The Start of Riveting a Tender Tank in 3/4" Scale

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Carrdo
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The Start of Riveting a Tender Tank in 3/4" Scale

Post by Carrdo » Sun May 20, 2018 8:35 pm

Since I have never done this before, I have a few beginner's questions. Aesthetics is important here so I want to get it right.

I would start by riveting the tender tank sides to the tender tank bottom which has a 1/4" high upturned lip all around it. The tender tank sides are one piece of 61-3/4" long sheet metal which will have four 90 degree 3/4" corner radius bends in it to form the tank sides and ends.

Assume for this example that the rivet spacing is 1/8" centerline to centerline.

The questions are:

Should I mark the rivet spacing on the flat sheet before or after bending the 90 degree tank corners? As a corollary question, does the corner bending operation distort the rivet spacing, if it is first laid out on a flat sheet and if so how does one do the rivet spacing/drilling around a 90 degree bend on the tank or ...?

Where is the best place to start the drilling operation, in the middle of a straight tank section or ...?

The centerline of the last rivet hole on the ends of the flat or formed tender tank sides should be 1/8" also or something less...?

Does one use the digital readout on the mill when drilling the rivet holes and/or are there other methods one can use such as a portable drill...?

I was given a long piece of narrow predrilled brass strip some time ago by another builder who presumably used it when constructing his tender tank but how he used it I don't know. If I set everything up on the table of the mill, I have to figure out a way to hold the parts together securely, straight and square and not distort anything in the process so an interesting exercise is coming up.

If I haven't thought of something, please add it.

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Bill Shields
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Re: The Start of Riveting a Tender Tank in 3/4" Scale

Post by Bill Shields » Sun May 20, 2018 9:18 pm

I would drill the holes BEFORE bending...that way you know they are spaced correctly from the get go...and it is much easier to handle as a flat sheet.

I would start at one end and work to the other end.

yes the holes in the bent area are going to become somewhat elliptical, but a light redrill and the rivet head should cover it.

I am not convinced that making it from one piece, bent on all 4 corners is the best way to do it, but would suggest that you not finish cut the tank bottom until after you have all of the bending done and know the required bottom dimensions...remember that the bend line is not exactly the center of the sheet metal thickness...it's usually closer to 30% out from the inside (depending on the material).

I am in the middle of making a similar construct...and I am going to bend the rear corners and a short length of the back as one piece, then work forward from there with a flat piece then bent corner on the front where it ends in the coal bunker face...drilling holes for rivets before bending.

but then I am not the best sheet metal worker in the world and take this one step at a time....especially since the brass is so $$$$ these days.

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Re: The Start of Riveting a Tender Tank in 3/4" Scale

Post by Greg_Lewis » Sun May 20, 2018 11:17 pm

I made mine to match my prototype, which had one sheet for the back and one for each side. The side sheets were bent at each end for the rear curve and the front 180 degree curve back into the coal bunker. I used a bar similar to what you were given to space out the rivet holes. I drilled one hole, anchored the bar with a machine screw and nut, and then drilled the subsequent holes. I bought a whole pack of drill bits and as soon as one seemed to start to dull, out it went. On runs longer than the bar, I used the last hole to locate the bar for the next batch. I used machine screws as I went along, perhaps every 10 or 20 holes, to hold it all together. Cleco clamps are faster if you want to try them. They fit into the hole and expand to hold things together.

I had to plan out the hole locations so that the hole nearest an edge or corner was at the right spacing. I don't remember the distance from the edge or corner, but I'm a detail freak and I used what I measured on a prototype tank.

I folded the tank bottom down so I could rivet from the outside. I ended up making several different rivet setting tools to get into various places, and set some rivets that were in the middle of the sheet by using a home-made die in my radial arm drill press.
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Re: The Start of Riveting a Tender Tank in 3/4" Scale

Post by Fender » Mon May 21, 2018 7:00 am

My first suggestion would be to practice on scrap material with your planned materials and rivet spacing. I used an air gun and a homemade bucking tool on the inside of the tank, which tool resembled a jumbo nail set. (You need at least three hands to do it with a hammer, a manual rivet set and a bucking tool, and I was one hand short.) After you can get good results on the practice materials, then start on the tank.
From my experience, put a rivet at each end of the sheet, then one in the middle, then halfway between those, etc. Otherwise, the holes will "creep" out of alignment, if you start at one end and work towards the other. I used clecos to hold it all together, and put the rivets in between the clecos.
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Re: The Start of Riveting a Tender Tank in 3/4" Scale

Post by JBodenmann » Fri May 25, 2018 6:48 pm

Hello My Friends
I would suggest making a drilling fixture from a steel strip. It can be made using the digital read out on the mill. Then you can clamp it to the work piece for drilling the brass. Also, when coming to the end of the run of rivets, the last rivet is seldom the correct distance from the edge of the sheet. So you may want to "fudge" the last dozen rivets or so, altering their spacing ever so slightly so as to have the last rivet the correct distance from the edge. Rivet spacing is not as critical as them being in a nice straight line. One little soldier out of line will be most apparent, the spacing, although it must be close is not so critical. A while back I posted a thread on assembling a 3/4" scale tender. It may be in the 0-6-0 thread or a separate tender thread, I don't remember. I also think I would lay out the rivets after you bend any edges. It's easier to line up the rivet holes with the edge, than the edge with the rivets. It would be a shame if you laid out and drilled all them rivet holes, and then not have the bend parallel. Just my two cents, there are many ways to skin a cat
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Re: The Start of Riveting a Tender Tank in 3/4" Scale

Post by Greg_Lewis » Fri May 25, 2018 9:23 pm

To add to what Jack wrote above, I bent my side sheets first and then match-drilled the holes. To get the spacing around the curves I made up a paper template on the computer and then pasted it on the work.
Greg Lewis, Prop.
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Re: The Start of Riveting a Tender Tank in 3/4" Scale

Post by tetramachine » Sun May 27, 2018 3:09 pm

cleco's are the best to align sheet metal work like this. I'd start at the center of the back sheet, then work L-R out, to the side panel. There are spring stoppers that attach to the drill bit, so as not to stab the material when breaking through while match drilling.
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Re: The Start of Riveting a Tender Tank in 3/4" Scale

Post by LVRR2095 » Mon May 28, 2018 8:30 am

tetramachine wrote:
Sun May 27, 2018 3:09 pm
cleco's are the best to align sheet metal work like this. I'd start at the center of the back sheet, then work L-R out, to the side panel. There are spring stoppers that attach to the drill bit, so as not to stab the material when breaking through while match drilling.
Do they make clecos small enough to use on a 3/4” scale tender? Those are some mighty tiny rivets.

Keith

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Bill Shields
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Re: The Start of Riveting a Tender Tank in 3/4" Scale

Post by Bill Shields » Mon May 28, 2018 8:44 am

1/8 and 3/32 clecos are available

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Re: The Start of Riveting a Tender Tank in 3/4" Scale

Post by LVRR2095 » Mon May 28, 2018 8:55 am

Bill Shields wrote:
Mon May 28, 2018 8:44 am
1/8 and 3/32 clecos are available
Bill, isn’t 1/8” and 3/32” a little big for a scale tender rivet in 3/4” scale?

Keith

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Carrdo
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Re: The Start of Riveting a Tender Tank in 3/4" Scale

Post by Carrdo » Mon May 28, 2018 1:53 pm

I plan to use 1/16" or 1/32" dia. brass (or maybe iron) rivets. It depends upon the the tank material I end up with as I haven't quite decided on that yet.

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Re: The Start of Riveting a Tender Tank in 3/4" Scale

Post by Fender » Mon May 28, 2018 3:29 pm

1/16” diameter clecos are also available. This is what I used on my project.
Even in 1.5” scale (1/8 full-size) a 1/16” rivet is pretty big for cabs or tenders. These would correspond to a 1/2” rivet in this scale. But the rivets I’ve actually seen on full-size locos were typically 3/8” or 1/4” diameter.
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