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Post by doubletop on Jan 14, 2015 9:38:43 GMT
hi pete, that is a very nice impressive job! very well done! you might like to consider using the drain cock tapped holes in the cylinder block for valve setting to centralise the valves. i find this very accurate and better than doing by 'sight', so long of course as the passages to the drain cocks are not obscured by the pistons at the end of their stroke. cheers, julian Thanks Julian I think I've got the approach sorted now. With the cylinders out, using a depth micrometer I've recorded the position of the end of the valve rod extension with the valve just opening on both inlet ports, for both valves. The difference is exactly 0.25" which is what it should be for the Dart. As you suggested I'll use the drain cock holes to reference the BDC and FDC of the crank. That will overcome trying to eyeball the drive line angle. As long as I set the valve position to have the same difference from those recorded at both ends the valve will be correctly located in the mid position. Checking the Wallace model Don gave me the valve hasn't started to open at BDC, FDC so the position of the valve rod won't be exactly the same as that recorded. I'm quite comfortable this will work (although checking the drawings the piston overlaps the drain cock hole by 1/16")regards Pete
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Post by doubletop on Feb 1, 2015 9:41:00 GMT
The valves got set and I pinned it all in place without a boiler how do I test it on steam?
I'm very happy with that and the rest of the guys were impressed. Don gets a mention and thanks again Don for the valve gear design work.
Pete
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Post by doubletop on Sept 26, 2015 7:50:47 GMT
I hadn't realised that it was 7 months ago when we tried the running the motion with 'borrowed' steam. I've been doing various small jobs, and made a start on my TOAD driving trolley. but most significantly the boiler is built and I'm in the process of painting it. Anyway this is a bit of a heads up for anybody who uses Don's improved valve gear design. Something I discovered today when doing tidy up jobs before the boiler goes in properly for the first time. Don's design has the lifting levers sitting lower in full forward gear than Martin Evans design. I noticed it when I found I couldn't get into full forward, what's more if you push forward gear hard the brakes will go on. My first attempt at fixing the problem was to 'relieve' the rear brake beam. It wasn't enough Completely chopping the middle out of the beam wasn't going to work either, due to the asymmetric nature of the primary and secondary brake rods. So I resorted to a yoke that provides the necessary clearance to the lifting levers and the brake beam. Installed From the underside showing the why this mod is needed A quick zap in the sandblaster and a coat of paint and I'll be back to where I thought I was this morning. Hope that helps somebody Pete
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Post by springcrocus on Sept 26, 2015 8:52:10 GMT
A perfect example of modifying things to suit rather than just following the drawing and then giving up if something doesn't fit / work. Great job, Pete, and thanks for sharing that.
Steve
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Post by doubletop on Sept 28, 2015 9:49:31 GMT
Steve
Problem solving is part of the fun. None of the Martin Evans designs I've worked on are complete (Rob Roy, Simplex and now Dart) so there's always something you've got work out.
Pete
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Post by doubletop on Nov 8, 2015 9:39:21 GMT
Well a big day today. The boiler is in and plumbed up, a few bits temporarily in place just to get it to run but at the point of 'no excuses' so we gave it a go.
This brief clip is my mentor taking it for a run. He gave it a bit of a blast up the incline, getting some wheel spin, and then applied the vacuum brakes to see how well it would stop. Followed by a slow run back into the station.
The only bit that didn't work too well was the expensive chime whistle I bought when in the UK the other month.
As you can imagine I'm pretty chuffed but still plenty to do before it becomes a regular runner.
Pete
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Post by mattscrutton on Nov 8, 2015 10:07:30 GMT
Running well, regarding the whistle, try mounting it vertically. If its the type sold commercially by the main suppliers they don't like being on their side.
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Post by doubletop on Nov 9, 2015 8:29:40 GMT
Thanks Matt
I'll give it a try. I'd only fitted it quickly to comply with the requirement for a whistle. However, I don't think the smoke signals qualified.
When you say vertical, steam inlet at the bottom or the top or doesn't that matter?
Pete
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Post by ejparrott on Nov 9, 2015 9:12:04 GMT
Steam inlet at the bottom, otherwise it fills up with water!
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Post by doubletop on Nov 9, 2015 9:31:48 GMT
Of course!! daft question on my part. However, an easier fix as it just needs the feed pipe bending a bit more.
It may also explain why it wasn't too good in the horizontal as it could have filled a bit in that position
Pete
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Post by doubletop on Jul 11, 2017 8:33:48 GMT
Now fixed following the Photo Bucket fiasco
Pete
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Post by doubletop on Nov 16, 2017 9:50:01 GMT
Keeping it all in one place. A few of us went out for a bit of a play yesterday. Mid-week, next to no public so we had the place to ourselves to do what we wanted.
My main purpose was to get some shots of the motion to see if there was anything that needs attention. The beginning has a shot of the "haystack" at the back of the track after the grass had been mowed (maybe we should have done a walk round before we started running!!). For some reason I'm afraid there's no sound on the first section looking at the motion.
The gland nuts may need nipping up, a bit of a high pitched squeal on some of the starts. Other that a good clean out to remove the grass and not a lot else.
Pete
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Post by steamer5 on Nov 16, 2017 19:51:14 GMT
Hi Pete, Looks like you’ve got her running very sweetly!
Cheers Kerrin
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Post by doubletop on Nov 17, 2017 4:09:01 GMT
Kerrin
Thanks; I'm quite pleased with it.
It has been set up exactly to Don Ashton’s design geometry. All the fixed drive train components (cylinders, motion plate, trunnions etc.) were accurately located relative to each other. The eccentrics were pinned to the crankshaft, with the correct lead, at the point of assembly of the whole crank(no grub screws). The valve and valve rods were also setup and locked and pinned on assembly, no other adjustments have been made since completion. Testament to Dons design and ensuring that it was followed.
Pete
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rrmrd66
Part of the e-furniture
Posts: 339
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Post by rrmrd66 on Nov 17, 2017 8:24:26 GMT
Keeping it all in one place. A few of us went out for a bit of a play yesterday. Mid-week, next to no public so we had the place to ourselves to do what we wanted. My main purpose was to get some shots of the motion to see if there was anything that needs attention. The beginning has a shot of the "haystack" at the back of the track after the grass had been mowed (maybe we should have done a walk round before we started running!!). For some reason I'm afraid there's no sound on the first section looking at the motion. The gland nuts may need nipping up, a bit of a high pitched squeal on some of the starts. Other that a good clean out to remove the grass and not a lot else. Pete Hi Pete This is really useful video. I am finishing off my Stephenson's valve gear for my 5" Hunslet and being a complete newcomer to all of this have trouble getting my head round of exactly what does what. I am using the Don Ashton/Bill Hall optimised geometry, with the assistance of Julian Atkins. My boiler, ex Weston Steam, is due in August 2018 so it will be some time before I get to run the engine on steam. Thanks a lot Malcolm
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Post by doubletop on Nov 17, 2017 10:54:25 GMT
Malcolm
Glad to be of assistance. You can see from this that Don's design works well. Bill Hall was a name new to me only this week when I was give a copy of a paper of his on engine indicators.
With Don, Bill and Julian on your team you shouldn't go far wrong
Pete
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jwkb23
Active Member
Posts: 18
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Post by jwkb23 on Jul 10, 2021 7:42:45 GMT
Hi, I am just looking to start building the motion on my Dart and was wondering if there was any way of getting a copy of the information meantioned in this thread. I appreciate that 3.5 years later it might be a bit hopeful but worth a try...
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Post by doubletop on Jul 14, 2021 10:04:41 GMT
Hi, I am just looking to start building the motion on my Dart and was wondering if there was any way of getting a copy of the information meantioned in this thread. I appreciate that 3.5 years later it might be a bit hopeful but worth a try... You are lucky, I am currently an infrequent visitor here these days and we sadly lost Don to Covid last year. However, I do have a copy of his design docs. Just PM me with your email address. In the meantime how about sharing some photos of your progress so far, or a link to your build thread. Pete
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jwkb23
Active Member
Posts: 18
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Post by jwkb23 on Jul 14, 2021 21:22:54 GMT
Hi, I am just looking to start building the motion on my Dart and was wondering if there was any way of getting a copy of the information meantioned in this thread. I appreciate that 3.5 years later it might be a bit hopeful but worth a try... You are lucky, I am currently an infrequent visitor here these days and we sadly lost Don to Covid last year. However, I do have a copy of his design docs. Just PM me with your email address. In the meantime how about sharing some photos of your progress so far, or a link to your build thread. Pete Hi Pete, I have dropped you a PM. I will post some pictures when I have actually done something meaningful.
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Post by doubletop on Jul 14, 2021 21:49:54 GMT
You are lucky, I am currently an infrequent visitor here these days and we sadly lost Don to Covid last year. However, I do have a copy of his design docs. Just PM me with your email address. In the meantime how about sharing some photos of your progress so far, or a link to your build thread. Pete Hi Pete, I have dropped you a PM. I will post some pictures when I have actually done something meaningful. James Email sent I had thought you may have done the frames etc. but then realised that without this you wouldn't know what needed to be different. Pete
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