I saw some photos of late that raised my eyebrows a bit. Would someone tell me where this practice came from? I have never seen or read about it. I do know the Pennsy apparently lightly drove bolts after seal welding, but this was done cold, not as pictured here, and thus had the effect of stress relieving the seal weld in addition to swelling in the bolt in the hole.

The result achieved here is cosmetically appealing, but shouldn't the bolts be driven cold? The finished product looks like the beautiful work common on many roads (CN, GTW, UP, and others), but this was achieved driving the bolts cold. After all, isn't the object of driving the bolt to swell the bolt threads into the threads in the sheet, thus achieving a better seal and more structural integrity? Is this to hide the fillet weld on the bolt? Is this even a legal practice? Matt Austin, what do you think?

Greetings:
A couple of comments:
1) Tit snaps and "merry go rounds" as per the drawings work best with wrought iron or very soft steel staybolts such as A-31 (if at the low end of the carbon range of the specification). Some railroads used a steel referred to as 2210, which I believe were 10% carbon content, hence very soft and easily driven.
2) It did not appear to me that the bolts on the former M&NF No.14 had been driven prior to welding (unlike the UP procedure). Not saying that it won't work, but I question whether the bolt will upset into the sheet after being heated red hot.
J) Stathi Pappas obtain very nice results with a merry go round on Sierra No. 3's firebox.
J.David

Thanks for providing this. Unless I'm misreading it, though, the report is silent on what method of post-weld stress relieving was done... if any. Are there other contemporary reports from the MBMA or other sources that indicate how this would have been done? (I'm presuming that the logic was that because this was a 'seal' weld, the HAZ would be so slight as to make normalization of weld-zone stresses cost-excessive.

I do note some interesting detail about how the seal weld beads failed in the pullout-test pictures...

Sir J.David, a video link of Stathi performing the UP procedure:
http://www.youtube.com/watch?v=fN4juqEZ ... ata_player

Cheers, Jason

J. David - you hit the nail on the head regarding why I questioned the heating, then driving of the bolt. You are correct that bolts do not appear to be driven prior to welding. See picture below.

I still can't figure out the thought process behind the welding prior to driving. This is backward from the UP practice Matt posted, obviously.

I did run across this mention of heating stays prior to driving in the NBIC. J. David, you are on the ESC. Can you elaborate on where this practice originated or at least this reference in the code came from?


Attachment 3
NB11-1803

i) If the ends of staybolts are heated to facilitate forming of the head or expanding the threads into the sheet, the lower critical temperature of the sheet and staybolt material shall not be exceeded.

The "lower critical temperature" for low carbon steel is about 1100ºF or about a blood red color. It is the temperature at which molecular changes begin to take place.

Jason

Well, I was thinking the lower critical temperature was well exceeded based on the photo. I'm guessing at least 1600-1800F based on the color.

The questions I have incude; why the apparent ½ inch protrusion of the staybolt beyond the side sheet, why are they seal welding before driving the end of the staybolt over. and why the need for heat at all? Staybolts should be a soft material and not need the heat. Railroad seal welded on the firebox side and not on the outside of the side sheet side so why are we welding here.

These pictures raise more questions than answers for me.

Respectfully,
Robby Peartree

I re-read the post by Matt regarding UP practice as reported to MBMA. The tit snap illustrated in Fig 1 is different than the drawing of the beading tool/snap included as a separate attachment. Which one was used? Was this simply a mis-print? Anyone driven bolts with a snap as illustrated in Fig 1? Obviously, Stathi's driving of bolts on Sierra 3 was with the snap/beading tool shown in the drawing. Comments?

Also, I ran across another video of heating before driving on a different locomotive. I cannot tell if they are welded prior to driving. I will say that they do not appear to be heated as much as the ones in the photos posted. Again, where did this heating of bolts come from? It seems to me it would be a leaky bolt from the start once it cools down. Also, I thought seal welding of bolts was done only on the fireside or interior sheets, not on the wrapper side?

http://youtu.be/cDzcZCRFqD4

Howdy all,

Thanks for the kind comments J David and Jason. In regard to the question at hand, I have driven bolts both cold and have experimented with some heat (though the great majority have been done cold). I have found that the ones driven hot do not leak as long as they are driven totally, not just to a pretty head. The critical temperature was observed during this process. My preference after this experience was to go back to driving the bolts cold as it eliminated a step and was faster. My method has been to set the threads using a cup snap and 60 gun from the inside with a substantial buck on the outside. After setting the threads, the inside was bucked and the merry go round (up beading style as above) driven on the outside with a 40 gun. At no point was a seal weld applied until after all driving was complete, and this being only on the inside sheet. I actually prefer no seal weld, but the evidence does suggest it to be a superior technology, so I did employ it on my locomotive. I hope this is of some help.

Best

Stathi

Mr. Pappas,

Thank you for your very forthright and complete answer. How did you come to try the method of heating prior to driving for the few you experimented with? Also, what material do you prefer for stays? A31 perhaps?

Again,
Thank you!

The NBIC code, S1.2.4 clearly states that rigid staybolts may be seal welded before or after driving.

Yes, but NBIC also clearly states that when bolts are heated, critical temperature is not to be exceeded, which is apparent here.

Greetings:
There have been a number of questions raised, I'll give some answers/opinions in no particular order:
49CFR Part 230 does not specify how a staybolt is to be installed, it is the result that counts with the FRA (read: no leakage at installation and in service). NBIC rules are rather like a cookbook with methods of installation specified.
There are at least two types of tools which can be used to install staybolts and get that nice rounded head: the tit snap and the merry-go-round. Either will produce a nice head (AND a leak free staybolt). I have used both: the tit snap with a No.60 riveting hammer and the merry-go-round with a No.200 chipping hammer. But, but, but remember, the staybolts were wrought iron or NOS steel bolts. At this time (I'm older) I would need someone backing up my elbow if I was going to drive bolts with a tit snap.
Watch how quickly Stathi drives staybolts in the video: those staybolts were soft, probably 50,000PSI tensile steel with low carbon content (maybe 15~20%?).
I would GUESS that staybolts in No.14 have a much higher carbon content/higher tensil steel, and to drive them, per se, let alone have a pretty head on them, heat was essential.
A semi-digression: when we did the side sheets and door sheet on our (Valley Railroad) No.40 several years ago, I bought a couple of tons of what was supposed to be 60,000PSI steel. Well, the range allowed by ASTM goes up into the 70s' and this stuff was right up there. I refused the load, they took it back and annealed it, bringing the tensile down into the mid 60s'. Even at that, those were tough bolts to drive. We ended up upsetting them with a No.60 riveting hammer. Some of the guys were strong enough to finish the head with the No. 60, I couldn't, I had to turn over the edge with a No.200 chipping hammer. Of course, we were heading them up cold.
Our practice is to leave 3 threads exposed from the sheet for heading. The bolts on No.14 appear to have 5 threads exposed, way too much, in my opinion to upset into the sheet. Or for that matter head up at all cold.
Now, all that said, is the method used on No.14 going to work? My guess is that they will have no problem getting through their initial hydro. What I question is the long term viability of a staybolt that isn't tightly upset into the sheet. If it isn't tight in the sheet, scale will build up between the (loose) threads and eventually the weld will crack and bolts (not all at once) will leak, and will prove to be unrepairable because there is no way to get scale out from between the threads (of course you can change out the staybolt). Now perhaps with the head of the bolt hot, the threads will upset into the sheet. I have never tried or heard of this method, I don't know.
There is a reason why you prove tubes (or staybolts) tight BEFORE you seal weld...
Be well,
J.David