rbrown7713 Posted May 25, 2016 Author Share Posted May 25, 2016 That's OK, The Train department has some interesting bearings that are 1/8th id. and 1/4 od, they would work. I have some axles and wheels with a 1/8th inch axle and the .250 od comes out to be 6.35mm. and the other brgs. that I found on ebay, the OD was 6mm., but both of these bearings would work with some rework of the journals. When guys on this forum say that they converted to bearings, how did they do it? I certainly appreciate your help and I will start my designing of the journals as soon as I get some bearings, payday. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted May 25, 2016 Author Share Posted May 25, 2016 OK, I ordered my bearings, and I went with the 3x6x2.5MM, flanged. They will fit both my 3mm axles and the 1/8th axles. I will have to turn down the 1/8th inch axles about .018 inchD, but that is fine, this way I have all of the same bearings. I will design the journals to fit. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted May 25, 2016 Author Share Posted May 25, 2016 I thought that I would share a method the I use to check shapes that I am making. I made a pen with a spring loaded ink refill and inserted into a mill collet, that way, I can observe whether my shape is correct or not. Here is a video from YouTube, Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted May 25, 2016 Author Share Posted May 25, 2016 I am sorry to say that I made a big mistake on my patterns for the trucks, so I will just fill with more Bondo and start all over. I have decided to not make the trucks with working springs, too difficult and besides, the springs that would work would be so small, it wouldn't look scale. So, back to the drawing board and mill. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted May 28, 2016 Author Share Posted May 28, 2016 I mentioned how I would tackle the problem of a sagging mold section. This ladder like brace will be placed in the top, second part of the mold, keeping it from sagging and therefore having a straight part. This is only necessary in long parts like the roof not the sides, since the window opening actually touch, therefore keeping the mold from sagging. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted May 29, 2016 Author Share Posted May 29, 2016 Here is the first two parts out of the molds, the steps and the end piece. I am happy with them. This is the first time that I used plastic instead of epoxy resin, seems just as strong. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted May 29, 2016 Author Share Posted May 29, 2016 Well, I cast the side and it came out very good, has a few flaws, like dents, but I think I will leave them in as it represents an 80 year old car. I will cast the other side tomorrow. The rivets show well. Bob. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted May 31, 2016 Share Posted May 31, 2016 After seeing so many short cars, that actually looks too long! Great job. Looks like alumilite? http://www.alumilite.com/store/p/1022-Alumilite-Regular-Tan.aspx Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted May 31, 2016 Author Share Posted May 31, 2016 Hi Joe, it is supposed to be an 82 ft. car excluding the couplers, making it about 85 ft.. I will investigate aluminite, I have heard of it, but I am using a hard plastic from BITY mold supply. The stuff that I am using is too quick, 5 minutes pour time and I think it is setting up too fast, so they have one that gives me either 10 minutes or 15 minutes, so I am going to ask them about that. The plastic that I am using yields good parts, but a little too quick on hardening, by the time I get the second part of the mold on, it is setting up and not letting the weight take the mold down where it is supposed to be. Bob. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted May 31, 2016 Share Posted May 31, 2016 Don't change because of anything I said. It just looked like what I used in the past. I tried several products looking for what works best. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted June 1, 2016 Author Share Posted June 1, 2016 I talked to the people at BITY mold products about changing to the 10 minute pour time and he didn't recomend it because the urethanes are susceptible to moisture while stirring. Since I am here in Florida and it is humid, he says that it would be worse for the absorption of water and might make it worse, so I will stick with what I am doing. The parts are coming out good, but when I put the second part of the mold on, it is already starting to set up and I am unable to get the mold down where it is suppose to be and the flashing is too thick. I think next time, I will bring it into the house where it is cooler and dryer so I might have more time to pour. Another method that I might try is to spray nitrogen into the mixing bucket, that way it might shield the plastic of absorbing moisture. Bob. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted June 1, 2016 Share Posted June 1, 2016 One good thing about air conditioning, is it should help pull extra moisture out of the air. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted June 1, 2016 Author Share Posted June 1, 2016 You are right, so I might pour the parts in my house, even though my garage is air conditioned, it is not as good as my house, thanks. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted June 2, 2016 Author Share Posted June 2, 2016 Well, I received my Hudson today and can't wait until I have a bunch of heavyweights to pull behind it, so many cars to build and so little time. Bob. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted June 2, 2016 Share Posted June 2, 2016 Wow, that B&O smooth side looks beautiful with her. What make is the Hudson? Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted June 2, 2016 Author Share Posted June 2, 2016 The Hudson is a MTH J3, New York Central. There is a broken part, the lead four wheel truck and I am trying to contact MTH for parts and not having much luck, but we shall see. The B&O is a 4 1/2 inch stretch, to make it an 85ft. car. I am not sure whether it is easier to build a car from scratch or stretch one. I have a mold for the MTH ribbed 4 1/2 inch section as well as the smooth one. I also have molds for the smooth and ribbed PS cars. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted June 6, 2016 Author Share Posted June 6, 2016 I ordered the part for the Hudson and I had to buy the whole lead truck, cost 25.00 plus 9.75 shipping. The broken stud was fixed with super glue, seems to be very strong, but I will have to remember to pick it up by the wheels and not the boiler. Here is something that I had to go through to get the correct thickness of the window frames because of the plastic setting up as I was installing the second part of the mold. The stuff was setting so fast that it made the window frames too thick so I had to machine them down on the mill. This probably wouldn't have happened if I had used the epoxy that I am used to, but I am trying new things. Here are some pictures of the setup on the mill, cutting the inside of the frames for consistent thichness. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted June 7, 2016 Author Share Posted June 7, 2016 OK, back on the trucks. Here are a few pictures of the pattern cut out of Bondo, in steps. The hole is the hole for the 6mm bearing. The journal bearing cap will go on later. I have marked the locations of the bolts and rivets. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted June 8, 2016 Author Share Posted June 8, 2016 Here is one side with the rivets and bolts installed for the mold. I am talken tweezers. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted June 9, 2016 Author Share Posted June 9, 2016 Here are some hints on my methods of installing small rivets and bolts. I used a popsicle stick to hold the rivets before cutting, turned it over and held, and then used a grinder to cut to size. I used Elmers glue to hold in place. The one photo is to remind that even cnc machines can have a brain fart. In Mastercam, there is a varify screen to see if everything is cutting as programmed. I run that, and if everything looks good, I put it on a floppy and install it on the Anilam controls and run it, without any failures, except on this one. The first copy of the truck frame cut without any errors, but I discovered, as you can see in the picture, the first program, out of seven, the outline which required two depth cuts, the first cut error, about .0265 inches varied from the program, not in the first truck frame, but in the second one. Very interesting, shouldn't have happened, but it did, so all that I am saying is to be aware of rare happenings that could occur. Since I didn't notice it while it was mounted on the machine, 0,0,0, was lost, so I couldn't just fill whith Bondo and recut, so I added a piece of 1/32 ply to repair the pattern, so, there you have it, I am now ready for some wax and then pour some urethane molds. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted June 9, 2016 Author Share Posted June 9, 2016 I forgot something, to cut out the radii of the cuts, here is the final version before waxing and molding. Bob. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted June 10, 2016 Share Posted June 10, 2016 Very interesting. Thank you! Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted June 10, 2016 Author Share Posted June 10, 2016 The mold is done and later today I will make some parts. It came out perfectly and will make some good parts, not finished yet, have to add some stuff. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted June 10, 2016 Author Share Posted June 10, 2016 I poured the truck faces and the frame and everything went well with the exception of some bubble around the bolts in the truck frame, I forgot to drag a toothpick in the holes where the bolt heads are to release any air, but I will next time and also, I used too much spray mold release, caused a rough finish. The frame mold turned out good. I have changed how I pour my molds in that I pour directly on the granite and border the soon to be poured mold with plywood and clamps. Lot easier, also can reuse the plywood borders and comes apart easier. The excess urethane on the table just comes right up in several pulls. I will pour some better truck frames and post them later. Next, tomorrow, I will pour the first part of the roof mold. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted June 11, 2016 Author Share Posted June 11, 2016 Here is what I was after. The bearings slip right in with no back drilling. Bob. Quote Link to comment Share on other sites More sharing options...
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