Bogstandards "Paddleducks" engine

[shred]

It's sort of traditional when I get a new machine to use it to make a simple engine to get a feel for how it works and what all the knobs do.

This time around I decided to try Bogstandard's "Piston Valve Engine from mainly junk materials" -- it's a little 2-cylinder twin engine that I'd been meaning to give a go for a while now. Plans and text are posted in the download section. With any luck I can finish it in less than the year the my loco took

Of course the plans are metric and while the new machine has a DRO that will speak metric, I still don't have metric drills, reamers or stock material, so I get to adapt and improvise. So far that's been limited to switching the bore for 3/8", changing the piston rods to 1/8" with 5-40 and 4-40 threads as well as 3/16" crosshead guides.

Anyway, after Day 1, I got the block bored, the glands, caps and piston made, plus started in on the cross head blocks and broke one tap. We'll see how square everything ended up later..

 

[malcolmt]

Hi Shred

"after Day 1, I got the block bored, the glands, caps and piston made, plus started in on the cross head blocks and broke one tap.!

I would call that almost prolific.

Nice work, I'm looking forwards to watching this come together.

Kind regards

Malcolm

 

[ozzie46]

I also plan to build this engine. I have even obtained some cast iron window sash weights for the cyls. ;D

Ron

 

[Philjoe5]

Thanks for the progress report. I'm with Malcolm - seems a lot was accomplished in 1 day especially with new tools and converting metric, :bow:

Cheers,
Phil

 

[deere_x475guy]

Shed I have been eyeing that engine for a long time now. I am looking forward to seeing your progress.

 

[shred]

Well.. I did have the entire day to play. Normally I do well to make a part or two per day, what with the rest of life intruding and all.

 

[shred]

Tried to hack the crossheads out of the blocks today. That didn't go so well. Looks like the piston hole is considerably off-center. Oh well, it's good practice with the new machine. I'll carry on a bit and see when I need to make a new set. These still have a lot of ugly left in them, so it wouldn't be a big loss.

One thing I did notice was the resemblance to a certain common household plumbing fixture from certain angles. I believe our British cousins might refer to it as a 'bog'. If that was a sneaky joke by John, it was a very clever one

One thing that did turn out ok was rounding the parts using some filing buttons on the belt sander. If you've not run across filing buttons, they're easy and useful for this sort of thing-- take some drill rod, turn it down to the size you want, drill it out, then harden it, but don't bother tempering-- then you have some super-hard (but brittle) buttons. Just the thing to slide up next to your part on a rod and file or sand away. When the level of the part gets down to the level of the buttons, they are too hard for the file to dig into, so it stops cutting. If you are using a sander, make sure they can roll or they will get ground down eventually.

Here's the crossheads with some rounding applied--

 

[Bernd]

Hey Shred,

Those holes that are off center, how about soldering a plug in them and recenter the hole?

Bernd

 

[shred]

Hey Shred,

Those holes that are off center, how about soldering a plug in them and recenter the hole?

Bernd

That was one thought (though a little trickier now since I'd have to use the bores to align the work), but really they're ugly enough that I think I may just redo them and try to make them look nicer next time.

 

[bentprop]

I'm greatly interested to see how you get on with this engine,Shred.I started one last year,but ran into so many problems,I gave up ,and started something simpler.It was probably a bit too ambitious as my 2nd engine.The piston rod holes in mine were in the right place,but the support rods didn't line up with the cylinders in the block.I was on to my 3rd bottom plate before I put it aside.I don't know where I went wrong,probably somewhere during the marking out.
I'll revisit this engine when I have a bit more experience,as it is a nice engine to see running.

 

[chuck foster]

looking good so far shred 8)

i will be watching this build very close as i have thought about building one of these engines myself (after i get the other 100 projects done) :big:

is this engine going to be used in a boat or just as a display?

chuck

 

[shred]

looking good so far shred 8)

i will be watching this build very close as i have thought about building one of these engines myself (after i get the other 100 projects done) :big:

is this engine going to be used in a boat or just as a display?

chuck

I'm probably just going to display it, not having a suitable boat or desire to get into yet another hobby; boatbuilding (aside; I'm always faintly amused by the occasional justifications I see in plan sets like some of Elmers Engines "this could be used in a model boat".. as if the model engine itself weren't enough justification to make it). I'm considering building a small boiler for it since I had a lot of fun playing with live steam on my little loco. That might make an entertaining pair.

 

[chuck foster]

your little loco looks great and from what i see you had allot of fun with that build 8)

chuck

 

[shred]

Quick update-- my mini-vacation and resulting Evil Honduran Chicken Flu kept me out of the shop, but after standing up for 3 whole hours in a row yesterday, I felt well enough to visit a friend's CNC shop this afternoon. He gave me a couple used-but-still-ok end mills (what I think of as 'big' ones; 1/2" and 5/8") that I used to crank out a couple more brass blocks to make another set of crossheads from. That's it so far... more to come.

 

[Philjoe5]

Shred, thanks for the update. I have downloaded Bogstandards build log so I'm watching this thread with interest.

Cheers,
Phil

 

[shred]

Got the 2nd set of crossheads done tonight. Much better than the first set. They still need a date with the bling-fairy, but are good enough as-is for me to move on to the next part.

Cutting brass goes a lot faster when you can plow through it with a 5/8" end mill.

 

[shred]

Made a little more progress on the 'ducks engine. Got the top plate made, partly blinged and tapped 22 #2-56 holes in the block.

The engine turning was a bit of an experiment but it came out nice and is pretty easy (though a little tedious)

I did it on the mill just to play with the concept and quickly realized the way to index the plate was to ignore the DRO and just use "one crank" of the X handle per swirl, then one crank of the Y at the end of a row. Even though it wasn't 100% precise, it's tough to tell by looking at it how rough the indexing was-- I was off by a 1/8 turn several times.

I used a little DremelTM craytex bit, but that broke right at the end, so I'm going to try some other options next (annoyingly, Dremel has discontinued their little metal end-brush that I was about to try). I have several craytex sticks but would need to whip up a holder for them since they're way too whippy as-is. Bogs uses grinding paste, but I'd rather not mess with getting that all over the mill.

 

[Metal Butcher]

Your project looks really good! :bow:

I have been following your progress with great interest.

Would like to give it a try someday when I feel I'm ready for a more complex build.

In your thread there is mention of the plans in the down load section, but I can't find them. Is that were you got them?

-MB

 

[shred]

Your project looks really good! :bow:

I have been following your progress with great interest.

Would like to give it a try someday when I feel I'm ready for a more complex build.

In your thread there is mention of the plans in the down load section, but I can't find them. Is that were you got them?

-MB

Thanks. The downloads section seems to be broken right now, but I think I got them from a link off some site called 'rake60.com' or something

Scope through this thread: http://www.homemodelenginemachinist.com/index.php?topic=615.0 -- the links are there along with a bunch more pics of the originals (note that contrary to what I wrote then, I'm building this using the same de-metricification I used on the Slightly Loco-- holes, threads and stock like drill-rod are converted to a convenient imperial size, the rest remains metric-- it's easy enough for me to switch digital calipers and the DRO to metric; I just bail out on drills, fasteners and threads, hopefully making a note of it so I don't hose myself later on.

 

[shred]

I got a little time on the Paddleducks engine today. Didn't make much beyond the crosshead rods, but I did a lot of tweaking and assembly. The top end is all assembled and running on air (a squirt in the appropriate port slaps the piston & crosshead to the other end). Unfortunately the battery was dead in my shop camera, so no pictures of any operations (note to any following along.. you might want to make the piston rods a few mm longer to easier accomodate the cross-head lock nuts. I will be needing some thin ones later on)

for future reference and other de-metricifyers, I went with #2-56 for the crosshead bars and #4-40 for the piston rod thread. The crosshead rods are 3/16" and the piston rod is 1/8".