Author Topic: Chris' Build of a Lombard Hauler Engine  (Read 296081 times)

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #675 on: February 06, 2017, 04:33:53 PM »
A slight diversion on the way to starting on the steering gear - decided to finish up the engine beds, which I had rough cut down from a bigger bar a while back. Using  fly cutter, I smoothed off the cut edge and took it close to dimension, then flipped it over and took the rest off the other side to get rid of the bend in the bar (caused when cutting down a wider rolled bar, the internal stresses at the sides cause it to bow slightly when cut lengthwise).

The moved the table in so that it left a .125 lip, and took the bar down the rest of the way. The lip will wrap around the top of the main frame rails, and the recess sits against the side of the rails.

After lots of cranking on a number of shallow passes, the recess was done, and the mounting bolt holes were drilled/tapped:

Here is the first engine bed bolted in place

and both beds, with the drive chain/sprocket held about where they will go. The differential frame bolts to the bottom of the engine beds, and the crankshaft bearings and cylinders bolt to the top of the beds.

Here is the blank that will get milled into a shallow T-shape to form the cross bar that goes across just behind the cylinders. Also still need to make a set of brackets that project out from the sides to hold the crosshead rail.


« Last Edit: June 04, 2018, 01:24:57 AM by crueby »

Offline b.lindsey

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #676 on: February 06, 2017, 05:24:02 PM »
The frame is really starting to take shape now too Chris. Loving it!!!

Bill

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #677 on: February 06, 2017, 07:42:59 PM »
For the crossbar between the engine beds, I started with a piece of 3/8" square bar and took some off both sides to make a 1/4x3/8 bar (did not have that size already). Taking some off both sides evened out the bend that the bar took when milling the first side.

then notched one side

and then the other to form the T shape.

and trimmed the bar to length, rounded over the tip of the vertical bar, and drilled mount holes at the ends.

Next up is to make the angle brackets that come off the side of the engine beds, to hold up the crosshead bar. These brackets will be inset and silver soldered onto the beds. First step was to mill in the recessed sides.

The portion at the bottom will become the top surface of the bracket. Here is a picture of the 3D model to show where I am going with this:





« Last Edit: June 04, 2018, 01:25:03 AM by crueby »

Offline cmitcham

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #678 on: February 06, 2017, 10:42:29 PM »
chris, you often speak of removing some from one side, some from the other to even out the bend. the bend must not be there while you mill the second side, so how quick do you have to be? or are you holding the bend at bay with the vise?

thanks!
calvin.

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #679 on: February 06, 2017, 11:23:34 PM »
chris, you often speak of removing some from one side, some from the other to even out the bend. the bend must not be there while you mill the second side, so how quick do you have to be? or are you holding the bend at bay with the vise?

thanks!
calvin.
In the case of this bar, the bend was less than a millimeter, I've had some brass bar curve at least a 1/16th to 1/8" over 6 inches.

Speed does not come into it, the metal is flexing as you cut it. When they manufacture bar stock by rolling, it introduces stresses into the metal, and if you take a lengthwise cut it will flex somewhat. Over a short length, it is negligable, but over a 4 or 5 inch cut you can see it if you hold a straightedge up to it. When cutting lengthwise on a bar with a hacksaw or recip saw, with the bar held in the bench vise, you can watch the kerf at the top open up as you go farther into the metal.  Now, some alloys/products are stress relieved when manufactured, but most brass and some steels are not, and will show this bend.

For brass, it can be avoided by putting the bar stock in the oven at 500-F for an hour (after degreasing first!) and letting it cool. For steels, it all depends on the alloys, for most the process is more complicated.

The easiest way to deal with it for steel is to take part of the depth off one side, flip it over, take more off other side, and come back and finish on the first side to the desired thickness.

I am not a metalurgist, and dont know all the ins and outs of crystal/grain structure and the like, but have learned to deal with the effect. When turning on a lathe, you are taking the same amount off all sides, so it never shows up, but if you split a bar down the middle, or take some off one side, it can occur. I think it is mainly an effect on bars that were rolled to size, not on cast metal.

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #680 on: February 06, 2017, 11:32:45 PM »
Well, Photobucket appears to be in the process of hacking up a hairball and wont let me in to upload, so am falling back to PostImage for these. At least it seems to be serving up previously uploaded pictures.

Got more done on the little brackets for the side of the engine beds. After milling the sides to form the recessed areas, I turned them sideways and notched them to give room for a small screw to hold them in place while silver soldering. The screws will be milled off flush after soldering.

Then, drilled for the screws,

The parts ready to be sawn apart:

and after sawing,

At this point, each was held in the corner of the mill vise and both edges taken down in the one session, so that the two edges would be perpendicular to each other:



One of the brackets held up where it will go.

Next steps are to mill notches in the sides of the engine bed so the brackets will sit in with the vertical flange flush, and drill the holes to hold them for soldering...
« Last Edit: June 04, 2018, 01:25:26 AM by crueby »

Offline 90LX_Notch

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #681 on: February 07, 2017, 01:00:58 AM »
I think this thing is so cool Chris.  I hope that you can make it to Cabin Fever one year with it and the Shay.  I would just love to see them both as I'm sure others would too.

-Bob
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My Engine Videos on YouTube-
http://www.youtube.com/user/Notch90usa/videos

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #682 on: February 07, 2017, 01:18:58 AM »
I think this thing is so cool Chris.  I hope that you can make it to Cabin Fever one year with it and the Shay.  I would just love to see them both as I'm sure others would too.

-Bob


Thanks Bob! I was there (no models with me though) the year before I finished the Shay, had a great time there plus at some of the railroad museums. I am hoping to make it back there again with the models.

Offline zeeprogrammer

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #683 on: February 07, 2017, 11:21:03 AM »
I think this thing is so cool Chris.  I hope that you can make it to Cabin Fever one year with it and the Shay.  I would just love to see them both as I'm sure others would too.
-Bob
Thanks Bob! I was there (no models with me though) the year before I finished the Shay, had a great time there plus at some of the railroad museums. I am hoping to make it back there again with the models.

That would be great. Leave the elves at home (they may skip out on you) and bring cookies. I would sure love to see your models and it'd be great to meet in person.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #684 on: February 07, 2017, 05:20:43 PM »
I think this thing is so cool Chris.  I hope that you can make it to Cabin Fever one year with it and the Shay.  I would just love to see them both as I'm sure others would too.
-Bob
Thanks Bob! I was there (no models with me though) the year before I finished the Shay, had a great time there plus at some of the railroad museums. I am hoping to make it back there again with the models.
That would be great. Leave the elves at home (they may skip out on you) and bring cookies. I would sure love to see your models and it'd be great to meet in person.

I figured I'd drop them off at your house for that weekend, you know what they can be like if left all alone!

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #685 on: February 07, 2017, 05:25:46 PM »
This morning I got the slots milled for the side brackets on the engine beds. The slots are 1/4" wide, so used a 3/16" end mill, cut across and then smoothed up the edges and took them out to a nice slide fit.

Here are the first two brackets test fit in place

Then used the holes in the brackets to mark out and spot for the bolt holes to hold them in place during silver soldering

A couple shots of the part test fit on the main rails. All looks good, so next up will be to silver solder the brackets in place, and come back and mill off the screw heads. The top cross brace only gets bolted on. More holes will get drilled/tapped in the bed rails later on as the engine itself gets constructed.




« Last Edit: June 04, 2018, 01:25:39 AM by crueby »

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #686 on: February 07, 2017, 05:26:44 PM »
That was scary - got 403 errors trying to make that last post. Hope the forum gremlins are not back again!   :killcomputer:

Offline Roger B

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #687 on: February 08, 2017, 09:30:08 AM »
Just catching up with this build again. Magnificent work on the chains and frames  :praise2:  :praise2: I see you are already thinking about the next project  :)  :wine1:
Best regards

Roger

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #688 on: February 08, 2017, 01:14:12 PM »
Just catching up with this build again. Magnificent work on the chains and frames  :praise2: :praise2: I see you are already thinking about the next project  :) :wine1:

Thanks Roger!

And always at least one project on the future drawing board! Next time the weather is a bit better I want to take a run over to the Marion steam shovel that I found out about near here - can't get too close to it, but it looks impressive in the pics I've seen posted about it.

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #689 on: February 08, 2017, 09:58:04 PM »
I was going to get the brackets silver soldered onto the engine beds today, but I decided to skip to the start of the steering gear assembly instead. To paraphrase (badly) the old song, It's my workshop and I'll procrastinate if I want to!

Anyway, the steering mechanism has two 14 tooth gears, one 45 tooth, and one toothed quadrant arm that if a full circle would be 96 tooth. For my model they are all cut with a set of module 0.7 gear cutters. I started with the two small ones, turned a 1/2" steel bar down to .441", slotted the bar where the two gears will be cut off so I knew how far in to cut the teeth, and set up the rotary table vertically on the mill. The cutter was centered on the workpiece by eye - the tool marks from facing the end made it easy to see the center. With the cutter set to just touch the side of the bar, I moved the table in another .0594, the depth of the teeth.

With the #2 cutter (14 to 16 teeth range) in the arbor, I started cutting the teeth. For the Sherline rotary table, the table moves 5 degrees per full revolution, and there are 50 tick marks on the wheel. So, for these gears, it works out to 5 full turns and 7.142 ticks per tooth. I like to pre-calculate all the moves, and follow a list of them rather than trying to figure it out on the fly - a little spreadsheet math worked it out to be a sequence of 5 full turns from the last tooth, then stopping at the ticks for 0, 7.1, 14.3, 21.4, 35.7, 42.9 and back around again for the rest of the teeth.
Here are the first few teeth cut,

and on around to finish off the rest

Then moved the chuck back over to the lathe to drill the center hole (forgot to do that when setting up the blank) and part off the gears:

Then it was time to make the larger 45 tooth gear. I turned a bar to the outside diameter of the gear, 1.295", drilled the center hole (remembered this time) and gave the end a little profiling since one surface will be visible - this gear sits horizontally above the frame rails.

and then like with the smaller gears, went around cutting the teeth

For this gear, the sequence was much simpler since it is an even 8 degrees per tooth, so the sequence was once around to 0, 30, 10, 40, 20 ticks

Once it was done, parted off on the lathe, and these three are done:

Next up will be to make the quadrant gear, which sits at the bottom of the gear train and turns the front axle assembly. Here is what it will all look like:


The part that I have not decided how to make yet is the steering wheel, have to search out how others have done them and see what method seems best for this one. The spokes and rim are all round, which makes it tricky. Suggestions anyone?

« Last Edit: June 04, 2018, 01:25:53 AM by crueby »