Author Topic: Hornsb-Akroyd Crawler Tractor build  (Read 24676 times)

Offline GailinNM

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #15 on: December 24, 2016, 12:57:45 AM »
I sawed up about 12 pounds of 1/2 plate. About 1/2 of that is being turned into chips.

The strips were saw cut to the 1.265 length with about 0.05 extra for clean up.  A stop was set up of the band saw and the strips just fed through.  A stop was installed on the mill vise and one end cleaned up on all the parts.  Thenthe other end was cleaned up bringing the parts to the 1.265 length.  One of the flat faces was cleaned up as the extrusion was a bit rough.  I would ha fly cut it if I were doing in on a manual machine, but with CNC I did a climb mill operation around all 4 sides do I did not have any burr to cleanup. Flipping the part over, the corners were notched out to form the pad which contacts the ground and the rest of the top cleaned up to bring the thickness to 0.484.  I thought I had photos of these operations but have lost them.  But we are big boys and girls and have our own favorite ways to clean up a block of metal. 

Any way after another 1/2 a dozen hours I ended up with a box or parts that looked like this.
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 #16 on: December 24, 2016, 03:05:22 AM »
Off to a great start, thats a lot of metal!  How big is the finished model going to be?

Offline Dave Otto

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #17 on: December 24, 2016, 03:06:40 AM »
Hi Gail

Well progress is progress; looks like lots of repetitive work is in your future.
What do you know about the large stack (cooling tower?) in the photo. I would have thought the Hornsb-Akroyd engine would have been a tank cooled engine. It is too large to be the exhaust; that is why I wondering if it was some sort of cooling tower? Or maybe something to preheat the oil that it was using for fuel. Any ideas?

Dave

Offline GailinNM

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #18 on: December 24, 2016, 01:37:04 AM »
Dave: The large stack is the vaporizer for the theavy oil that the Akroyd engines burned.  He used several different methods during this period and this is the about the largest of the bunch.  A photo of this tractor taken about a year later had an almost no stack. I will probably make a much smaller stack. He may have been converting to a lighter oil at this time.

The Woolwich locomotives  predated this tractor by about 8 years and also used a large vaporizer. It was a different shape but was about the same size On the models I built I put the battery in it so it worked out well for me.
Gail in NM
I would like to be the kind of person my dog thinks I am.

Offline Dave Otto

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #19 on: December 24, 2016, 03:44:39 AM »
Thanks Gail

Was the vaporizer heated by the engine exhaust, or cooling water, or maybe some of both? It appears from the photo that the engine exhaust goes into the vaporizer.



Dave

Offline paul gough

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #20 on: December 24, 2016, 05:03:48 AM »
Here's the only other image I have, a bit late as you already started work, but the crawler area of the photo might show a detail useful to you, despite being a bit different to the one being modelled.

Offline GailinNM

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #21 on: December 24, 2016, 07:59:12 AM »
Chris: Sorry I missed your question about the size of the model.  As currently drawn it will be 6-5/8 inches wide by just under 12 inches long.  But, as mentioned earlier, I can stretch it out in 5/16 increments by adding links.  The chassis can also grow if I stretch it beyond the length of the tracks.   

Dave: I am no expert on the oil engines.  I know just enough to make a fool of myself when talking about them. We do have some experts on the foorum however so maybe one of them will chime in with some more info.  I have seen some photos of the vaporizer column showing an access door near the bottom and the photos show several pipes going to the column from the engine besides the induction pipe. I suspect the access door was to insert preheat blow lamp in to get things started.  A blow lamp was also used to preheat the hot bulb in the head for ignition and the combustion heat kept it hot after the engine was running.

  I really have not paid too mluch attention to the engine as I know that it is impractical for me to build a working one in the size that I want.   This model will be powered by a small gasoline hit and miss engine However here are a coouple of links to Hornsby-Akroid engines running on Youtube.

Paul: Thanks for the last PDF.  It is of one of the later steam powered crawlers.  Quite different , but you can see the relationship.
Gail in NM

The last link has nothing to do with this thread but I enjoy in so much that I try to post the link at least once a year.  It's "Sweet Georgia Brown" with tractor. Indulge me -- it's Christmas time.





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

Offline Dave Otto

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #22 on: December 24, 2016, 05:59:50 PM »
Thanks Gail

I had completely forgot about the torch and vaporizer bulb; for some reason I was just thinking about preheating the heavy fuel and not the actual hot bulb vaporizer which I am familiar with. Many years ago I used to help out with a Fairbanks Morse model Y oil engine at out local fair.

Dave

Offline GailinNM

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #23 on: December 24, 2016, 10:05:24 PM »
The tread plates were set on edge in the mill and two edges rounded over using an 1/8 radius corner rounding end mill.  Up one side and down the other, then flip the part and do the second edge.  I set it up so the two cut did not quite match so a 1/64 wide flat joined the two cuts.  lThis was so I would not lose the reference edge dimension for following operations.It remained at 0.875 between those two small flats.
Gail in NM

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

Online b.lindsey

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #24 on: December 24, 2016, 11:35:52 PM »
That is a lot of parts Gail, but looking good. Nice that you have the CNC to assist with the handle cranking :)

Bill

Offline crueby

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #25 on: December 24, 2016, 11:45:44 PM »
Looking great so far, watching along closely!   :popcorn:

Offline GailinNM

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #26 on: December 25, 2016, 01:06:16 AM »
Bill: I have had CNC in the shop  since 1982 so coming up on 35 years.  I can almost write G Code in my sleep.  For the corner rounding it was only 6 lines of code -- 5 minutes top.  Then put part in - push button.  Of course it still takes time as I have to stand there and put part in and push button. But while the mill is cutting the part I am deburring the just finished part. And, since the stroke 5 years ago, I no longer have the strength and endurance to crank handles for long periods of time.  But the next operation is where the CNC really shines.  When I designed the part I did so with CNC in mind.  If I were going to make it manually I would have designed it differently.

Chris: this is where it starts to get fun.

The detail work on the track plate is all done with an 1/8 end mill.  The plate is held in the vice on parallels by the lug (which rides on the ground) with a small space between the vice jaws and the bottom of  the lugs that form the hinge.I cut a few thou beyond the width of the hinge part and into the base part to give a square bottom space for the hinge when viewing from the outside of the track. I made the hinge lugs 0.003 narrower than the spaces between them so the hinges woould be free.  The groove through the middle is clearance and alignment for the sprocket.

Now for those with sharp eyes you will notice that the hinge pin holes are all ready drilled in the photo.  This is because I followed Chris' lead and milled the part first and then drilled the holes so I did not have to peck drill the long hinge pin holes. Then I ran the milling program again to clean up the burrs from the drilling operation.  It was quicker and easer than hand deburring. The photo was taken during this clean up pass. The drilling will be shownd in the next post.
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 #27 on: December 25, 2016, 01:24:23 AM »
Very slick!

Offline 10KPete

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #28 on: December 25, 2016, 02:10:23 AM »
With age and experience come wisdom!  :old:

Great stuff Gail! I'm watching both of you crawlers closely....

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Offline 10KPete

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Re: Hornsb-Akroyd Crawler Tractor build
« Reply #29 on: December 25, 2016, 02:11:17 AM »
With age and experience come wisdom!  :old:

Great stuff Gail! I'm watching both of you crawlers closely....

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.