70 camber bolt restoration question or two

[Bill L.]

Upon reviewing the archives I found the following regarding the camber bolts are just wanted to confirm.

1. Camber disc on bolt is plain and bolt is phosphate.
2. Washer is dark and plain.
3. Nut is plain or phosphate.
4. Separate disc is zinc.

In addition, I observed the following assuming mine are original.

M mark on the disc attached to bolt.

There is also a mark on the separate disc with a circle and funny looking what appears to be an F maybe.

My question is do you phosphate the entire bolt and disc as an assembly and then remove phosphate from the disc?

If so, what is the best way to just remove the phosphate on the disc to achieve the plain steel finish?

Thanks, Bill

[Mike Z.]

Re: 70 camber bolt restoration question or two

Upon reviewing the archives I found the following regarding the camber bolts are just wanted to confirm.

1. Camber disc on bolt is plain and bolt is phosphate.
2. Washer is dark and plain.
3. Nut is plain or phosphate.
4. Separate disc is zinc.

In addition, I observed the following assuming mine are original.

M mark on the disc attached to bolt.

There is also a mark on the separate disc with a circle and funny looking what appears to be an F maybe.

My question is do you phosphate the entire bolt and disc as an assembly and then remove phosphate from the disc?

If so, what is the best way to just remove the phosphate on the disc to achieve the plain steel finish?

Thanks, Bill

Bill-
When I pulled my 70 LS-5 parts off, during restoration, I found:
Camber bolt and adj disc were intergrated and both appeared to be black phosphate
Lock Washer was black phosphate
Nut and rear adjustment disc were cad (silver), not zinc or natural.
Could have been running changes (my car is July 16 build), but this config is similar to my 66 BB. Hope this helps.
Mike

[Bill L.]

Re: 70 camber bolt restoration question or two

Bill-
When I pulled my 70 LS-5 parts off, during restoration, I found:
Camber bolt and adj disc were intergrated and both appeared to be black phosphate
Lock Washer was black phosphate
Nut and rear adjustment disc were cad (silver), not zinc or natural.
Could have been running changes (my car is July 16 build), but this config is similar to my 66 BB. Hope this helps.
Mike

What you observed makes so much more sense Mike. I will wait of rot hers to chime in as well. Mine is an early June build.

Bill

[Joe L.]

Re: 70 camber bolt restoration question or two

What you observed makes so much more sense Mike. I will wait of rot hers to chime in as well. Mine is an early June build.

Bill

Bill------


The camber bolt was black phosphate-finished. The "integral" cam was not really integral in the truest sense. The cam was a separate piece which was pressed onto the bolt at the manufacturing plant. This cam was natural steel finish. I have several really old NOS examples (1960's vintage parts) of this bolt assembly. All are as I describe.

The separate cam was dull zinc plated. The bolt and separate cam often have the markings you describe.

[Bill L.]

Re: 70 camber bolt restoration question or two

Bill------


The camber bolt was black phosphate-finished. The "integral" cam was not really integral in the truest sense. The cam was a separate piece which was pressed onto the bolt at the manufacturing plant. This cam was natural steel finish. I have several really old NOS examples (1960's vintage parts) of this bolt assembly. All are as I describe.

The separate cam was dull zinc plated. The bolt and separate cam often have the markings you describe.

Hi Joe,

The bolt and cam, in addition to being pressed on, appear to have a small weld. That is why I am asking about the plain disc on a phosphate bolt. if just pressed on that would explain the finishes.

Bill

[Rich P.]

Re: 70 camber bolt restoration question or two

2 different camber bolts used by the General from 64-early 70's (63 was unique) 1 style with M on the bolt head and the other style was plain bolt head with M on the eccentric washer. If memory serves me the bolt with the M on the washer is pressed on and originally the bolt was black while the washer was cad then pressed together and the style bolt with the M on the bolt was soldered on and the entire assembly was cad. The loose washer (with the flying F in a circle was also cad. If you blast the bolts and look on the inside where the shank goes through the washer you may be able to see the serration marks.

Rich.

[Mike Z.]

Re: 70 camber bolt restoration question or two

Well, Alan; not trying to be a "smarty" but to my knowledge silver fasteners used in the C-2 were all cad, not zinc-which would have been not in common use at the time and probably more expensive at the time. We see zinc used heavily today, but it was not used in the 60's to any degree on US autos. Cad is not a EPA friendly chemical and not many shops can provide re-plating today. Most of the repro fasteners are made overseas, where use of zinc has been common place for years. If you compare real cad to zinc; zinc has an almost chrome luster, at least a very high luster; whereas cad is much more muted. To me, zinc is way over the top and the fasteners look like what they are-reproductions and out of place for a 60's era US made automobile. Just my opinion, as a Corvette restoration shop owner and presenter of multi National Top Flight cars.

Joe & Bill: I agree NOS pieces were separate pieces-have a few; but the OEM parts, which I have pulled several off original cars, appear to be intregal (at least I can't get them apart-whereas NOS can be easily separated): at least on several 66, 67 and now a 70 (current project) I have personally pulled apart (both the OEM bolt and the washer were black phosphate, certainly not cad or zinc: the NOS disc is natural, with a black bolt). Joe, have you checked OEM parts to confirm?

Hold everything: I just checked the 66 & 67 TIMJG and both read the same: "The adjustment cam bolts have two styles. Both have an "M" logo. If the logo is on the head of the bolt only is black phosphate. If the logo is on the front cam washer, the bolt and the cam washer are black phosphate". Guess we are both correct and I guess the examples I have done are all the same with the logo on the front cam washer. Pays to check the manual.
Mike

[Bill L.]

Re: 70 camber bolt restoration question or two

2 different camber bolts used by the General from 64-early 70's (63 was unique) 1 style with M on the bolt head and the other style was plain bolt head with M on the eccentric washer. If memory serves me the bolt with the M on the washer is pressed on and originally the bolt was black while the washer was cad then pressed together and the style bolt with the M on the bolt was soldered on and the entire assembly was cad. The loose washer (with the flying F in a circle was also cad. If you blast the bolts and look on the inside where the shank goes through the washer you may be able to see the serration marks.

Rich.

HI Rich,

Sounds like you were on the right track.

Thanks, Bill

[Joe L.]

Re: 70 camber bolt restoration question or two

Well, Alan; not trying to be a "smarty" but to my knowledge silver fasteners used in the C-2 were all cad, not zinc-which would have been not in common use at the time and probably more expensive at the time. We see zinc used heavily today, but it was not used in the 60's to any degree on US autos. Cad is not a EPA friendly chemical and not many shops can provide re-plating today. Most of the repro fasteners are made overseas, where use of zinc has been common place for years. If you compare real cad to zinc; zinc has an almost chrome luster, at least a very high luster; whereas cad is much more muted. To me, zinc is way over the top and the fasteners look like what they are-reproductions and out of place for a 60's era US made automobile. Just my opinion, as a Corvette restoration shop owner and presenter of multi National Top Flight cars.

Joe & Bill: I agree NOS pieces were separate pieces-have a few; but the OEM parts, which I have pulled several off original cars, appear to be intregal (at least I can't get them apart-whereas NOS can be easily separated): at least on several 66, 67 and now a 70 (current project) I have personally pulled apart (both the OEM bolt and the washer were black phosphate, certainly not cad or zinc: the NOS disc is natural, with a black bolt). Joe, have you checked OEM parts to confirm?

Hold everything: I just checked the 66 & 67 TIMJG and both read the same: "The adjustment cam bolts have two styles. Both have an "M" logo. If the logo is on the head of the bolt only is black phosphate. If the logo is on the front cam washer, the bolt and the cam washer are black phosphate". Guess we are both correct and I guess the examples I have done are all the same with the logo on the front cam washer. Pays to check the manual.
Mike

Mike------


The known-original bolt assemblies on my 1969 were just as the NOS bolts I have. The attached cam was completely rust-covered (but not in any way pitted) when I removed them. So, I am confident that these were natural and not black phosphate. The separate cam was obviously plated. The bolt, itself, obviously black phosphate. They are not like that now as I had them completely zinc plated.

As far as zinc versus cadmium goes, once-upon-a-time I took small scapings from a bunch of original "silver" plated original parts from my 1969 and some earlier Corvettes. I analyzed those scrapings in our lab using atomic absorption spectroscopy. Every single one was zinc, not cadmium.

I used to think that the dull silver plated parts were cadmium with the shiny silver parts being zinc. One of the platers I used to be responsible for regulating gave me quite a lesson in this one day. He explained to me that zinc and cadmium can be virtually impossible to distinguish by appearance. He also told me that either zinc or cadmium can be dull or shiny depending upon how the plating is done. He showed me examples of both as they did both zinc and cadmium plating.

[Michael G.]

Re: 70 camber bolt restoration question or two

Joe, you are correct about zinc and cad. About the only fasteners that always had cad back then were lock-nuts. On the others, it was usually optional and zinc was cheaper, so guess which one was usually chosen?

The appearance of the two electroplates can be virtually identical, depending on how the plating is done. There are those who swear that they can tell the difference in color or luster, but, having been a GM fastener engineer and a fixture on the GM plating committee for many years, I've seen about every variation of both. Many times I couldn't tell the difference and I was supposedly an "expert".

Today, if you can find cadmium plating, it usually is fairly dull and whitish compared to what used to be available. I don't know why. I suspect its really something else passed off as cad....I haven't bothered to have it tested though...

If you're restoring a car and can get real cadmium, its worth the trouble (for most non-critical fasteners) as you'll find that real cad lasts a lot longer than zinc without corroding.

[Alan S.]

[Bill L.]

Re: 70 camber bolt restoration question or two

Hi Bill,
The 'loose' cams from my 71 had 2 different marks….
One the 'f" you describe, and this one which for me is unusual too.
I believe the 'f' represents Ferndale Fastener Division. I don't know what it's a 'division of though!
Regards,
Alan

Great pics as always Alan.

Happy New Year!


Bill