24 replies to this topic

[timkel]

What is the history of the 1928 nickle bolts?
Are they plated? or some kind of alloy?
Were these in early or late production thompsons?
What was the purpose?

[AZDoug]

I can tell you electoless nickle doesn't flake when applied at less than .001", and possibly thicker, as I have used ElNick for surface treatment of parts on chemical processing equipment.

I also have an *S* bolt that is bright, that takes to blue very easily. Now whether it was a blued bolt somebody stripped, or it was never blued, I don't know.

I do not know the metalurgy of the original bolts***, but when the nickle content gets high enuf in steel, they don't blue anymore.

*** The original AOC drawing, #45-1-13 dated 1920 calls for either H-2 or N-2 steel (I can't tell if it is an N or H), so that should be some info, if anybody can determine what that steel compostion is....

Now, looking at other parts of the TSMG (Colt,) there are what appear to be nickle plated trigger parts, and a nickle plated catch on the buttstock hardware, so i am going to assume that if these were plated, they plated the bolt as well, as compared to making it out of something else. OTOH, it may all just be high nickle steel that doesn't rust.

It would also be easier to make some sort of determination if I could closely inspect a guaranteed 100% original Colt gun, that there is no question as to the originality of teh parts.


Doug

[timkel]

Thanks for the info.
I did a search for "Nickle bolt" which came up empty.
I will try "bright bolt"

Thanks
timkel

[PK.]

There are exceptions to everything, but- the Colt parts I have examined have not been plated, and would take blue. This includes bolts, stock latches and internals.

When you get enough nickel into steel to prevent rust (or bluing) you get stainless steel and it won’t harden. If you put in just a bit, it makes the steel tough.

The print referenced to call for “N2 steel”. I have searched but have not been able to find a composition or cross reference to a modern alloy. I think it safe to assume that this was a carbon/nickel alloy similar to that used in Winchester rifle barrels and other receivers of the time.

It was common practice to leave hidden and reciprocating parts “in the white” during the period these guns were made.

I do not believe electroless nickel plating was developed until fairly recently. If these parts were plated they would have been done with the standard process of electro plating the steel first with copper, then nickel. It would be obvious.

Phil, I wold love to see that AOC bolt, if you feel you can send it to me for examination.

I have seen NO evidence that the parts were treated in any fashion other than being left “in the white”.

[Arthur Fliegenheimer]

PK,
Colt nickel-plated the rivited weight attachment to the 1921 actuator for the initial Navy models.

[AZDoug]

I did some web searching last night and found one obscure reference that M1 tool steel may be similar to N2 steel.

I think the only sure way, I go find a 1920's Mechanical Engineers handbook, and look it up there for composition, as it appears many of these older designations for steels were folded over into the AISI numbering system (1018, 4130, etc) later on.

Doug

[PK.]

AF,
As I said, “There are exceptions to everything”, but I have examined three such in recent time (two in house now) paying particular attention to this very thing and can say without doubt: These are not plated.

I will go further and state that the fact of the actuator knobs being blued while the remainder of the part is bright gives a strong clue to this discussion as well.

Phil,
I appreciate your confidence in me- I will give your bolt the utmost respect and won’t shoot it more than 25000 rounds.

[AZDoug]

Electoless nickle plating was invented in 1946, so they didn't use that process in 1921. :-)

Doug

[SecondAmend]

N2 Steel

Features
Steel with non-rustproof magnetic nickel prepared from a "master batch" based on a iron-carbonyl powder with a maximum granule size of 6microns. This material is good for the fabrication of structural parts possessing very good mechanical properties due to its elevated carbon content. It is suitable for heat treatment as well as surface treatment.

Composition

%C1 %Ni2 %Fe
0,4-0,6 7,5-8,5 Compl.

(As cut & pasted off a Website. Found using Ask Jeeves which often gives different results than Google). I think the company was a steel vendor called Alliance. Wasn't really paying attention).

Edited by SecondAmend, 10 April 2004 - 04:22 PM.

[PK.]

Very interesting , please share your source.

[SecondAmend]

Source:

http://www.alliance-...m/htgb/0007.htm

[PK.]

While I appreciate SecondAmend for researching a bit, I have to agree with Phil that the usage of the term “N2” by the Alliance Co. to describe a modern powdered metal product may not have any relevance to the historical alloy specified in the AO prints.

The following is the text of a mail I sent Phil after inspection of his AOC marked bight bolt:

“Your bolt appears to be as all others (bright and blued) I have examined by any maker. The hardness is within the specified range, and the steel responds instantly to cold blue. There is no doubt in my mind that if I dropped it into the hot salts it would come out black as night. It is not, nor has it ever been plated.

The hardness is important as it indicates the material is likely the same as that used in other original bright bolts and later blued parts.

The pitting evident in the extractor and ejector slots as well as the bolt face is likely from corrosive primers and is the result of rust that formed from the salt deposited after firing. This is little different than if you left the bolt on your lawn overnight and the dew and dog pee got to it; it would be red rusted all over in no time.

I believe that a nickel alloy steel was used in the manufacturer of the bolt (as indicated by the drawing), but that the amount of nickel is not sufficient to significantly impede corrosion, rather only to impart the toughness required of a part hardened to the degree these are (Rc48). This is the case with other parts such as the famous "nickel steel" Springfield rifle receivers and Winchester barrels.

I therefor have to assert that I have seen no evidence to date to suggest that the bright bolts found in Colt, Savage and AO factory guns are any different than the blued replacement parts, except for the black oxide treatment of the latter.”

Thanks to Phil for allowing me to inspect his part, as the amount of data grows, so does our confidence in the indicated findings.

[ThompsonCrazy]

What type of cold blue did PK use?

[21 smoker]

Phil,... just revisiting this thread and your info on the sintered metal or powered metal caught my eye.Yes this type of metal is used in automobile applications...I seen it used for camshaft and crankshaft spockets,mostly with rubber drive belts...they are extremely brittle,often shattering during routine removal for seal replacements...it`s use in firearm production would be interesting to view...from afar...I`m glad that much engineering went into our Thompsons...everytime I pull the trigger,Thanks for the above info,out.

[PK.]

Brent,

I used Brownells Dicropan T-4. After degreasing with acetone, the bolt took and immediate, dark stain that I had to really hustle to remove before it penetrated to deeply. Keep in mind this is a touch up product.

I have done this on countless parts and stock to accretion a basic metallurgy using primarily Formula 44/40 and the T4 mentioned above. If it will blue with these products it will rust and it will hot blue.

On another note; the sintered metal process is being steadily replaced by a similar, but more exacting process called MIM (metal injection molding). The parts are stronger and more precise. I may be mistaken, but I believe the internals of S&W revolvers are now fabricated with this process.

[timkel]

Does this mean that all bolts are really the same steel?
Were early bolts("nickle bolts") left as bare steel and later bolts blued?
So nickle bolts are just a myth?

[PK.]

Yes, I believe that to be correct.

I have not to date found any evidence to suggest otherwise, but you can bet I will keep looking at this issue, as well as all things Thompson technical.

[LSU Tiger]

Since home bluing was mentioned, I don't feel off base to ask this. Has anyone tried the home parkerizing kits on the market and what did you think?

[timkel]

Sounds like if anyone has a blued bolt and wants a bare steel(nickle) bolt, all he has to do is remove the blueing.
I wonder if thats where all those nickle bolts on Ebay came from???

[Arthur Fliegenheimer]

Next thing you know there will be a cloud of suspicion over the Colt buttstock oilers nickel plate status, not mention the Navy actuator weight, firing pin, hammer, sear. sear lever, rocker. discounnector.......