Author Topic: Chris' Build of a Lombard Hauler Engine  (Read 295546 times)

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #510 on: December 30, 2016, 01:59:28 AM »
Looking great  Chris.
Little parts are sluch fun.  Reminds me of a cartoon from years ago that shows several men crawling aroundon the floor of the office of Micro Parts, Inc.  Caption read "We dropped last weeks production".
Gail in NM

 :lolb:

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #511 on: December 30, 2016, 10:13:59 PM »
Some more progress on the chains, so far so good! I started today by making the drilling jig for the chain side rails. Picked a chunk of 5/8" wide brass that was thicker than the rails are wide, then milled down the face of it, leaving 0.100" rails on the top and one side:

then switched to a smaller end mill and evened up the inside corner, finishing with a notch so that the corner will fit square onto the top corner of the mill vise, so I can index it the same every time from there:

Then, flipped it up vertical, with a parallel bar under it to make sure it was level to the mill, and milled out the wider openings in the top:

then a deeper cut for one side of each opening, for the lower leg of the rails to drop into:

Here is how the rails will sit in the jig. The jig will sit down on the top rail, so the rails will be held by the vise:

And the first test run, three parts held in place, centered up the front/back travel on the table on the part and locked that down, then positioned the drill at one end and zeroed the handwheel so I can get back there quickly. To use, start at the zero position on the right, drill, advance 6-1/2 turns, drill, advance 5-1/2 turns to next part, and repeat.

followed by the actual drill

And here are the first set of parts. If the vise was wider, I would have made 4 (or more) at a time. At least this way, it is repeatable positioning with minimum time, and only one drill change every three parts.

After a trial fit, I decided to go from a 3/32 drill (which matched the size of the rod), up to a 0.096 drill so the parts would move easier. Here is a picture with the first cross pin rivetted in place, and the next one (at the top) just slid into place to show the continuation. What I did was peen over one end of the rod in the rivetting jig, assemble the parts for the one link, then hold it on the anvil and peened over the other end of the pin.

The first pin that I cut was a little too long, so I removed it by filing off the head, and tried another one 10 thou shorter - that seems to be the sweet spot, no slop, but loose enough for the rails and roller to pivot. Here is a shot of where it will slide in at the bottom of the track:

I may need to go back and grind a little bit off the round roller guide at the ends, where the chain turns around, it looks like it might rub on the chain rail as it makes the turn. But, all in all, it looks like I can go into mass production mode on these parts. One set down, 143 to go.... 
 :o
I think there will be a number of sessions at the bench interspersed with some time on the computer designing up the next parts (sprockets, differential, frame) in the 3D program over the next week...
« Last Edit: May 31, 2018, 09:02:53 PM by crueby »

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #512 on: December 31, 2016, 12:37:59 AM »
In trying to decide whether to use the lathe to part off the pins to length, or set up the chop saw with the abrasive wheel to do it, I was noticing that the rod (some 3/32 steel) was not parting cleanly, and seemed to be moving in the chuck. So I stopped, ran the bar out a few inches and tightened up the chuck again, and wiggled the outer end - could see the bar moving sideways back and forth in the chuck. So I shone a light behind it, and could see that the chuck jaws are only touching the bar at the innermost corner, leaving an unsupported V down each jaw face.

As the Mythbusters would say, Well - There's Your Problem!

I then put in some 3/8" bar, same gap. This would explain sometimes when threading bar with the tailstock die holder and larger thread sizes, that sometimes the bar would slip in the chuck, leaving a score around the bar at the inside corner of the chuck jaws.

I then got out my older 3-jaw chuck (also Sherline brand) that I had left set up with the jaws reversed to avoid the chore of reversing them back and forth constantly for larger or smaller stock, set up for normal inward jaws, and tried that one: it clamps down evenly on the whole length of the jaws. Parting off with that chuck went nice and smooth, without the movement and wobbling.

So, questions for you guys: is the gap I am seeing due to a worn set of jaws and/or chuck? Is it supposed to be that way? If not, anything I can do to fix this short of buying a new chuck?

 :help:

Offline GailinNM

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #513 on: December 31, 2016, 01:47:59 AM »
Can you reverse the jaws on the newer chuck and see if it is OK on larger stock? If so use it for larger diameter stock and use the older one for smaller.
Gail in NM
I would like to be the kind of person my dog thinks I am.

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #514 on: December 31, 2016, 02:37:39 AM »
Can you reverse the jaws on the newer chuck and see if it is OK on larger stock? If so use it for larger diameter stock and use the older one for smaller.
Gail in NM

Hi Gail,

On larger stock with the jaws reversed it only grips on the shorter steps, which on these chucks is only about 3/16", so it would be fine for that. The one thing I much preferred about the newer chuck was that they staggered the tommy-bar holes around the rim, so that there was always a pair positioned well for tighten/loosening, on the older chuck they are evenly spaced a 3rd apart, so on some stock the positions are awkward. Small price to pay for a better grip, so I may do as you suggest if there is no easy/cheap way to fix the newer one. For now I will continue using the old one.

Chris

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #515 on: December 31, 2016, 02:58:34 AM »
I ran through and bent/cut to length a bars worth (3' long) of the side rail stock, enough for about 3 dozen pairs of side rails. Went pretty quickly, less than an hour. Then got started turning down some more pins to test the length on them some more. To repeatably cut the to length quickly, I took the frame from the dial indicator holder, took out the indicator, and swung it in till it would touch the end of the rod. Starting with the parting tool lined up with the end of the rod, I cranked in the distance equal to the desired length of the pin, and tightened down the indicator frame.

With this setup, I can loosen the chuck, run the rod out till it touches the frame, tighten the chuck, then run the parting tool inwards to cut to that length. Instant length stop, as long as I leave the long axis feed crank in the same spot for each part.

After cutting a few of them, I drilled some more side rails, and did a test assemble:

Not bad, but a little tight, could use a little longer pin to let it flex easily, figure if it lays over under its own weight than it should be fine for the model.

So, will adjust it back out a little and try again. The assembled chain segments can be recycled (except for the pins) by filing off the head of a pin and pushing it back through. A couple more tests and it should be good. If I was setting up a cnc machine to do this, I would probably go back to the stepped pins, but for manual machining the simple straight pins are much faster to do.
« Last Edit: May 31, 2018, 09:03:28 PM by crueby »

Offline b.lindsey

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #516 on: December 31, 2016, 04:27:06 AM »
Those links really look the part Chris!!  Your patience and persistence are to be admired as your results plainly show!! 

Bill

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #517 on: December 31, 2016, 04:30:02 AM »
Those links really look the part Chris!!  Your patience and persistence are to be admired as your results plainly show!! 

Bill
Thanks Bill, with the jigs it looks like it will be quicker to make than the tracks were, there are a couple dozen more parts but they are lots simpler.

Offline ///

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #518 on: December 31, 2016, 07:56:56 AM »
Very very nice. Really enjoying following your build!  :ThumbsUp:
Simon

"The reality is that without cheap imported machines, I would be spending my time doing something less creative and less enjoyable" - Captain Jerry

Offline Steamer5

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #519 on: December 31, 2016, 08:17:47 AM »
 :popcorn: :popcorn:
Looking good Chris!

Wonder if my rivet squeezzer would work on those pins, wouldnt need the mod ive done.
 The standard head with the right bits would probably work

Cheers Kerrin
Get excited and make something!

Offline gbritnell

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #520 on: December 31, 2016, 03:26:06 PM »
Chris,
I'm truly enjoying this build. Your fixture work is extremely informative and I really like the bending jig.
This is going to be an amazing machine.
gbritnell
Talent unshared is talent wasted.

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #521 on: December 31, 2016, 03:42:01 PM »
:popcorn: :popcorn:
Looking good Chris!

Wonder if my rivet squeezzer would work on those pins, wouldnt need the mod ive done.
 The standard head with the right bits would probably work

Cheers Kerrin

I built a simaler squeezer tool a couple of months ago when Florian did posts on his, it works great on the shorter rivets, but on these long pins there is a tendency for it to widen farther down or bend since it is such a slow pressure. Doing it with a hammer  is working very well, the quick impacts just heading over on the last 10 thou or so. The squeezer tool is going to get a big workout on parts like the water tank and the faux firebox shell.

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #522 on: December 31, 2016, 03:42:47 PM »
Chris,
I'm truly enjoying this build. Your fixture work is extremely informative and I really like the bending jig.
This is going to be an amazing machine.
gbritnell

Very very nice. Really enjoying following your build!  :ThumbsUp:

Thankx!!

Offline Steamer5

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #523 on: December 31, 2016, 03:56:22 PM »
Hi Chris,
 Yep can see how that would happen! Haven't used mine in anger yet, always seems to be something that pops to the top of the list. Made it to close 3/16 steel rivets for the loco frames, its a 16 ton wire crimper so its got enuff drive its just the "C" arms that may not hold up! Shouldn't be a problem on the 3/64 ones for the tanks, even though they are stainless!

Cheers Kerrin
Get excited and make something!

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #524 on: December 31, 2016, 04:20:50 PM »
Hi Chris,
 Yep can see how that would happen! Haven't used mine in anger yet, always seems to be something that pops to the top of the list. Made it to close 3/16 steel rivets for the loco frames, its a 16 ton wire crimper so its got enuff drive its just the "C" arms that may not hold up! Shouldn't be a problem on the 3/64 ones for the tanks, even though they are stainless!

Cheers Kerrin
Mine will be much easier, being brass rivets. 16 tons ought to form yours just fine!