Potty Popcorn Engine

[SBWHART]

Well I had a desaster on my Loco work I chipped a chunk out of the wheel flange its totaly US, this realy pissed me off I've consigned the loco under the bench whilst i get over my sulk, I'll just have to buy a new wheel.

In the mean time I decided to get on and do a bit on this.

Her's the assy drg

I showed the fly wheel build on another thread her's a pic of it

I was planning to fabiricate the cylinder in three parts but then I found I chunk of 1 1/2" square brass left over from the loc chimney, I realised that I could make the cylinder in one peice from this.

So marked it out and set it up in the four jaw.

Drilled and reamed the bore out 1/2" then turned a mandrell up for it to fit on.

With this in the spin-indexer milled the cylinder to shape.

Then milled the steam ports

So that I ended up with this

Cylinder covers

One thing a beginner struggles with is lack of kit for drilling holes on a pitch circle.

Well if you have one of those digital protractors you can use it to acuratly mark out the holes.

With the bar in the lathe
First put a small centre into the bar then using a pair of deviders mark the circle in the end of the bar.

Then zero the protractor up on the bed of the lathe, put the protractor on the chuck jaw, rotate to get it zero, then mark across the bar with a scribbing block, rotate the chuck until the protractor is showing 90 deg mark across again, job done.

Centre pop and drill holes

I decided that I would like something fancy on the cover, so with the chuck mounted on the spin indexer and with a vee shape fly cutter form a star in the end.

That doesn't look bad.

Stew

 

[steamer]

Actually I like that a lot Stew!

Dave

 

[Brian Rupnow]

Stew---You are my new hero!! You do lovely work. ---Brian

 

[metalmad]

Thats a great idea!
I love it, Pete

 

[bearcar1]

Yeah but how'd you bust the wheel? ??? :hDe:

Sorry Stew, I do not mean to scratch an old scab. Terrific job on the cylinder and cover. Me likes alot!!

BC1
Jim

 

[larry1]

Stew, Great job. larry

 

[Deanofid]

Looking great, Stew. You do nice work!

 

[tel]

Looking good Stew - off to a flying start on another masterpiece!

 

[jonesie]

looking good stew, sorry about your wheel. thanks for the pdf files they look good after a quick look. i am also going to make the cylinder from one piece, but i think i will start with the flywheel. i will try to post pics as i go but need to finish up a couple projects, need to get my farmboy running for a local show then on to the popcorn. thanks again for the files jonesie

 

[SBWHART]

Thanks for your support chaps

Good luck with your build jonesie, any problems with the drawings just send me a PM

If anyone else wants a free copy of the drawing just send me a PM with your email adress, but I must warn you they are untested so their will be mistakes.

Got on with making the valve chest, this was fabricated and silver soldered, I used some hex bar fly cut down to size.

The bits for soldering I losely pined together with 1/16" brazing rod

And soldered together

I squared the fabricarion up as you would a casting, then centre drilled for the valve rod position, and set it up in the four jaw with a wobble bar

Drilled it through 3mm then drilled and tapped 1/4* 32*8mm deep

Marked out for the bolt holes drilled these through 3mm then used the chest as a jig to spot through and drill and tap the cylinder, and drill the cover 3mm.

Slide valve milled a bit of brass to size and milled the vlave pocket in the base flipped it over and milled the cross slot for the rod and cross bar.

These are the bit for assy.

Slide valve in the chest.

That valve cover is just calling out for something.

Stew

 

[lazylathe]

Awesome stuff as usual Stew!!!!

This is going to be another winner!!!!!!!!!!

Andrew

 

[tel]

If anyone else wants a free copy of the drawing just send me a PM with your email adress, but I must warn you they are untested so their will be mistakes.

Put me on the list please matey.

 

[SBWHART]

Thanks for you're interest Guys.


Added a bit of fancy work to the steam chest cover, its a bit flimsy to grip so soft soldered it to a chunk of brass, centering it by eye.

Then over onto the spin indexer, centred the tool again by eye, you don't do the cuts on centre you off set it a bit, to cut the star .

Gave it a bit of heat to melt it off the solder, and a clean and polish.

That looks better.

Made a start on the piston, turned the piston up from a bit of stainless steel:- thanks Dave :thumbup:, made it about 0.3mm over size, and put a groove in it for the packing, parted it off, and screwed it onto the rod with studlock, I'll give it a bit of time to cure before I bring it down to size.

Stew

 

[Brian Rupnow]

Stew---if you would be so kind as to send me a set of the prints, I would be very gratefull. If you click on the link to my web page, all of my contact information is there. Thank You----Brian

 

[ShedBoy]

Great start there Stew. Those little stars look a little like a compass symbol. Looks great.
I will be watching

 

[Brian Rupnow]

Stew---Thank you for the drawings. They are very well done. Did you have formal training as a draftsman at some point in your career? It has been my experience that most good machinists don't make mechanical drawings, and most mechanical draftsmen don't machine.--And, out of curiosity---How is the crosshead guide attached to the cylinder cap?----Brian

 

[tel]

They are very nice drawings, and more in line with what us old school ME's (dinosaurs) are used to!

A pox on CAD, and all who sail in her!

 

[Brian Rupnow]

Tel---Up untill I was 50 years old, I wholeheartedly agreed with you. I loved working on the drafting board. At 50 I had been doing so for 31 years, and I was damn good at it. Computers, CAD---who needed it. Then suddenly reality jumped up and bit me on the ankle. Nobody wanted to do business with me unless I could churn out amazing designs on a computer. Drafting board was equated with "Horse and buggy!!!"---If you couldn't do it on a computer, then you must be far to "old school" to design NEW IMPRESSIVE WHIZ-BANGS for your customer. So at 50 I went creeping back to college to learn Autocad. It wasn't that terribly difficult---but after 3 years, just as I was starting to get good at that, suddenly the customers wanted 3D, with animations, and "full associativity" (whatever the heck that is.) So off I went to learn 3D Solidworks. To make a long story short, I am amazed and impressed daily by what I can do now on my computer with CAD, and so are my customer base.----But---- deep in my heart of hearts I'd still like to be perched on a drafting stool, a cigarette in one hand and my trusty 2H pencil in the other, flogging lines onto an E size vellum, with my squeaky old Keuffel & Esser parallel track drafting machine.

 

[Tin Falcon]

It has been my experience that most good machinists don't make mechanical drawings, and most mechanical draftsmen don't machine.-

Well Brian am a little younger than you my first mechanical drawing classes were in Jr High then in high school. I learned to hate drawing title blocks over and over also the repeated hand lettering.
never really did the autocad much a tad bit in college. But when I took my USAF machinist courses bit later in life we had to learn a little mechanical drawing .
I sit here at my Oak Mayline drafting table and type on the laptop loaded with alibre 3-D the drafting arm behind the CNC control computer there are still a few lead holders in the carousel near by.
Tin

 

[Maryak]

Brian,

Anybody who can produce a set of drawings using a drafting board etc., has my utmost admiration. If you have the misfortune to be like me, then CAD is a godsend because a well used flypaper, complete with dead flies, was far more presentable than my hand drawn efforts.

Apologies for the hijack of the thread.

Best Regards
Bob