Author Topic: Hornsb-Akroyd Crawler Tractor build  (Read 25347 times)

Offline GailinNM

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Hornsb-Akroyd Crawler Tractor build
« on: December 23, 2016, 08:46:07 AM »
It's all Chris' fault.  His excelent build thread on the Lombard Hauler Engine

http://www.modelenginemaker.com/index.php/topic,6515.0.html

 got me thinking about a old but not forgotten desire.  It started in 1953 when
Howard McEntee published an article about a redio controlled Cat tractor in the
August 1953 Popular Science.

http://tinyurl.com/j3b4mhr

Of course it was beyond my  abilities as a young teenager, both financial and skills.  But now, 63 years later those problems are far behind me.

Over the last half a dozen years have  built  10 IC engine powered Gauge 1
locomotives using 3/8 bore x 1/2 inch stroke Hit-N-Miss engines. Several of these
were stand off scale of the first IC powered Woolwich. So it seemed reasonable to build a stand off scale of the first IC powered  Crawler tractor, the Hornssby-Akroyd Crawler Tractor built in several forms in the early 1900's. 



It used the same basic engine as the Woolwich locomotive so most of the engine design work is all ready done.
Gail in NM
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Offline Steamer5

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #1 on: December 23, 2016, 06:55:46 AM »
Hi Gail,
 Dam! More  :popcorn:, have to follow Chris's lead & buy by the truck load!

Looking forward to this one too!

Cheers Kerrin
Get excited and make something!

Offline fumopuc

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #2 on: December 23, 2016, 07:12:20 AM »
Hi Gail,
good idea. I will following along with interest, as already done with Chris and his Lombard Hauler.
Kind Regards
Achim

Offline rudydubya

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #3 on: December 23, 2016, 09:37:06 AM »
Greetings Gail.  I'll be following along too.  Looks like a challenging and fun project.

Regards,
Rudy

Offline Jasonb

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #4 on: December 23, 2016, 09:40:07 AM »
Should be a bit more reliable than the steam powered ones before it, there are a couple of large scale models of those ebout which may be of use for detail of the running gear.

Offline GailinNM

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #5 on: December 23, 2016, 10:00:26 AM »
Glad to have you along for the ride Kerrin , Achhim, Rudy and Jason.
Don't worry about the pop corn supply Kerrin. This will be a slow thread.

Mother Nature has not been kind to me the last 10 years so I work slow. I am losing my vision and have to use visual aids to read the dials and DROs any more.  I also had a stroke a few years ago and had to learn how to print my name again. And nerve damage has reduced my sense of feel.  My touch typing is coming back but I still make lots of errors and don't see the computer monitor well enough to catch them all.  So don't be too critical. I am still making chips but I have to have some assistance with assembly. I have already lined up a friend who I have worked with before to help.  I will be machining two sets of parts, one for him and one for me.

To clarify, when I speak of stand off scale, I mean stand WAY off and compare to a fuzzy photo and say "well it could be".  If you wear glasses it helps to take them off also. But the finished model will have the flavor of the original.

Not much documentation exists of the proto type.  The above photo is most of it. Only a few were builtm but Horssby built a lot of steam powered tractors and later multi cylinder tractors.  I am taking some details from them to assist the design. The design is not complete, but is far enough along to start building with confidence.
So to start with here is a preliminary side view of the track layout.
Gail in NM


« Last Edit: December 23, 2016, 10:46:43 AM by GailinNM »
I would like to be the kind of person my dog thinks I am.

Offline Roger B

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #6 on: December 23, 2016, 10:27:33 AM »
An interesting build  :ThumbsUp: I will be following along  :wine1:

I always liked these crawlers and many years ago built an even more' stand off scale' one with Mechano powered by a Bowman steam engine. The bars along the sides operated the steering brakes.
Best regards

Roger

Offline paul gough

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #7 on: December 23, 2016, 09:21:28 AM »
Might be of interest. Paul Gough

Offline crueby

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #8 on: December 23, 2016, 03:29:52 PM »
Oh good! I get to watch someone else making all the track parts!!

I saw that picture while researching the Lombard, it should be a fun one to run. Looking forward to popcorn munching along!

Offline Dave Otto

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #9 on: December 23, 2016, 05:57:24 PM »
Interesting project Gail; it will be fun to follow along with your progress.

Dave

Offline GailinNM

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #10 on: December 23, 2016, 04:29:12 PM »
Thanks for the PDF Paul.  Building something like this is kind of like assembling a jigsaw puzzle with out the picture of it.  Every little part or bit of information that gets added gives you a better idea of what the finished article will look like. 

Roger:  Neat model.  Nothing like having toys to play with. Especially ones that you have built.

Chris: Glad to have you along.  The Hornsby tracks are very different from the Lombard tracks, but both have a lot of parts.  I have a CNC mill and lathe so the multiple parts will be easier for me. Not that any of the parts could not be made on manual machines, but with my failing vision I ccan not.  Also, since this is a "look alike" and not a scale model I won't have as many details. I will also be using more aluminum and brass instead  of stainless steel.

Dave: Glad to have you with us.  I will probably need all the moral support I can get before this is over. 

GGail in NM

« Last Edit: December 23, 2016, 04:34:18 PM by GailinNM »
I would like to be the kind of person my dog thinks I am.

Offline GailinNM

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #11 on: December 23, 2016, 05:05:39 PM »
So, with most of teh preliminary comments out of the way it's time to make some parts.  Like Chris, I stated on the tracks.I have built similar parts to most of the other parts on the project but have never built any tracks.  I wanted to make sure that  they were functional first.

The track plates are 6061 aluminum. The overall size of each plate is 1.265 x .875 x .484. I initially drew them as 1.250 wide but wanted to use 1/8 x 1-1/4  dowel pins for the hinges.  After measuring the dowel pins I found that most of them were about 0.005 longer than the nominal 1-1/4 so I widened that track witth by a 1/64 so the pins would not protrude.

I got a good buy on some 1/2 x 10 extrusion pieces 12 inches long.  So the first operation was to saw it into 10 inch long strips that were  wide enough to finish to the 0.875 dimension.  I have a roll in band saw, moving head, that will take 14  inch tall parts so I set up to cut the strips through the plate with with the10 inch length being parallel to the length of the saw blade. This gave me a straight edge with little machining to clean it up.
Gail in NM
   
I would like to be the kind of person my dog thinks I am.

Offline crueby

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #12 on: December 23, 2016, 05:11:36 PM »
Thats quite a setup in the band saw!

How will the dowel pins be held in position in the track plates?

Offline GailinNM

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #13 on: December 23, 2016, 07:11:46 PM »
The dowel pins will be held in place with a dab of Loctite 680 on each of the outer hinge tabs on each plate with the hinging action taking place on the inner tabs. More on that later.

The saw set up is not pretty but it is safe and functional.  The roll in band saw has an adjustable counter weight to set the cutting pressure and a hydraulic cylinder to set the max rate of feed. Once set up it is automatic.  Took about 2 minutes to cut each strip.

In the preliminary drawing above there are 40 plates in each tread.  I think that this will be enough but I cut 45 for each side in case I need to stretch things out a bit to fit everything inside the chassis.  Two battery packs, one for ignition and one for the radio, radio, servos, gear boxes, CDI ignition and things like that.

I got 7 plates out of each strip. I cut 26 strips.  This gives me 180 plates, 45 for each track, 2 tracks per tractor and 2 tractors. Plus a couple of extra to screw up.

After the strip were cut they were milled to the 0.875 finished dimension.  No photo of the operation, but I have multiple 4 inch vices on the mill spaced 4 inches apart. The strip was set on parallels in each of 2 vices so each end was rigidly supported and the first edge of all  strips cleaned up. Then flipped over and all the strips were milled to width.
Gail in NM

I would like to be the kind of person my dog thinks I am.

Offline crueby

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #14 on: December 23, 2016, 07:20:43 PM »
Seeing all that stock gives a better impression of how many parts.

I also started with 5 or 6 extras, used them all for goofs, but that was a manual setup vs the cnc.

 :popcorn: