Twin Cylinder Steam Engine

[NickG]

Darren, looking great, all that attention to detail is definitely paying off.

Nick

[Darren]

Thanks guys, I'm just taking my time and being careful, thankfully no real slip ups yet, 

Look what I found in a skip today, that's solid alloy at each end and a chrome tube in between, it's quite heavy too....

Twin Cylinder Steam Engine

[Divided he ad]

Wow Darren.... You got that roof on quick!!!

What you gonna do with that then?


Got you some simple brass bits today.....(wasn't a lot there!!)   We'll sort out what you'd like later   




Ralph.

[kvom]

May be a grinder stand in Darren'd future 

[Darren]

Cheers Ralph 

No idea what I may do with the stand thing, what ever it was? I just saw the alloy and grabbed it. If I hadn't sorted my tapping stand/drill a little morphogenesis would be going on 

[Darren]

Decided to do a bit more to the crank webs tonight..

First thing was to drill and tap the holes for the clamping screws. I used a center and the mill to find the center between the two rods. The center finder is 5mm and the mill showed me a 1/2mm gap. Exactly as it should be  So let the center finder kiss one rod and back away 1/4mm. Perfect.

Twin Cylinder Steam Engine

Using the stop each piece was center drilled, note the use of a Stanley knife blade to lift the 4mm rod.
(the rods are 4 & 5mm dia, so from the center line the 4mm rod is 1/2mm shorter than the 5mm, the blade is exactly 1/2mm)

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Drilling the 2.1mm hole right through. Note the liberal use of WD40, I find Stainless a bear to drill as it work hardens in a flash, grabs the drill bit and snaps it off. Or it just rounds the end of the drill bit.
So what I did here was use cobalt drill bits, plenty of fluid and peck drill leaving plenty of time to let things cool. It worked a treat.

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Then I drilled 2.5mm to half the depth for thread clearance. Finally the remaining half of the hole was tapped 2.5mm.

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Not a very clear picture, the parts where marked with a sharpie that Ralph left behind the other day  and two center lines scribed with digital calipers from both sides. This leave two marks with a tiny gap in between. This shows the true center and any error clearly.

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My slitting saw didn't like SS  So I attacked it with a junior hacksaw.....

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A bit more cleaning up and they are done

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Unless you are really sad like me, forget SS here, you might find brass to be much easier to work with 

[bogstandard]

Darren,

Unless you are really sad like me, forget SS here, you might find brass to be much easier to work with 

I was wondering how long it would take you to realise that barbed wire knickers hurt. Those crankwebs were a good example of self flagellation.

But you have done a great job with what you had.

Nothing against the way you did your slots as you achieved the correct result, it is just that I would have used a slightly different method to obtain the same result. There are always more ways to get the same results, and by showing them, people can choose the way they want to go.
The pic shows how I do it. If you take it steady, you can get results as good as a slitting saw.
I drew it up incorrectly, so I put my excuse at the top of the sketch. Makes it look like I am one of those brainy lefties.

John

[Darren]

Darren,


I was wondering how long it would take you to realise that barbed wire knickers hurt. Those crankwebs were a good example of self flagellation.

But you have done a great job with what you had.

Yep, only bar I had the right size at the time, still is.......not that I would put myself through this again, I must shell out and buy some brass next time....

Nice tip on sawing there, mine are off a bit but ok.

[Darren]

I'd had a good nights kip and it's been raining all day so no garage building to tire me out today. So being nice and allert, instead of the usual deleted tired self I decided that I wanted to tackle something a little complicated this evening.

So I picked on the eccentrics as the plans suggested these could be taxing to produce.

Started with a 20mm SS bar, turned it to 18mm

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I had a nice 4mm parting blade so I squared it off with the grinder and honed it with a diamond stone to give a good edge to cut the 4mm slots.

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Parted them off and took them to the mini lathe to tidy up and true up the lengths. I used the mini lathe cos it's metric and easy to understand the dials as I dislike imperial measurements.

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I used the lathe to find the center, lined them up on the mill and used the mill dials to set the off center by 3mm.

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Finished with a 5mm drill bit

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Drilled and tapped a bar 5mm and machined the off center to a true center 

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Here I'm using the center finder to locate the position for the grub screw holes

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Drilled 2.4mm and tapped 3mm for the grub screws

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All fits nicely

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You could say I'm

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All turned out nicely and true to size, can't see what the fuss was about these are easy peasey to make, it's the rest that worries me 

[sbwhart]

Nicely done Darren

Your realy pushing out some good work 

Stew

[bogstandard]

Darren,

The reason people have trouble with eccentrics is they think the sky will fall on their head if they don't use a four jaw independant to make them.

The way I showed is the easiest way I think they could be made, and your comment proves it. Once you have set up the first one, you can make a hundred all the same, without having to set up the four jaw every time.

Doing everything the way the 'flat earth society' (old phart machinists) does it, can lead to all sorts of problems, a bit of lateral thinking cures all that.

If it turns out right, there is absolutely nothing wrong with the method.


John

[Brass_Machine]

...

If it turns out right, there is absolutely nothing wrong with the method.
...

OT
Woohoo! Had the same thing in a different sense. Common practice in performance engines is to port (making bigger and polishing) the intake and exhaust ports of the head. Now depending on the make of the engine, the ports may already be to BIG. We found (with dyno testing) we would get more HP by decreasing the intake port size and dimpling the walls (think golf ball) than with a traditional port job!In fact, several motorcycle manufacturers have now been decreasing stock ports!
/OT


Truer words were never said John!

Eric

[Darren]

Don't get me wrong John, If I hadn't read your instructions I'd probably have used the four jaw as well, and struggled.

Nope, your ideas show that a real newbie could do it....opps...I just did.....

[Divided he ad]

Got to Say Darren that lathe of yours really does do a good job of the Stainless 

This method of eccentric making will be logged and certainly referenced for future use.... It really does look damn easy!!!   


Oh Darren..... Not too "allert" then ehh!! 



I have the strangest feeling that your going to be really proud of this little engine when it's finished   



Glad your keeping us up to date on it's progress 




Ralph.

[Darren]

Got to Say Darren that lathe of yours really does do a good job of the Stainless 

Yes, I've manage to get turning SS down to a fine art, either 303 or 316. Those grooves are a 4mm plunge cut at full width and they turned out rather good.

I found the trick with HSS tooling and stainless is low rpm and low feeds, about 3-400 rpm. With tungsten tips the opposite is true and here I use 2-3000 rpm with a high feed rate, slower and the finish is not so good.

I think that's why peeps have difficulty with tips and SS, not enough speed. Of course others may have different ideas, though the above seems to work for me.


Drilling, milling and tapping is another ball game, but at last I'm beginning to get a feel for those too. A little way to go yet but it's comming.

Practice, practice, practice 

[Darren]

The eccentric straps....

After testing my patience last night trying to drill a piece of plate/sheet brass and achieving nothing but broken drill bits and ruined pieces I eventually turned my attention towards some bar stock. If this means nothing to you see here for an explanation...http://madmodder.net/index.php?topic=1127.msg9154#msg9154

As you can see this is hex bar stock

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Two pieces where trued up to an exact 4mm thickness in the mini lathe

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I find the collet holder makes an excellent square, stands there all by itself leaving two hands free 

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The piece was positioned using my center finder (I'd be lost without this now  ) Then center drilled before drilling to a depth of 11mm 1.5mm dia.
I then ran a 1.6mm drill bit through ready for tapping.

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Just to prove there are indeed two of them 

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The center was found and a step drill used to take the bulk of material away before cutting in half with a slitting saw.

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Yep, still two of them, not messed up yet 
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The slitting saw leaves an excellent finish. All these joints will need is a quick swipe over with a diamond file to de-bur and dress them.

I need to order some 2mm screws and taps to clamp these back together before continuing. Having drilled the holes before splitting I can be sure that they will line up perfectly   


I used a pair of these as ultra thin parallels, they work quite well....

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[Darren]

Gosh that post sounds so dry.......

I had lots of fun making these honest....

 

[bogstandard]

Darren, it was most probably the frustration from yesterday showing thru.

Now you have drilled your new ones quite successfully, you must be feeling a lot happier.


John

[kvom]

I love the idea of shaping the straps with the hex stock.   

[Divided he ad]

Nicely done sir 


You'll find tapping those easy with the combination of your "easy machining" bar stock and your tapping stand 



Post read fine to me.... What does that say about me?!?




Looking forward to the continuing developments 





Ralph.

[sbwhart]

Well done that man.

 


Hope you remembered to mark them up so you don't get them mixed up 

Cheers

Stew

[NickG]

Darren, they are looking good, great idea using the hex bar and like the ultra think parallels! 

Well, I probably won't be back on here until the weekend, at which point I may have met some of you at Harrogate hopefully. 

Nick

[Darren]

Now you have drilled your new ones quite successfully, you must be feeling a lot happier.

Never a truer word spoken, I was starting to worry about my machinery being a bit naff, thankfully this normal brass drilled very smoothly.

I did swipe the tips of the drill bit to take the edge off, though I don't know how much this helped cos I wasn't taking any chances with a sharp one.
You could say I'd had enough of frustration by then 

Thanks for this little tip John, all added to the database for future ref 

[Darren]

I love the idea of shaping the straps with the hex stock.   

Thanks but the idea really came about due to what I had to hand that was big enough. Should look nice though 

[Darren]

Darren, they are looking good, great idea using the hex bar and like the ultra think parallels! 

Well, I probably won't be back on here until the weekend, at which point I may have met some of you at Harrogate hopefully. 

Nick

Nice description, the blades where just sitting there staring at me saying, "me, me, me" 

Worked really well too