Author Topic: Chris's Holly Pumping Engine Build  (Read 154134 times)

Offline mklotz

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Re: Chris's Holly Pumping Engine Build
« Reply #1665 on: November 18, 2021, 05:37:51 PM »
Someone with your creative skills shouldn't have to hand-tap that many holes.  What you need is a modelmaker's power tapping machine.

I'm thinking of a stepping motor that drives the existing tapping machine via gears.  A programmable chip (e.g. Arduino) drives the motor for a user-selectable number of tap rotations (thus limiting depth of thread).  Once those are completed it reverses and backs the tap out and awaits the next hole.

Like everyone else, I've run out of superlatives to describe your work, cleverness, speed, persistence, documentation, etc..  Suffice it to say that I'm overwhelmed.
Regards, Marv
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Offline crueby

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Re: Chris's Holly Pumping Engine Build
« Reply #1666 on: November 18, 2021, 06:03:24 PM »
Someone with your creative skills shouldn't have to hand-tap that many holes.  What you need is a modelmaker's power tapping machine.

I'm thinking of a stepping motor that drives the existing tapping machine via gears.  A programmable chip (e.g. Arduino) drives the motor for a user-selectable number of tap rotations (thus limiting depth of thread).  Once those are completed it reverses and backs the tap out and awaits the next hole.

Like everyone else, I've run out of superlatives to describe your work, cleverness, speed, persistence, documentation, etc..  Suffice it to say that I'm overwhelmed.
Sounds too much like the firmware w*rk I used to do!  For fine taps you'd also want force feedback detection to know if it hit bottom of a shallow hole, bound up with chips  etc, and back out. Then you need the chip brush, oiler, wiper,...  Cookie fetcher...


I'd rather do things by hand, thats the fun of it.


 :cheers:

Offline crueby

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Re: Chris's Holly Pumping Engine Build
« Reply #1667 on: November 18, 2021, 07:08:28 PM »
For all my complaining, the tapping didnt really take that long

Got the cylinder bolted onto the faceplate with the bottom end now at the faceplate,


and turned the top end down to final size. Used the tailstock/plate again just to ensure no wobble or digging in and disasters while taking the bulk of it down. Here, there is just a thin cylinder left near the bore:

then removed the tailstock support, and took some light cuts to trim off the final cylinder wall, leaving the flange that locates the cylinder cap:


Then moved the faceplate/part over to the rotary table, which is still locked in at the settings for the bolt circle from the other parts, and started drilling the holes, starting with a center drill to spot the locations. I had also set up the cylinder and top cap, marking out the locations of two of the front holes so that I would have the cap location lined up with the bosses. I'll use the still-square section of the cap to locate the valve and steam/exhaust passages, so everything lines up correctly.

 :cheers:

Offline Kim

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Re: Chris's Holly Pumping Engine Build
« Reply #1668 on: November 19, 2021, 12:13:26 AM »
Beautiful!   :popcorn:
That's a lot of screws there Chris!  And I'm sure you FEEL that - you tapped every one of those holes :)

Kim

Offline cnr6400

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Re: Chris's Holly Pumping Engine Build
« Reply #1669 on: November 19, 2021, 01:56:19 AM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:
"I've cut that stock three times, and it's still too short!"

Offline Don1966

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Re: Chris's Holly Pumping Engine Build
« Reply #1670 on: November 19, 2021, 03:47:47 AM »
 :Love:……….



 :cheers:
Don

Offline crueby

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Re: Chris's Holly Pumping Engine Build
« Reply #1671 on: November 19, 2021, 04:28:33 PM »
Thanks guys!
Got the last of the holes drilled in the top of the cylinder, and set the parts up on the engine for a family shot:

Then on to drilling the holes for the valve tubes in the base/top caps. These are larger diameter than the ones in the HP cylinder, to handle the increased volume of the steam. Started out with a 1/4" drill, and stepped up the size several times to the final diameter to keep a smoother hole - too deep for the boring head to be practical. The final drills were too large for the drill chuck (3/8" max) and too long for it anyway, ran out of column height, so the last few drills were held in the three-jaw.


Five passes on each hole in the base to finish them off:

On the top cap, with its curved surface, started with making flats with an end mill to give the drills a good surface to start on

the switched over to the drills - about halfway done on the first hole, will continue after lunch.

When these holes are done, will drill in from the sides for the inlet/exhaust passages...

Offline crueby

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Re: Chris's Holly Pumping Engine Build
« Reply #1672 on: November 20, 2021, 05:02:47 PM »
Quite a bit accomplished on the cylinder caps today. Started out by bolting the top cap to the faceplate (drilled out the tapped holes from attaching the cylinder to clearance size so the screws could go through to the tapped holes in the caps).

then turned off the square portion, after marking the front face centerlines for the grid work to come. Also turned the top face to a shallow dome.

Moved the faceplate over to the rotary table and marked out the grid to be put into the top. Started by milling in the openings on one side


then the other

followed by, you guessed it, the remaining two sides

and finished off with the four center squares, plunge cut in then milled out

leaving a mostly-done top cap for the cylinder to wear as a shiny new hat

The valve tubes and inlet/exhaust flanges still need to be added to the top cap. Well, bottom cap too!

Then bolted the bottom cap onto the faceplate, and bored out the cavity in the bottom to let the piston rod gland be recessed in, as well as a counterbore for the o-ring to seal the piston rod.


Next will make the piston rod gland and get its screw holes drilled/tapped while the piece is on the faceplate. After that, can start shaping in the sides of the block. The block bolts to the engine frames down two sides - for those screws the left/right sides need to be undercut to form an opening for the screws to go in. On the real one that gap was big enough for someone to reach in and set the nuts and get wrenches in to tighten them. At this scale, its going to be some fiddly work with needle nose and open end wrenches to get the screws in.

Offline cnr6400

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Re: Chris's Holly Pumping Engine Build
« Reply #1673 on: November 20, 2021, 05:46:49 PM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn: Looking great Chris!
"I've cut that stock three times, and it's still too short!"

Offline crueby

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Re: Chris's Holly Pumping Engine Build
« Reply #1674 on: November 20, 2021, 05:59:55 PM »
:ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn: Looking great Chris!
Thanks!  It sure seems like this cylinder is going a lot faster, given how similar it is to the first one.

Offline Kim

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Re: Chris's Holly Pumping Engine Build
« Reply #1675 on: November 20, 2021, 06:45:25 PM »
Great work, Chris!  :popcorn:

It sure seems like this cylinder is going a lot faster, given how similar it is to the first one.

Like seeing a movie for the second time - it seems to go faster because you know what's coming next :)

Kim

Offline Don1966

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Re: Chris's Holly Pumping Engine Build
« Reply #1676 on: November 21, 2021, 03:21:01 AM »
Awwwww….. the smell of brass. Dog you just got to show of that brass you know ……I……………likeeeeeee… :Love:


 :drinking-41:
Don

Offline crueby

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Re: Chris's Holly Pumping Engine Build
« Reply #1677 on: November 21, 2021, 05:46:17 PM »
Thanks guys!

And for the record, here is what the shop elves did to the last guy who said my lathe was only good for woodworking...



Offline crueby

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Re: Chris's Holly Pumping Engine Build
« Reply #1678 on: November 21, 2021, 05:51:07 PM »
Some more done on the IP cylinder base this morning. Got the piston rod gland made and fitted

then started taking the sides down to final dimension, leaving the cylinder mounting ring sticking out (this is how the original had it, in case you wondered)

Here it is with all four sides taken down - the front/back edges overhang more than the left right ones do:

and had to pose it with the other parts:

Now am recessing the sides at the bottom for where the bolts that hold the base to the engine frames will go. Plenty of room on the full size engine for someone with a wrench to get in there, for the model its going to be a pain in the swarf to run them in:

One side slotted, one to go. The bottom/side edges get taken back a little more, to where the horizontal blue line is in the photo.

Offline cnr6400

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Re: Chris's Holly Pumping Engine Build
« Reply #1679 on: November 21, 2021, 09:20:45 PM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:
"I've cut that stock three times, and it's still too short!"

 

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