|
|
Post by GWRdriver on May 4, 2006 0:51:40 GMT
This is a Belpaire boiler for my Double TICH (7.5"ga) The barrel OD is 6-1/8".  |
|
|
|
Post by chris vine on May 5, 2006 2:17:50 GMT
Hope the rest of the loco is to the same standard!!!!
Chris.
|
|
|
|
Post by Nexuas on May 5, 2006 7:37:32 GMT
Yes it looks spot on. I am just about to start on a boiler and I am hoping to make it as neat and accurate as possible, but being new to the Model Engineering lark am not sure all will go to plan...
Although the boiler inspector at the local club made some encoraging nosies when I showed him the boiler bushes I had made...
|
|
|
|
Post by jgb7573 on May 5, 2006 10:15:04 GMT
Hi nexuas,
Just give it a go. I've seen lots of boilers nowhere near as neat as this one that work fine. It's good to aim for the best, but don't be disheartened if it isn't a Duke of Edinburgh Award winner at the first attempt. So long as it holds pressure safely and you are happy with it, then it's fine!
John
|
|
|
|
Post by Jo on May 5, 2006 10:41:45 GMT
Has anyone mentioned the idea of not drilling the bushes all the way through until after the boiler test?
Saves a lot of messing around bunging up the holes each time you find that it is pretending to be a watering can..
|
|
|
|
Post by GWRdriver on May 6, 2006 15:29:04 GMT
It sounds good in theory . . . . One of the difficulties with post-drilling bushes is that for most of us all that we will have at our disposal is a hand-held power drill. These usually provide neither the correct drilling speed nor a way of holding the drill steady and in-line as the point digs in and breaks through, usually leaving a very ragged sometimes chewed out hole which isn't fit for a decent thread.
|
|
|
|
Post by alanstepney on May 6, 2006 19:45:46 GMT
Plus the problem of swarf in the boiler.
|
|
|
|
Post by chameleonrob on May 6, 2006 21:50:02 GMT
would it count as modifeing the boiler, which would then require a retest?
|
|
|
|
Post by GWRdriver on May 7, 2006 12:51:08 GMT
Re: Re-testing . . . . .
Being in the USA (and not having access to the written regulations), I don't "have a dog in that hunt", as we say in the South, but I think that unfortunately would be a an opinion rendered by an individual testing official and could go either way. IMHO it would NOT require retest because the structural design of the boiler, which determines its pressure capacity and safety factor, has not been altered, only the status (open or closed) of previously planned and designed-for steam or water access points. The key would be that these are previously planned and designed-for openings. That we know they will be blocked off for testing is a foregone conclusion so this (IMHO) would be qibbling over the manner of blocking off.
If one was ruled against in this question, then the same faulty (IMHO) logic could be used to say that after remoival of plugs a tested design had been altered. Barry Harrison up Chester way is a chum and was/is a Federation boiler committee member so I'll give him a shout to see what he thinks.
|
|
|
|
Post by GWRdriver on May 20, 2006 20:00:24 GMT
I have put this question to Barry Harrison but I've as yet had no reply.
|
|
|
|
Post by GWRdriver on May 24, 2006 13:35:51 GMT
Here's a bit more progress to view . . . I've just now finished the dome and base for my TICH boiler. The dome flange and base are made from rings of SAE660 cored bearing bronze stock.  The most challenging job was contriving the setup to fly-cut the fishmouth in the dome base, but my idea of using two V-blocks as "clamps" worked just fine.  You might wonder why I had to resort to such a precarious looking setup, although it was actually very sturdy an stable. As most of us must, from time to time, ater evaluating my available tooling and machine capacities I found this was the only way I could get the reach and stroke required to make the fishmouth cut in one pass. The barrel was bored for the dome base to presses into the barrel rather than saddle it so the fishmouth was actually cut simply to reduce the amount of excess metal inside the boiler. Less metal inside, more room for steam!  |
|
|
|
Post by chameleonrob on May 24, 2006 20:07:28 GMT
Nice pics. I'm going to have to do somthing similar soon (ish), the only way I can do it with my tools is to drill and tap the stud holes in the dome bush, use them to bolt it to the toolpost on my (3.1" centre height) lathe and take cuts with a long, custom made, cutting tool held in the 4 jaw chuck, I'm not looking forward to it.
rob
|
|
|
|
Post by GWRdriver on May 24, 2006 22:52:05 GMT
Rob,
Sounds like the time and place for a bar style flycutter mounted between centers, or rather in the 4-jaw at one end and the tailstock center at the other. Perhaps this is what you intended.
|
|
|
|
Post by chameleonrob on May 25, 2006 13:50:10 GMT
the reason I'm going to hold the tool in the 4 jaw chuch is that the chuck is 4.5" dia and the radius is 3" so the workpiece can go along side the chuck allowing the chuck to be used as a large flycutter with the tool held across the face of the chuck.
rob
|
|
|
|
Post by GWRdriver on Jun 4, 2006 14:53:14 GMT
Chameleonrob,
I've heard back from Barry Harrison and he agrees with virtually everything I put to him (see my post above), and that pre or post drilling of bushes should not be cause to re-test as a result of a design change. I emphasize the word should because Barry agreed, as I stated above, being human there could be instances where a testing official might be overly zealous or misinformed.
|
|
|
|
Post by chameleonrob on Jun 4, 2006 20:02:09 GMT
Chameleonrob, I emphasize the word should because Barry agreed, as I stated above, being human there could be instances where a testing official might be overly zealous or misinformed. Thats more or less why I questioned it! I'd hate it if someone had read it and then had problems later. You've confirmed my guess about the situation, thank you. rob |
|
