- Joined
- May 27, 2010
- Messages
- 2,999
- Reaction score
- 1,171
One more twin engine of my build list. Please advise plan and casting vendor address.
Vimana Vee Twin
- Thread starter Modhydro
- Start date
Help Support Home Model Engine Machinist Forum:
We are doing this build as a verification of the castings and proofing of the plans. Rather than have Mr. Kadora offer the stuff as not verified, we are going to complete this build, make any necessary adjustments and then I'm sure he will be offering the stuff for sale.
Please be patient and the finished product will be worth it. The more checking we do up front, the better off everyone else should be.
As for Mitch being a lurker, that was me as well. A friend from work got me looking at the site a couple of years ago. Once upon a time he was building a Tiny Inline 4 Cyl IC. It got me more excited about doing something. Take the plunge and start a thread of your own. It doesn't have to be a whole engine. I did some posts on lathe modifications and even a tool or two.
Steve
Please be patient and the finished product will be worth it. The more checking we do up front, the better off everyone else should be.
As for Mitch being a lurker, that was me as well. A friend from work got me looking at the site a couple of years ago. Once upon a time he was building a Tiny Inline 4 Cyl IC. It got me more excited about doing something. Take the plunge and start a thread of your own. It doesn't have to be a whole engine. I did some posts on lathe modifications and even a tool or two.
Steve
Things have been a bit slow around the shop with some house projects taking precedence.
I am working on the crankcase cover and the sideplates opposite that carry the main bearing as well as the cam gearchest and cams themselves. Stay tuned for some new posts coming soon. I should have these subassemblies done by the end of the weekend and have lots more to share.
Steve
I am working on the crankcase cover and the sideplates opposite that carry the main bearing as well as the cam gearchest and cams themselves. Stay tuned for some new posts coming soon. I should have these subassemblies done by the end of the weekend and have lots more to share.
Steve
I am trying this again. For some reason the site crashes when I attached photos.
I am making progress again. I am doing things a bit differently from the method that Juraj used on his initial engine. He glued the parts together with epoxy to gang drill the holes all at one time. I made dimensioned drawings for all the parts and aligned them as a subassembly with mill clamps, but still did the gang drilling to ensure alignment.
One thing that is a bit different with doing a model or anything from that matter from rough castings means establishing a datum. By rough castings, I don't mean the quality. These are actually very nicely done and as good as you will ever find. Being that these came out of the sand, there isn't a dead true surface so we need to pick one face that is close and start there. I did it on a belt sander holding the parts gently and being sure not to rock them and sand a rounded surface. If you are worried about ruining a part with power tools the same thing can be accomplished with hand lapping on a smooth plate. You also eliminate the risk of burnt fingertips. It is amazing just how quickly a part will go form warm to sizzling your fingers followed by the impact of the just released part hitting the wall. Don't ask me how I know.
I am going to post this without the photos and then try photos after.
Steve
I am making progress again. I am doing things a bit differently from the method that Juraj used on his initial engine. He glued the parts together with epoxy to gang drill the holes all at one time. I made dimensioned drawings for all the parts and aligned them as a subassembly with mill clamps, but still did the gang drilling to ensure alignment.
One thing that is a bit different with doing a model or anything from that matter from rough castings means establishing a datum. By rough castings, I don't mean the quality. These are actually very nicely done and as good as you will ever find. Being that these came out of the sand, there isn't a dead true surface so we need to pick one face that is close and start there. I did it on a belt sander holding the parts gently and being sure not to rock them and sand a rounded surface. If you are worried about ruining a part with power tools the same thing can be accomplished with hand lapping on a smooth plate. You also eliminate the risk of burnt fingertips. It is amazing just how quickly a part will go form warm to sizzling your fingers followed by the impact of the just released part hitting the wall. Don't ask me how I know.
I am going to post this without the photos and then try photos after.
Steve
That was really strange. I didn't do the manage attachments and the photos were still there from the last try. The session crashed, but the stuff stuck.
I will try to move on to the actual facing operations once we have established the flat datum.
The first ones show decking the front cover. My parallels didn't have the increments to hold the casting above my vice jaws so I simple cut a piece of .032" aluminum to give me the cutter clearance I needed. Since the jaws are only holding on points due to the irregular shape, I took very light and easy cuts. The results were a very nice finish. Notice that the parallels must be under your flat surface which in these cases were not at the vice jaws. It would be an easy mistake to mess up this stage.
I will try to move on to the actual facing operations once we have established the flat datum.
The first ones show decking the front cover. My parallels didn't have the increments to hold the casting above my vice jaws so I simple cut a piece of .032" aluminum to give me the cutter clearance I needed. Since the jaws are only holding on points due to the irregular shape, I took very light and easy cuts. The results were a very nice finish. Notice that the parallels must be under your flat surface which in these cases were not at the vice jaws. It would be an easy mistake to mess up this stage.
No crash that time and it all stuck!
Looking at the castings it seemed the the round boss inside the front cover was favored low in comparison to the crankcase. I put it under the crankcase aligned the two and then drew the ID onto it. The photo shows the offset. Since I had the plug to locate the crankcase on the rotary table from before, I figured it would be an easy thing to make a mandrel to fit inside of it and transfer punch the actual center line directly on the casting.
I set the punch marked casting in the mill and drilled with a center drill on the mark. If you take your time and barely kiss the workpiece with the bit you can adjust to get the drill mark and the punch concentric sort of like a bullseye. There isn't a lot of depth to the punch mark so you need to be pretty close right off the bat. It didn't dawn on me in the shop, but in posting these photos, I should have clamped the front cover and cam gear box castings together and drilled them both at once. I just had to re-indicate the hole since I wasn't that smart the first time around!
You can see how nice the alignment of the castings winds up though.
Looking at the castings it seemed the the round boss inside the front cover was favored low in comparison to the crankcase. I put it under the crankcase aligned the two and then drew the ID onto it. The photo shows the offset. Since I had the plug to locate the crankcase on the rotary table from before, I figured it would be an easy thing to make a mandrel to fit inside of it and transfer punch the actual center line directly on the casting.
I set the punch marked casting in the mill and drilled with a center drill on the mark. If you take your time and barely kiss the workpiece with the bit you can adjust to get the drill mark and the punch concentric sort of like a bullseye. There isn't a lot of depth to the punch mark so you need to be pretty close right off the bat. It didn't dawn on me in the shop, but in posting these photos, I should have clamped the front cover and cam gear box castings together and drilled them both at once. I just had to re-indicate the hole since I wasn't that smart the first time around!
You can see how nice the alignment of the castings winds up though.
Now that we have trued up castings, machining can move forward to get it to be a subassembly.
The next step was to mount the front plate in a four jaw chuck and face off the mounting spigot that goes into the crankcase as well as its mating flat surface. As before I used a center in the tailstock to get close, but then used and indicator to pick up the previously drilled center hole. Once I was happy with the centering, light cuts were taken to bring the part to the correct dimensions. With just a bit of "Tapmagic" on the part, it cut beautifully.
With the front cover machined on both sides, the whole assembly can get gang drilled. I mounted the crankcase back on the rotary table with the centering ring and then clocked it to the existing holes. Once this was clamped to the table, the fresh castings were aligned on the same transfer punch mandrel and clocked correctly. Once clamped the holes were drilled through both pieces guaranteeing their alignment and eliminating one whole setup.
The final photo shows the parts layed out next to each other.
The next step was to mount the front plate in a four jaw chuck and face off the mounting spigot that goes into the crankcase as well as its mating flat surface. As before I used a center in the tailstock to get close, but then used and indicator to pick up the previously drilled center hole. Once I was happy with the centering, light cuts were taken to bring the part to the correct dimensions. With just a bit of "Tapmagic" on the part, it cut beautifully.
With the front cover machined on both sides, the whole assembly can get gang drilled. I mounted the crankcase back on the rotary table with the centering ring and then clocked it to the existing holes. Once this was clamped to the table, the fresh castings were aligned on the same transfer punch mandrel and clocked correctly. Once clamped the holes were drilled through both pieces guaranteeing their alignment and eliminating one whole setup.
The final photo shows the parts layed out next to each other.
Bill,
It started out great, but this past spring and summer wound up kind of rough for me on several fronts. The last of the issues was the bonus of enjoying a 100 year flood that wound up with about 8" of water in my shop.
Here are a couple of photos. They were after the torrential rains and when the water was actually receding.
Both kids are now in college so I should be able to get back to it. Juraj has been extremely patient with me and I want to get this finished up for him and all the others to see the finished result.
Once this is done he will have the full drawing set and I think will be offering the castings.
Steve
It started out great, but this past spring and summer wound up kind of rough for me on several fronts. The last of the issues was the bonus of enjoying a 100 year flood that wound up with about 8" of water in my shop.
Here are a couple of photos. They were after the torrential rains and when the water was actually receding.
Both kids are now in college so I should be able to get back to it. Juraj has been extremely patient with me and I want to get this finished up for him and all the others to see the finished result.
Once this is done he will have the full drawing set and I think will be offering the castings.
Steve
Rozlo
Active Member
- Joined
- Oct 19, 2015
- Messages
- 33
- Reaction score
- 0
Steve,
Crap sorry to see your shop like that. But good to hear about the engine drawings and castings. Like I said I'm just getting started and again after a 20 year layoff from machining so I'm pretty much a newbie again. But I patients and it will come together. Thanks for the reply, and keep making chips.
Bill
Crap sorry to see your shop like that. But good to hear about the engine drawings and castings. Like I said I'm just getting started and again after a 20 year layoff from machining so I'm pretty much a newbie again. But I patients and it will come together. Thanks for the reply, and keep making chips.
Bill
