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| Four Truck Shay |
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| dsquire:
Bernd What! Only one week on the job and already you are being tempted by others. Must say, you have been doing a fine job so far. I'll be keeping an eye on you. Just because I'm not replying doesn't mean I'm not watching. :lol: :lol: :lol: Hope you are having fun at the river. Cheers :beer: Don |
| Bernd:
:update: Got a bit more done on the trucks. I said this was going to be a slow build. ::) I've got all the holes drilled in the bar stock for the two trucks that will go under the tender frame. There are to many holes to count, plus I need to tap about half of them. I'm at the point now were I will need to do some bending of one part. Here are some progress pictures to look at. Not much but...... Any way. The first picture shows marking the place on one side were the archbar needs to be cut and bent. I did this on the fixture I made to drill all the holes. I just zeroed in the one end and ran a pointed scribe were the cut needs to be made, then turned the part 180° and scribed the second line. This way the bends will come out even from either end. More on why they are cut and how much later. All four are scribed. Now here comes the hard part. Taking one of this straight bars and........ ....turning it into something that looks like a "V". Looks like another jig or fixture is in order here. That'll be next. Bernd |
| Bernd:
Another :update: I have finally figured out how I was going to make the bending jig for the lower archbar of the truck. This is the only bar that needs to be bent, but also needs some accuracy to the finished product. So a jig was in order. I made it out of aluminum because I have lots of it, plus it will need some welding. Here's how I went about it. I took the dimensions from the print and drew up the basic shape on AutoSketch. I added the dimensions I needed so I could get and idea of how it was going to fit on the rotary table. Each side of jig is 10.5° from the center line. Then up from the center line to the bottom of the jig is 4.128" minus half of the cutter which has a dia. of .250". The 1.530" dimension will come out automatically when the sides get cut on a 10.5° angle. Next problem to be solved was how to mount it on the rotary table. I used a piece of 3/4" MDF secured to the rotary table. Here's the template placed on the MDF to see how the jig will fit. Looking good so far. Next the rotab was placed on the Bridgeport mill and zeroed in. Here's my first error I made. Drilled the hold down holes to close to the bottom. :palm: :doh: So another piece of stock was cut and the holes relocated. I mounted the messed up plate on top so I could use it as a scrap piece to see if I indexed the table right. Glad I did because I made two more minor errors as I went along. :coffee: Anyway, I set the 4.003" dimension to the y-axis so I could use the x-axis powerfeed. As you can see that the scrap piece did get milled a little bit. Next I indexed the table around 90° to 270° minus 10.5° or 259.5° to cut the first leg of the angle. But I forgot something. After I had finished the first cut at about .125" depth I turned the table to 280.5° to cut the other leg. That's when I came to me, I needed to add .125" to the "Y" axis readout on the one leg and subtract .125" from the "Y" axis on the other leg from the center line to get the 1.530" deminsion on the bottom of the jig. :doh: Glade I had used the srcapped piece for a trial run. Once I had that done it was just a matter of a couple of passes to finish the jig. Another shot of my error. :hammer: Action shot, looks like it isn't cutting. Milling out the other side. Take notice of that bolt sticking out. :bang: Notice it isn't sticking out any more? The clamp nut on the arbor ran into it making a pretty loud racket turning at about 700rpm. Needed to clean my pants after that. So here they are the bad piece on the left and the good one on the right. Next it needs to be trimmed to the correct heighth. I used a set of jo-blocks to set the veriner heigth gage and scribed a line. This set the heigth to 3.300". This will give you and idea of how the flat bar will be bent. The bar actually needs to be laid on it's side for the bending. There's a few more things I need to do to finish the jig. That will be the next installment. I've also had some time to contemplate the gears that need to get used. I had sticker shock when I found out the price. Now I need 8 sets of gearing, both gear and pinion, for the four trucks. Boston gears would cost me $716.40, Martin Gears would cost $660.40 that doesn't include shipping and handleing. I am very seriously considering making my own. I'll elaborate on that though a bit more later. That's it for now. Bernd |
| dsquire:
Hi Bernd Looks like you have really got things on a roll. Just watch those long bolts sticking up, they can scare the ____ out of you. You don't need that kind of excitement. For the price of those gears you could probably get some nice tooling and make your own and still have saved a few bucks. You would still have the tooling left for future use as well. Take care and keep cool. Hopefully it isn't too hot in your basement shop. :D :D Cheers :beer: Don |
| Bernd:
Hi Don, Nice and cool in the basement. Hasn't been to bad outside latley either. Just dry that's all. I might as well get into the gear end of it right now. After I researched the price of the gears I remembered Kozo designed and made his own gears for the Climax which has offset bevel gears. I have all three of his books. I started studying the makeing of the gears. It's quite complicated but he has made it easy by giving all the formulas and shows examples of each calculation. What I didn't know was that the same would apply to bevel gears that are on center. All you need to do is ignore the offset of the gears and you have your standard bevel gears. BTW, for you gear challenged memebers miter gears are 1 to 1 ratio, bevel gears are greater ratios, such as 2 to 1 or 3 to 1. Right now I'm pretty sure that I will be "trying" to make the gear sets. The one interesting statement Kozo made about the gearing was that the modeler could make more accurate gears than the prototype since they had no way of figuring out the numbers for the gears or had the equipment to cut them. As a matter of fact the prototype gears were a guesstimate when the were made. They made wooden molds and cast them till something worked. Talk about custom made gears. Also right now there are several side tooling projects that will need to be done in order to help in the construction of this engine. One of course will be to make the gears and fixture to cut them. For once I have purpose for a project. Seems much more fun than just building something for the sake of building it. :ddb: Hopefully I can get this jig finished before next weekend. Bernd |
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