Model Engine Maker
Supporting => Vehicles & Models => Topic started by: GailinNM on December 23, 2016, 08:46:07 AM
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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.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0001_zpsxdexbpzz.jpg)
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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Hi Gail,
Dam! More :popcorn:, have to follow Chris's lead & buy by the truck load!
Looking forward to this one too!
Cheers Kerrin
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Hi Gail,
good idea. I will following along with interest, as already done with Chris and his Lombard Hauler.
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Greetings Gail. I'll be following along too. Looks like a challenging and fun project.
Regards,
Rudy
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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.
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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
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-00001_zpshnspz0us.jpg)
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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.
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Might be of interest. Paul Gough
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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!
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Interesting project Gail; it will be fun to follow along with your progress.
Dave
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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
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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
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0002_zpso7q7vzxz.jpg)
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Thats quite a setup in the band saw!
How will the dowel pins be held in position in the track plates?
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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
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0003_zpszvgtvirh.jpg)
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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:
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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
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0004_zpsutrf21vm.jpg)
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Off to a great start, thats a lot of metal! How big is the finished model going to be?
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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
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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
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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
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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.
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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.
https://www.youtube.com/watch?v=qMDVLQVpeD0
https://www.youtube.com/watch?v=RX6UJVZjkTQ
https://www.youtube.com/watch?v=rZanAMesCeY
https://www.youtube.com/watch?v=jbN-jO11vKg
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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
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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
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0005_zpsoz6nhulb.jpg)
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That is a lot of parts Gail, but looking good. Nice that you have the CNC to assist with the handle cranking :)
Bill
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Looking great so far, watching along closely! :popcorn:
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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
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0006a_zpsrx0loudf.jpg)
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Very slick!
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With age and experience come wisdom! :old:
Great stuff Gail! I'm watching both of you crawlers closely....
Pete
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With age and experience come wisdom! :old:
Great stuff Gail! I'm watching both of you crawlers closely....
Pete
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Thanks for the comments Chris and Pete.
Pete, I will accept "Crawler" comment as long as it does not become "Creepy Crawler". Actually crawler is quite descriptive of operations in my shop. Because of the vision problems, if I drop a part I most often get down on the floor in baby crawl position with a flashlight to look for it. If that does not yield results I sweep the area and then look through the dustpan. This is also how the shop dog earns his keep. He generally keeps a close eye on me and when I drop something he goes over to sniff it to see if it is edible. That tells me where to look as I can see him. To give him incentive I will regularly "drop" a peanut or other morsel on the floor. And all of this gives me incentive to keep the floor swept up as chips and kneecaps do not get along wery well.
New set up to drill the hinge pin holes. This operation will finish the track plates except that I later put a bevel of the groove for the sprocket clearance. I dont think it is really necessary as the sprocket teeth will have a bevel on lthe ends of the teeth, but a little extra insurance that the sprocket will engage the track will not hurt.
The drilling operation is a 3 step process. Four if you count the deburring ooperation that follows.
The parts were set up in the vice withl a single parallel held against the moving jaw with a spring. This left a space under the holes with clearance for the drill/reamer to run into. To teh right is a stop plate that is ground and perpendicular to the vice bed, The parts are put in the vice and pushed up against the stop with a pusher that is narower than the part and machined ned square on the end and rests on teh parallel. This is to make sure the art is vertical.
All the parts were center drilled.
The next operation was done with an 1/8 dreamer. As dreamers are not a common tool in most home shops I will explain a little bit. A dreamen is a combined drill and reamer. The tip is a drill bit with a length of about 3 hole diameters long. and a few thou smaller in diameter than the finished hole size. This transitions into a reamer that then finishes the hole to diameter. You can see the tip of the dreamer in the photo.
The third operation was to open up the holes on the right side of the photo with a 0.127 reamer so there is a free hinging action.
After alol of this the parts were set up as in the previous post and the tabs were all chased with the 1/8 inch end mill at high speed to remove all the burrs left by lthe drilling and reaming operations. This is quicker than hand deburring for me.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0006b_zpsubdmh6su.jpg)
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I had not heard of the 'dreamer' tool before, clever setup.
Were there supposed to be pictures in the last post? Did not see any...
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Chris, Sorry but teh computer had a glitch while I was posting and posted before I was finished. It has been edited and should be right now.
Gail in NM
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Ant he pile of finished tread plates.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0006c_zpsukn1gxcc.jpg)
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Wow - now THATS a pile-o-parts!
:popcorn:
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Thanks Chris. You and I both know about piles of parts. By the time you finish the chains on your suburb Lombard Hauler you will make my piles look small.
Here is a test fitting of the track plates. Outside view on top and inside view on the bottom.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0007_zpsitjx4zyy.jpg)
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With the trqck plates complete, rollers are necessary to be able to assemble the tracks. These area simple drill and cut off operation. The rollers are 5/16 (0.312) diameter lx 3/16 (o.187) ling with an easy clearance hole for the 1/8 diameter hinge pin. I used a 3.2mm (0.126 inch) drill for the clearance hole. The were set up on the CNC lathe and took about 2 hours to run including the setup and programing time. I deburred the hole manually on the manual lathe running a small counter sinking tool in the lathe and holding the part in fingers. I was about able to keep up with the lathe so the parts were ready about 15 minutes after the CNC lathe wias finished.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0008_zpsrdexzgbc.jpg)
[IMG]
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Hands and knees, flashlight, yep sounds like my shop sometimes... but my dog hasn't learned the chip sniffing thing and probably won't 'cause I never have food in the shop... I keep telling meself to figger out how to enclose the bottoms of everything so bits won't get under.. you'd have to see it..
Nice track parts, Gail!! I'm having a blast watchin' you and Chris....
Pete
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Hands and knees, flashlight, yep sounds like my shop sometimes... but my dog hasn't learned the chip sniffing thing and probably won't 'cause I never have food in the shop... I keep telling meself to figger out how to enclose the bottoms of everything so bits won't get under.. you'd have to see it..
Nice track parts, Gail!! I'm having a blast watchin' you and Chris....
Pete
Well come on in, the swarf is warm! We got a couple of tractors going, time for you to build a tracked crane!
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Chris is right, Pete. Don't let us lhave all the fun, or insanity depending on how things are going. Besides cranes there are also tracked shovels.
Here are two photos of my ditcher, which although is not a tracked vehicle did run on tracks. It is the same as a tracked version except the tracks are replaced with a self propelled railroad flatcar. And there were a lot more tracked versions built than ditchers so there is a lot information on them available. This really applies to this build as I spent several months trying to get sow speed - high torque clutches and brakes to work on it. It ran one one steam engine that ran all the time. All the hoisting drulms, slew movement and track movement were done with clutches and brakes. I tried disks, cones and a few other things and finally ended up with dog clutches and brakes for everything. A little jerky but not bad. Overall the ditcher took about 6 years to build.
The crawler tractor will have all dog clutches and brakes except for the friction clutch that engages the engine ot everything else. It will be a manual friction clutch to dis engage the engine for starting.I may disengage it with a servo for gear shifts also. Still working out the details on that.
So these photos do relate to this thread.
(http://i338.photobucket.com/albums/n404/NMSteam/Ditcher2-0001.jpg)
(http://i338.photobucket.com/albums/n404/NMSteam/Ditcherinside.jpg)
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That ditcher is spectacular!
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Hi Gail,
NOW that is just so dam cute! A build thread on that would have been fun to follow!
Cheers Kerrin
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I don't think even you guys would understand just how passionate I am about things on tracks...both types!! Add steam to that and I'm smeared all over it.
I grew up with Caterpiller; other than a time out for a trip to the Pacific on an 80' speed boat, my Dad was with CAT his entire life. I went everywhere with him as a kid and as an adult owned a few CATs. Steam is just so obvious..... There was a locomotive in the park near our house and I was all over that thing... anything mechanical.....
I'm struggling to keep the active projects to something I stand a chance of enjoying while I'm alive.
That is one beautiful shovel, Gail. :praise2: :NotWorthy: :ThumbsUp:
:cheers:
Pete
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I don't think even you guys would understand just how passionate I am about things on tracks...both types!! Add steam to that and I'm smeared all over it.
I grew up with Caterpiller; other than a time out for a trip to the Pacific on an 80' speed boat, my Dad was with CAT his entire life. I went everywhere with him as a kid and as an adult owned a few CATs. Steam is just so obvious..... There was a locomotive in the park near our house and I was all over that thing... anything mechanical.....
I'm struggling to keep the active projects to something I stand a chance of enjoying while I'm alive.
That is one beautiful shovel, Gail. :praise2: :NotWorthy: :ThumbsUp:
:cheers:
Pete
Sorry for the sideTrack on this thread, but Pete, do you know of sources for plans for early Cats?
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Thank you for the kind comments everyone.
I want to be clear that the ditcher was a joint project with my friend Jim. Jim and I have been working on projects with each other for 20 or so years. The ditcher was our most ambitious project. Jim is not a machinist but can bend sheet brass like no one else I have ever seen. He also has a very artistic eye to make things look right. He did the research on the ditcher and made all the rough sketches to a "it chould be abllult this long" scale. I made the CAD drawings to something that was workable and machined the parts. A lot of non functional detail parts were purchased as brass castings from Trackside Details. It was disassembled and reassembled many times to get things working right. The sorst part is that he lives a bit over 600 miles away. Since I can no longer drive we only see each other face to face a couple of times a year.
Jim wii be helping me assemble the Hornsby Crawler.
Pete, you probably know that the Hornsby Crawler was the grandfather company of CAT with the patents passed down through Holt and Best to eventually form CAT. Don't worry about if you can finish a project in your lifetime. Remember that it's the journey and not the destination that counts. I figure that this will be my last major project before being moved into the old folks home. Maybe I can take it with me and run it on the lawn there. And maybe I will be able to sneak in a few other smaller projects before then. Got to work fast.
Gail in NM
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Thanks Kerrin.
That build was started before there were any serious model enginering forums on the internet and I was just starting to useing digital cameras to document builds. So no build thread was ever done.
Chris,
Not many CAT drawings that I know of for early CATs. Coles has (or at least had) castings and drawings for the Holt engine. Several of them have been built by folurm members. George Brittnell has shown photos of his quite oftem and offered grelat ladvice and assistance to other builders.
Gail in NM
l
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George himself would be extra proud of the ditcher. Really superb. A video of it shoveling would be great. :cheers:
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Here is an early very poor video of the ditcher while we were testing the controls and learning how to run it. I lost most of the good videos during a commputer crash. Need to make a new one showing it all painted up in finlished form. I actually llike the lunpainted version better as the paint covers up the details in photographs.
Gail in NM
https://www.youtube.com/watch?v=WVnqHXbH7WQ
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Now back to our regularly scheduled program -- at least for a little while.
With all the track parts completed it's assembly time. After holding two plates and a roller in position and inserting the hinge pin it was very clear that I either needed one more hand or an assembly jig. Jig option won oout.
A piece of 4.5 mm acrylic sheet was cut on the laser engraver with pockets for the rollers.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0009_zpsztaphfpl.jpg)
A length of track is assembled. The hinge pins are a finger perss fit in the track plates. Later, after I am sure I don't need to do any modifications, they will be Loctited iin place. They are firm enough for testing now.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0010_zpsmvcwtisd.jpg)
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Really cranking out those tracks! Very nice.
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Hi Gail,
At this rate you will have it finished by Xmas !! :lolb:
For somebody who said it would be a slow build, I'd hate to think what you could do if you were in a hurry!!
Looking really good!
Cheers Kerrin
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Thanks Chris and Kerrin.
I am sure that you and most others realize that a lot of the track work was done before I started this thread. I was a bit nervous about the tracks as I had not done any before so I wanted to be sure that they were going to be OK before publishing. With the tracks debugged things are going to slow up a bunch.
I cut a couple of sprockets on the laser for testig. Mounted them on shafts and clamped the shafts in a pair of vices.
Here is an assembled track ready to start testing.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0011_zpsgoih9kul.jpg)
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and to finish out the track segment of the build here is short video of testing in progress.
One of the sprockets shafts was mounted in the lathe. The other, on the left was mounted in a live chuck that has it's shank in ball bearings. I normally use it to support long thin spring winding mandrels in the lathe tailstock. On the first test run the sprocket teeth were "picking" at the rollers when the track was slack. A quick change to the tooth shape on the sprocket's design and a couple of new test sprockets solved the problem. I had not designed in quite enough clearancee in the sprocket.
The video just shows the track running, but a lot of tests were done. First the tension in the the track asl/ adjusted from very loose to who would of thought it. Again with no problems. The sprockets were offset by 1/4 inch each way and tens/ion tested again. finally with teh tracks slightly loose pressure was elxerted on the side of the track with a roller to simulate a hard turn. With no problems noted the track design is considered complete. I will still wait to secure the hinge pins however as something may show up and I might want to add another plate or two.
Now I am going to take a few days off from this thread to play with my new Christmas present that I bought for myself. I got a new industrial vildeo camera to mount on the tool makers microscope. Adjustable cross hairs, zoom len and all that sort of stuff. I can no longer see the cross hairs on the optical microscope on it. Preliminary tests are all looking good so a permanent mount has been started.
Gail in NM
https://www.youtube.com/watch?v=3zSvA4f58gE
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Thanks Chris and Kerrin.
I am sure that you and most others realize that a lot of the track work was done before I started this thread. I was a bit nervous about the tracks as I had not done any before so I wanted to be sure that they were going to be OK before publishing. With the tracks debugged things are going to slow up a bunch.
I cut a couple of sprockets on the laser for testig. Mounted them on shafts and clamped the shafts in a pair of vices.
Here is an assembled track ready to start testing.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0011_zpsgoih9kul.jpg)
Actually I had not realized that the track work was started earlier, but it is still an impressive job! The video looks great too, running very smoothly.
:popcorn: :popcorn:
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I did not mean to mislead any one. I had about a 3 week lead on the thread with the first week spent doing CAD work. The track parts went fairly fast as I coould do other chores between part changes on the CNC. Once I have a drawing I can program quite quickly and I do my designs to fit what the CNCs will do quickly and well. But now I will have a lot of manual operations and that will be painfully slow.
Gail in NM
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Gail,
What a great project. I know I'll enjoy watching your progress work but seeing the final self propelled machine will be something else!
I can't wait for the next installment.
gbritnell
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I did not mean to mislead any one. I had about a 3 week lead on the thread with the first week spent doing CAD work. The track parts went fairly fast as I coould do other chores between part changes on the CNC. Once I have a drawing I can program quite quickly and I do my designs to fit what the CNCs will do quickly and well. But now I will have a lot of manual operations and that will be painfully slow.
Gail in NM
No problem at all! Timeframes don't matter, the project is great, and we appreciate your sharing the adventure with us!
:popcorn:
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Hi Gail, very interesting to follow that great project. Thanks for showing the details.
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Hi Gail,
No problem that you started ahead of posting! It's still a great project! Just happy as to follow along, there's always something to learn, & possibly use in a project, keep up the good work!
Oh don't forget the peanut supply for the hound!
Cheers Kerrin
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Very nice project Gail, I have been following along quietly. These tracks on both your and Chris' builds are quite interesting!!
Bill
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I have only recently been seeing some plastic fabrication with laser engravers. Seems quicker and easier than milling those sprockets, even in acrylic.
With all your CNC gadgety, I expect to see some 3D printed parts before too long. :ThumbsUp:
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Gail, your track looks great!
And I love your steam ditcher. That is an incredible project!
Kim
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Thanks for the kind comments everyone.
Kvom: I have had the laser engraver about 15 years. I bought it used from an engraving shop that was upgrading to a higher power one. It has an 18 x 24 working area and a 30 watt air cooled metal CO2 laser. Still working well. I use it a lot for simple fixtures and temporary parts for testing. The track assembly fixture and the sprockets are a good examples. About 5 minutes CAD time and 3 minutes cutting time for each. I can not cut metal but can cut wood and plastics up to about 1/4 inch thick. Great entertainment and ssure makes gaskets easy.
The microscop/camera project went well. Took me a little longer than expected. I still have to redo the sub-stage lighting as the camera is not as forgiving to uneven lighting as the eye is. That will come later. With the zoom lens I I have about 5 to 40 magnification to the small LCD display I have on it. The camera has outputs for VGA and USB as well as the composite video I am using so I can hook up most any monitor. Here is a photo of the screen of an experimental 22 toothe 96 DP gear that was made using an engraving cutter. Gear was made about 2 months ago. Magnification was about 12 as the gear is 1/4 inch OD. This not completely off topic as I will be using the microscope for checking the gears on the crawler when I get to them. And there are going to be a bunch of them,
I will be back posting on the Crawler tomorrow. Been doing drawings on it today.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Tooling/06do22t%20microscope%20test_zps74wint8c.jpg)
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Kvom: I forgot to mention that I do have an old 3D printer. I sometimes use it to see if a part has that "Gee that looks ugly" problem. I have made a number of parts for the Gauge 1 locomotives that I have built. Mostly things like CDI enclosures and other things that are concealed or need to be insulating. I really use the laser a lot more as I am not very good at 3D CAD work. Too old to spend a lot of time tor really learn to do it well.
Gail in NM
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Since a few are munching popcorn here is a preview of coming attractions -- and a few notes about them.
First off,, I like ball bearings. They make things run so mulch smoother than sleeve bearings when you have a bunch of moving parts. And this build will have a bunch. Each tractor will have 28 in the track systems and rear axle assemblies. I am using bearing with rubber seals in the track systems to keep dirt out and all the internal bearings will be metal shields. Each bogie will have two 1/4 x 38 flanged rubber seal bearings as will the front axle. The rear axle will have a 3/8 x 5/8 rubber seal outer bearing and the internal parts of each rear axle assembly will have three 1/4 x 3/8 flanged bearings with metal seals.
If I bought name brand bearings from regular suppliers I could not afford this project. But, many years ago I found a supplier of low cost good quality bearings. They have alwayis had what I wanted in stock and shipped the same day by first class mail if I ordered in the morning with realistic shipping charges. . And all the bearings I use are US$1.00 each. Highly recommended. They are:
http://www.avidrc.com/product/9/standard-bearings/
Here are the links to the data sheets on the two bearings that will used in the track system.
http://www.avidrc.com/product/1/bearings/62/38-x-58-x-532-Revolution-R1038-RSZ-bearings.html
http://www.avidrc.com/product/1/bearings/788/14-x-38-x-18-Flanged-Revolution-FR168-RSZ-bearings.html
Up next will be the rear axle assembly. Pleas excuse the typos of the spelling of axle. My fingers have not been cooperating very well. A photo of the explodes assembly appears below. The photo is uploaded as a high resolution JPG. The forum soft ware should reduce it to reasonable size for display, but depending on your browser you should be able to view the full size image by clicking on the header somewhere or maybe use the scroll bar.
EDIT: Just noticed that the drawing calls for a R1038ZZ bearing. That should be a R1038RSZ bering with a rubber shiield on one side as shown in the data sheet link.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/REAR%20AZEL%20EXPLODED%20ASSEMBLY_zps8xxfjuxf.jpg)
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Hi Gail
I have been quietly lurking in the background following your crawler tractor build with great interest. I don't usually don't make "wow/amazing/ awesome" posts. Now I may have something useful to contribute, as tracked vehicles have been a long term interest of mine. I have built and successfully run several 1/6 scale tank models, weighing 30 to 50 Kg. My particular interest being the transmission and steering systems.
But first I want to comment on how you have trained your dog to find those small items that get dropped on the floor.
(http://i901.photobucket.com/albums/ac218/v8vixen1/116.jpg?t=1482927681)
This is 'Molly' also known as 'Von Poop' standing guard on a model panzer chassis. I tried to train her to sniff out things that drop onto the workshop floor using peanuts and treats, like you did, but have not had much success. She prefers to react to a full dinner plate rather than titbits.
I have designed and built several different types of steering system, all remotely controlled by R/C servos. I have built dog clutch/brake steering, multi-plate clutch/brake steering and also a fully proportional Double Differential (DD) steering system. The DD steering is the most refined of the three systems and is my preferred system for more modern tanks. The dog clutch/brake system is most appropriate for your crawler being true to the original.
I have studied your last drawings and can see you are proposing to have drive pegs and a series of drilled holes for the pegs to drop in to. I found that with such an arrangement, the hole and the peg need to be stationary and in perfect alignment before they would engage. I made design changes to my steering systems to allow the peg to drop into a shallow slot before fully engaging into the hole. This gives a much larger target for the pin to aim for and will ensure the pegs engage easily even when moving slowly forward or backwards. I use a similar arrangement on the dog clutches which change the gear ratios in the transmission gearboxes. They have become known over here as "Mike's sychro-mesh slots"
(http://i901.photobucket.com/albums/ac218/v8vixen1/P1060483.jpg)
These are the dog clutch/brake steering components from my latest tracked vehicle project. I have fitted the dog pins (pegs) into the drive gear and the fixed bearing housing. The movable drive plate contains the slots and drive holes. This arrangement is the mirror image of your drawing, that does not matter, either will work the same way. My drive pins are 4mm long and the slot is only 1 mm deep, there are full depth drive holes on either end of the engagement slot. The servo moves the drive plate out of engagement with either the pins on the drive gear or the fixed bearing housing. Then the slots allow the servo to move the pins into partial engagement where it can rotate until the full depth holes and pegs are in correct alignment where they pop into full engagement The drive holes are at either end of the engagement slots and will work just as well in the forward and reverse direction. These engagement slots make it possible to apply the steering commands while the crawler is moving slowly in the forward or reverse direction.
(http://i901.photobucket.com/albums/ac218/v8vixen1/P1060535.jpg?t=1482931329)
The two output shafts are held in constant engagement with the two drive gears by the two light springs. The crawler with move in a straight line
(http://i901.photobucket.com/albums/ac218/v8vixen1/P1060532.jpg?t=1482931368)
This shows the drive plate engaged with the drive gear
(http://i901.photobucket.com/albums/ac218/v8vixen1/P1060533.jpg?t=1482931368)
Here, the drive gear has been disengaged, bringing the plate into contact with the fixed pins on the bearing housing thus locking the track and causing the crawler to skid turn sharply to the right
(http://i901.photobucket.com/albums/ac218/v8vixen1/P1060530.jpg?t=1482931368)
This is the opposite side. The plate is engaged with the gearwheel and both tracks will turn
(http://i901.photobucket.com/albums/ac218/v8vixen1/P1060531.jpg?t=1482931368)
Here the plate is locked to the pins on the bearing housing. One tack with still turn and the other is locked, the crawler will skid turn hard left.
I also found it necessary to fit a spring loaded arm on the servo. This is necessary to prevent the servo stalling and drawing excess current if the pegs are fully engaged. I have used 'servo savers' from model buggy race cars or fitted springs to the operating levers. The spring also helps the pegs snap into the holes when they eventually line up.
I hope my experiences will be of some use to you. It would be a simple matter to mill some 'Synchro mesh slots' between adjacent holes in your design. They will make your clutch/ brake steering so much easier to opperate
Mike
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Mike,
Thank you for your words of wisdom gained from experience. A very nice detailed post. This is my first tracked vehicle so any advice is welcome. Your tank chassis looks great. Much more detailed than what I am building.
First things first. The shop dog is Coot. He is the young Coot and I am the Old Coot. In case Old Coot is not a common expression on your side of the pond it generally refers to a Crazy Old Man in my world. I use an assortment of small treats of different sizes and colors to train him so he has to get close to identify them. The favorite shop snack for both him and me is roasted peanuts in the shell. I keep a big bucked of them in the shop and they are a favorite for shop visitors and grand kids also. He can hear a peanut crack from 100 feet away and shows up instantly for his. I taught him to shuck his own so now he gets one in the shell, takes it to his "place" which is a piece of carpet in and out of the way place and shucks his own. No lluck teaching him to clean up the shells however, but at least they are in one place.
On the ditcher clutch/brake testing I found that the dog clutches worked well below 100 RPM if spring loaded and the ratio of the holes to pegs diameter was at least in the 5:4 ratio. My sp[rocket speed is targeted at 70 RPM in high gear and 24 RPM in low gear so I think I will be OK with what I have for the steering system.
But I think you h ave solved the problem I was faced with on the transmission which will be running at a mch higher speet. I thnk th "Mike's sychro-mesh slots" will make the gears shift work much better. Since that part of the design is still not drawn I plan to give it a try.
Thanks for your input. I have read some of your other posts over time so I know you know what you are talking about.
Gail in NM
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After a slow start this morning the project is back on track. (pun intended of course).
I had a dimensional bust in my CAD drawing for the front axle. But that part is still at least a week away so I can still proceed with the rear axle parts.
Going to start with the Outer bearing holder and brake detent. It starts out life as a 1-1/8 diameter piece of 12L14 steel bar. The end is faced and turned down to 0.75 diameter for 0.188 to fit through the hole that wil eventually be in the frame. It is bored 0.437 for the finished length for a free easy fit on the 0.375 axl and to clear the inner race of the bearing. This bore in then opened up to 0.625 for the outter bearing. The depth of this bore was sized so the outer bearing stands proude by 0.015. I could be flush but it's just the way I like to do things.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0012_zps0kn94913.jpg)
And the parted off with a little bit left for cleanup.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0013_zpsdwxcvyx4.jpg)
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after changine collets, the part wasreversed in the lathe and faced off to length.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0014_zpsicuvpspr.jpg)
The four mounting holes were drilled for a 2-56 tap size. The holes were drilled to a depth where the drill bit just dimpled the bottom of the part and did not hit the collet.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0015_zpsowcwvxbg.jpg)
Then the 12 flat bottomed detente holes were put in with a 5/32 center cutting 4 flute end mill.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0016_zpse7f9gkeg.jpg)
The mounting holes were finish drilled to make them through holes with a hand drill, then lightly counter sunk and tapped 2-56. A quick rub of the detente face on some 400 grit abrasive paper to remove any burrs finished the parts.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0017_zpsxbl5rkr3.jpg)
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Hi Gail,
More great progress!
On the hound training front, you need to find honey roasted peanuts! Had our hound rolling over sitting up & just about anything else the kids could come up with in no time flat!
Mike ,
Glad you chimed in on the clutches, going to have to read it again to get my head around it, but it sounds like you have invested some time on getting them sorted!
Cheers Kerrin
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Gail,
Very interesting project. Nice job on the track. Lots of pieces!
Chuck
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Much of the day has been spent cleaning up the CAD files. I discovered the flange thickness on the 1/4 x 3/8 flanged bearings master file was wrong. This of course shifted the positions of lots of the bits on the rear axle assembly and changed quite a few other things on parts drawn but not built. I changed the 1/4-32 nut from 3/8 across the flats to 5/16 AF and added a shoulder to it. That got rid of the thin spacer on the rear axle and made it suitable to use on the front axle I have been drawing on. None of this affects any parts that have already been made. All this sounds simple enough but it does take time to justify everything and update the drawings.
So to feel like I accomplished something today I had to make a fe chips. Next up on the list was the Clutch and Brake Dog for the rear axle. It slides on the axle and is keyed to the axle so they are locked to each other for rotation. Refering to the assembly drawing, whet it is slid to the right the dogs engage the detente plate just mad locking the axle to the frame for a skid turn. When slid to the left it will engage the drive gear to drive the track. In the middle position the track is free so a gradual turn in that direction will be made. The groove in the middle of the dog part is to engage a yoke, not yet drawn, that will do te shifting by a radio control servo through spring loaded linkage.
I started with a slightly oversize bar of Bronze (SAE660) nnd cleaned it up to 1 inch diameter. Bronze was chosen as it will slide on the steel axle and key smoothly. It was drilled and reamed 3/8 diameter to fit the axle. The 1/16 inch wide groove for the yoke was put in and the blank was parted off.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0018_zps6huamkrw.jpg)
After cleaning up the cut off side in the lathe to bring it to length the keywas was cut with a 3/32 broach.
Ready to broach showing the broach and bushing.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0019_zpsbxn3f7yr.jpg)
To illustrate how the broach and bushing are set up.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0020_zpsm7xyew0g.jpg)
The broach in use on the press. It takes about 300 pounds of pressure. There is clearance below the part so the broach can be pushed all the way through and it drops out the bottom.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0021_zpshhj4rvsv.jpg)
The blanks with the keyway broached.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0022_zpszk8b3czy.jpg)
Gail in NM
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Watching along Gail!....Looking great!
Dave
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Gail, thanks for the bearing supplieir link. I have bookmarked it for future use. It's good to know you have had a good experience with them too!
Bill
Edit: Gail, I have also started a sticky topic in the Outside links and suggested reading category for bearing suppliers and have added your link there as well.
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I'm also here! Very interesting project. Love the video of the track test.
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Thanks for the kind comments and for following along everyone.
Side note toe the pevious post. The key way could have been planed in using the lathe lathe and I have done so many times. But the broach takes 30 seconds to put the keyway in and planing would have taken 20 or 30 minutes.
With all the lathe work done on the Dog plate it was moved over to the CNC mill and mounted in a vertical collet holder. A Stop had been positioned in the collet so I could fliip the part over to do the second side with out loss of my vertical position reference. Also to keep me from losing the part in the collet when dropped it. I milled out the 4 pins usling a 3/16 4 flute end mill. If I were making this part on a manual machine I would have made the disc thinner and drilled holes and inserted pins.
The dogs were milled and then given a quick rub on some abrasive paper tor remove burrs. The part flipped and the dogs on the other side milled. The erotational position is of no matter.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0023_zpsqyugykac.jpg)
And the finished part. The right one still has the burrs on the near side.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0024_zpsbatxekwx.jpg)
Gail in NM
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Wishing everyone a Happy New Year.
To start the year off right I had to make at least one part, even if it is a simple one.
Here is the Sprocket Washer. While the collet fixture was on the mill I drilled the 6 mounting holes a clearance for 3-56 screws. Drilled deep enough that I could part off 4 washers 1/16 thick. Stock was a short piece of 3/4 diameter 12L14 steel.
Over to the lathe and I bored out the center to0.385 for an easy fit on the 3/8 diameter axle. Parted off to 1/16 thick.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0025_zpslvcxgtbd.jpg)
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What is the purpose of the sprocekt washer? It has more holes than the clutch parts, so not part of that? Do you have a diagram of what the assembly will look like? Great stuff so far, keep it coming!
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Chris,
Thanks for looking in and keeping me honest.
Go back to post #64 and there is a drawing of the rear axle assembly. There have been a few changes in the drawing that I mentioned later. I will post a new drawing when I have done a few more parts to make sure that it agrees with what I have done.
The sprocket washer is in the lower right of this drawing and and clamps the sprocket to the axle which is to the left. The washer really is not needed but the hub would not look right with out it. It is also shown in place on the sprocket part of the drawing in the upper right part of the drawing.
Next up will be the axle.
Gail in NM
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Chris,
Thanks for looking in and keeping me honest.
Go back to post #64 and there is a drawing of the rear axle assembly. There have been a few changes in the drawing that I mentioned later. I will post a new drawing when I have done a few more parts to make sure that it agrees with what I have done.
The sprocket washer is in the lower right of this drawing and and clamps the sprocket to the axle which is to the left. The washer really is not needed but the hub would not look right with out it. It is also shown in place on the sprocket part of the drawing in the upper right part of the drawing.
Next up will be the axle.
Gail in NM
Gotcha - thanks! I had missed that drawing.
:popcorn:
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On to the rear axle.
The rear axle starts life as 3/4 inch diameter 12L14 steel bar.It has 4 diameters plus a threaded section cut on it in the first chucking.
Ath the end is a 1/4 diameter section with the end of it threaded 1/4-32. The 1/4-32 thread was selected as I wanted a fine thread so I could have a thin nut and a 1/4-32 tap and die were on hand. That thread is used on many small spark plugs used in model IC engines. The 1/4 inch diameter section will have three 1/4 ID ball bearings and a spacer mounted on it. Two of the ball bearings will be part of the drive gear/drive detente and the third will be the inner axle support bearing. The spacer length will be used to adjust the axial play of the axle at final assembly time so it's length will be adjusted then.
Next is a 0.015 wide section that is turned to0.312 diameter. It's purpose is to prevent fouling the outer diameter of the bearing next to it that is on the 1/4 shaft by the 3/8 diameter next section. A washer could have been used for the same purpose but then I would have to make the washer and remember to put it in at assembly time.
Third section is 3/8 diameter. It fits the inner race of the outer axle bearing and is the sliding surface for the brake/clutch dog. It was turned 1 or 2 tenths (0,.0001-0.0002) oversize and then finished to size to fit the bearing with a 1200 grit dilaamont finishing stick from EZ-Lap. I knew from previous use that the 3/8 inch reamer I used for the dog plate cut about 0.0001 oversize in bronze so this should give a niche sliding fit on the axle. But I tested it anyway and it slid very smoothly.
The 1/2 inch section is not critical. It goes between the outer bearing and the sprocket mounting face and has nothing mounted on it.
Then it was parted off leaving enough stock to make the sprocket mount.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0026_zpsjzgxraet.jpg)
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0027_zpsadvxfjey.jpg)
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Getting in on the ride Gail. You and Chris are stream lining her bud. Two great builds going on at one time. Awesome!..... :ThumbsUp:
:drinking-41:
Don
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Your ticket has been punched. I hope you enjoy the rides. Chris is building a showpiece and I am just building a sort of looks like it model. The commonality of the two threads is they both have tracks, lots of parts and Chris and I are both having fun.
With one end of the axle finished it was reversed in the lathe and the end turned down to 3/8 inch diameter for the sprocket mount. They looked so ragged in the lathe photo I had to take an after photo after cleaning them up.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0028_zps7ofktgzz.jpg)
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0029_zpsyvqjrs3u.jpg)
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A simple job to start the morning off right.
The rear axles w ere moved to the vertical collet holder on the mill and the six drive/clamping holes that mount the sprocket were drilled 2-56 tap size. The holes were lightly countersunk and then hand tapped 2-56.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0030_zpsgscpqasp.jpg)
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The last operation on the rear axle is to cut the slot for the key that mates with the clutch/brake dog.
The slot was cut with a 3/32 center cutting 4 flute end mill with the axle resting on a parallel in the mill vice. I went back and forth 2 times to make sure I had clean surfaces and remove any lumps caused by cutter deflection.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0031_zpsbalxtxai.jpg)
Here are the completed rear axles.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0032_zps71wg1zkj.jpg)
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Great progress, still watching along...
:popcorn:
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Thanks Chris.
Now what's a key slot with out a key to go in it.
The key is made of 12L14 steel and is 3/32 inch square with rounded ends to match the key slot in the rear axle. I made the length 0,.007 inch shorter than the key slot so the key could be pivoted into place. When the key and slot are the same length the key is a pain to install.
From previous use I knew that end mill that I cut the slot with cut a couple of tenths under size and the broach was spot on. So, if the key was fitted to the slot in the axle it should be a nice sliding fit in the bronze dogs. So I cut the keys to be spot on and knew that I would have to draw file them a little bit to make them fit the axle properly.
A quick bit of CAD work showed that I could get 7 on the end of a stub of 1-1/8 12:14 bar that I had. The end was faced off on the lathe and then the key outline cut 0.110 deep on the mill so I would have some to mill off to bring them to the 3/32 thickness.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0033_zpsqtqwuvcl.jpg)
Then back to the lathe and the disc of keys was parted off leaving a thin web to hold the keys in place.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0034_zpsgdezwxxj.jpg)
The disc got a few rubs on some abrasive paper to remove the milling burrs.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0035_zpspcdg7yeo.jpg)
Using a set of parallel jaw pliers to grip an individual key it was flexed back and forth a few times to break it away from the disc. Sorry for the oout of focus photo.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd
%20Crawler%20Tractor/Horn-0036_zpsjgai5agk.jpg)
Gail in NM
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Then milled to the 3/32 thickness.
I took about 3 draw file strokes on each side to bring the size to fit the slot. Then all sides were polished a few strokes on 600 grit abrasive paper. A test showed that the key was a smooth sliding fit in the cluthc/brake dog keyway.
No matter what I tied I could not get these last two photos to load from PhotoBucket so they are attached.
Gail in NM
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Not much exciting progress. I discovered why I had trouble posting the final two photos is the last post. I had unintentionally turned off the fixed aspect ratio in my photo editing program when editing. Photobucket was happy enough with the resulting JPG code but the forum software was not.
I received the stock I had ordered for the bogie wheels today and a servo saver that I think will work to operate the cam that operates the yokes for the cluth/brake dogs. I have t do some torque measurements to make sure. If OK then need to make a CAD model and fit the whole thing into the bracket. And that determines if I can use the 64 tooth drive gear as drawn or I have to drop down to a 60 tooth. In other words lots of design in CAD for the next few days.
I did slip some of the completed parts on the rear axle to check for fit and everything is fine. And to take a break from CAD to ckear the fog I made up 20 washers that back up the front axle mount and bogie axle mounts inside the chassis. 1/2 diameter x 1/16 thick steel with a .166 hole in the center. I won't need them for a while but it satisfies my chip making addiction for the day.
Here are photos of the rear axle test assembly.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0039_zpscsdc1uu4.jpg)
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0040_zpsg0lqcxph.jpg)
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I have never seen anyone make keys that way!! I knew there was a reason I watch this space.....
Pete
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Pete: I lvuse tlhat technique for quite a few small thin parts. For small complex ferrous parts I part them off with only a few thou extra thickness and then dust the extra off with my improvised surface grinder holding the parts on a magnetic chuck. For non-ferrous parts that are complex I some times have to make soft jaws for the mill vice. For anything hat has some parallel clamping surfaces, like the keys, I jsut finish them in the mill vice.
I took a break from the CAD work for another small job. I made the 1/4-32 nuts that will be used on the inside part of the rear axle, and on the outisdes of the front axle and all the bogie axles. I will need 24 so I made some extras to feed the swarf bunnies and in case I add some elsewhere in the design.
Started with 5/16 AF brass hex stock in the CNC lathe. Faces off and beveled the corners so they will not foul the outer race of the bearins they will be holding and then parted off to 3/32 thick.
Made a stop to fit the hex collet and put 0.265 hole in the end of it to provide a runout space for the 1/4-32 tap. Then did the tapping operation in the manual lathe. Because my finger don't work very well with small parts anymore I slipped the blank on the smooth end of a drill bit and inserted it into the coller. Then I could slide the nut blank into the collet and close the collet.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0041_zpsdmalqekn.jpg)
Nuts were tapped using a spring loaded tap driver tin the tail stock to keep the tapo perpendicular to the nut.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0042_zpskh35kv2g.jpg)
After a quick rub on 400 grit abrasive paper on both sides of the nut tor remove any burrs left by the tap I had a small pile.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0043_zpsxuvco5jt.jpg)
And now back to the CAD work.
Gail in NM
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Not a lot of parts progress. Mostly CAD work and every thing is still fitting on paper.
I did take a little break from the CAD and make the front axles. Simple enough turning job out of 1/2 inch diameter steel. 1/4 inch diameter to take two 1/4 x 3/8 bearings that will be in the front sprocket and a bit threaded to take the retaining nut. A little relief so the axle will not foul the outer race of the bearing. Other end is tapped 8-32. The chassis will have a slot in it so the bolt can be slid fore and aft to tension the track.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0044_zpsvmgwx04w.jpg)
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So it has been a couple of weeks since I posted. Most of my tools are old and worn out, just like me. So a couple of MD visits for a tune up on my old body so I could spend a few days working on tools.First the air blast Loc-Line coolant line on the mill split. Patched it enough for operation and ordered new parts. Then the bar feed on the CNC lathe was giving me trouble. Poor desilgn. I know as I designed it, So up dated the design and started to run some washers for the crawler. Worked perfectly. Ran two washers and an non related air line on the tool changer split. Air line had a mixture of imperial fittings, adapters, metric air line and back to imperial fittings. No chance of getting air line local so changed everything over to imperial fittting and imperial air line that I had. But missing one fitting. Hardware store is 3 milesa away but I ride a mobility scooter and it is cold and raining. Next day it is still cold but rain has stopped so I now have the fitting. So with a little bit of colorful language I now have everything working.
First up were some washers on the CNC lathe. On the left side in the photo are just some thick /backup washers to go inside the chassis to mount the front axle and the bogie axles. The front axle is mounted in a slot so I can adjust the track tension and the bogie axles are fixed. I know the original had some suspension system on the bogies but mine are fixed.
The washers on the right have a relief on one side so they can cover the bearings with out fouling the outer race. They are also thick to space the suspension links (dummy) from the lower bogies to the upper bogie.
I only will need about 20 of each washer but with the CNC lathe I ran 35 of each so I would have plenty to feed the swarf bunnies.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0046_zpsxzebw2s1.jpg)
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Happy to see you back in the saddle Gail. Thanks for the update.
Bill
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Glad to be back Bill.
To satisfy my "got to make chips" urge while repairing the CNCs I turned up the bogie axles on the manual lathe. They start as 1/2 inch 12L14 steel. Turned down to 3/8 for the inner bearing, a section of 5/16 to the outer bearing and further reduced to 1/4 inch to match the inner race of the outer bearing. The 1/4 inch is then threaded 1/4-32 for the retaining nut with enough length to take the spacer/washer just pictured and the dummy suspension link. The other end is drilled and tapped 8-32 for the mounting bolt.
Photo shows the raw axle and one with the two bearings and nut in place along with/ the mounting bolt and washer in place. The spacer/washer for the 1/4 inch end had not been made yet when photo was taken. 16 of these were made.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0048_zps5cmlz8i1.jpg)
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Those are looking great!
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Gail........... I'm really enjoying your build thread and the work you're doing. Even more important........ I really like your "keepin in keepin on" attitude! We can all learn a lot from that! :praise2:
Jim
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Thanks Chris and Jim.
With the bogie axles complete it is time to move on to the bogie wheels. They should be a bit more interesting than turning shafts and making washers.
Started off with 1-3/4 inch diameter 6061 extruded aluminum bar stock. Polished theOD a bit with some 320 grit abrasive paper to take out any stray bumps on it and that will be the finished outside except of the groove to clear the rollers.
Sawed of pieces thick enough to be able so surface both sides an bring to a finished part length of 15/16 (0.937). I kept the length dimension quite close as the bearing pockets will be referenced to the ends.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0049_zpsz7bby3z6.jpg)
A 21/64 (0.328) hole was drilled through. This hole provided clearance for the 5/16 diameter section of the axle to pass through and forms the seat for the outer race of the 1/4 X 3/8 ball bearing on the outside end of the axle.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0050_zps0g4pe9xq.jpg)
Gail in NM
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One end was opened out to 3/8 diameter X 1/8 deep to take the outer ball bearing.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0051_zpsrc7shzxr.jpg)
The other end was first bored out to 1/2 inch diameter to provide clearance for the inner race of the inside ball bearing and provide some extra space for the 3/8 shaft section of the axle. I had made the 3/8 axle section longer than the thickness of the ball bearing so I could lightly chamfer the end to make installing the bearing easier. Then the end was bored out to 5/8 diameter X 5/32 deep for the ball bearing outer race.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0052_zpsuvnahutf.jpg)
Gail in NM
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The chuck on the lathe was then switched out for a 1-3/4 diameter 5C collet. This collet is one that I had made up from a 2 inch clutch collet blank and has a 3/16 grip. I already had this collet as 1-3/4 inch is a size I often use for flywheels on small engines.
The clearance groove for the track rollers was then cut in with a 3/32 parting tool using three cuts to get the correct width. The groove is 1/332 inch wider than the rollers. I cut the groove in after I had done the bearing pockets as it is not centered and it is easier to see the difference in diameters of the bearing pockets than the amount of off center the groove is. Gets rid of one more place to screw up measuring from the wrong end.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0053_zpsyq2fglsy.jpg)
A 0.015 X 0.015 bevel was put on each edge of the groove to help guide the roller into the groove in case the track is deflected.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0054_zpsiqplpv7e.jpg)
Gail in NM
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Looking good! Very interesting project
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Thanks SamC.
Moving the collet over to the CNC mill the spokes were cut. The inside spoke pattern is different from the outside because of the different bearing sizes. The outside spokes are also recessed slightly (0.05 inch) for appearance. The spokes are cut 5/16 deep on each side leaving a thick web between them so I did not have to worry about registration between the two sides.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0057_zpsdea53ide.jpg)
A pair of finished bogie wheels showing the inside of one and the outside of the other.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/Horn-0058_zps6s5cn8ai.jpg)
And the obligatory group photo showing the outside in the group on the left and the inside in the group on the right.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0060_zpskjwojsyw.jpg)
Gail in NM
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Those look fantastic! Definitely a time when CNC works out best.
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T^hanks Chris.
With my failing eyesight CNC is the only thaing that makes it possible for me to machine many parts anymore. With out it I would have had to quit building toys several years ago.
With all the parts done for the lower bogies I assembled them. I wanted 0.001 to 0.004 end play on the bearings. When I drew the parts I allowed 0.003 so if all the parts were right I would be in the middle of this range. Now there are 4 machined dimensions that contribute to this end play so even if they were held to 0.001 tolerance if they were all in one direction they would put me over the edge of my overall tolerance. Of course some would cancel out with a plus erron on one and a minus error on another. Still I know that it "ain't going to happen". So when designing I considered that I could put a shim between the outer race of the inner bearing and the bogie wheel if I had too much end play or between the inner race of the outer bearing and the axle seat if I needed more end play.
So the kower bogies were assembled and and the end play checked with a dial indicator with the axle held in the lathe and pushing back and forth on the bogie wheel.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0061_zpsjsdhedjq.jpg)
Wonder of wonders 10 out the 12 were withing tolerance. The two that were out had too much end play by a few thou. A 0.004 shim between the inner bearing and the bogie wheel brought them right into the middle of the range. The shims wore made out of 0.004 thick poly-carbonate sheet cut on the laser cutter.
Now the lower bogies are all matched assemblies and will remain that way through the rest of the build. Only the nuts will be removed to assemble them to the dummy suspension parts when the time comes which will be much later.
Gail in NM
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The upper bogie wheels were made in same manner as the just completed lower bogie wheels. The OD of the upper bogie wheels is 7/8 inch while the lower bogie wheels was 1-3/4. Much smaller. Since I did not have any 7/8 stock I turned down about 4 inches of one inch diameter. I drilled the center clearance hole all the way through going 1/2 way from each end and parted the blanks off a little over the required length to allow a clean up cut on each end as I brought them to length. Then the rest of the lathe work was the same as the lower bogie wheels. On the mill I only cut spokes on the outside as there was only a 1/4 inch difference between the inner bearing OD and the wheel OD. The same axle was used as was used on the lower bogies. The most important difference was that I only needed 4 upper bogies instead of the 12 for the lower bogiess.
Here is a photo of them all mounted and tested ready to install.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0062_zpsalyrqzpo.jpg)
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Most of my tools are old and worn out, just like me.
It seems you've been saying that for some time now. I'm thinking you've hit upon some kind of preservative.
Give it up. You're not the only one who could use it. What's the secret?
Fantastic quality work BTW ;D
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Damn Gail or a man with poor eyesight you do some great work. Keep at it man your and inspiration..... :praise2:
Don
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Hi Gail. I have been following your build from the start. Keep up the good work.
Vince
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Zee, Don & Vince: Thanks for the kind comments. It is always more fun when your activities are shared.
It seems you've been saying that for some time now. I'm thinking you've hit upon some kind of preservative.
Give it up. You're not the only one who could use it. What's the secret?
Zee: A good dose of cutting fluid everyday helps a lot. But is has got to be the good stuff. If it does not have "....contains a chemical known to the State of California to cause......" some where in the label it probably does not do you any good. Or work well for making chips either. Your new shop is looking good. You need to get it finisheed up so you can take your dose of "medicine". An occasional martini may have to suffice until then.
Next up will be the sprocket s.
Gail in NM
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Ok Coot, here's a treat, don't bark now; I'm sneaking in the back door. Gail, sorry for the absence, but, I have been following along when I can. Wonderful build. I was thinking about all the multiple parts and with my "1 out of 3 attempts " method of machining, I'd use up several feet of stock. Interesting last few days here, I'll catch-up again when I can. Keep your oil can full ;)
Cletus
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Cletus, Glad to have you following along and glad to hear (from another thread) that your parents are doing well. You should have your helper back in the shop soon, in at least a supervisory role. The young Coot won't bark at you. He's too busy shucking peanuts over in his corner. He doesn't get any freebies -- has to shuck his own. The Old Coot might bark a bit however if he has just screwed up a part.
But, I did not screw up much of anything in the last frew days. Here are the completed sprockets. Two different flavors, 4 front sprockets and 4 rear sprocked. They are identical except the rear sprockets have 6 holes for 2-56 bolts to secure them to the hubs so they can take the driving torque.
They start out as 3/16 plate. The 3/8 diameter hub hole is put in and for the rear sprockets the 6 drive holes. Then the spoke cutouts were milled in with a 5/32 end mill and the sprocket contoured. 1/54 X 1/8 inch Tabs were left on every third tooth, 4 total, to hold the part in place while contouring.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0064_zpsydprgtxs.jpg)
Each sprocket was clipped out of the plate with a small pair of diagonal wire cutters. I did not have to worry about the remaining bits of the tabs as they are removed by the45 degree bevel on the tooth ends. The bevel was put one by mounting the sprocket on a stub arbor and attacking it with a vee shaped cutter. First one side and then the other. Hard to see the cutting tool in the photo as it blends in with the background, but it's there. The bevels are to keep the teeth from trying to "pick up" the edges of the slots on the tracks when there is side pressure on the tracks. The slots in the tracks are also beveled to guite them in.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0065_zpsicibewbx.jpg)
he 8 sprockets ready to go.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0066_zpsy9nn2nrr.jpg)
Gail in NM
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Those sprockets came out great!
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Those sprockets came out great!
Indeed! :ThumbsUp:
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Yup, nice looking parts Gail.
I have been enjoying your project.
Dave
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Thanks Chris, Zee and Dave.
No new parts for now. I had a few decisions to make before I could go much further. First up was how to get power from the engine and transmissions up front toe the drive axles in the rear. I would guess that the original used a chain drive. Well, I don't have as much ambition as Chris and there is not much in the way of commercial ones in the size I would need. Besides it is all concealed inside the chassis s time for an alternative solution. I thought about a gear train as I am used to cutting gears, but finally decided that a timing belt would be the easiest and use the least room.
Then on to finding room for servos (3), radio, CDI and two battery packs and still leaving enough room for the two transmissions, one for high/low gear and one for forward/neutral and reverse. Still have to design the transmissions.
Now everything fits so the chassis size is finalized and the parts are mostly drawn. The JPG shows what I think will be the final configuration. The engine may move fore or aft a bit to suit the transmissions, but not by much. I my standard "Carl" in for a driver. Looks too big but I have smaller ones.
Probably two more days of drawwing before making any more parts.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/SideView%2020170202_zpswt0eczin.jpg)
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The CAD work is going slower than expected. It always does.So, I took a break from it to make a few chips. Some of the chassis parts are stable enough to make.
First up is the front lower spreader, what would be called a bolster in a locomotive terms. It odes not show in the drawing of the previous post as it is hidden behind the front sprocket, although you can see the bolt that secures it to the chassis side in the front sprocket opening at the 7 o'clock position. It connects the front plate to the skid plate with a 45 degree angle.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0067_zpsfcz9jtis.jpg)
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Hi Gail,
Great project. For the drive connection could you maybe use a shaft with a worm drive on the end? With that you could gear it down quite considerably with just one pair of gears.
gbritnell
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Hi George,
Thanks for looking in and the comments.
I am not a big fan of worm gears and I don't really need than much reduction from where I am at with the design. But you got me to thinking about a drive shaft going to the back again. I had thought about it early on, but discarded it for reasons that have now disappeared. If I used a worm gear I would have to have one set of bevel gears to get from the transverse mounted engine to the drive shaft anyway so a second set of bevel gears would not be a problem.
Over all I need about 75: reduction in high gear and 150:1 for low gear between the engine and the rear axle.
This is my current thought on the drive train. First off getting from the engine to below the deck is fairly well fixed as I will be using the same design that I used on the Baldwin Mechanical locomotives that I built 2 years ago. It incorporated the tangential clutch coupled to the engine through some coupling gears for a rocking motion to a coupling gear that is under the deck. At this point I have 3.86 reduction. This will be followed by the forward/reverse gears with dog clutch shifting and the same servo will also disengage the clutch on the engine as it shifts from forward to reverse. Plan is to keep this at 1:1 input to output.
A pair of spur gears will couple to the high low gear box that will shift from 1:1 to 2:1. Gears are drawn at 1.25:1 and are on the ends of shafts so they can be easily changed to tweak the speeds if I need to change them after "field trials".
Then the drive shaft with 2:1 bevel gears on each end for 4:1 additional reduction and finally a lay shaft that couples to the rear axles with 4:1 reduction. Total about 72:1/144:1. That is close enough to my 75:1/150:1 that I think I need. And the spur gears coupling the gear boxes will give me a place to adjust if necessary. Besides I like bevel gears a lot more than I like timing belts. I have made about 75 sets of bevel gears that I have used on models so I can knock them out fairly quickly.
I realize that this probably makes no sense written out as text so I will clean up a drawing this evening and post it in the morning if I can.
Gail in NM
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Here is a rough CAD sketch of the gear train that may help make some sense of the non sense that I tried to explain in the previous post.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0068_zpsdrkkdkdb.jpg)
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Boy I'm glad you said this:I realize that this probably makes no sense written out as text so I will clean up a drawing this evening and post it in the morning if I can. I'll be working on it until then :thinking:
Cletus
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Gail, I went back through this thread but didn't find the answer; how will you steer this thing? The two sides seem to be locked together at the double 16 tooth axle.
Pete
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Pete,
I explained it some back on post #64 but it will be more clear if I elaborate here now that more parts have been made and more drawings posted.
First off in the latest drawing I show the 64 tooth gear attached to the rear axle. That should have been labeled as "Rear Axle ASSEMBLY". In post 64 I had in exploded view of the rear axle but to make things easier I am posting it again now.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/REAR%20AZEL%20EXPLODED%20ASSEMBLY_zps8xxfjuxf.jpg)
The 64 tooth gear and associated clutch plate have not yet been made so there are no photos of it. At the time I was not sure that I could get every thing else around the gear and that I might have to drop down to a 60 tooth gear. Now I know that the 64 tooth gear will fit.
The As you noted the two 64 tooth gears are coupled to each other with the 16 tooth gear pair that locked to each other. The 64 tooth gears are free wheeling in bearings on the axle and have a dog clutch face as a part of them. The dog is double sided and is keyed to the axle. When slide one way it engages the 64T gear through the clutch face to drive the axle. When in the middle the axle is free wheeling and drag will cause a gradual turn as the other axle will be under power, and when slid all the way away from the gear the other side of the dog engages the brake facing which is bolted to the frame and locks the track to the frame for a full skid turn. The left and right dogs are driven through yokes by a servo which allows both axles to be powered when it is in the center position and goes through the above routing for one axle or the other as it if moved away from center.
I used two 64T gears so I could put the inner axle bearings between them on a bracketIt seemed to be the easiest way to get the inner bearings mounted so the axles were independent.
I will probably get to the 64 tooth gears and clutch plate in ablut two beks when all the other gears are finalized. I want to cut all the gears at once as I need assistance to mount the indexing head on the mill as I no longer can do it by myself. It only weighs about 40 pounds -- but getting old sucks.
Hope this clears it up for you (and quite possibly others).
Gail in NM
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Got it! Thanks Gail.
Pete
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I'm still following along and enjoying the build :praise2: :praise2: :wine1:
I think that you said somewhere that you had made some O gauge locos with hit and miss engines. Are there any details available?
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Thanks for following along Roger. Not much of note accomplished on the crawler for the last few days. Some more CAD detailing and metal sawed and squared up for chassis parts. My band saw has has a few issues so I took 1/2 a day off to correct them. And since we have had n ice weather I worked outside to prep the flower beds for spring.
Roger, your memory is fairly good, but the locomotives were Gauge 1 instead of Gauge 0. For those not familiar with the gauges, Gauge 1 is 1-3/4 inches (45mm) bet/ween the rails and Gauge 0 is 1-1/4 inches between the rails. I have built ten locomotives using this engine design in Gauge 1. I wont clutter this thread up wit a lot of photos of them, but since it is the same engine design I will show a little bit.
Here is a Woolwich Arsenal locomotive and was the first IC powered locomotive produced. I built 6 of these with minor variants plus 2 prototypes.
(http://i338.photobucket.com/albums/n404/NMSteam/Woolwich%20Locomotive/PC2013-4s_zps164c9068.jpg)
ANd here is a video of one of the prototypes running at idle on a track so you can hear what the crawler should sound like.
https://www.youtube.com/watch?v=a-csJ3As7dc
And finally a video of the last IC locomotive built with this engine. It is a Baldwin Mechanical as used during WW1 as a trench locomotive for moving goods and personnel to and from the front lines, mostly in France.
https://www.youtube.com/watch?v=xXnWSJOSuE0
Gail in NM
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Thank you Gail, very nice models :praise2: :praise2:
The Ffestiniog Railway in North Wales has a much modified version of the Baldwin fitted with a diesel engine and an additional pair of carrying wheels at the front.
I was confused remembering the gauge as I have models in both. In the picture the high level is 32mm gauge and the low level 45mm.
Is that your outdoor line? It looks to be dual gauge, what is the second gauge 2", 2.5" or the strange 'American Standard' 2 1/8" ?
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Thanks Roger. Yes, the track is dual gauge for one loop. 45mm gauge and 2-1/2 inch galugle. The track belongs to Jim, my building friend, in Utah, about 600 miles from me. Each loop is 250 foot long, a scale mile in 1:20..7 scale which is popular for live steamers in the Rocky Mountain reagon as we have numerous 3 foot narrow gauge mining railways.
Sorry for the delay in updating this thread. Not a lot of progress on the crawler but I have not been idle. Back in the beginning of this trhread there was a photo of the band saw setup sawing strips of 1/2 inch plate for the trread plates. I was sawing through the 10 inch section of the plate. When cleaning up the strips to width I noticed the the cut had a bow in it of about 0.-25 inch. This is normally an indication of insufficient tension in the blade. So I set up my shop built tension gauge. Sure enough my calibrated thumb that I had been using to set tension had gotten out of calibration. By about 2:1. Blade tension should have been 15K to 20K PSI. I measured 8K. While I was at it I decided to change the tires on the saw blade wheels as the old ones were getting really bad. Went with polyurethane tires. Because of the odd size of this saw they were cheaper than the old rubber tires. Took a few days to get them but they work very well.
So with that and a few other shop and household chores out of the way it is back to the crawler.
Nest up was the 64 tooth gear and clutch drive plates for the rear axles. They started off life as some 1144 steel barstock 1-3/8 diameter. Faced the end and turned down an 1/8 long section to 1 inch diameter for the clutch plate. Then parted off to a little over 1/5 inch thick. I know there is more overhang from the chuck than is desirable, but with sharp toos and slow feeds I had no problems. Besides none of these dimensions are very critical.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0069_zpsumzp3udd.jpg)
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The blanks were held in a 1 inch collet and faced off to 0.250 inch long. This dimension is some what critical as a bearing is going to be installed in each side with a spacer in between the inner races. If the dimension is held it makes it easy to get the spacer length right so there is no axial pressure on the bearings.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0070_zpspor1idh2.jpg)
Then the blanks were center drilled, drilled and reamed 3/8 inch diameter for the bearings.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0071_zpssducy0rr.jpg)
Gail in NM
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The blanks were moved over to a vertical 5c collet on the milling machine and the 12 holes that engage the dogs for the clutch were put in with a center cutting 5/32 4 flute end mill going to a 0.140 depth. The collet may look a little funny as it is one of my standard ones that I made up from a 5c clutch dollet blank that has both 1=3/4 and 1-3/8 pockets in it.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0072_zpsilfttyoc.jpg)
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The blanks were then mounted on a mandrel held in a dividing head on the CNC mill to cut the gear teeth. The dividing head is an ancient Ellis head that I put a 5C collet closer on and am driving with a stepping motor being driven with a Sherline rotary table controller. My CNC controller does not have a 4th axis but provides an Index Out pulse on command and then waits for and Index back pulse from the Sherline controller when the indexing is complete before continuing.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0073_zpsz0xg1lms.jpg)
And for those of you who nust have some action here is a 40 second video clip of the gear cutting. Two passes are made for each tooth.
Gail in NM
https://www.youtube.com/watch?v=MkYW26nGCNI
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Gosh. Even with close-up shots the parts look fabulous.
Outdoor track...envy.
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Thanks Zee. I am not much for running trains, I mostlly like to build things. My track is a pile of LGB track that I set up for testing before hauling my toys off to steamups on other peoples tracks.
Finally here are the finished parts ready for assembly.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/hORN-0074_zpsvkaxn8s5.jpg)
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Gail I always enjoy your builds and have been silently following along. This is a really neat project.
-Bob
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Thanks Bob. BTW I really enjoyed your Ultra Tiny project. I built a 1/16 X 1/16 bore-stroke years ago so really appreciate what you accomplished. I got the ports a little off so it was harder to start than yours. I put a microphone near the exhaust on it and fed a freq counter and it measured about 40K RPM at 15 PSI as I recall.
I ran into a minor problem with the crawler. The just completed 64 tooth gear/cutch disk is supported by two FR168 ball bearings with a spacer in between them to take the axial pressure on the inner races when mounted.
I made up the spacers to ny drawing and installed the two bearings and spacer in the gear and assembled to the rler axle assembly. The gear did not turn freely. Disassembled the axle assembly and measured across the bearing faces. It measured about 0.009 more than it should. Removed the spacer and it still measured the same so it must be the flange thickness on the bearing. China bearings so any thing is possible. Measured 0.e036 thickness. Off to the internet for specifications. Found two different specifications. One for 0.023 amd one for 0.036 thickness, with most manufacturers not even bothering to dimension it. SKF and other brand names showed 0.0336 and since that agreed wit what I had measured on my bearings I decided that it must be right.
So where had "I" screwed up. Went to my CAD model of the bearing that I had made years ago and I had drawn the flange thickness as 1/32 (0.0313). Why? Well probably because I normally keep the snap setting on the CAD lat 1/64 inch and assumed the thickness was 1/32. This was the first time that it had bit me.
After changing the /model of the bearing I had two choices. I could counter bore the 64 tooth gear by 0.004 on each side or I could change the spacer thickness. Since I had allowed an extra 0.05 on the axle length to allow for tolerance build up from machining and plate thicknesses I went with changing t spacer length. none of the mating parts would be affected.
New spacers made, installed and everything is fine.
Gail in NM
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You can pull their leg, but not mine; Coot figured that out didn't he? I once heard " The difference between good and great is how well you cover the mistake " Think you're well on the way to past great.
Cletus
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Of course Coot figured it out first. He's smarter n me. But most of the time he doesn't tell me the solution right away. He likes to see me squirm for a while.
Gail in NM
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Of course Coot figured it out first. He's smarter n me. But most of the time he doesn't tell me the solution right away. He likes to see me squirm for a while.
Wrong. Wrong. Right. Right. ;D
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Not to sure about that Zee. The young Coot outsmarts the old Coot quite often. But, thanks for the vote of confidence.
Minor change in the gearing. I wanted to get the drive shaft over to the left side of the chassis so I would have a big open volume to stuff all the goodies into. I could run it down the center but that would effectively divide the interior into two compartments. Same volume but less flexibility.
To do this I needed to change the 16 tooth pinion driving the 64 tooth hear to a 22 tooth pinion to space things out far enough for the bevel gear. And I needed to change the bevel bears from 16/32 tooth combo to 13/26 tooth. Changing the bevels still gives me the same gear ratio, but the 16 to 22 tooth change draped that section from 4:1 to about 2.9:1. No big deal as I have 4 places up stream towards the engine that I can pick up the difference.
So of to make some 22 tooth pinions. First off the blanks. 1/2 inch diameter with a 3/16 wide face for the gear face and 3/8 diameter 1/8 inch long for the hub.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/HORN-0075_zpsuuzxzni0.jpg)
And cut the teeth. If you were paying attention, you may have noticed that on the 64 tooth gear the cutter was on the side of the gear away from the operator and turning CCW. On this gear the cutter is near the operator and turning CW. This is because I wanted to conventional mill the steel gear and climb mill the brass gear. And I wanted the cutting forces to press the gear against the mandrel in both cases.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/HORN-0076_zpsghiyomyb.jpg)
And, except for the set screw holes, are the 4 finished gears. All the set screw will be done later after the indexing head is off the mill.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/HORN-0077_zpsyjn4kirs.jpg)
Tomorrow I will start on the bevel gear blanks and maybe even get some teeth cut. The bevel gears will be parallel tooth (constant tooth height) gears. If anyone wants details on how to cut the bevel gears let me know and I will include the calculation methods, other wise I will keep it brief.
Gail in NM
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Still following along with a big bucket of popcorn!
You mentioned that you wanted to climb mill the brass gears. Why is that? What's the advantage?
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Thanks for following along Chris. Your Lombard is looking reat/. It's amazing how fast it is progressing. You seem to get 3 or 4 parts done a day and I get 1 part done evry 3 or 4 days.
With CNC I prefer climb milling in almost all situations where I have a solid rigid setup. But, it only works with CNC where you have a precisely controlled feed rate and most importantly very small amounts of backlash. The primary advantage of climb milling is cutter life and reduced chip chip welding. In climb milling each chip starts out thick and tapers back to a feather edge. In conventional milling the cutter enters the thin edge of the chip and rubs until it gets enough pressure to actually enter the metal and start cutting. In alumnium this pressure friction welds any fine chips that migh be in the cut to the bae material giving a poorer surface finish.
I would have climb milled the 64 tooth gear except for the way my Bridgeport CNC is set up. To get the proper spindle RPM for steel I needed to use the back gear on the spindle. While this reduced the RPM, it also reverses direction of rotation. I have a semi automatic spindle start for the forward direction, but to start the spindle motor in reverse is a two handed manual operation. Knowing that I would forget to do that, it was best to conventional mill that part. Note also that I had a Micro Drop coolant unit runnning when doing the steel so recutting chips was not a problem wilth surface finish.
Book chapters have been written about this subject, so I have just touched on it. But with manual equipment you never have to worry about it as the only safe way to mill with it is to conventional mill in all cases except to maybe dust off a cut to remove chip welding in a cut that you have just conventional milled.
I probably told you more about the subject than you wanted t o know but it's hard to explain with just typed words.
Gail in NM
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Hi Gail, I am another following along in deep admiration of your work and learning so much from your methods.
Thank you for the explanation on climb milling, it really helps me understand some of the issues.
I would also appreciate the details on those bevel gears. Your explanations just make sense and so clarify what can be difficult subjects. Please keep them coming.
MJM460
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I'm also following along Gail. I've actually been here from the start. Cool build sir!
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Thanks for the details, that was a perfect level of explanation!
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On my Bridgeport I use carbide tooling and climb milling almost all the time. I tend to take pretty conservative cuts even with a fairly rigid machine.
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Thanks everyone.
KVOM: Like you, I climb mill on my manual machine. All my roughing cuts I conventional mill and then climb mill the finish cuts. It can be a valuable skill, but in general it is not for beginning machinists. To climb lmill on a machine that has significant backlash you have to know the machine very well. And the cutter and materials all make a difference also. I have had my manual mill for over 40 years so I know these things. If I went to another shop I would not try to climb mill on their machine as I would not know it's characteristics.
In rereading my post I see that I committed the cardinal sin of not explaining the WHY you have to be careful. I hate it when someone says do this or don't do thhis and does not explain why or what happens. Sorry about that, it was late.
When climb milling, the cutter action tends to move the material in the direction that takes out the backlash on the feed screw. So, lets say that we are trying to feed a cut with a 0.001 inch chip load per tooth. And we have 0.020 if bacjkash in the machine axis. When the cut starts a 0.001 thick chip is generated. But in cutting that chip, the cutter moves the material to take out the backlash. The next tooth then tries to take a cut to produce a 0.021 thick chip and that often leads to a broken cutter. Often followed by the expression "Oh $###, I will never try that again". If you want to learn to climb mill, do so on some scrap and with a junk cutter. The place to learn is not on a part that you have a few hours invested in.
Gail in NM
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Gail's points are spot on, and much depends on the equipment used and the material cut. Heavier mills ...generally speaking...do much better with climb milling
Dave
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Gail's points are spot on, and much depends on the equipment used and the material cut. Heavier mills ...generally speaking...do much better with climb milling
Dave
Great explanations. Now I understand why I get a better finish with conventional milling than with climb milling (even with a light cut) with my Sherline mill.
Jim
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Thanks for the kind comment Jim .
Sorry for the delay in posting everyone. The MD's changed on of my medications that was losing effectiveness and it interacted with one of my others meds and turned my brain to mush. I now have pill "C" to counteract the side effects of pill "B" and it seems to be working. If they tell me next week to take pill "D" to counter the sides of pill "C" I am going to tell them that it's time to start over.
So after 10 dys of screwing up I got some usable blanks for the 26 tooth bevel gear.Would you believe silly things like 0.718 does not equal 0.781 and that 11/64 bore dies not fit a 5/32 shaft. Here are some photos of the process. Chris is doing a great job on the math behind bevel gears. My method is a little different, but I I won't go into it until after I am sure that the brain is clear enough that I am not writing garbage.
First off a few photos of the blank development and then a couple photos of the finished 26 tooth gear. And, finally a poor quality video of cutting a couple of the teeth. Each tooth takes 3 passes with the gear being indexed 1/4 tooth between passes and the Z axis adjusted at each index. Then between teeth the blank is indexed 1/2 turn, actually 2 quarter turns in the video.
The gears measure good, but the proof of the pudding will be if they match the 13 tooth mating gear which is up next.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/HORN-0078_zpsujielvqj.jpg)
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/HORN-0079_zpsaiqx8jv4.jpg)
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/HORN-0080_zps9qnguxto.jpg)
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/HORN-0081_zpszpcijo5c.jpg)
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/HORN-0082_zpsnfy939yh.jpg)
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/HORN-0083_zpsukvymskq.jpg)
https://www.youtube.com/watch?v=M8tXVYWT6b4
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Glad to see you are getting better! I am interested to see how you did the bevel gear calculations and layout when you are up to it.
Reminds me of the old movie "Whats Up Doc", where the old judge is taking his pills at the bench, and talking about all the pills he has to take. Something like:
"The red pill is to remind me to take the blue pill..."
Q: "Then whats the green pill for?"
A: "They are afraid to tell me...."
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Chris,
Your "What's up Doc" bit is about right. Between Diabetes, Stroke, AMD and a few other ailments that go along with being an old Coot, I figured if they would add about 60 calories to each pill I would not have to eat anymore.
I have a spread sheet also and a Pascal program I wrote many years ago. Both of them are set up for the general form of bevel gears and include the equations for skew bevel gears. But I don't use them anymore. With CAD I do a graphical solution anymore and let the CAD do the math. Besides when I am done it gives me every thing I need to program the CNC. Here is a copy of the graphical solution that Dan Rowe wrote some years back. Mine is similar but involves even less math.
Gail in NM
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Slick diagram - have to study that one some more...
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Got tlhe 13 tooth mating bevel pinions done. I needed 4 but while I was set up for the 26 tooth gear I finished up the 4 extra blanks with the oversize bore in them. So I made an extra 4 pinions to match them. The extras will go into the "future projects" bin. The bevel gears run smoothly in a temporary lash up for testing.
That is the last of the gears that go in the chassis portion. There will be more gears to cut for the two gearboxes but those will all go on to the power unit that bolts on to the chassis. That will let me work on the engine and gearboxes separate from the chassis and bolt them to each other after all the fittin filing and fussing are done. But for now it is back to the chassis unit. Next up will be the jockey brackets hat hold the bevel gear pairs.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/ORN-0079_zpsmaqirvfa.jpg)
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/ORN-0080_zpsoqn2biur.jpg)
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Those look great!
:popcorn:
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Nice gears Gail.
Chris the diagram I use for all bevel gears starts the same way draw a rectangle using the number of teeth for the sides. The diagonals are the pitch line. This works for both parallel depth and true bevel gears.
Dan
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Nice gears Gail.
Chris the diagram I use for all bevel gears starts the same way draw a rectangle using the number of teeth for the sides. The diagonals are the pitch line. This works for both parallel depth and true bevel gears.
Dan
Looks like a great way to do it. The main thing I was struggling with was finding the proper face width on the teeth.
Also, what about the calculations for the 2nd/3rd cut on a parallel depth gear? How do you do that?
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Chris,
I use a book called "Gear Design Simplified", it has the formulas I use. It also stated that the face length should not be longer than 1/3 of the theoretical pitch cone. That is a modern rule and does not apply to historic gears like Shay gears.
Dan
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Chris,
I use a book called "Gear Design Simplified", it has the formulas I use. It also stated that the face length should not be longer than 1/3 of the theoretical pitch cone. That is a modern rule and does not apply to historic gears like Shay gears.
Dan
Thanks, I will look that one up.
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Chris,
I use a book called "Gear Design Simplified", it has the formulas I use. It also stated that the face length should not be longer than 1/3 of the theoretical pitch cone. That is a modern rule and does not apply to historic gears like Shay gears.
Dan
Thanks, I will look that one up.
My copy just arrived, looks lkke just the reference book I was looking for. Thanks!
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Chris,
I use a book called "Gear Design Simplified", it has the formulas I use.
Thanks, I will look that one up.
My copy just arrived, looks lkke just the reference book I was looking for. Thanks!
Chris that's the book I use to make the Gear spreadsheets that I posted in plans and drawings and very good book.
Gail outstanding work bud and your and inspiration to follow..... :praise2:
Don
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Sorry for not having posted for a while. Things got busy. I chad a party for 77th birthday and made it a triple 7 party by stretching it out for 7 days. Also got a new retaining wall built for the front yard and a lot of other gardening done.
In the shop. made a jig for drilling and tapping the set screw holes in the gear hubs. Screwed it and a few gears up. Seems the Bridgeport was out of tram in the X axis by 0.070 in 10 inches. How do you knock a BP out of tram by that much and not know it? I don't know. I was OK a couple of weeks before and I don't remember any crashes. Any how it is back in tram to within 0.0005 in 10 inches in both axis now. New drill and tap jig made and the gear hubs almost done. While I was traming the Bridgport I made a few modifications to it to help with the low vision situation. One more mod to go on it soon as some parts arrive from China.
Here are a few photos of the drill tapping of the gear hubs
First up is the jig mounted in the mill. The Jig is a 3/4 inch cube of steel. The holes on top are sized for a tap drill. The hole is the end is for a 5/16 diameter hub. The other end is identical except the hole is for a 3/8 diameter hub. If you look in the hub hole you can see a hole coming in from the bottom of the jig. It is sized as clearance for a 2-56 tap.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/ORN-0081_zpsq4iubccm.jpg)
Here is a gear in the jig ready to drill. I just hold the gear in place by hand for drilling. If you look to the right side you can see a rod that goes into the jig. It is a knockout bar to remove the gear as they can be tight some times from the burr raised by the drill.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/ORN-0082_zpslh60vibq.jpg)
Then the gear is rotated 180 degrees and the jig used for tapping the hole. Of course all the gears were drilled first and then tapped.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/ORN-0083_zps5qgr54b0.jpg)
Up next will be the gear box that holds the bevel gear set and the drive gears for the rear axel and the associated shafting.
Since there seems to be a lot of interest in bevel gears I will try to clean up my CAD solution to constant height bevel gear design and publish it in the next week. It's easy as it uses the CAD to do all the math.
Gail in NM
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Those CAD drawings would be very interesting Gail and looking forward to seeing them. Can you gave a sequence of how you go about it? By the way great work and Happy 77th!
Don
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Slick setup for drilling and tapping the gears - have to remember that one!
:popcorn:
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Happy 77 Gail.
And yes, always interested in seeing bevel gears being made.
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Glad to see an update Gail. I love this project.
-Bob
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Congratulations on your 77th, Gail. Hope the party was a grand one. Still following quietly.
Regards,
Rudy
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Thanks for the kind comments.
I have attached a PDF file of the bevel gear design sequence that I use. If I have forgotten any thing or you need clarification on any of it let me know and I will revise it.
Gail in NM
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Great reading Gail and thanks for taking the time to do the write up. I will add it to the gear spreadsheet in plans and drawings in the parallel depth bevel gears section if it's alright by you, and post a modified spreadsheet after.
Don
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Great document - makes sense reading through the first time, think I will go through the exercise with the most recent gears I cut, think that would internalize it better. Thanks!!
Chris
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Belated birthday greetings Gail, Still following and learning :popcorn: Best Wishes Terry
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Birthday, what? And a week long party. Shoot, it takes me two weeks to get over a two day drunk anymore: don't see how you kids do it :stir: :lolb:. What did Coot get you for your birthday? Carry on.
Eric
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Thanks for following along everyone and thanks for the kind comment on the bevel gear PDF,
Don, the PDF is in the public domain so you can do what ever you would like with it. Your spread sheets are are well known and quite respected. You do a lot of work on them.
Chris, If you go through te\he exercise with the gears you recently cut I hope the results look a lot like yours. It would be good to know that I have not mislead anyone.
Eric, Doc does not let me drink anymore so recovery was quick. The 7 days was actually 2 days getting ready, 2 days of party and 3 days clean up/recovery. Coot is not much for presents. Just a friendly pounce and tail wag. But that is all I ask from him and it means a lot. Actually Coot had a couple of friends over for the party, but they mostly stayed in the back yard playing with the grandkids except when food was involved.
Progress on crawler is slow. Mobility scooter batteries died. I put in a set of old ones I had but they were even worse. New batteries will arrive Wednesday so I can go grocery shopping again. When I run out of groceries I don't eat and then progress on anything really slows down.
After tapping the gear hubs, I reamed them to remove the burrs left from the tapping operation. Made up the shaft that the rear axle drive gears and one set of bevel gears mount on. The shaft is 3/16 diameter with flats for the set screws in the gears. The ends are stepped down to 11/8 diameter to fit a 1/8 X 1/4 flanged ball bearing on each end. The bearings will fit in each of the chassis side frames to support the shaft.
Next up will be the bracket tosupport and align the bevel gears on this shaft and couple to the drive shaft coming back from the engine gear boxes.
Gail in NM
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/ORN-0084_zpso0n1i5kj.jpg)
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Everything looks really good Gail.
-Bob
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Parts look spectacular as always. The way it always is: takes longer getting ready and cleaning up afterwards than the party does: hmm, seems I've heard Lou say something along the same lines :lolb: :lolb:. That's all you could ever want from Coot anyway. DOG has started helping me keep the wheels on my motorcycles, um, well, um, lubed :lolb: :lolb:. I could just choke him, but, at our age: when you gotta go, you gotta go :naughty:. :lolb:
Eric
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Nice looking parts Gail!
Dave
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Thanks Bob, Eric and Dave.
With most of the parts made for the rear axle bevel gear drive it's almost time to tie them together. The main part still needed is the bracket to hold everything in place.
Since I am building parts for two crawlers I need two brackets. I started out with some 3/8 6061 plate and brought it to width and long enough for both brackets plus some space for a saw cut between them.While it is still righd I milled out the inside where all the goodies go and drilled and reamed the 1/4 and 5/16 inch holes for the bearings. Notice the engraved line that I put in to indicate where to saw.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/ORN-0085_zpsldpxekwc.jpg)
After sawing apart I rounded the end where I had saw cut.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/ORN-0086_zpsilwk83fi.jpg)
A family photo of all the parts ready for assembly. The spacer above the 26 tooth gear has not been mentioned. It keeps the far side bearing in place and positions the 26 tooth gear. Also, not shown, is a collar that goes on the 1/ 8 drive shaft to keep the shaft in place and retain the outter bearing for that shaft. It is a stock I item that I make up in bulk so was on hand. but never fear, my stock is low and I won't have enough to finish this project so I wii be making some more soon. The little fly specks in the upper left corner are 2-56 x 1/8 set screws for the gear hubs.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/ORN-0087_zpsdsgs6td8.jpg)
Assembly starts with the pinion, inner bearing, bracket, outer bearing and collar strung like beads on the 1/8 inch drive shaft. Every thing is pressed together with firm finger pressure and tightened up. The bearings are 1/8 1/4 flanged ball bearings. They are a kiss fit in the bracket so there is no axial pressure on the inner races of the bearings.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/ORN-0088_zpsvzbydbo1.jpg)
The 3/16 X 5/16 flanged bearings are installed from the inside of the bracket.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/ORN-0089_zpsjalh9jef.jpg)
The bevel grar and spacer are positioned between the bearings in mesh with the pinion and the 3/16 shaft run through the whole mess and the gear set screw tightened.
(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/ORN-0090_zpslzd48lfd.jpg)
The drive gears for the rear axle assemblies are added and the sub assembly is ready to install in the chassis. Of course I had to play with it for a little while. Runs smooth as silk with almost no backlash. (Sigh of relief).
Gail in NM
[(http://i338.photobucket.com/albums/n404/NMSteam/Hornsby-Akroyd%20Crawler%20Tractor/ORN-0091_zps79z1jvub.jpg)
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That gear bracket came out great!
And I missed that you are building two crawlers, both the same
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That gear bracket came out great!
And I missed that you are building two crawlers, both the same
What that fellow who has elves working for him said. ;D
Seriously. Nice! :ThumbsUp:
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Thanks Chris and Zee.
Yes, both crawlers will be the same. It does not take a lot of extra time to make a second set of parts once you are set up. I will assemble one crawler and the second set of parts will go to my building buddy in Utah for him to assemble. Actually he will come down here to do the assembly, probably in October. We have been building toys with each other for over 20 years. Right now he can't do much as he is spending 1/2 of his time in California with his elderly mother (90's) but we still help each other when we can and make the Post Office rich as we send parts back and forth.
Gail in NM
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Thanks Chris and Zee.
Yes, both crawlers will be the same. It does not take a lot of extra time to make a second set of parts once you are set up. I will assemble one crawler and the second set of parts will go to my building buddy in Utah for him to assemble. Actually he will come down here to do the assembly, probably in October. We have been building toys with each other for over 20 years. Right now he can't do much as he is spending 1/2 of his time in California with his elderly mother (90's) but we still help each other when we can and make the Post Office rich as we send parts back and forth.
Gail in NM
Nice!
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Gail........the parts look great and it really helps seeing them assembled into an assembly. :ThumbsUp:
So Chris..........please.......... please tell me that you're also making a second set of Lombard parts for your good friend that lives out in Oregon! :naughty: I'll be more than happy to reimburse you for the postage cost. ;D
Jim
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Gail........the parts look great and it really helps seeing them assembled into an assembly. :ThumbsUp:
So Chris..........please.......... please tell me that you're also making a second set of Lombard parts for your good friend that lives out in Oregon! :naughty: I'll be more than happy to reimburse you for the postage cost. ;D
Jim
Um, yeah, right, sure Jim, but the postage will be a bit high for these heavy parts. $4.6 million, must be prepaid in cash!
:ROFL:
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Gail,
Which city does your friend in Utah live. We have an informal hobby machinist club in the Salt Lake area.
If he is interested he cam PM me. In fact we are having a get-together this Saturday.
Mike Nay
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Hi Gail
Any progress on this project or are health being a problem ?
Best wishes
Per