Author Topic: Vulcan Beam Engine - AJ Reeves Castings  (Read 9158 times)

Offline Zephyrin

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Re: Vulcan Beam Engine - AJ Reeves Castings
« Reply #30 on: October 04, 2017, 06:42:49 PM »
great looking these suspension links congratulation!  a difficult part


The strap can be made as in the ETW plan, in one piece of 1.6 or 1.5 mm soft steel turning first the treaded part. You need a small (but strong !) bending device with a roller, bending without it would lead to twisted edges upward, awful, and requiring lot of filling or hammering. the correct length of the strap in adjusted with a jeweller file at the end.

I modified the valve too, as ETW had not given lap on admission, but clearance on exhaust.

Offline Emelbe

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Re: Vulcan Beam Engine - AJ Reeves Castings
« Reply #31 on: October 04, 2017, 06:55:05 PM »
Hi Zephyrin

Thanks for your kind words.  I did briefly (very briefly) think about making the straps from flat, but I went for a cold shower and completely dismissed the idea!!!!  To get the correct length I made the upper bush and very gradually adjusted the length of the strap on my disc sander until it mated with the lower part of the hole.  It was a fiddly job but very satisfying when completed.

Cheers

Martin

Offline Emelbe

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Re: Vulcan Beam Engine - AJ Reeves Castings
« Reply #32 on: October 07, 2017, 10:07:45 AM »
A quick update as to progress.  After turning the cross-shafts I fitted the suspension links to the beam and spent an hour or so adjusting the fit to get rid of any slop.  Next up was the two big questions, how do they line up, and when do I drill the holes in the entablature for the outside bridle links?  So back to the lathe to make the main crosshead and drill the upper cylinder cover.  The piston was rod fitted and the rough initial check on alignment wasn't too bad but not quite right, it looks like I will have to adjust the position of the main castings to get the suspension links to hang vertically with the cylinder bore.  I think the minor discrepancy will be due to the measurement problem when drilling the beam, it's not much but enough to spoil the finished model.

I don't think it would be a good idea to drill anything until I've made the piston and piston gland and tested for alignment properly, so its time to get to work on the cylinder. 

Offline Chipswitheverything

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Re: Vulcan Beam Engine - AJ Reeves Castings
« Reply #33 on: October 07, 2017, 10:22:39 PM »
Hi Martin, the Vulcan is really coming on now, giving a good idea of how the engine will eventually look.    Very pleased that the soldering idea proved handy to you.
  Re. alignment and getting that side of the build satisfactory, I must admit that my Stuart Major beam took a lot of small fiddling adjustment to achieve smooth motion, although I had endeavoured to be accurate in dimensions and squareness, etc.  The height and separation of the many moving elements in a beam engine does cause its share of problems with extrapolation of small discrepancies.  Dave

Offline Emelbe

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Re: Vulcan Beam Engine - AJ Reeves Castings
« Reply #34 on: October 07, 2017, 10:50:03 PM »
Hi Dave

Think it's going to be a case of pinching a bit here and there, it's not a lot, probably be about 2mm max, which is what I had to adjust the holes in the beam to centralise them in the bosses.  Trouble is with me, I don't know whether it's a blessing or a curse, I really notice these things (my excuse for not decorating etc.).  Have made the piston so I can see exactly what I am dealing with now, so will sort it tomorrow, hoping it's just a matter of elongating a couple of holes in the stays and the cylinder pedestal.  As I said earlier, cheers for the tip about soldering.

Martin

Offline Emelbe

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Re: Vulcan Beam Engine - AJ Reeves Castings
« Reply #35 on: October 08, 2017, 04:01:32 PM »
Good news and bad!  I've resolved the problem of the suspension links not hanging vertically, that was straightforward, move the cylinder assembly until they did.  As I thought it wasn't much, around 1.5mm away from the beam pivot, and re-drill the pedestal.  Now the bad news, the Entablature Frames and Side Stays are out, I guessed they would be, but was hoping to maybe salvage them. I probably could by packing them out, but I think they would look terrible.  Ah well, these things are sent to try us, I've decided to order new castings and re-do them completely.  As it happens I'm delighted with the result, the beam falls nicely under its own weight which can't be all bad.

Now the confusing bit, to get the holes in the beam to line up with the cast bosses I had to reduce the distance to the pivot, so one would think the cylinder would have to be moved closer to the pivot as well, but in my case it had to be moved away, if anyone has any ideas please let me know. 

Offline Jasonb

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Re: Vulcan Beam Engine - AJ Reeves Castings
« Reply #36 on: October 08, 2017, 04:54:49 PM »
The links on some engines are not vertical, some more so than others, also the cylinder will only be under the end of the beam at one point in it's rotation even on an engine with vertical links.

I think there was a thread on here where we talked about the differences on various models and full size.

Where are the frames out? can the top be skimmed while they are mounted on the base if they are not equal

Offline Emelbe

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Re: Vulcan Beam Engine - AJ Reeves Castings
« Reply #37 on: October 08, 2017, 06:59:32 PM »
Hi

Not sure what's happened, checked and double checked the original measurements, that's why I was confident in fitting the stays and entablature in the first place.  The reason I want the links to be vertical is, to me, they don't look right if they're not.  Suppose it's all hypothetical now as I'm happy with them now, it really would have bugged me if I hadn't have fixed the problem.  Every model is a learning curve!

Cheers

Martin

 

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