"Robby" a Novel Mill Engine

[Tennessee Whiskey]

Nice job Tim. I couldn't really tell by the photo, but, the narrative was enough to make me go; "I could have just used that " Great slitting saw tip .

Cletus

[fumopuc]

Hi Tim, I am still following along. Nice job with the con-rod.

[tvoght]

Thanks Whiskey and Achim for checking in.

I made a piston rod end of brass. I have no process pictures, but I can tell you that it was made from a length of 3/8" brass rod in a collet (in the lathe, and in a collet block at the Bridgeport).
It's shown here with the connecting rod and the joint pin. It's not clearly visible in the photos, but the piston rod end is threaded for the piston rod.




Here is the mechanism coming further together.


Thanks for looking,

--Tim

[b.lindsey]

Its really starting to come together Tim. Nice job all around!!

Bill

[Don1966]

Love the connecting rods Tim , they look great. ...........


 
Don

[steamer]

Looking great!    Love the design.   This should be fun to watch run!!!
 

Dave

[tvoght]

Thanks to Bill, Don, and Dave for checking in!

Next on the build list is a built-up crank, starting with two crank disks.
When it comes to my CNC modus operandi, you'll see a lot of similarity here with some of the previous parts. I'm beginning to discover what works for me,

Here two pieces of 1/4" thick steel are stacked and clamped on the Bridgeport for drilling and reaming of the crankpin and crankshaft holes. I glued a paper pattern on the top piece to help me eyeball the position of the center hole with confidence that the outline would lie within the extent of the material.
By placing both holes over the slot, I can clamp directly to the table.


Both the shaft and the crankpin holes were drilled. Note that the paper pattern only helped me to eyeball the position of the larger hole and the orientation of the stock. The DRO was used to determine the actual hole spacing.


The holes were then reamed.


You can see how shoulder screws were again used for clamping to the CNC tooling plate.



Roughing passes were taken, leaving around .010 inches of meat for the finishing pass.


Here are the stacked crank disks after the finishing pass at full depth with a smaller diameter endmill.


Thanks for watching!

--Tim

[tvoght]

The main shafts were made from 12L14 leaded steel rod. I cut two lengths and finished the ends in the lathe, then cut keyways in each at the Bridgeport.



303 stainless ground rod was used for the crankpin. I used Loctite 609 to bond the crankpin in place while using one of the main shafts for temporary alignment during cure. Spacing in this setup was established by the connecting rod itself.


Loctite was applied to the main shafts and the assembly was set up to cure in-situ. I made one regrettable mistake. I didn't pay attention to the orientation of the keyways when I assembled, So the keyways are not oriented in any particular way with regard to the crank or to each other. This is of course only a cosmetic problem. I'm not sure it will be obvious or troublesome to any but the most critical observers.


Thanks for watching!

--Tim

[fumopuc]

Hi Tim, it seems to be an interesting construction. Waiting for seeing it in motion.

[b.lindsey]

Really looking nice Tim. You are making some rapid progress too.

Bill

[Dave Otto]

Coming along nicely Tim!

I'm enjoying seeing all your setups and great progress!

Dave

[vascon2196]

Tim...what a great looking design...and a cool little mechanism! I'm going to share this build with my Kinematics students...and I'll be following along until the end!

[Art K]

Tim,
The whole setup looks good. I like your use of shoulder screws, I wouldn't have thought of that, and I don't have them lying about.
Art

[sshire]

Tim
This is getting more fascinating with each step.
The work is first rate and I'd love to see it in Rhode Island ( finished or not.)
As for the unaligned key slots; totally unacceptable. I'd toss it and start over. 

[tvoght]

Achim, BIll, Dave, Chris, Art, and Stan: Thanks for commenting.

I have no recent activity to report, and vacation planning and vacationing may delay things for a while.

Chris, if any of your kinematics students have come to this point, here's a big shout out to them.

Stan, I hadn't really been considering exhibiting any work in Rhode Island, but I can throw this engine in the trunk. I'd like for you to see it.

--Tim