Half shaft resto

[Jordan S.]

My 70 ls-5 half shafts have surface rust and a small dent. I puchased a used set ($63 for the pair - 2 1/2" from a 70) and started my own resto. The pic in the pink basin shows the weld seam which appeared as I was bead blasting. I think they look OK but am not sure if its worth the effort to sand out all of the minor surface pitting on the tubes. I do intend to have the car judged one day. What do you think??

[Terry M.]

Re: Half shaft resto

All that "minor surface pitting" is from the shot blast operation that was done to the half shafts on Mark IV motored cars. It is supposed to be there.

[Patrick H.]

Re: Half shaft resto

All that "minor surface pitting" is from the shot blast operation that was done to the half shafts on Mark IV motored cars. It is supposed to be there.

Yup.
For the most accurate appearance you could have your local machine shop shot blast them for you, and you'd be as good as new.

[Jordan S.]

Re: Half shaft resto

Yup.
For the most accurate appearance you could have your local machine shop shot blast them for you, and you'd be as good as new.

Thanks for the replys. How would "shot blasting" change the appearance from what I have now?

[Grant W.]

Re: Half shaft resto

My 70 ls-5 half shafts have surface rust and a small dent. I puchased a used set ($63 for the pair - 2 1/2" from a 70) and started my own resto. The pic in the pink basin shows the weld seam which appeared as I was bead blasting. I think they look OK but am not sure if its worth the effort to sand out all of the minor surface pitting on the tubes. I do intend to have the car judged one day. What do you think??

Hi Jordan
Nice restored 1/2 shaft. Mind if you share among us how you restored them. I have NOS ones but I like the look of yours. Thanks, Grant

[Patrick H.]

Re: Half shaft resto

Thanks for the replys. How would "shot blasting" change the appearance from what I have now?

Slightly/somewhat duller. Without seeing them in person, yours appear a tad too shiny compared to a shot blasted piece.

Patrick

[Timothy B.]

Re: Half shaft resto

The half shafts look very nice to me. I would like to know how you restored them.

[Terry M.]

Re: Half shaft resto

Jordan,
It looks like you have done a fine job just as they are. They will age and some of the gloss will fade with time. Your challenge will be to keep them from rusting too much now that the metal is bare.

Would you consider writing a story of what you did to restore them for The Restorer? I suspect a lot of members would like to know what you did.

[Terry B.]

Re: Half shaft resto

Jordan,

I think your's look pretty good. I would agree they might be a little too shiney. You should send a picture or two of yours to Greg Gorniak. He restored mine and many others on this board. He can tell you what you need to do to make them look like his. You can see pictures of his work at https://www.ncrs.org/mvc/services.htm His contact info is on the site.

I hope this helps,

Terry

[Dan L.]

Re: Half shaft resto

I'd be interested to know your process. Did you use glass bead? Then what did you do? Thanks.

[Jordan S.]

Re: Half shaft resto

Thank you for the kind words. I would be honored to write a restorer article but I think I need to "perfect" the finish first. This was a first attempt but I still am not sure what the "correct" finish for the tube should be. Smoother?? More Dull?? Highlight the longitudnal weld? I tend to be a bit obsessive...trying to make it perfect but don't know what perfect should be.

Here's the process to date. Degrease with brake cleaner. Bead blast w/ medium glass bead, wash w/ Eastwood metal wash. Then sand tube by hand w/ cross hatch pattern 100 grit then 220, 400 then 1500. I used metal wash for wet sanding instead of water to prevent rust during sanding. Polish w/ dremel tool buff using fine autobody polishing compund. Wash w/ metal wash and allow to dry. Apply a thin stripe of Eastwood's metal blackening solution to the end of tube at the weld w/ a papertowel and wipe off after about 20 seconds. I plan to clear coat with diamond clear satin to prevent rust.

I know I can get it closer to perfect If someone with a known original or top flight level resto would post a picture. I have resto books for reference but don't want to "repro a repro".

[Terry M.]

Re: Half shaft resto

Stick to a known low-milage original if you can find one or better yet several. Anything else is just someone's idea of what it should look like, and those ideas are like some parts of the body in that everybody has one and yet they are all different.

Also remember the chassis parts are difficult to judge. Low light conditions, or worse yet shadows on a sunny day, and poor access make for a lot of latitude under the car.

Here are two examples for you -- but your research should include more examples than these:

[Chuck S.]

Re: Half shaft resto

Thank you for the kind words. I would be honored to write a restorer article but I think I need to "perfect" the finish first. This was a first attempt but I still am not sure what the "correct" finish for the tube should be. Smoother?? More Dull?? Highlight the longitudnal weld? I tend to be a bit obsessive...trying to make it perfect but don't know what perfect should be.

Here's the process to date. Degrease with brake cleaner. Bead blast w/ medium glass bead, wash w/ Eastwood metal wash. Then sand tube by hand w/ cross hatch pattern 100 grit then 220, 400 then 1500. I used metal wash for wet sanding instead of water to prevent rust during sanding. Polish w/ dremel tool buff using fine autobody polishing compund. Wash w/ metal wash and allow to dry. Apply a thin stripe of Eastwood's metal blackening solution to the end of tube at the weld w/ a papertowel and wipe off after about 20 seconds. I plan to clear coat with diamond clear satin to prevent rust.

I know I can get it closer to perfect If someone with a known original or top flight level resto would post a picture. I have resto books for reference but don't want to "repro a repro".

The genius in your restoration method is the application of the blackening solution...the HAZ is a tough look to replicate, but yours looks pretty close to how I think it would have appeared.

My thought was always that the longitudinal seam should have about the same degree of blackening as the yoke welds because the steel had to have been subjected to similar heat levels in both cases, but that was without any real knowledge of the processes. The longitudinal weld was done at a different time in the manufacturing sequence, and is virtually invisible (has no visible weld bead) compared to the yoke welds.

The bead blasting is pretty straight forward for most of us. My opinion is the cross hatch sanding with four grades of paper is masochistic overkill. The surface appearance can also be restored close to freshly fabricated tube by simply burnishing the bead blasted surface with steel wool.

Depending on how much rust you started with, the cross hatch sanding may, in my opinion, needlessly remove or alter original texture detail such as the shot peened appearance for big block cars mentioned by Patrick (Bead blasting would also slightly alter the surface texture, but it's the best alternative I know for removing the rust).

I've not seen an original big block half shaft, but I believe the shot peened look for big block cars mentioned by Patrick would be closer to the appearance immediately after bead blasting without any further treatment, but in your case, I wouldn't mess with the results you've obtained. In my opinion, fresh shot peening would be a dull dark matte gray, where freshly bead blasted steel is a lighter matte silver-gray.

[Gary B.]

Half shaft resto; longitudinal seam weld

My thought was always that the longitudinal seam should have about the same degree of blackening as the yoke welds because the steel had to have been subjected to similar heat levels in both cases, but that was without any real knowledge of the processes. The longitudinal weld was done at a different time in the manufacturing sequence, and is virtually invisible (has no visible weld bead) compared to the yoke welds.

Chuck,

I agree there is no weld bead to speak of with the long. seam weld, but the HAZ for that weld is very clear, as can be seen in Terry's second photo. I bought newly made half shafts for my '66 from Long Island Corvette and they have all the features one would expect, including the original surface finish to the tubing, which is virtually impossible to recreate - unless the half shafts are to be shot peened. But shot peening isn't correct for the non-HD suspension. For standard suspension cars, I highly recommend the LIC half shafts to anyone who doesn't want to try and restore originals, which, absent the shot peening step, will in most cases be detectable as not-quite original.

Gary

[Terry M.]

Re: Half shaft resto

The second photo I posted is of the drive shaft, which is not shot blasted. I suspect for the shot blasted half-shafts the heat affected zone would be diminished, and perhaps even removed, by the shot blasting process. The first photo seems to show that.