Author Topic: Chris' Build of a Lombard Hauler Engine  (Read 17313 times)

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #570 on: January 11, 2017, 06:12:34 PM »
Loved the video, Chris. I can tell your Hauler is going to have a great sound once it's all in operation.

Good solution to your problem. I guess some things just don't scale down so good and the flanges are one. Knowing what you know now, could the flanges have been made taller (not scaled down as much) to solve the problem?

Jim

No - the flanges only surround the center rollers, the side rails of the chain are above the flanges. To make the flanges taller, I would have had to make the rollers a larger diameter or the side rails narrower, which was not practical. Looking back at the photos of the real one, it is surprising that they did not have problems too, given the rough ground they would be going over, but I guess it worked out fine in full size. At the size of the scaled down model, the grooves in the track plates are more of a suggestion than a retainer!

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #571 on: January 12, 2017, 12:48:54 AM »
Got a start on the sprockets for the roller chain end brackets. Started with a chunk of 3/4" 303 stainless bar, and drilled the axle hole on the lathe,

and then moved the chuck and bar over to the rotary table on the mill, set the mill depth for the thickness of the sprocket, and cut the valleys of the sprocket 60 degrees apart:

Then to make the sloped sides of the teeth, offset the mill .230 in, and the table by 15 degrees, and made another pass on each tooth:

and then .230 back the other way from zero and 15 degrees the other wayfor another pass:

That completed the tooth shapes, so moved the chuck back onto the lathe, and tapered the ends of the teeth a bit on the one side so that they will self center on the links of the chain:

and then parted off the sprocket, leaving it slightly thick to allow for a cleanup pass:

and tapered the other side while holding it in the 3-jaw (handy that it is 6 teeth) :

Here is the finished sprocket

and testing it in the chain - runs very smooth!

So, that proves out the design for the sprocket, time to make 7 more of them!

- - - - - - - - - - - - - - - - -
Oh, and this time the forum gave no errors, but PhotoBucket appears to have died mid-post, so these pics are on another host! Sheesh! 
 :killcomputer:

Online b.lindsey

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #572 on: January 12, 2017, 02:13:45 AM »
Looking Great Chris, and nice adjustments as you are going along too.

Bill

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #573 on: January 12, 2017, 04:22:17 AM »
Looking Great Chris, and nice adjustments as you are going along too.

Bill
Thanks Bill, after all that work on the chains, I'm glad that there was a way to keep them! Lombards patents showed using road wheels, so that is always an option if the chain approach fails. I'm learning a lot about sprockets, never did them before. The 3d app makes them easy, since it allows drawing shape, size and number of teeth, and the pitch distance, it figures out the diameter needed for those constraints, and you can go back and change any parameters later. SO much easier than hand drafting it all.

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #574 on: January 13, 2017, 09:55:29 PM »
The rest of the roller chain sprockets are made:

Next up will be the brackets and stepped bolt guides to hold them in place...

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #575 on: January 14, 2017, 12:44:42 AM »
Got the first batch of the sprocket end guide bolts made, 4 down 4 to go. Started with a length of 303 steel bar, and turned in the shape of the guide:

and then parted it off and drilled/bored the hollow in the end to make it look more like the original cylindrical guides:

Here is what it looks like with the sprocket in place,

and the chain around that,

and sitting in front of the track plate where it will be installed, once the brackets are made and the old cylinder guides cut off:

This should run much smoother, and not slip off like the first attempt. More parts tomorrow...

Offline Steamer5

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #576 on: January 14, 2017, 02:18:02 AM »
Hi Chris,
 O:-)  :popcorn:
Been to check the crop, looks like it's coming on nicely, hopefully there will be enuff to get thru to next season!

 :lolb: :lolb:
Cheers Kerrin
Get excited and make something!

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #577 on: January 14, 2017, 02:55:48 AM »
Hi Chris,
 O:-)  :popcorn:
Been to check the crop, looks like it's coming on nicely, hopefully there will be enuff to get thru to next season!

 :lolb: :lolb:
Cheers Kerrin

Excellent! Might even be enough for some movies between engine projects!

Looks like better weather than here, snowing and the temperature is dropping faster than a small part over shag carpeting...

 :cheers:

Offline Brian Rupnow

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #578 on: January 14, 2017, 03:09:54 AM »
Chris---It's about time for you to get another "attaboy!!!" Great work, I check in every day.---Brian

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #579 on: January 14, 2017, 04:39:23 AM »
Chris---It's about time for you to get another "attaboy!!!" Great work, I check in every day.---Brian
Thanks Brian! 

Just finished turning down the profile on the rest of the roller guides, ready to bore in the hollow outer ends like the first one has.

This weekend we have another RC boat meet at a larger pool at a winterfest, should be a fun time. Taking the Alfa sub and the rowboat. We usually get a couple dozen boaters.

Offline Steamer5

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #580 on: January 14, 2017, 07:08:23 AM »
Hi Chris
 That's about 1/3 of the field, not sure there will be enuff for the movies!

Cheers Kerrin
Get excited and make something!

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #581 on: January 15, 2017, 02:07:32 AM »
Some more done on the roller chain sprocket brackets this evening. Started with some 1/4" square 303 bar, and took one side down to make two .200 x .250 bars, each long enough for 4 brackets:

and then drilled the 4-40 tap holes for the sprocket bolts, and the clearance holes for the adjustment slots:

followed with milling out the recess for the bolt heads so the clear the sprockets. There will not be enough room for hex heads and wrenches, so these will be socket head screws.

Here is the first set of brackets, ready to be cut apart and the ends cleaned up. You can also see here that I have added some short lengths of 4-40 screw threads to the base of the shoulder bolts. When I originally drew them up, I was thinking that I would turn in the section for the threads, and thread with a die, but realized that for such short sections of thread that need to go right up to the shoulder, that I was better off drilling and tapping both the bracket and the shoulder bolt and adding some threaded rod cut from a screw. The rod is held into the shoulder bolt with some red loctite. This way I can be sure to be able to draw up the bolt completely. The axle portion that the sprocket rides on is slightly longer than the thickness of the sprocket, so they can spin freely.

Next up is to cut the brackets off the longer bar, and then cut the cylinder guide off the track frames so I can fit these new sprocket assemblies...

Offline Flyboy Jim

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #582 on: January 15, 2017, 05:03:18 AM »
That worked out well, Chris. I've filed your idea of threaded rod away. I've run into that problem of not being able to thread a shaft clear up to a shoulder and usually just turn that area away, but I can see that sometimes that wouldn't leave enough threads.

I wonder if that would be a good time to go ahead and turn the shaft for the threads and then cut the threads manually with the threading attachment? I've got one of the attachments that I haven't used yet. Might have to experiment with it.  That said, I think your procedure would be a lot quicker.

Jim

Sherline 4400 Lathe
Sherline 5400 Mill

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #583 on: January 15, 2017, 02:57:37 PM »
Jim, I've got the threading attachment for my sherline, but the time and effort it takes to install and remove makes it impractical for anything but large or oddball threads, rarely use it.

Offline crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #584 on: January 16, 2017, 10:09:55 PM »
Today I started the modifications to the track frames to take the new sprockets. Started by cutting apart the brackets from the longer bar,

then milling off the old cylinder guides,

and marking out for the mount holes for the new brackets

and getting the chains fitted/tensioned


Here is a test of the reassembled first track - all seems to be working, not derailing any more:

So, on to modifying the second frame...