A Forum Project locomotive

Jerm · Post by **Jerm** » Wed Jun 29, 2011 6:12 pm

Thanks, I might take you up on that. At the moment I'm pondering farming out some of the more complex work to a local machinist. I think I could build the boiler, but the fittings for it... Not so sure. I'd probably follow your initial example and use Mamod wheels. Now, is the prototype using Mamod cylinders as well? I think that's what I would try.

Jerm · Post by **Jerm** » Thu Jun 30, 2011 6:36 pm

I spent some time last night going over the diagrams and consulting Peter Jones' book (Building Small Steam Locomotives) and my confidence is confirmed. Yes, I think I can do this.

Couple of questions, though.

Are there suitable commercial substitutes for the safety valve and regulator? These I know are beyond my capability at this time, as are the cylinders, wheels etc. which I'm planning on purchasing.

While in the shower this morning (all my best thoughts occur there) it occurred to me that his model doesn't have a lubricator. Was there any thought to accommodating one on the prototype?

And finally - and this is a pretty newbie question, I admit - I saw in the diagrams that the crank pins on the driving wheels need to be off set 180d, not 90d. Since the motion appears to based on a Mamod, which has 90d offset (I think), will that not work?

I'm pretty excited about getting started with this. I've got a convention and a wedding coming up so July is pretty much shot, but I'm hoping to start work first weekend of August.

Pretoria · Post by **Pretoria** » Thu Jun 30, 2011 7:04 pm

See "Building Dante" in Projects for the same thread re crankpin angles:

Keith S wrote:
Looks great so far. One thing: Are you quite certain the cranks should be 90 degrees with single-acting cylinders? With only two power strokes per revolution, I would think it would run smoother with the cranks set at 180 degrees. However I am willing to admit I am very tired and my stupid brain and I aren't getting along right now.

Pretoria wrote:
Quite right (compare to car engine). You need cranks at 180d for only two power strokes.

Jerm · Post by **Jerm** » Thu Jun 30, 2011 7:36 pm

Duly noted! Cheers!

DLRdan · Post by **DLRdan** » Thu Jun 30, 2011 8:00 pm

As the crank pins have been sorted I'll do the other parts. The wheels, cylinders and safety valve are availiable comercially. The valve to look for is the mamod safety valve with the SHORT spring, it looks slightly different to the one in the design but will still fit. There is not lubricator on the loco and I have not found it nessecery to include one, just squirt some steam oil in to cylinders before the run. The regulator is unique to this loco im affraid but im sure we can come to an arrange men when the time comes

90733 · Post by **90733** » Thu Jun 30, 2011 8:11 pm

Hmmm, maybe its about time I started one to?

It'll be the experince tht counts

spooner · Post by **spooner** » Thu Jun 30, 2011 8:14 pm

You could use a order commercial valve as a regulator.

DLRdan · Post by **DLRdan** » Thu Jun 30, 2011 8:43 pm

Not really as the loco is so small, none of the comercial ones will fit in

Pretoria · Post by **Pretoria** » Thu Jun 30, 2011 9:50 pm

DLRdan:55486 wrote:As the crank pins have been sorted I'll do the other parts. The wheels, cylinders and safety valve are availiable comercially. The valve to look for is the mamod safety valve with the SHORT spring, it looks slightly different to the one in the design but will still fit. There is not lubricator on the loco and I have not found it nessecery to include one, just squirt some steam oil in to cylinders before the run. The regulator is unique to this loco im affraid but im sure we can come to an arrange men when the time comes

Like this

http://cgi.ebay.co.uk/MAMOD-SAFETY-VALV ... 3a67b22b61

DLRdan · Post by **DLRdan** » Thu Jun 30, 2011 9:59 pm

Thats the one.

Jerm · Post by **Jerm** » Fri Jul 01, 2011 1:44 am

Okay, that is all my questions answered. Still feeling pretty confident I can do this. The plan is to start gathering materials later this month.

DLRdan:55486 wrote:The regulator is unique to this loco im affraid but im sure we can come to an arrange men when the time comes

That would be super! I would happily pay for materials, labour and postage, if that is what you are offering. I was visited a local tool and die company to reduce the flange on some wheels (4) by a few millimeters and it ended up costing me $60 ( £38 ). Even if it ends up being more than that it will still be more cost effective then a local outfit, I wager.

You'll forgive me sir if I misread (tomorrow is Canada day, it's a long weekend and it's been a rough week, hence I'm about to start my third pint) but I think that is what you were inferring.

(Drinking Steam Whistle Pilsner, brewed in a roundhouse in Toronto. Appropriate, eh?)

Jerm · Post by **Jerm** » Tue Jul 26, 2011 2:23 am

Evening all! I wanted to make a quick reply to say that Canada Post left a padded envelope filled with all the commercial parts I ordered. This weekend I'm starting work on the frames!

DLRdan · Post by **DLRdan** » Tue Sep 06, 2011 11:35 am

Well over a year since the original post I have some more updates. On very close inspection and trail of the drawings some errors have been found. First is the thickness of the port block material, this is made from 3/16ths brass not the 1/8th stated. The second is the hole on the front foot plate that holds the smokebox. This is further back than the drawing shows. I have also found an easier way of making the steam pipes at the front. I have made a new folder with the revised drawings in for download and would like to appologise if these mistakes have caused anybody problems.

Link to the drawings: http://www.mediafire.com/myfiles.php#oj7q5y1nn9wau,1

And as some of you may already know, Dante is no longer alone.....

dougrail · Post by **dougrail** » Tue Sep 06, 2011 12:50 pm

Photos?

Jerm · Post by **Jerm** » Tue Sep 06, 2011 8:08 pm

DLRdan:58414 wrote:Well over a year since the original post I have some more updates. On very close inspection and trail of the drawings some errors have been found.

Good thing various factors have delayed my starting, then.

At this point I have to divide my time at the house is between railway, workshop and visiting with parents. So I think I'm going to let this go until the railway season ends then time won't be so tight.

Annie · Post by **Annie** » Tue Sep 04, 2012 2:37 pm

I've been looking for a basic and simple loco to build as a first attempt at live steam and I'm delighted to have found this thread. Perhaps it should be made a sticky thread so new chums like myself can easily find the links to the drawings.

LakeshoreMike · Post by **LakeshoreMike** » Mon Oct 01, 2012 10:39 pm

I'm happy to have found this thread, directed to it by Dan himself after looking at his next version at Elsecar yesterday.

Can I just expand a little on the 180° setting for the cranks. This is totally correct for two single acting cylinders. However, before someone has the idea of coupling the wheels together to make an 0-4-0 for greater adhesion, coupling rods with cranks at 180° will definitely not work. The moment the driving axle slips the coupling rods will jam.

Of course, you could always couple them with a chain

Keith S · Post by **Keith S** » Tue Oct 02, 2012 12:25 am

Yes, if you look at some of the early tinplate live steam engines with single-acting pairs of cylinders, you will see that the piston rod and coupling rod on only one side will be offset from each other by 90 degrees. That way the coupling rods can be quartered but the pistons can be 180 degrees apart.

DLRdan · Post by **DLRdan** » Tue Oct 02, 2012 10:22 am

Glad you could find the thread by my poor description. As for someone having the idea of adding coupling rods......

<object width="420" height="315"><param name="movie" value="http://www.youtube.com/v/c1jk_Se6e5A?ve ... ram><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/c1jk_Se6e5A?version=3&hl=en_GB" type="application/x-shockwave-flash" width="420" height="315" allowscriptaccess="always" allowfullscreen="true"></embed></object>

I will say that if built to the plans, this is not possible. The loco in the video has shorter cylinders than the plans show. This is because on the original loco the piston comes half out of the cylinder at rear dead centre, increasing the wear. The drawn loco has the longer cylinders to correct this.

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