Nipple Size for Uberti - mystery solved?

[dcriner]

Confusion reigns supreme for the correct nipple thread size for Uberti reproduction Navy and Army revolvers. Dixie calls for a metric 5.5 x .9 thread. Track of the Wolf calls for an English 12-28 size. Both of those sizes, metric and English, are nearly identical if you do the math. But which is correct?

I ordered a set of Ampco/Treso nipples from TOW, purportedly size 12-28 per the TOW website. The nipples came in Treso packages, afixed with TOW's stocking sticker, saying: Nipple for Colt Army or Navy revolver 12-28 thread, No. 11 cap Ampro. But wait - I peeled off the TOW sticker. Underneath the TOW sticker, the Treso package says: Revolver nipple M5.5 x .9 thread. So, TOW is talking out of both sides of its mouth :grin:

Here is my theory: The two thread sizes are close enough that either will work. Manufacturers probably use metric or English taps and dies, whichever they have at hand - or, if they have both, whichever they think is correct. I suspect Treso makes their Colt Ampco nipples only in the metric thread. Who knows what size tap Uberti uses for their female cylinder threads?

Now, I will say this: the new Treso nipples were hard to get started into the cylinder. But once they got started, they threaded in easily. I'm content.

 

[Norinco]

Seeing as it's Italy, I would guess metric.

 

[Pete Gaimari]

I use those nipples on all my guns. You'll find the Remington #10 caps are a perfect fit.

 

[Zonie]

Your thoughts are correct about the closeness of the threads on a M5.5 X .9mm and a #12-28 item.

The theoritical major (largest) diameter of the metric thread is 0.2165 inches while the #12 is .2160. One half of a thousandths of an inch difference.

The lead (leed) of the metric thread is 0.0354 inches while the lead of the #12-28 is .0357 for a three ten-thousandths difference.

Although the guns were made in Italy where they normally work to the metric system I would bet the taps used to thread the nipple holes were the #12-28 size.

According to my metric thread charts the M5.5-.9mm thread is not a standard fine or course metric thread.
That's not to say there cannot be a M5.5-.9mm thread because a large manufacturer can make any thread they choose to make but if I were Uberti I would opt for some standard American taps rather than having special taps made.

In any case, either thread should work fine in your gun.

 

[dcriner]

The theoritical major (largest) diameter of the metric thread is 0.2165 inches while the #12 is .2160. One half of a thousandths of an inch difference.

So, that may explain the slight difficulty in getting the metric nipple started - if Uberti tapped the nipple threads in the cylinder to English dimensions. But once the metric nipple started, the cylinder's female threads were chased, and all was well.

By the way, using a screw extractor to remove the stuck nipple posed no risk to the finish of the cylinder, i.d. or o.d.

 

[dcriner]

After thought: might be good to chase those metric nipples with a 12-28 die. Might make them start easier into the Uberti (English?) cylinder taps?
Doug

 

[Zonie]

I wouldn't try to chase the existing threads.

There is always the possibility of cross threading and screwing up the existing threads.

Then too, you really don't know which threads your new nipples have on them and as you said, they were marked with both thread sizes on the package. Then you would need to measure the major, minor and pitch diameters to the nearest 1/10 of a thousandth of an inch and see where your threads measurements fall into the allowed tolerances.

 

I just received some 5.5 x .9mm stainless nipples for my Lyman/Uberti .36 cal Remington. Date code XX7. I began to install those nipples. They thread in but when I begin tighten them, they just go around, never tighten. :hmm:

So, what could the thread size be, please?

Could they be 6.0 x .9mm?

Paul

 

[54mountain]

this may or may not help, but my Pietta's take a 6mm X .75 nipple

 

[Zonie]

Are you sure it is a Uberti?
If it is it will have the Uberti logo stamped on it.
That logo shows a octagon with a round circle with rifling grooves in the middle. There is a large "U" stamped in the center of the "rifled" circle.

If the gun is the typical Lyman Pietta made Remington it will use a 6mm X .75mm nipple.

 

Yes, it's a Lyman (top of the barrel) and made by Uberti (Uberti logo on left side of the barrel) and it's a .36 in a full size Remmy frame. I measured those original nipples and the outer diameter of the threads is .235 inches. The thread looks to be finer than the .9mm ones. So I ordered TOW's 6mm x .75mm thread nipples.

Thanks!
Paul

 

[Zonie]

6mm equals .2362 inches so your .235 measurement confirms that this is the size of threads your gun has. (The external major diameter of a thread is always equal to or less than the fastener size.
The amount less depends on the class of the threads.)

My information says that Uberti uses the smaller thread but for whatever reason your gun is different.

 

[Shoeless]

VTI from time to time has sales on Uberti nipples in packs of 24 or 36....

 

OK, the TOTW nipples came in as .225x32 and .475 length. The threaded part is 1/64 inch smaller in OD. Doesn't anyone make the correct 6mm x .75mm threaded ones?

Argh,
Paul

 

[Zonie]

A 6mm thread has a theoretical major diameter of 6mm but the actual external thread may be somewhat undersize to provide machining tolerance.

Metric threads have a rather complex system of fits but one reference I found indicates that the lower limit of size for one class would allow the 6mm thread to actually measure .228 inches.
A slightly looser class of threads would allow a 6mm thread to be even smaller.

 

Zonie,

Today I received from TOTW, 6mm x .75mm SS nipples. They fit! :bow: I did have to chase the threads as the nipple threaded portion was about two threads longer. I just happened to have several 6mm x .75mm taps and dies. (In the past I have made screws for the Mosin PU mounts).

 

[Zonie]

Glad to hear they are working.

Now, what we need is for some British made muzzleloaders with Whitworth threads on their nipples. :rotf:

 

[swathdiver]

Just got in a set of Treso 11-50-16s from Jedediah Starr for my Pietta New Model Army made in 2012 [CI]. The threads are not even close.

The caliper showed the threads to be .235 in width so I gather these guns have M6x.75 threads.

Is my thinking right here fellas? That would mean that the guns really need 11-50-10s, right?

 

[pargent]

You would think a cheap set of thread gauges would be the go .

 

[pargent]

:rotf: original hand cut lock screws can be fun to match