I have a '72 BB. I know they BB drive and half were shot pinned. What is the finish suppose to look like. I had mine sandblasted and then I powdercoated them clear. This created a nice look for them. However, I was looking at Quanta's finishing of drive shafts and theirs looked more like shiny steel and the ends were black. I thought the harding process GM used on the BB shafts created more of the look I currently have. Is Quanas' look correct of is the blasted look corred? Lastly, what are the ends that hold the Ujoints suppost to look like? I am hoping I didn't get it wrong but...hey it wouldn't be my first or last mistake.
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Re: Drive Shaft finish??
The tubes and welds should have somewhat of a "textured" appearance. Sandblasting leaves a somewhat of a "sparkle" finish. I do not know what clear powdercoating would do the appearance but I doubt that it would not look like shotpeening.Dick Whittington -
Drive Shaft finish
Brandon,
For '66 anyway, the driveshaft and halfshafts tubes started out with a longitudinal weld seam and circumfrential welds at each end where the yokes attached. With rusting, sanding, sand blasting and I suspect shot peening in the case of BB applications, the discoloration of the welds may be obliterated and I suspect all areas will take on the same surface look, which probably is not the shiny finish that you describe with the Quanta restoration.
On SB cars, there should indeed be blue/black discoloration from heat at all weld seams and shiny natural steel at all other locations on the tubing, prior to any changes from surface rust.
As some point I assume that drawn-over-mandrel (DOM) tubing started to be used and in that case there would be no longitudinal weld seam. I don't know when or if DOM tubing was used with Corvettes, but it wasn't used in 1966 and I'm guessing it wasn't used in 1972.
GaryComment
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Re: Drive Shaft finish
I am gathering that what I have done would be about as good as I am gonna get. I am hoping to get them on the chassis in the next month or so and don't want to install them if they are going to be way off base. I plan on driving the car when I am done so after a little road grime I imagine it would be hard to tell one from another. I just want to make sure I am not way of on what I am doing.
Thank you for your input,
BrandonComment
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Re: Drive Shaft finish??
Brandon-----
The big block HALF SHAFTS were shot-peened. However, the driveshaft was not. The driveshaft was the same for both big block and small block applications. The driveshaft was NATURAL EXTRUDED TUBE. This finish varies from a "dull steel" to an almost "brown" coloration. It is virtually impossible to duplicate without "re-tubing" the shaft with a fresh piece of extruded tube. Even then, without constant preservation effort, the tube will rust and the finish will be permanently gone.
I do not think that the "turning down" service offered by Quanta and others actually re-creates the original finish, at all. It might for those rare cases in which the natural extruded tube finish came out looking like this, but those cases are few-and-far-between as far as I'm concerned. Of course, it's POSSIBLE that the original finish looked SOMEWHAT like this, but I'd never have a driveshaft treated to this. One thing FOR SURE: the original finish DID NOT include the circumferential machining marks left by this methodology.
Much of the tube available today for driveshafts is, apparently, manufactured using a different method than the original tubes. These tubes do look very much like the Quanta-restored tubes. So, even if you re-tube today, I don't think that you'll get a driveshaft tube that will look like original.
The yokes welded to the ends of the tube were natural cast iron and the welds attaching them to the tubes usually evidence the "bluing" which is characteristic of such welds. Consequently, the yokes and the welds are also VERY difficult to return to their exact original appearance. Some folks might be able to recreate the "bluing" using cleverly devised restoration methods, but you'll NEVER restore the original as-cast finish of the yoke ends exactly as-original. So, for the most part, driveshaft restoration to as-original appearance is virtually impossible.In Appreciation of John HinckleyComment
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Joe: Drive shaft; extruded tube
Joe,
When you say the draveshaft was made from "extruded tube" what do you mean by this? When I read "extruded" I assume it means no longitudinal weld seam, i.e., DOM tubing. But I know for a fact that my original '66 drive shaft had a londitudinal weld seam. You couldn't tell this from the outside, since my driveshaft was terribly rusty, but when I cut the shaft in half, the longitudinal seam with the classic blue/black discoloration was clear as day.
GaryComment
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Re: Joe: Drive shaft; extruded tube
Gary-----
I can't describe the process that was used to manufacture the tube stock. However, this kind of tubing is known as 'extruded tube'.In Appreciation of John HinckleyComment
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Joe: Drive shaft; extruded tube
Joe,
I know that these days it's a bear to find driveshaft tubing with the original OD and ID that has the longitudinal seam weld, but something very close to teh original '66 OD/ID dimensions can be found. I'm not sure how it's really made, but I guess from flat stock that rolled into a tube and welded. Of course, the driveshaft shop wanted to know why the heck I would ever want seamed tubing when modern DOM seamless tubing is so much better.
GaryComment
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Re: Joe: Drive shaft; extruded tube
Gary------
Regardless of how the original tube stock was actually manufactured, the surface finish, coloration and texture is very unique and virtually impossible to restore in the exact-original appearance.In Appreciation of John HinckleyComment
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Re: Joe: Drive shaft; extruded tube
Joe,
I agree completely. I think It's virtually impossible to restore an orignal drive or half shaft to its orginal look. The only way I know how to get very close is by re-tubing and then re-shot peening in the case of BB half-shafts.
GaryComment
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