Walking Beam Progress

[chiliviking]

Now that I got the DRO on my mill project completed I got back to working on my beam engine. I have made several changes to my engine as I go along both in material selection and design. My cylinder is made of cast iron rather than the 1018 the plan called for. Also I made the bore 1.125” rather than the 1.040” called out in the plans so I could use a ready available piston ring. I know many on the board offered good instruction on the making of cast iron rings but at $5 a store bought ring fits better in my timetable.

After I made the decision to overbore the engine I thought I hade been very careful to measure the cylinder wall thickness with the new bore but then I realized that the plan called for the exhaust port to travel under the steamport channels which was .180” that I hadn’t accounted for in my calculations. I thought I had painted myself in a corner but after staring at the design for a couple days I decided I didn’t like the idea that the original exhaust port ran through the bolt hole for the steam chest and decided that rather than one large exhaust port 4 smaller ports could be placed on a 45 degree angle and enter the steam channel from the side rather than from below.

Drilling the exhaust ports on an angle and having them come out where they are suppose to is always a tense time for me however the DRO made it a snap.

I made another diversion from the plans in the choice for the flywheel. PM Research sells a really nice iron casting for a 7 ½” flywheel cheaper than you can buy the material to make the 8” steel flywheel. The flywheel is wider than the plans call for which requires some rework of the dimensions on the baseplate but I prefer the look of a little wider wheel.

I have started the layout for the beam as I think that will be my next move. I have laid awake at night trying to plan the order of events and mountings required to mill the pockets that lighten the beam and give it somewhat of an “I-beam” casting look.

 

[Philjoe5]

Nice work CV. You're making some good progress. I just received my brass for the motion links and the CRS for the baseplate today. I spent almost a week making these little darlings, the three rocker arms:

My beam is fairly simple. I just used a ball mill to mill some grooves on both sides.

I finished both cylinder heads and the rocker supports.

It looks like we're focusing on the same place.

I want to complete the valved actuating mechanism first so I'm going to make the valve links next. If you've looked at the mechanism you'll see that there is a potential binding screw connecting the valve link to its rocker arm. I asked Scott about that and he uses loctite on that screw. I'm planning to over size the hole in the valve link on that end and insert a sleeve.

I like your design for the exhaust port. You are right...there's a steam chest screw in that location that only has 2-3 threads to grab into.

I'm also working on a 1.5x scale mill engine so will be back and forth between these two engines. I'll post a progress report on the mill engine soon.

Thanks for the update,

Cheers,
Phil

 

[BobWarfield]

That's a nice big-un, innit?

;D

BW

 

[Brass_Machine]

Nice work... Both of you!!

Can't wait to see the finished creations. That cylinder with the brass is the type of contrast I love.

Eric

 

[SmoggyTurnip]

My cylinder is made of cast iron rather than the 1018 the plan called for.

Why did you make this change?

 

[chiliviking]

The decision to use cast iron for the cylinder is that I think it is more stable after it is machined, it easily machines to a nice finish for the bore and it hones nicely. I'm sure that 1018 would make a fine cylinder and this is probably overkill for an engine that will be run infrequently however when I do a project I try to balance best material with reasonable cost and that is why I'm making changes in material. I was lucky and found a piece of brass for the cylinder cover at the scrap dealer that was close to the right size at a reasonable cost.

 

[chiliviking]

Philjoe....You seem to be coming along nicely on your engine. I think it would drive me nuts to try and do 2 at once. Did you find a source for the 1/2 o.d. x 5/16 i.d. flange bushing for the beam at the center. All I could find in 5/16 i.d. was 7/16 o.d.. I guess it would be easy to just make them.

 

[Philjoe5]

CV,
Scott told me that MSC carries the bushings but I'm sure I'll make them.

I want to get the valve mechanism working next. You appear to have a lot of that machined. It looks good.

The benefit of doing two engines at once is that if I hit a troublesome problem ???, I can switch to the other engine and take some time to think my way through the problem.

Being a barstock guy at heart I want to try to make a 6 inch flywheel from a slice of CRS. I have a 6 inch slice of alum to practice on.

Thanks for the update. It's really cool to see someone else building the same engine I am.

Cheers,
Phil

 

[S_J_H]

WOW Chili, it looks great so far! Man you work fast!
:bow:
Steve

 

[gilessim]

Great work there guys!, how did you drill those dagonal ports without the drill bit slipping?

Giles

 

[chiliviking]

To keep the drill from slipping on an inclined surface I first plunge in with a centercutting end mill slightly larger than the planned drill size. I usually plunge to a depth just enough to make a full circle at the bottom.

 

[CrewCab]

how did you drill those dagonal ports without the drill bit slipping?

To keep the drill from slipping on an inclined surface I first plunge in with a centercutting end mill slightly larger than the planned drill size. I usually plunge to a depth just enough to make a full circle at the bottom.

I was wondering that as well guys, thanks for the explanation ;D

Dave

 

[chiliviking]

I've got all the parts major completed and have moved into what I call the "fit and finish" mode. I had painted the beam and pressed the bushings in this morning. The flange bushings at the main fulcrum point required a run of a reamer through them to produce a nice slip fit on the fulcrum pin. All the other bushings were a nice slip fit as installed and required no further attention. Next adjustment was required on the piston rod to keep the piston travel centered in the cylinder. I applied some air to it and began a trial and error method of adjustment on the eccentric for valve timing. When I got it fairly close and it was trying to run then I moved to adjusting the length of the valve rod to fine tune the timing and it sprang to life!!! I must have the timing fairly close as it will run smoothly at slightly under 100 RPM.

Rather than use the 4 round legs the plans call for I intend to build a hardwood base with a raised center to locate the flywheel above the base. I had some surgery yesterday and as soon as I heal enough to get in a car I will go to town and select some hardwood for the base. I will disassemble it and begin the finish work shortly. I think much of it I am going to paint in clear lacquer as there is nothing prettier than a nicley machined peice of steel.

 

[chuck foster]

very nice looking model :bow:

now all you have to do is get us some video of this beauty running!!!!

i would be willing to be when it first ran you had an ear to ear grin.............that couldn't be wiped off with a 2 x 4 .........
of course you did.............i know i always have that same big ear to ear grin after all these years.
the first run is always the best.

kudos to you on a wonderful looking engine.

chuck

 

[chiliviking]

Yes the grin was definately ear to ear and always is the first time an engine that you have built starts and runs no matter how many times you have done it before.

 

[chiliviking]

Any suggestions or guidance on the use of clear lacquer over freshly machined surfaces to preserve the finish?

 

[zeusrekning]

That looks really nice. Are you planning to bling it up any? I think Bog should jump in on the lacquer thing though.
Tim

 

[bretk]

Boy that's a nice looking engine! I have done the lacquer previously, I always washed in soap and water then dipped the parts in acetone prior to clearcoat, and haven't had any chipping so far.

-Bret

 

[CrewCab]

I'm sure the grin will be there for a long time to come .......... and deservedly so ....... that's nice work 8)

Dave

 

[Philjoe5]

CV,
Nice work on a beautiful engine!! :bow: I'm quite far from completing mine but I have finished the valving part and I'm satisifed with the result. While waiting for a piece of brass for this engine I went full out on the scaleup of a mill engine. My goal is to complete both of them this year.

Thanks for the photos and the motivation to get mine done! ;D

Cheers,
Phil