Author Topic: Mill engine (Read 13294 times)

Pete49 · « **on:** August 17, 2012, 03:14:37 PM »

I started this mill engine by Patrick J Verner a little while ago, just a bit each day. I thought I would take some pics of the parts I have made so far. I'm making them from scrap I have laying around for example the flywheel was an old 5kg dumbell weight (old Aussie made). Anyway here the pics of where I'm at for now.

b.lindsey · « **Reply #1 on:** August 17, 2012, 03:58:48 PM »

That looks to be a sizeable engine Pete!! Looks like you have a lot of the parts made already too. Is there s picture anywhere of the finished engine that will result from your work?

Bill

Pete49 · « **Reply #2 on:** August 18, 2012, 04:27:06 AM »

I agree it looks like a fair size but like eating a whale just 1 piece at a time.

The only picture of this engine I have seen is in the plans. I will upload them here as they are public domain when they were on steamengines.org. If not OK the admin can remove them. I can't link the website as its long gone unfortunately.
Pete

Pete49 · « **Reply #3 on:** August 18, 2012, 04:45:58 AM »

And once again I show up as an old fool. Its a beam engine not a mill engine

The mill engine is on the waiting list depending how this on goes (my capabilities) Please accept my apologies

Pete

steamer · « **Reply #4 on:** August 18, 2012, 07:53:43 AM »

They used beam engines in Mills Pete....it's all good!

Dave

Pete49 · « **Reply #5 on:** August 18, 2012, 03:24:49 PM »

whew saved again ....

Thanks Dave. Heres a picture of the engine
Pete

Pete49 · « **Reply #6 on:** August 23, 2012, 04:10:06 AM »

OOPS

I attached the wrong pic should have been the beam engine not the mill eng. I have attached the correct pic

Well I struck a problem with the engine in as much as I couldn't see how the d valve was going to work and had me at a standstill ands just before I asked here it came to me. The plans show the rod working the d valve as a 1.38" 1/4' diam and the steam chest has a .188' diam hole for the rod to go through, the same as the hole through the d valve

Now the rod has been remade with a extra .5" length @ .188" and all is good again. Pics to follow.
Pete

Pete49 · « **Reply #7 on:** August 24, 2012, 02:17:08 PM »

but today Murphy came and visited

Just starting to put bits together and find I have to make a new cylinder

oh well back to the drawing board...errr plans

Pete

Bearcar1 · « **Reply #8 on:** August 24, 2012, 10:01:15 PM »

What got buggered with your cylinder Pete? Perhaps there is a simple fix (relative) that can be done that will save you from starting from scratch again.

BC1
Jim

tel · « **Reply #9 on:** August 24, 2012, 10:10:17 PM »

Yep, tell all Pete, there could be a simple work around

Dean W · « **Reply #10 on:** August 24, 2012, 11:02:53 PM »

What the other fellows said, Pete. Tell us your troubles. Someone may know a way to make it right without starting over. Two (or six) heads are better than one.

Pete49 · « **Reply #11 on:** August 25, 2012, 03:19:47 AM »

Went to bolt the cylinder head on and find the cylinder is off centre and all the tapped holes for the steam chest are out of whack by half a hole

Luckily the cylinder block is aluminium so can be melted down

I might look for some brass to make it out of as it says in the plans, just a matter of finding some close to the size I need but not heading to Adelaide in the near future so may be a little while before I get back to it. Other than that I fell I have done a reasonable job on it so far and with only 1 major stuff up so I'm in front

Pete

Pete49 · « **Reply #12 on:** September 03, 2012, 01:19:44 PM »

Looks like this build will be on hold for some time.I was trying to fathom the way the slide valve was going to work when I got a pm from a member here letting me know there was a guy that had the answer and supplied the link. I have emailed him but no answer in a week so I'll wait and hope I get a reply. I have other things to amuse me so I'll find a box to put it in for now.
Pete

steamer · « **Reply #13 on:** September 03, 2012, 01:28:31 PM »

Hey Pete,

don't stop now.....show us the drawing and we'll sort it out....

Dave

steamer · « **Reply #14 on:** September 03, 2012, 01:48:41 PM »

Post the cylinder, the valve, the eccentric, make sure the steam ports on the cylinder are shown....

Dave

Pete49 · « **Reply #15 on:** September 04, 2012, 07:14:32 AM »

the problem is the way the valve is supposed to operate. The valve is worked by the motion of a eccentric lifting and dropping as it rotates....no problem there, the problem is the beam (on an eccentric)driven by the overhead crank is meant to drive the valve eccentric and I can't see how this would work. The site I went to explains that the eccentric movement can't be made to rotate the other eccentric at the valve end. Hope I explained it right, basically the bar with the holes in it has an eccentric to drive it and needs to convert that to rotary motion at the other end to turn that eccentric
Pete

steamer · « **Reply #16 on:** September 04, 2012, 10:44:59 AM »

Does the second eccentric have to make a full revolution to operate the valve up and down?

To answer this , is the valve travel equal to TWICE the second eccentric eccentricity?.....or just 1X or less?

If it's 1X or less, the second eccentric is just a lever.......with a big pivot pin mind you...

If it's 2X then your right.....it won't work as designed.

Dave

Pete49 · « **Reply #17 on:** September 04, 2012, 12:54:46 PM »

I will double check in the morning Dave but I'm pretty certain its x2 as the bar is on the circular part and the valve actuator is on the eccentric. It seemed odd at the time and now not so odd but I'll check first
Pete

Groomengineering · « **Reply #18 on:** September 04, 2012, 06:43:52 PM »

Dave, thank you for pointing out the obvious possibility.

Several years ago I spent hours (days?) staring the drawing thinking 'no way will this work', never occurred to me it might be a 'rocking arm'. May have to dig the drawings back out and build one.

Cheers

Jeff

Pete49 · « **Reply #19 on:** September 05, 2012, 03:42:20 AM »

Well I checked it out and yep still looks like x2 to me. The actuator has to lift and drop and the eccentric has to do a full revolution to do that. The way it is designed it can't do it as the bar can only rock the shaft not spin it. Maybe Jeff can explain it better.
Pete

Don1966 · « **Reply #20 on:** September 05, 2012, 04:43:17 AM »

Pete I don't know if this will help, but on the Beam engine I built the eccentric arm moves a pivot arm on a fulcrum that lifted the slide valve.

Don

steamer · « **Reply #21 on:** September 05, 2012, 10:09:18 AM »

Pete,

You could move the pivot for the arm forward towards the cylinder and make it a true belcrank lever.....that would be in keeping with practice. You will have to lay out the throws, but if the arms on the bell crank ar different lengths, it shouldn't be so bad.

Dave

Pete49 · « **Reply #22 on:** September 05, 2012, 02:30:09 PM »

Thanks Don & Dave for the suggestions but I know diddly squat about this stuff except what the plans show. I don't come from a machining background and am self taught (not vewry well it seems

)
Pete

Groomengineering · « **Reply #23 on:** September 05, 2012, 06:56:46 PM »

Ok I'm baffled again

Time to dig out the plans and crank up Solidworks. I need the practice anyway.

Cheers

Jeff

Bearcar1 · « **Reply #24 on:** September 05, 2012, 09:18:39 PM »

Pete, I have to agree with your very first statement that you made regarding getting the valve to operate properly. In the drawings that you sent to me, it shows eccentric #1 fastened to the crankshaft and driving a shaft (a flat bar actually) via a driving strap, which is all well and good. That is how most all standard steam engines handle driving the valve. The problem herein lies at the steam chest end of the equation. Here, that same bar has an identical 'strap', exactly like the one on the crankshaft end, that gets attached to a double-wide eccentric #2, riding on an idler shaft in that location. On this 'double wide' eccentric is the driving rod end and another shorter strap that drives the valve. Picture two identical eccentrics connected by a long bar that has a driven strap around each eccentric at both ends of the bar. The idea being that when one eccentric turns, the other will follow the same movement. It won't. Not unless the idler shaft is physically being driven at the same speed as the crankshaft. The two eccentrics will have a tendency to want to bind quit easily unless they are synchronized accordingly. Your best course of action is to figure out a method of driving the eccentric at the cylinder, through some sort of chain/rope/gear drive, thus eliminating the crankshaft eccentric or change the design and utilize a bellcrank/lever arrangement at the valve chest instead of a second eccentric. I may be wrong here, but I just don't see this design will function very well unless it is altered in some form.

BC1
Jim

Pete49 · « **Reply #25 on:** September 06, 2012, 03:42:59 AM »

Jim you nailed it exactly. With my limited knowledge however it looks like it will now be a static model as I haven't the ability to sort it though I will continue to try.
Pete

Arthur Dent · « **Reply #26 on:** December 06, 2012, 04:21:04 AM »

Did you get this sorted?

Pete49 · « **Reply #27 on:** December 07, 2012, 03:25:45 AM »

I think I have I am sorting out the mounting of the lever and the angle. I have decided to take Bearcat's suggestion and use a bell crank so it will be a little different to the drawings but will hopefully work.
Pete

Pete49 · « **Reply #28 on:** January 16, 2013, 02:59:16 AM »

While I was waiting to finnish the RT I was puzzling over the problem I have with this engine and decided to make this little one to see if it will help me understand the problem I have and yep it has solved the problem.

I am now in the process of assembling the original engine and will make a similar valve system so watch this space. (not too often as I need to dodge the heat.

) anyhow I have attached the pic of the little model I started on. Its 5" long overall and 3" high
Pete

steamer · « **Reply #29 on:** January 16, 2013, 10:30:09 AM »

Good for you Pete!...glad you sorted it out!

Dave

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Author Topic: Mill engine (Read 13294 times)