Author Topic: Chris's Mann Wagon Build  (Read 130050 times)

Offline crueby

  • Full Member
  • *****
  • Posts: 18554
  • Rochester NY
Re: Chris's Mann Wagon Build
« Reply #1080 on: November 30, 2020, 11:49:33 PM »
Thanks Kim!

Not much to show today, it was my mothers birthday so was over there most of the day.  ^-^

Did finish painting up the flywheel, matching pattern to the other cab parts with the yellow stripe. For touchup, had a happy find, that the Yellow Oxide color of the Liquitex acrylic artists paints that I have is a dead match for the Caterpiller Yellow spray paint. In the picture it is on a short bit of 1/4" rod to keep the paint out of the hole in the hub. Still a few dabs to do in touchup where the paint bled under the striping tape.


I was about to start in on the reverse links, but I found a booboo in the CAD parts for it, and need to make some adjustments there (one of the connecting links was in the wrong place).

Offline crueby

  • Full Member
  • *****
  • Posts: 18554
  • Rochester NY
Re: Chris's Mann Wagon Build
« Reply #1081 on: December 01, 2020, 07:49:04 PM »
Yesterday and today got working on the reverse gear links. These started out as two pieces of 1/8" thick 303 stainless flat bar, with holes drilled in either end. One of those holes will stay and become the anchor point for the control rods, the other will be trimmed off.

Got out one of my tooling plates, this one a aluminum flat with a bushing screwed to the bottom at one end that fits into the rotary table center hole, along with a pair of t-nut bolts to hold it to the table. The table was centered up, and moved out to the radius of the center of the link, where a line was scribed along the arc. Then moved the table in and out half the distance between the holes, and adjusted to intersect the scribed line to drill/tap holes to screw the blanks down (the holes were laid out to be on that radius).

With the two blanks screwed to the plate, moved it to the radius of the eccentric yoke end holes, and drilled two more holes at 6 degrees either side of center.


Ran in two more screws through those holes (milling can put a lot of force on the part, and the screws are small, so more is better). Then chain drilled holes along the length of the slot - used a drill a little smaller than the final slot in case of any wandering by the bit.

Followed by milling out the slot to size, doing a series of passes going progressively deeper - these small mill cutters can flex and pull a few thou to the side on deep through cuts otherwise.

With the slot done, trimmed the arc on the outer edge:

Then trimmed away the inner edge

and trimmed the ends close to final (will clean up the small arcs on the belt sander). The near end was trimmed back to remove the screw hole, that was just there to help hold the parts.


So, the two parts ready for cleanup on the belt sander:

and after cleanup:

Then got them installed on the eccentric followers.


Turning the crankshaft over by hand made it apparent that the holes in the cover plate were a little small in places, so that was taken off and the holes trimmed back.


Next up will be the control linkages and the hand lever to actuate the reverse gear. Lots of fiddly little parts!

Offline propforward

  • Full Member
  • ****
  • Posts: 1656
  • MN, USA
Re: Chris's Mann Wagon Build
« Reply #1082 on: December 01, 2020, 08:22:57 PM »
It’s great to see your step by steps on how to make such parts. Very informative and helpful! Really impressive work as always.
Stuart

Forging ahead regardless.

Offline cnr6400

  • Full Member
  • *****
  • Posts: 2728
Re: Chris's Mann Wagon Build
« Reply #1083 on: December 01, 2020, 08:46:58 PM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:

You found the "missing link(s)" - hiding in that stainless plate!   :Lol:
"I've cut that stock three times, and it's still too short!"

Offline crueby

  • Full Member
  • *****
  • Posts: 18554
  • Rochester NY
Re: Chris's Mann Wagon Build
« Reply #1084 on: December 01, 2020, 09:22:30 PM »
Thanks guys!  And there are plenty of times when I go back to earlier builds to remember 'how'd I do that last time?'

Offline crueby

  • Full Member
  • *****
  • Posts: 18554
  • Rochester NY
Re: Chris's Mann Wagon Build
« Reply #1085 on: December 02, 2020, 10:27:33 PM »
Gotten a start on the reverse gear control levers, starting with the holder for the rod that goes across the top of the boiler below the crosshead guides. At either end of this will be an arm leading back to the slide links, and at the far right end is a crank arm that will connect up to the control lever next to the driver. This holder is let into the engine block mounting plate, with countersunk screws coming up from underneath with some Loctite 638 for good measure.

Then got started on the control arms, milled from some flat 303 bar stock:

Following the milling operations, the arms were silver soldered to round bar to form the center section, and after cleanup started to do the final shaping on the belt sander. Here is as far as I got, some done on the left side arm,

whereupon the belt sander ate the bearings inside the belt tensioning idler wheel. Started out with some squealing sounds, then when it was shut off the bits of bearings inside the race blew up, so it only rotates about 10 degrees now. Considering that this sander (a 1x30" Dremel) is at least 35 years old and has been used on countless projects, I can't complain! So, it is going to need some repair/replacement work, have to see if the bearings will come out and what size, may just replace the unit since other bearings are likely in similar condition. If so, will at least salvage the motor section out of it, those come in handy for other tools (my buffing wheel is built from an old furnace blower motor from my parents house, salvaged when the rest of the furnace was replaced).

Offline crueby

  • Full Member
  • *****
  • Posts: 18554
  • Rochester NY
Re: Chris's Mann Wagon Build
« Reply #1086 on: December 03, 2020, 07:45:19 PM »
Okay, going to backtrack a little on the reverse gear for this engine. Using the parts I have made so far, I was moving things by hand to check clearances and movements, and realized something about where I connected up the control linkages. With the raise/lower rod up at the end of the slide link, the movement of that end in forward and reverse results in a large arc on the control linkage, which is not a great thing for equal movements in forward and reverse. While this is the way that the Mann truck in Vancouver has it, and it obviously works okay there, down at model scales at least it is an issue. It will work this way, but I think moving that control link endpoint to the middle of the slide link will result in better motion. I've made models that have it both ways, starting with the Stuart D10 that was my first build many many years ago, and more recently the Kozo New Shay and the Lombard Hauler, which both have the connection in the middle of the link. Of the two setups, the Shay/Lombard is much better behaved, and the re-reading of old texts I have done shows that this is a better approach.

So, I am going to re-work the slide links to change this layout, meaning that the links I made the other day will go in the spares bin for now - the extra days work will be worth it in the long run.

For a picture of what I am on about, here is a view in the CAD version of how I had designed it, matching the Vancouver machine:

The control rod in green at the bottom is connected to the hand lever by the driver - it raises and lowers the slide link to select forward and reverse. The current design has the other end of the linkage up at the top, shown in red. This is fine, till I rotate the crankshaft and watch the motions. Given the short slide link - short due to the space available - the end connection point moves through very long  different arcs that vary a bit depending on if it is in forward or reverse. If the connection is moved down so the pivot point is in the middle, shown in blue, that arc gets very short and is more consistant. The big problemm with having a long arc is that it introduces a larger vertical motion to the slide link during the crank rotation, making the slide link change position a bit relative to the follower inside the link.
More pictures as the re-design is done!
 :cheers:

Offline pgp001

  • Full Member
  • ****
  • Posts: 812
  • West Yorkshire - UK
Re: Chris's Mann Wagon Build
« Reply #1087 on: December 03, 2020, 07:53:14 PM »
You look to have some interference between the inner control link and the trunk guide in that image ?

Phil

Offline crueby

  • Full Member
  • *****
  • Posts: 18554
  • Rochester NY
Re: Chris's Mann Wagon Build
« Reply #1088 on: December 03, 2020, 08:20:03 PM »
You look to have some interference between the inner control link and the trunk guide in that image ?

Phil
Ah - didnt see that before! Nice catch! Fortunately in the new setup, that inner link is no longer needed so that goes away!  Guess that would have been a nasty surprise later on.


I just finished drawing the new version in Fusion (gotta love how quick things can be moved when they are just electrons) :



I think this will work out much better overall. Need to remake the slide links, and make a longer square pivot bar at the bottom, but that is not bad.

Offline pgp001

  • Full Member
  • ****
  • Posts: 812
  • West Yorkshire - UK
Re: Chris's Mann Wagon Build
« Reply #1089 on: December 03, 2020, 08:33:32 PM »
Chris

I spend all day every day in my job designing special machinery in Solidworks, so I get a bit nerdy about looking for errors in my own assemblies, it is just second nature after a while.
I have to check some of our younger designers output as well, that makes for some very interesting conversations   ;D

I also have a policy of never using any published model engineering designs until I have modelled them in 3D first to prove they are OK, you would be surprised how many have serious errors that have been circulating for years.

How does your new version work out on the LP side, that has a bigger diameter trunk guide ?

Phil

Offline crueby

  • Full Member
  • *****
  • Posts: 18554
  • Rochester NY
Re: Chris's Mann Wagon Build
« Reply #1090 on: December 03, 2020, 08:42:36 PM »
Chris

I spend all day every day in my job designing special machinery in Solidworks, so I get a bit nerdy about looking for errors in my own assemblies, it is just second nature after a while.
I have to check some of our younger designers output as well, that makes for some very interesting conversations   ;D

I also have a policy of never using any published model engineering designs until I have modelled them in 3D first to prove they are OK, you would be surprised how many have serious errors that have been circulating for years.

How does your new version work out on the LP side, that has a bigger diameter trunk guide ?

Phil
Hi Phil - I always welcome another set of eyes, that was a daily thing when I was a firmware engineer. Amazing how someone who has no idea how an algorithm works can still spot a goof by asking 'gee, what does THAT part do?'. Answer:  'Oh, that controls the .... um.... whoops!'

On the LP side, the eccentrics are spaced over from the crank web farther so that they line up on the valve chest there - the guide and the cylinder are so much larger that everything on that side is farther apart. I had ALMOST goofed that when turning the crankshaft, was just about to start cutting the eccentrics next to the crankweb but fortunately took another look at the drawings before turning on the power! Those kinds of close calls are fun. As long as they are caught in time!
Chris

Offline tghs

  • Full Member
  • ****
  • Posts: 1034
Re: Chris's Mann Wagon Build
« Reply #1091 on: December 03, 2020, 08:48:23 PM »
you're going to need to adjust the length of the intermediate lifting rod,, so the link is in the upper position,,
what the @#&% over

Offline crueby

  • Full Member
  • *****
  • Posts: 18554
  • Rochester NY
Re: Chris's Mann Wagon Build
« Reply #1092 on: December 03, 2020, 08:56:31 PM »
you're going to need to adjust the length of the intermediate lifting rod,, so the link is in the upper position,,
That was done - in the 3D version the links were in a position to draw them conveniently, but I did check the limits. The length of several of the links had to be adjusted for these changes. And, I usually (not always, which has caused issues) check dimensions for linkages on the model as-built-so-far to make sure any tolerance stacking has not bitten me in the butt.

Offline cnr6400

  • Full Member
  • *****
  • Posts: 2728
Re: Chris's Mann Wagon Build
« Reply #1093 on: December 03, 2020, 09:19:25 PM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:

Glad you detected the problem early on! These things happen. The links that went in the spares box will give Mr Ethan Oll something to polish. :Lol:
"I've cut that stock three times, and it's still too short!"

Offline crueby

  • Full Member
  • *****
  • Posts: 18554
  • Rochester NY
Re: Chris's Mann Wagon Build
« Reply #1094 on: December 03, 2020, 09:32:26 PM »
:ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:

Glad you detected the problem early on! These things happen. The links that went in the spares box will give Mr Ethan Oll something to polish. :Lol:
The shop elves are trying to make them fly like boomerangs!  Two cracked windows, one broken lamp, and one elf with a concussion so far...

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal