Constructing the Martin Lewis Little Engines Northern Tender

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Wed Dec 14, 2016 7:32 pm

I always fear the last 10% of the construction of anything as this is usually where I make serious mistakes. It has happened many times before.

Anyway, to press on.

The first photo shows the quarter rounding operation on the bending head plate bottom edge as this edge will be the one in contact with the 1/16" thick steel tank sheet as it is being bent around the 1.5" diameter wrapper bar to form the 3/4" corner radii on the tender tank. You want to have a radiused - not a sharp edge here. And mark which side of the bending head bar is the top or bottom as it is easy to get it reversed.

Now for the tricky bit.

The bending head plate has to be precisely located/drilled/bolted between the bending head end plates to closely follow the wrapper bar to make the 90 degree corner radius. Actually, it has to be able to rotate slightly more than 90 degrees in order to compensate for any spring back in the sheet metal. That is why the jig base plate has a center cutout to allow for this. Since it is the bottom edge doing the bending on the bending head plate, it is this edge which has to be on the center line of the 1.5'' wrapper bar centers and not the center line of the bending head plate. In addition, the bending head plate has to be raised the 1/16" thickness of the sheet metal to be bent (as well as + 0.002" to give some minimum clearance).

The bending head plate also has to have a cutout at each end of the plate as shown in the first photo so it will clear the wrapper bar bearing end plates. In addition, the bending head plate has to be square to the feed table surface and the 1.5" diameter wrapper bar itself. As well, the gap between the wrapper bar and the bending head plate has to be uniform along its entire length and not be tilted in any way.

That is a lot of things one has to get right.

The light weight, made up threaded rod clamps are the right ones need for this operation. Initially, I had the end plates clamped to the bending head center plate with a large furniture makers clamp (as seen in the previous post) which totally unbalanced the whole setup as it was so heavy and cantilevered out on one side. Of course disaster ensued, everything tipped over and the result was the broken file seen in the second photo.
Attachments
222 Machining a Quarter Round on the Leading (contact) Edge of the Bending Head Plate.jpg
223 Setup to Locate Bending Head Plate in the Correct Position for Bolting to the Bending Head End Plates.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Sun Dec 18, 2016 3:42 pm

One of the last operations and one of the most complicated to setup. I had to use every trick in the book to make this one work.

Firstly, I did not have enough vertical travel on the mill to install the drill chuck, a drill and to set the work on the table of the mill. Had to hang the work off the side of the mill's table and support it on the machined ways of the knee.

Secondly, 4 separate parts had to be clamped in place to make the setup work. The forming head assembly wants to rotate all over the place now as it was designed to do this. But it mustn't for the drilling and tapping operation.

Thirdly, the setup must leave room for all of the parts to be aligned, checked for square, parallelism and have a uniform and on size gap. So one cannot just clamp things anywhere without considering this aspect of the setup.

It was "interesting" :roll:
Attachments
225 The Complicated Setup Needed to Drill and Tap the Bending Head End Plates.jpg
226 Another View.jpg
227 Another View.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Thu Dec 29, 2016 8:31 pm

Finally finished but not without incident which I won't go into.

To drill and tap the opposite end plate for the two 3/8-16 NC cap bolts, the entire complicated setup had to be reversed! See the first two photos.

In addition, I found that I needed another extra large toolmakers clamp, which I didn't have, to keep the end plate exactly where I needed it to be for the drilling and tapping operation. So, spend $$$$ as well.

The finished basic unit is shown in the last photo. The bender works as designed AND IT SHOULD after all of the misery it has put me through.

Will add my own touches such as handles on the bending head center plate to give added hand control while bending the tender tank sheet metal and to drag the beast about as it is heavy.
Attachments
228 Reversed Setup for Drilling Opposite End Plate Bolt Holes 3 and 4.jpg
229 Drilling 4th Bolt Hole in Opposite End Plate.jpg
230 Finished Tender Corner Radius Sheet Metal Bender.jpg

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Trainman4602
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Trainman4602 » Wed Jan 18, 2017 4:30 am

That seams like a lot of work for just four corners. I did that by using a vee block made from angle iron. Carefully lined up and pressed in the arbor press. Works well In fact I made four tenders with rounded corners using that method.
Attachments
Picture 535.jpg
Picture 572.jpg
Picture 706.jpg
ALLWAYS OPERATING MY TRAIN IN A SAFE MANNER USING AUTOMATIC AIR BRAKES

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Wed Jan 18, 2017 2:58 pm

Hi Dave,

Yes, it involves a lot of work to make this bender but the advantage with it is that it is very difficult to make a mistake in the bending operation with it.

Perhaps you could explain with a few additional pictures your method?

I understand the principle behind it but I would like to know exactly how you locate and set the bend location and how you prevent the flat sheet from moving or sliding out of position when bending it in the arbor press?

Setting something up " carefully" as you describe it could involve many little tricks that I and others have yet to learn.

Perhaps there will be another video on this?

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Wed May 10, 2017 6:19 pm

Back with some additional work on the 3/4" scale couplers. These things are fighting me to the bitter end but I have been in this situation many times before so there is nothing new here.

My old camera died recently and I am just learning the basics on the new one so my pictures may not be the best.

After silver soldering some two piece knuckle assemblies together, nothing would fit or move in a coupler body as I added too much solder as I wanted to ensure a strong joint.

Had to employ the setup shown in the second photo to get rid of the excess solder while still leaving a 1/32" root fillet for strength.

The first photo is of the knuckle head - tailpiece joint with the excess solder and the last photo is after the excess has been removed.

This should not happen if one uses the right grade of solder for the job and if one takes care about what one is doing but sometimes things don't work out as planned.
Attachments
377 A Two Piece Steel Knuckle After Silver Soldering.jpg
378 Setup for Removing the Excess Silver Solder with a Small Diameter Ball End Mill.jpg
379 The Final Root Fillet.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Thu May 11, 2017 7:58 am

Looking back on my posts, I don't see any description or photo of how the two piece knuckle/tailpiece is aligned and held for silver soldering these parts together.

Well, just design and build another fixture!

And then there is the lead in cam on the tailpiece to allow for a smooth locking/unlocking of the tailpiece in the lifting pin slot. On the original design, this was filed but...

Well, just design and build another fixture! (which goes on the rotary table)
Attachments
380 Fixture to Align Knuckle Head and Tailpiece for Silver Soldering Together.jpg
381 Fixture to Machine Cam Lead in on Silver Soldered Knuckle Tailpiece Assembly.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Tue Sep 12, 2017 7:30 pm

The metal bender setup and ready for action (which it won't see for some time) as now I have to profile the tender tank which will be made from a single piece of sheet steel to give as few seams as possible (as per the original M. Lewis construction notes). The single sheet will be 7-9/16" wide by 62" long by 1/16" thick. This is going to be an interesting job to profile such a large thin sheet and Martin Lewis doesn't give any instructions on how he did it (the original was made out of copper).
Attachments
231 The Bender Setup and Ready for Action.jpg
232 The Bender Setup and Ready for Action.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Mon Jan 01, 2018 4:57 pm

Frustration!!

The last time I posted regarding coupler construction, I thought that construction of the couplers was nearly finished. Not so!

When I tried to assemble a matched pair of couplers, I found that the couplers would not lock or mesh properly. I found that the overall length of the knuckle head was about 1/32" too short (or about 1/16" overall per pair). In addition, I noticed that the nose profile of the knuckle head could be altered slightly to give a more positive lock while at the same time allowing for some slack when the couplers were coupled together as per the originals.

Next, it was discovered that the coupler knuckle tail piece profile needed to be changed slightly as small changes here made a huge difference in how these couplers function (lock and unlock). This only became apparent with a matched pair of couplers were assembled.

All of the above meant that weeks of work now had to be repeated as new, slightly altered, knuckle head templates and tail pieces had to be produced along with all new knuckle heads and tailpieces. Existing coupler knuckle pieces just became so much expensive scrap. See the first photo. As a side benefit, the fixture used to hold the knuckle head and tailpiece in the correct relation one to the other for silver soldering together needed to be modified. This wasn't a particularly easy fixture to make to begin with as much trial and error was involved. Fortunately, I had original coupler parts which gave the necessary alignment.

Then, to compound the problem, I had the misfortune to jam and break a drill on the first new modified knuckle head produced (on the very last drilling operation) which absolutely refused to move without destroying the knuckle head. At that point, I quit in disgust.

It is not often that a New Year's present comes along but today it did. By drilling through from the opposite side of the knuckle head nose (the last operation repeated again), I was able to "push out" the broken drill pieces (by pure luck) and salvage the part. See the second photo - the broken drill is that minuscule bit on the vise closest to the viewer. The new revised tailpiece is the one on the left -it looks almost the same as the two unmodified tailpieces to it's right but...

So now we are back to about where we were four months ago. Better luck this time ??
Attachments
152 Frustration - Knuckle Head and Tailpiece Assemblies Needing Modification.jpg
153 A Slightly Modified Knuckle Tailpiece on the Left with a Salvaged Slightly Modified New Knuckle Head.jpg
158 New Modified Parts in the Modified Holding Fixture.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Wed Jan 10, 2018 5:11 pm

Success at last(!!!) but these coupler parts fought me to the bitter end and with some of my own mistakes thrown in for added frustration.

The first, somewhat blurry, photo shows three of the new silvered soldered complete knuckles. It was at this point that I discovered that one of the tail pieces had been silver soldered in backwards - very easy to do but I knew about what could happen and had checked the unsoldered assembly twice to avoid this mistake....

Then, the next two tail pieces would not silver solder to the knuckle heads!

Did I use some leaded steel by mistake- I was certain that I hadn't and after a very bad few hours, I discovered what was wrong. As I had not been doing any silver soldering recently, I did not remember my own advice (oft repeated here in the past), the parts were not hot enough.

To repeat what I have found out before, with any silver soldering I do:

I only use structural (hot rolled) steel as it silver solders very well and gives a very strong structural joint. I do not trust any cold rolled steel as many grades have a high lead content and I have never been able to successfully silver solder any leaded steel (especially if one needs great structural strength). Others disagree but I will stick to my guns...

I have found one needs to heat, with hot rolled steel parts, (I use a propane flame only) to a much higher parts temperature than red hot. For me, I have to heat the parts to a very bright orange heat with a touch of yellow heat which is about 300 degrees F higher than a red heat. Especially when using a non cadmium silver solder and

One has to heat more than just the local joint area. I find that I have to heat the entire parts to have enough general reservoir heat to ensure that the silver solder will flow freely through the joint.

Black or white flux - no difference.

There it is, one has to sock the heat aggressively to the parts until the above is achieved.

The second photo shows three new couplers (the bottom two are a new matched pair and locked while the upper two are not a matched pair and are unlocked - the one on the upper left is an original coupler and the upper one on the right is new as I wanted to check that the new couplers are interchangeable with the originals - and they are.

Still to do is machine the dummy hollows on the side of the new coupler body castings as per the originals and to silver solder the two couplers casting halves together to make a solid coupler body.

The last photo is of all of the bits and pieces needed. Some of the more important bits and pieces have labels as shown in the photo, otherwise I tend to forget what they are for. Not getting any younger.

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Thu Jan 11, 2018 11:28 pm

The three photos referred to in my previous post.
Attachments
161 Three New Complete Knuckles.jpg
162 Three New Assembled Couplers.jpg
163 The Million and One Other Necessary Bits and Pieces.jpg

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NP317
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by NP317 » Fri Jan 12, 2018 11:32 am

Whew! That coupler adventure was a fight for you!!!! Thanks for sharing your trials and tribulations.
I now have renewed patience for the machining challenges I discover on my projects.
Happy New Year!
~RN

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