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PW Mainspring Not So FRIENDLY DBH Style, WHAT? "Click" to Login or Register 
Help needed. I got all geared up and started into doing this Elgin 18s ‘812’ sized main spring.

On the label it has .290mm and my calipers measured the old to be right there to .300mm so that is Ok.
I ordered it as an 812 equivalent.

My barrel is brass having a tiny hole (circular) AND a hook on the side of the barrel.

This part bought from Clark’s ebay store has the hook cut out AND a tabbed on top and bottom piece of steel added to the surface of the spring.

I thought it was removable because I had trouble pushing in the spring. I ended up removing it from the retainer, thinking I would disgard the tabbed piece, it’s tab being the way I would grip it and it’s ‘purpose’ to make engagment of the hook facilitated. MAYBE but it isn’t removable.

So Ok. The overal heigth must still fit the barrel..... NOPE the spring is just right but the tabs have no where to go. No cut outs in the barrel and the barrel top.

This spring does not fit this barrel. AM I SUPPOSED TO FILE THEM OFF? Though I have not seen this shape cutouts in a vintage PW does not mean they do not exist.

Does this sound like an Elgin 812 arrangement?
I included the movement serial number for Mr. Clark.
His listing said he is expanding into supplying PW mainsprings. They make them in house. I have no trouble with the quality.

I just haven’t done many so I haven’t seen many.
I got it into my KD128, after discovering it would not push in. (Unless, I miss aligned it while pushing), but even if it cleared the inside diameter of the barrel perfectly it (the tabs) cause the spring to rest too high.

So it sits in the winder waiting for me to attack the problem.

I was relieved that it did not come with a T end, being a brass therefore soft barrel. But this tab is incompatible and what the heck are they there for when the hook is fine? This much leads me to believe I have to file them off.

Am I using the wrong spring?

The seller is calling this a DBH double brace hole type.
Posts: 144 | Location: New York in the USA | Registered: September 23, 2018
IHC Member 1613
Is there a number scratched on the mainspring barrel...Barrel might not be right..Sounds like the mainspring is an 812 spring...What is the watch serial number...If someone else doesn’t look the number up and check what m/s the watch takes I will look it up tomorrow...
Posts: 2003 | Location: Chesapeake City, Maryland in the USA | Registered: September 27, 2011
Yes Sir, The watch is Elgin 426708 and the barrel COVER has that number. The spring removed was a T end with little nubs shaped like a pivot, round.

This replacement is a T style but NOT at the very end. I found out that the notch normally for ptying up the cover, while the little hole in said cover is occupied by the T end nub, well that notch FITS perfect with the T on this DBH Double Brace Hole style. I am still mifted at a loss because the spring is not down far enough at the Spot where the bottom TINY RECTANGLE nub, has no coresponding barrel ’slot’ to fit into.

Here is a pic file that has this DBH spring pictured. I can’t seem to get imgur link copy to retrieve actual pics and open them here. Need to figure out later. But here is a hyper link that gets the job done. Thnx.


If I must remove that bottom nub, I guess it will be the price to pay for this wonderful DBH ‘feature’. In my opinion, without a bottom slot holding the spring to the barell ALONG WITH THE HOOK that exists on the side of the barrel which mates to the hole at the end area, what does or could it help?

As I said the top nub sticks up and fits as if it was meant to go in the squareish hole in the barrel cover. The bottom nub has to still allow for the cover to fit down flat and square with the land on the barrel for that cover. The barrel bridge will keep the top down but it wont be FLUSH unless it is filed off.!

This is what I see after using the KD winder and have inserted the spring. It is impossible to have it catch the hook WHILE INSERTING because the only way to have the room for the spring to be joined with the hook is to WIND UP THE FIRST go around and hope that the hole CATURES the hook.

But after that happens I feel certain the nub will not end up going lower onto the barrel bottom. Hence the ONE THING to do after all the experimentation is FILE OFF the un used nub, OR PERHAPS both and let the hook be the ONLY ANCHOR.??

LESSON? A barrel must exist which takes a DBH double brace hole type spring! Order one if and only if the down side of a watch mainspring warrants and The Troublesome factors otherwise should be considered worth the effort.
Posts: 144 | Location: New York in the USA | Registered: September 23, 2018
I am not sure if I follow what your saying , is the new T-brace "tips" to large for the hole ? I have had to "dress" the ends to get a proper fit before
Posts: 1574 | Location: Maryland in the USA | Registered: June 04, 2015
The new WHOOPY Dual Brace Hole spring has not round pin sized nubs. They are the size and shape of the rectangular hole usually reserved for prying off the barrel via a tiny screwdriver.

My only conclusion would be to assume I have a good replacement and have two options available. Opt.A file off the second lower nub, so the spring seats fully into the barrel. OptB force it into the brass which is softer than the steel spring.

I really need to know if some PWs have a barrel having these rectangular shaped kT bars’..
The pic shows that they are not small ‘tits’ and the dressing needed may be a file. BUT if this is the correct DBH style the option to file seems incorrect, since it would not be added spring security. In fact if the hook failed then the top should begin to commence spinning after repeated winding with a nub anchor removed.

Opt C is install the barrel with the one side proud of the barrel top. I do not want to rely on the barrel bridge screws being hefty enough to dig the nub into the brass.

For some strange reason the repairman that installed the spring that I replace here did not install it with the tits in the holes, both bottom and top. But used a jeweler’s saw and cut into the T a bit on both sides and bent the tits up, like little horns. Then wedged the barrel somehow against them.

Sorta like a knotted rope that tightens when pressure is applied, I guess.
Posts: 144 | Location: New York in the USA | Registered: September 23, 2018
James I have found a number of old Elgin 18sz mainspring barrels that do not have a cut in the bottom for a double brace 812 mainspring. I always have done as you suggest and shave the bottom brace off so the mainspring will seat into the barrel snuggly. I then make sure the hole end will fit onto the hook on the sidewall of the barrel. Usually put a little angle in front of the hole end so the hole seats onto the hook better. Once this is done I installed the mainspring into the barrel. I have always found a couple of cuts in the mainspring barrel cap and use the one which will accommodate the upper double brace and then simply snap the barrel cap on and you should be good to go.

Posts: 580 | Location: Kingsport, Tennessee in the USA | Registered: November 26, 2002
ThankYou Rob.my curiosity exists about the last repairman’s abandonment of the standard T end. Perhaps either one of the holes was bigger and he did his work around.

In the teardown I might have just left the barrel as is, but I knew the spring was broken. And my journey began.

I assume with the cut outs to accept the DBH some barrels with hooks on the side would have been modified or would they be crafted with them?

The style of DBH double brace holes, may be a more recent evolution so vintage barrels were not using the ‘new technology’. This watch will get refit with a new spring, preserving the original barrel and matching number.

Different from ‘plug n play’ modules of today!
Posts: 144 | Location: New York in the USA | Registered: September 23, 2018
James off hand I don't recall any Elgin's that originally used a T end although there could be a few. Elgin's bread and butter was the double brace-hole end with a few exceptions. (1956 and 2542 and a few others) Many companies used the same width on their 18 size watches 20 Dennison. So you will see T ends in watches which call for DB simply because they were available and they fit. Illinois, Hampden, Rockford and others used a 20 dennison with T end's so you can see how they got interchanged.

Posts: 580 | Location: Kingsport, Tennessee in the USA | Registered: November 26, 2002
Thanks Again Rob. I remember a measuring tool that uses Dennison, some person with the same name.
What would that ‘ruler’ be used to measure? If Your saying the height is commonly spoken of and not in millimeters, Why on the labels are mainsprings given decimal measures?

Perhaps a Dennison is a unit of strength?
What other size references to watch parts use Dennison?
Posts: 144 | Location: New York in the USA | Registered: September 23, 2018

It is a Dennison gauge and it would measure the width and the thickness or strength of the mainspring. If your not sure what they look like just check on ebay I am sure they would have some.

Posts: 580 | Location: Kingsport, Tennessee in the USA | Registered: November 26, 2002
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