Constructing the Martin Lewis Little Engines Northern Tender

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Carrdo
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Location: Toronto, Canada

Re: Constructing the Martin Lewis Little Engines Northern Te

Post by Carrdo » Sat Jul 23, 2016 2:07 pm

More of a shot of the old lathe working than anything else. It is a belt driven 8 speed (4 direct and 4 back geared speeds) 13" x roughly 40" between centers and has a 6' bed overall.

The start of turning the bar between centers.

I did have to shim the tailstock and did find some interesting things inside the tailstock casting when I took it apart but I won't go into that.

The lathe now turns dead parallel and I am amazed at its accuracy for a 75 year old machine. If it could talk, I am certain it would have many interesting things to say.

It certainly is a machine and it behaves like a machine and it clanks like a machine as everything is purely mechanical. It needs to be kept well oiled but keep it well oiled and everything still moves as smooth as silk. It must have 5 layers of paint on it by now but I only removed those areas to expose the original brass instruction and identifying plates which are all there including one from the war production board.

When turning, the chips were flying off very hot which raised nice red welts on the back of my hands and arms so I need to deal with that. This rarely happens with the 9" SB.

The only thing with the old SB toolroom design was the limited hole size through the spindle which limited collet size to a little over 5/8". The post war design changed this.

Richard has exactly the same model SB but he has a 7' bed.

I really do like these old machine designs so I guess I will soldier on with my working museum ways.
Attachments
204 Start of Bar Turning Between Centers.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Te

Post by Carrdo » Wed Jul 27, 2016 10:53 pm

The sheet metal bender head roughed out.

The forming roll is is 1.5" dia and a shade over 8" long. The end pins are 1" dia. with everything being turned all over from the same bar.

I am now swimming in swarf (or chips) from the above.

To give the old lathe a chance, hone your cutting tools after grinding to produce a fine finish.

SB produces a data sheet on the basic HSS cutting tools to use with their lathes and what tool relief the various cutting tools should have and I use this for most of my turning operations.
Attachments
205 Sheet Metal Bender Head Roughed Out.jpg
206 Hone Your Cutting Tools to Achieve a Fine Lathe Turned Finish.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Te

Post by Carrdo » Wed Aug 10, 2016 12:13 pm

Different approaches.

The slightly revised knuckle head drawing looks good on paper but at the tip there are three blended radii involved so both knuckles will fully engage one with the other. This looks like a CNC job but it can be done manually if one is careful. We shall soon see.
Attachments
208 Richard Producing a CAD Drawing of the  Couplers.jpg
74 Drafting the Slightly Revised Knuckle Head Shape.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Te

Post by Carrdo » Sun Aug 14, 2016 9:15 pm

Machining the revised coupler knuckles.

Start by milling a HR steel rectangle 3/8" by 9/16" by 11/16" exactly.

Then I used the slightly revised knuckle head template to spot and then drill the three locating/forming holes in the knuckle blank. All of these through holes (1/16", 3/32", 1/8") involve deep drilling (11/16" deep) so they have to be pilot/step/peck drilled and one must clear chips frequently even with the sharpest of drills. Just exercise patience here as standard jobbers drills don't drill this deep well under the best of conditions.

The knuckle template is then located by the three drilled holes on one end of the knuckle blank for the rough milling of the blank.


The rough milling of the knuckle blank is again a game of patience, concentration and nerves as one has to mill as close as possible to the template outline without milling into the template itself.
Attachments
364 A Drilled Knuckle Head Blank with the Slightly Revised Knuckle Head Template.jpg
365 Rough Milling Knuckle to Template.jpg
366 Rough Milled Knuckle and Template.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Te

Post by Carrdo » Mon Aug 15, 2016 5:07 pm

More knuckle head machining operations specifically milling the 1/16" step down's at each end of the knuckle head and the finish rotary milling of the knuckle head base circle.

In the first photo the small plug 1/16" thick plug gauge is needed to keep the knuckle head square and vertical in the vise after the knuckle head has been reversed in the vise in order to machine the step down in the other end. Also, note the shaped clamp piece which is needed to securely hold the rough machined knuckle head in the vise for this milling operation. At this point there is virtually no straight/plane surface left for the vise to hold so one has to use a bit of imagination to have a good clamping force. It worked fine.

One can also see the original and the slightly revised knuckle head templates in this photo. Also, the various pins used to pin the knuckle head template to the knuckle head blank.

And since I did not show it previously, I did make a hardened drill fixture (from gauge stock) to drill the three locating holes in all of the knuckle head blanks from now on. It is the rectangular piece shown in the photo. For it to locate effectively, the length and width of a knuckle head blank and and the drilling fixture have to be exactly the same.

The base circle rotary milling operation is another custom setup due to the restricted space available. One needs to have a small extra long cutter for this operation so take only light cuts as you don't want anything to get away from you.
Attachments
368 Milling the Step Down on Each End of the Knuckle.jpg
369 Finish Rotary Milling the Knuckle Head Base Circle.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Te

Post by Carrdo » Tue Aug 16, 2016 5:06 pm

The external part of the knuckle head contour was finished by drum sanding in my high speed drill press. I am not a fan of hand work and it is all hand work here. There is very little to hang onto and the drum sander will rip the piece out of your hands if you press too hard.

You need to use the 1/16" thick plug piece to keep the knuckle head straight and square to the drum sander as seen in the photo when sanding. Also, the drum sander is offset a bit from the center hole in the drill press table as you have to have a solid surface at all times for the knuckle head to sit on.
Attachments
370 Finish Drum Sanding the External Knuckle Head Contour.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Te

Post by Carrdo » Tue Aug 16, 2016 6:18 pm

The last gasp of a revised coupler knuckle head.

Die filing the nose and the inner contour. The die filer table is tilted slightly forward to compensate for the taper on the Swiss Pattern Modelmakers file. I do have some of the special die filer files but they are far to big for a job like this.

Incredibly time consuming. Incredibly tedious but sometimes this is the only manual machine for the job as it is designed to precision file small and complex contours which no other manual machine can do.

One down and at least 5 more knuckle heads to go so I guess I won't be posting for a while.
Attachments
371 Die Filing the Nose and Inner Contour of the Knuckle Head Profile.jpg
372 A Finished Knuckle Head.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Te

Post by Carrdo » Thu Sep 01, 2016 1:52 pm

The very last operation on one of the best finished knuckle heads and the drill shattered!

And it would not come out no matter how hard I tried. I was not pleased to say the least.

Getting there on some of the couplers. I have been here before and have been thrown back. I guess I should stay positive.
Attachments
374 Shattered Drill in a Finished Knuckle Head.jpg
375 Getting There.jpg
376 Photo of Open Knuckle on Front Coupler of CNR 6218 Northern.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Fri Oct 14, 2016 1:44 pm

Soldiering on after a month away overseas.

More heavy duty machining (for me) on the tender tank sheet metal corner radius former.

Attaching the radius former to its baseplate via two, 1-3/4" long, 1/2-13 NC socket head cap screws. The photos make it look easy but it is anything but that. I needed a new larger drill chuck, new drills and a new 3/4" dia. end mill (for "counterboring" the socket screw head) and all of the nerves and trickery I could muster to pull this one off.

The design is a larger and heavier version of the corner radius former originally constructed by Gary Gillam of Australia for his magnificent Victoria R- Class Hudson which is being described in the Build Log also. I just don't know how he accomplishes such magnificent work in such a short time while I plod on for decades.
213.jpg
209 Setup to Tap Baseplate Thread Square.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Sat Oct 29, 2016 7:40 pm

Further along.
Attachments
216 Milling the Front Face Chamfer.jpg
217 After Further Machining.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Fri Nov 04, 2016 2:57 pm

Another boring setup.
Attachments
219 Finish Boring the Bending Head Side Plates.jpg

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Carrdo
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Re: Constructing the Martin Lewis Little Engines Northern Tender

Post by Carrdo » Thu Nov 10, 2016 3:25 pm

Getting there.
Attachments
220 Flycutting the Top Sheet Metal Feed Plate.jpg
221 Much Further On.jpg

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