to small block half shafts in '65.

[Tony S.]

Re: Half Shaft dab?

On C2's, the chassis was right side up when the chassis blackout occurred.

[Graeme B.]

Re: Half Shaft dab?

The paint run ,up or down, would depend on whether the paint daub was applied to the shaft toward the front of the car or the rear.Make sense? My car ('69) also had yellow crayon marks runing the length-ways ,4 on one side and 2 on the other.
Was this a check for bolt tabs bent over?
Cheers, Graeme.

[Mike Z.]

Re: Half Shaft dab?

I agree with Gene. In '65, the L78 half shafts were shot peened, a green daub was added (sometimes a white stripe) and then the BB half shafts were covered with a low gloss asphalt type black paint. I think that was done before being installed on the chassis. Different rules apply to small block half shafts in '65.

OK, let's say you and Gene are correct: green dab applied prior to install. So, I invision half shafts lined up at the sub-contractor factory-then the inspector comes along and checks whatever he is checking and puts the dab of paint on the shaft (which has a run). The Same P/N fits either side of the car, right? So, how is it the runs always go the same way-if they were all line up the same direction at the factory; would it not be logical that when installed in the car that one dab would run UP and the other would run DOWN? I'm sorry, I just can't see it happening that way.
I understand the "black-out" was applied after the flip, but that would only mask the dab-I believe the dab would have been applied after any shot peening or preservative applied (you say prior-I believe preservative would have been applied at the sub-contractor that made the shaft), but prior to black-out process. So, I am back to when were the dabs applied? I have done a couple of 66s and now this 70 (1 SB and 2 BB cars) and I understand the differences between the two applications, and have judged several cars, I just had never given the topic much thought, till now-now it is bugging me.
Mike

[Mike Z.]

Re: Half Shaft dab?

The paint run ,up or down, would depend on whether the paint daub was applied to the shaft toward the front of the car or the rear.This is exactly my point-which side was it applied and when-prior or post flip. Make sense? My car ('69) also had yellow crayon marks runing the length-ways ,4 on one side and 2 on the other.I personally have not seen the crayon marks, but the green dab and white slash at the u-joints seems to be common-at least on BB shafts.
Was this a check for bolt tabs bent over?What the marks were for is part of my query also.
Cheers, Graeme.

Thanks for your input, Mike

[John H.]

Re: Half Shaft dab?

Don't over-think this. The green dab on the big-block half-shaft tubing was applied at Chevrolet-Warren (where the half-shafts were made), immediately following the shot-peening operation (which was done after the end yokes were welded to both ends of the tube). It was the only way the operators at Warren could differentiate between the SB and BB half-shafts (to get them in the correct shipping gondola), and it was the only way the assembly operators and inspectors at St. Louis could indentify them, as the two types of half-shafts were otherwise identical, including the Warren-installed U-joints and spindle flanges.