Flat head hit and miss engine???

[J Tiers]

Can't you change the opacity of parts so that the marker for interference is more easily seen?

Or is it an issue with certain curved parts that are not always "defined" well in the software? I notice that some packages do not really seem to "know" where certain types of surfaces are, typically "spline" surfaces, but sometimes others.

[sid pileski]

I'm not a SW user (I have SW but use it very little. Creo is my day to day tool) but I would be very surprised that you can't assign opacity to individual parts.
I'd also be surprised that it couldn't do interference checks. (Creo can)
There is no way that an industry leading software like SW and a direct competitor to Creo, would not have these capabilities.
Industry these days could not survive making changes on the fly to this extent.
The power is there.

[J Tiers]

I'm not a SW user (I have SW but use it very little. Creo is my day to day tool) but I would be very surprised that you can't assign opacity to individual parts.
I'd also be surprised that it couldn't do interference checks. (Creo can)
There is no way that an industry leading software like SW and a direct competitor to Creo, would not have these capabilities.
Industry these days could not survive making changes on the fly to this extent.
The power is there.

Having used an older version of Solidworks (SWX), I can say that as far as I know it does those things. I used many of them when using SWX. I did find SWX to be annoying in many details, mostly because I had used Pro-E and Alibre (Pro-E turned into CREO, I believe), whicjh are also annoying, but in entirely different ways from SWX.

But, yes, SWX does all the normal things that any parametric 3D program is expected to do, and has a ton of extensions for more capability.

[Cuttings]

Originally posted by brian Rupnow View Post

. . .My lathe has a very wide saddle which makes it almost impossible to run a live center in the tailstock to support the end of the material which isn't in the chuck. . .

Brian, as you know I have the same lathe. So far I haven't run into too much of a problem with the wide saddle. I have a live center on a MT3 mount with a bunch of adapters for different things that I got from Busy Bee a way back. It is quit long and I have been using it quit a bit lately to stablize parts a little more to cut down on chatter. It does bother me that when using the 3 jaw chuck you really have to watch when the jaws come out past the OD of the chuck, because then carriage won't pass under it then. I did see a mention somewhere that a fellow had modified the guard over the motor where the carriage runs into it so the carriage would go all the way up to the headstock. I have a 5C collet chuck which I use quit a bit and it has lots of clearance for the carriage.

[Dan Dubeau]

Checking for interference is easy in any software. Find the outer extents of the profile and do a 360 revolve. Then a simple boolean subtract/difference/interference check. I use it all the time in rhino to check interference of flips/slide units for checking fixtures. It might be a button "feature" of some software, but it's something that can be done within the basic feature set of any 3d solid modeler. I don't use solidworks enough to know if its a button feature or not. But I know you could do a revolve and intersect to see if things clear.

[Doozer]

Originally posted by brian Rupnow View Post

. . .My lathe has a very wide saddle which makes it almost impossible to run a live center in the tailstock to support the end of the material which isn't in the chuck. . .

... I have a live center on a MT3 mount with a bunch of adapters for different things that I got from Busy Bee a way back....

Many times a tailstock quill is not long enough for many setups.
So I have a few Morse to Morse taper extensions, of the same size taper
to reach out a bit more. Usually for using the center. I have a 2 to 2, a
3 to 3, and a 4 to 4 to fit all my lathes. They typically add 3 to 4 inches
to what you have. They are not expensive. Like less than $30 for a
3 to 3 extender.

-Doozer

[brian Rupnow]

Today the cam was finished and the cam and gears were mounted in their respective positions. The crankcase was drilled and tapped for the 3/8" shoulder bolt that supports them, and I am happy to announce that the gears mesh just fine with no "sticky" spots. I got lucky with the cam---Since it has a hardened wheel riding on it as a cam follower, I didn't require any flank radius on the cam. That makes the cam much easier to machine.

[brian Rupnow]

Today was assembly day. All the pieces fit where they are supposed to and everything thats supposed to go up and down and round and round seems to be doing it. This is an exciting milestone in the build, and after today I will be working on the governor mechanism that locks out the exhaust valve during the "miss" cycles.

https://youtu.be/vFaQ5wx1S3w

[brian Rupnow]

Whoever it was that said "Close only counts in horseshoes and hand grenades" should have also said something about model engines. Today I machined the support post which supports the hit and miss mechanism, and it clears the outer edge of the timing gear teeth by about 0.080". Thats okay. The timing gear only rotates and the post doesn't move, so they're never going to bump heads. My cad model told me that they would clear okay, but I never really believe it until I have the parts machined and assembled.----

[brian Rupnow]

Today I finished machining the governor and installed it. This is not a terribly challenging part of the build, but it is right on the edge of what I can see comfortably. It works. As the governor weights fly outward from centrifugal force, the spool on the crankshaft travels about 3/16", which is sufficient to move the "hit and miss lever" in and out to hold the exhaust valve open. Tomorrow I will work on the actual "hit and miss" lever.

[brian Rupnow]

At this point in the build, I'm getting right down to the nitty-gritty of things. The only remaining part to be made is the hit and miss mechanism. I think my best option is to make the actual hit and miss lever adjustable, both vertically and angle-wise in relationship to the part that rides in the governor spool on the crankshaft. I have roughed out something, and decided that it will catch under a notch filed in the swing arm that lifts the exhaust valve. Once I have adjusted it for the best possible hit and miss action, I may solder it in position and cut off the portion that holds the clamp bolt.

[brian Rupnow]

Today I machined the hit and miss mechanism and mounted it to the engine. I think it will work alright.--When I move the governor weights by had the weird shaped arm does easily rotate into place and if there was a notch in the swinging arm it certainly appears that it will catch it and hold the exhaust valve open. I'm not going to put the notch in the swinging arm until the engine is up and running. You only get one chance at something like this, and if you file the notch in the wrong place you end up having to machine a new swinging arm. I still have deburring and filing to do to make everything pretty, but first assembly is simply to show me that all the parts fit where they are supposed to.--

[brian Rupnow]

Great deeds were accomplished today. Ignition points and condenser were ordered and can be picked up tomorrow. New sparkplug was purchased and installed. New Viton piston ring and head gasket o-rings were picked up and installed. Finally made a new longer keyway bushing and was able to use it with my broach set to cut a keyway in the flywheel hub. (These broaches cost $100 each and will break if the keyway bushing is shorter than the hub being keyseated.---Don't ask me how I know!!) The keyway was cut in the crankshaft. There are some really nasty looking mig welds on the side of that flywheel that faces the engine, I will grind them down before I am finished here. So--For the moment everything is assembled, first time. I still have gaskets to make, add oil ports to the crankcase, and welds to grind. I also have to make a starter hub that attaches to the flywheel so I can use my electric drill as a starter.

[brian Rupnow]

Today I machined the starter hub which attaches to the flywheel and mounted it. Likewise machined the part which fits into my electric drill. I picked up the points and condenser and installed them. The two brass plugs that fit into the manifold above the valves were polished and then loctited into place. I still have to put in an oil filler pipe---haven't thought about it too much, but I've almost ran out of things to make.

[reggie_obe]

Could your start hubs and flywheel ends be designed as universal? One start hub fits any engine?
No wasted material, less of an impact on resources and the Rupnow fortune.