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Thought I'd take a break from the work bench and post a quick update. The other night I was in the shop until the early hours of the morning drilling a bunch of tiny holes and working on adding the block deck, as well as the front and rear plates.
The first thing I did was solder a piece of .020" (.5mm) nickel silver sheet on the block. This will form the block deck. After soldering I began to drill holes using a .5mm drill with the sensitive drilling attachment for the coolant jackets and the head studs.
After drilling I used a small 4 flute end mill to rough the block deck to size.
I still need to be able to bolt the block upside down to my fixture plate for a few more machining operations so I plunged into the cylinder bores just enough to get to the threads.
Using files, sand paper, and lots of beer I began to shape the block deck to the correct profile. The side closest in the pic is the finished profile. The opposite side still needs to be shaped, the pink markings are to indicate where to remove material.
Once all the machining is complete I will remove .005" from the block deck to achieve the correct thickness.
Now back to the bench to work on the ribbing and external bungs. Enjoy!
Last week I finally had a great opportunity to get some work done on the motor. Over the years I have remained in touch with my old high school engineering teacher, so in exchange for guest speaking in his classes I get to use the CNC mill on occasion. I used the CNC mill this passed week to machine out the crankcase. Iâ€™ll let the pictures to the talking:
The first roughing pass.
After investing so much time in the block, I like to always double check my tool paths. I marked the block with a marker, then ran the tool path removing only .0005" to make sure it was where it needed to be.
After over 6.5hours of run time:
Just a size comparison next to a US 1cent.
I know the question is going to be asked, "Wont this all be covered?", and the answer is that I do not know yet. Right now its just a fun challenge for myself to expand my capability.
Not a problem, I hope to meet you too one day, Jay. Hopefully at the NNL South in November!
Jay, no problem. Questions are fun to answer. The block has #4-40 threads through the entire block, that allows me to secure it right-side-up and upside-down on the fixture plate. The fixture plate is a must for machining something with such weird shapes and nowhere to pull a positive dimension other than the bores.
Annealing is a process of normalizing the crystallization structure in the material. To anneal brass and copper a torch can be used to heat it. I used oxy-acetylene because it was available, but Butane, Propane, or MAPP will work just as well. When heating the material, be patient, if you heat it too fast you'll warp it or blow a hole in it. Heat it slowly and constantly move the heat around over the piece so that the entire piece is heating evenly. Continue the heating process until the material starts to become a dark cherry red (like in the pic above). Keep in mind it will not stay red hot for long at all, so just move the heat around (or you'll distort the material). Once you have evenly heated the entire piece back the heat away. Do NOT quench the material, let it air cool. Now you can work the piece pretty easily!
Today I had some time to work on the engine block today. Just started machining out the area for the mains.
First I used a center drill to position the beginning of the hole accurately and precisely.
I use a drill that was slightly under-size. Drill bits tend to drill over-size in metal, so using a smaller drill bit is usually a safer route. Once the girdle is machined I will clamp it to the block and line bore the mains with a reamer.
Using a 1/8" end mill I started to remove material for the mains and girdle.
Today I took a break from working on the engine block. Decided to work on something different - the doors. Unfortunately when I cut out the doors out, one of the passenger side window frames warped, so I'm going to attempt to build the doors out of brass now. Not only will the window frames be stronger in brass, but the door skins will also be a more accurately scaled.
I first made a steel form to shape the brass over, then proceeded to anneal the brass.
Annealing the brass with a torch.
The steel form used to shape the brass over.
Thanks for looking, hope to get back to the engine block this week!
I haven't had much time to do any work on the model since I have been rather busy with work and classes. However, I thought I should post what the block should look like once completed. Today at work I did a quick rendering of the 3D model I made to design the block.
Tomorrow I hope to go into the shop and get some machining done on some jigs and fixture plates!
Nickel silver is not cheap compared to other metals. A 6" piece of 3/8"x3/4" bar stock is about $20. However, with the cost the advantage is having a part that is silverish in color and is able to be soldered. I had considered machining it out of 6061 but soldering 6061 is difficult, at best. Since I decided to machine the block out of multiple pieces, I decided to use something I can solder the other parts to. If I did the block out of 6061, I could glue the parts to it, but I just don't like the idea of gluing metal; it's not very resilient.
Machining nickel silver appears to be easy, but it takes a lot to get a nice surface finish. It galls really easily, do your speed has to by high and your feed has to be slow and consistent. Don't bother using a tool that's been used before, it will just gall badly and make a mess.
6061 is a lot easier to machine, but for this application, nickel silver is better suited. As stated, the main advantage of nickel silver over 6061 is its easy to solder.
Jason, the door frames are quite simple really; they're just built out of various sized strips of styrene. The main shape of the door frame was cut out of .015" styrene sheet, then strips ranging from .010x.020" to .100x.125" were used to build up the structure. Some brass rod was used in the B-Pillar to aid in holding its bent shape. If you flip back a couple pages you can see that I used .100x.125" strip styrene for the rocker area and drilled holes in it on the mill.
Hope that helps.
Jay, the block is machined primarily out of nickel silver. Nickel silver is a form of copper/silver alloyed brass, sometimes referred too as white brass. Some of the pieces are machined out of regular 360 cartridge brass. The parts out of 360 brass are parts that are not "wear" surfaces or surfaces that will remain unpainted. The nickel silver polishes out to a nice stainless steel color so the cylinder bores, crank journals, block deck, etc, once completed will look similar to a real engine and I wont have to worry about paint being scraped off from the motion of the pistons and crank.