TB2 - Modifications to the build

[kvom]

Dick,

Since I'm such a newb I think I can plan on messing up at least one :-[ If I run out I'll buy some extra stock locally.

 

[Dick L.]

Can we do a sectioning job on the cam ring so that we could use the threaded piston rod and fork idea? Adjustment could be done in the gap ,then loctite with a light grade (242 blue) if no room for a jam nut.I've attached some pdf to show what I mean. Dick

View attachment Cam ring insert.PDF

View attachment Cam Ring Assembly.PDF

View attachment cam ring.PDF

 

[Powder keg]

I like that idea Dick, But for that to work the we would need left and right handed threads on the ends of the piston rod and the forks. With out that, the adjustment would be a half turn at a time and on this little guy, too much or too little, I think. I think a setscrew will be easier. Plus if we use a hex head bolt, it wont look bad)

Wes

 

[Dick L.]

Hi Wes, yes it would take a bit of hassle to achieve. I've just been playing with the models of it as I go based on some things we discussed. The set screws will be fine on a small model this size with no real load. I'm hoping to build one complete as well as the team build which is why I'm modeling it. I'm sure I will try a few different things along the way.I'll be very interested in everyones setups and fixturing for their different pieces.
Dick

 

[Powder keg]

Forgot to add. Those drawings are awesome Dick!!! I like the removable insert at the bottom. I drew the cam ring up with Master cam. I scaled it up to 3X its original dimensions. I talked to my boss and he said I could mill a couple of them out after work one of these days)

Wes

 

[te_gui]

Was someone going to redraw this with our proposed mods in place or are we ready to start building? I thought I had seen someone volunteer...

Brian

 

[Dick L.]

I think what we need is a list of modifications that we are all aware of. So far the base is thicker, we are using oil cups, possibly an angled hole to fasten the flywheel,and set screws on the forks I think .
I was playing with the cam ring to see what else might work easily. I have drawn a lot of this engine but with no regard to changes (what I've mentioned is cosmetic) because as time allows I want to build another one complete.
I had also planned on using a small oilite bushing on the small bearing end I'm making and allowing it to be slightly above the surface on on side to act as a thrust bearing , keeping the valve body in arrangement.
Dick

 

[kvom]

possibly an angled hole to fasten the flywheel

First I've heard of this ???

In any case my instructor seems agreeable to me making the flywheels as an in-class class project.

 

[GailInNM]

I am ready to make the cams when I am sure that all the dust from modifications has settled. I don't want to lock anybody into anything that they are not comfortable with.

I drew up a modified cam ring with just a cosmetic modification to it. It would not affect any other part. I drew in two different forms. One is aluminum with CNC engraved lettering and filled with black lacquer stick and the other black anodized with the lettering laser engraved into the anodized surface. The anodized one depends on if I get my anodizing tank set back up. I have everything on hand for the anodizing, just need to set it up. I used to do, but quite a while ago.

Let me know what you would like. I would like to make them all the same.
1. Standard to Elmer's Drawing
2. Aluminium with engraved and filled letters
3. Black anodized with laser engraving

Gail in NM,USA

 

[Dick L.]

I think what happened was a lot of discussion happened here in the original thread...
Dick
http://www.homemodelenginemachinist.com/index.php?topic=2335.15

 

[kvom]

I for one like the black annodized version.

 

[bretk]

That aluminum one sure looks nice with the black filled letters ;D

 

[Powder keg]

I vote for the aluminum one with the black letters also)

Wes

 

[Brass_Machine]

I am up for either of the cam rings!

Eric

 

[Brass_Machine]

Dick,

Could you please explain a little about the oilite bearing for the small end? What did you have in mind so we can add it to the list of modifications?

Eric

 

[Dick L.]

Instead of just using the aluminum as the bearing surface I propose inserting a 3/16 id 5/16 od oil lite bushing in the small end bearing. If you look on page 219 of the plans on the top view the flywheel sets the sideplay of the valve body in the big end bearing. By using a bushing in the small end and leaving it above the surface slightly it will provide a thrust surface for the flywheel hub to contact keeping the drag off of the flywheel rim and the forks and cam ring. Hope this helps. I can do a drawing if it's still not clear. But I can't do it right now.
Dick

 

[Brass_Machine]

Instead of just using the aluminum as the bearing surface I propose inserting a 3/16 id 5/16 od oil lite bushing in the small end bearing. If you look on page 219 of the plans on the top view the flywheel sets the sideplay of the valve body in the big end bearing. By using a bushing in the small end and leaving it above the surface slightly it will provide a thrust surface for the flywheel hub to contact keeping the drag off of the flywheel rim and the forks and cam ring. Hope this helps. I can do a drawing if it's still not clear. But I can't do it right now.
Dick

No need for the drawing just yet. Though we may need them for the people doing the bearings when it comes time for them to build. I understand what you are saying. How would it interfere with the oil cups? would the just become ornamental then or do we drill a small hole in the bearing to allow for oil flow?

Also, would we want a bearing on the big end too?

Eric

 

[Dick L.]

Eric , On the small end it won't interfere with the oil cups at all. On the big end the strap of aluminum above the bore is only 1/8" . That is why I asked about making them a little taller when the oil cups were agreed on. No need to increase the height just for the cups but if you want a bearing on the big end too we would have to make them taller. I would want a matched set myself so I would change both (taller) or none.
Dick

 

[joe d]

I would want a matched set myself so I would change both (taller) or none.
Dick

That's my outlook too, it would look a little odd to me with them asymmetrical. Putting the oilite bushings in seems like a good idea to me too. Presumably just a question of drilling through the bushing for feed from the oil cups? Regarding Gail's cam rings, I like the anodized one best, but will bow to the group decision what ever it turns out to be!

Joe

 

[Dick L.]

Almost forgot, I like the aluminum with filled letters.
Thanks,
Dick