steam4ian
Elder Statesman
One good turn deserves another
Posts: 2,069
|
Post by steam4ian on Oct 31, 2009 12:08:26 GMT
G'day Chris
Stan Bray's book has a diagram with linkages that cause the tool post to follow an arc as it travels in. Too clever for me.
You could cut a flat template out of brass, Ali, heavy plastic sheet or whatever and clamp this template to the bed (lathe, quirky). Then clamp a stylus to the tool post and move the cross and compound slides to have the stylus follow the template. If the template is strong enough it can act as a restraint against digging too deep.
There's a pontification for you! ;D
Regards Ian
|
|
|
Post by drjohn on Oct 31, 2009 13:24:08 GMT
.....There's a pontification for you! ;D Took the very words out of my mouth Ian ;D DJ
|
|
redmog
Part of the e-furniture
Not Morgan weather
Posts: 461
|
Post by redmog on Oct 31, 2009 15:27:57 GMT
Trick or Treat. G'day Chris Stan Bray's book has a diagram with linkages that cause the tool post to follow an arc as it travels in. Too clever for me. Ian Thanks for offering the idea to me Ian. I'm afraid it arrived a little too late - I was in the workshop. I was going to try an ides I had off a member of this forum, But then realised it wouldn't work in my situation because the arc is not constant. Not to worry - I did it by eye, well, so far. I ground up a HSS tool as a flat scraper. Kept cranking the toolpost round to follow the angle so that it was always tangential in the centre of the tool. The most useful item was my mandrel crank handle that I made up a while back. I never switched the motor on but turned it by hand to just scrape the surface. Did the 'Trick' worked a 'Treat'. So far So good. Still thinking about he middle bit! Chris
|
|
redmog
Part of the e-furniture
Not Morgan weather
Posts: 461
|
Post by redmog on Nov 13, 2009 8:43:16 GMT
Smokebox Ring. You're right DJ. Mine and JB's smokebox plumbing might be a problem. I've asked this question before, with no response! I'm thinking of plumbing it before I fit the Ring and Door. Although the ring is a good push fit into the smokebox, I'm trying to find a way of securing it without a noticeable fixture. Chris The inner diameter of the door ring is far too small. How can I plumb inside there?I will enlarge it when I have the size from the door.
|
|
|
Post by Deleted on Nov 13, 2009 9:32:20 GMT
Smokebox Ring. You're right DJ. Mine and JB's plumbing might be a problem. Nothing wrong with my plumbing Chris: I've just had the operation! JB We seem to be neck and neck here, and very good it is too. Anyone taking bets on a completion date?
|
|
|
Post by drjohn on Nov 13, 2009 10:02:27 GMT
Smokebox Ring. You're right DJ. Mine and JB's smokebox plumbing might be a problem. I've asked this question before, with no response! I'm thinking of plumbing it before I fit the Ring and Door. Aha!! Well according to JB, you need Baggo "because he's very small" (JB's words, not mine!!) ;D ;D DJ And JB, it wasn't your plumbing you had fixed, it was one of your septic tanks!!! Lol!
|
|
redmog
Part of the e-furniture
Not Morgan weather
Posts: 461
|
Post by redmog on Nov 13, 2009 12:58:28 GMT
JB We seem to be neck and neck here, and very good it is too. Anyone taking bets on a completion date? No JB. But I'll bet DJ. is running a Simplex on his track before we can get steam up. At his work rate he could even be running a Black Five. Network Rail could do with DJ's services. Perhaps there are more hours in the day 'out east'. Chris
|
|
redmog
Part of the e-furniture
Not Morgan weather
Posts: 461
|
Post by redmog on Nov 13, 2009 14:40:29 GMT
Thin Tubes. Can this be right - 3/8" x 22g flue tubes? How can I work out the Safety Factor on these tubes. Common sense tells me that the calculation will be different from internal pressure. I can easily obtain 3/8" x 21g from a local company that specialise in refrigeration and air conditioning, but I'd like to be able to calculate the CSF. Chris
|
|
|
Post by baggo on Nov 13, 2009 15:28:39 GMT
Aha!! Well according to JB, you need Baggo "because he's very small" Who's been peeping! Chris, I don't know of a formula as such for the collapse pressures of copper tube but this table from Susan Parker's website may be of some help: www.susan-parker.co.uk/images/boiler/annealed-cu-tube-collapse1.gifThat suggests that the collapse pressure of your 3/8" x 22g tubes is about 400psi. Note though that these figures only apply to tube that is perfectly round and without any dents etc. If the tube is slightly oval or otherwise misshapen, the figures will be lower. The problem is that once the tube does go out of round it suffers catastrophic collapse and just flattens. Not dangerous as such but not much good in a boiler tube! John
|
|
redmog
Part of the e-furniture
Not Morgan weather
Posts: 461
|
Post by redmog on Nov 13, 2009 16:41:13 GMT
Collapse Pressure.
Thanks John. But that's a bit of a shock - Collapse pressure of 3/4" x 18g is less than 500psi. Looks like going for 3/8" x 18g for flue tubes, and 3/4" x 16g for the superheater flue tubes, even if only to feel more confident. Presumably tube gauge is measured as per British Standard Wire Gauge and not some unknown Tube Gauge. Chris
|
|
|
Post by baggo on Nov 14, 2009 0:47:55 GMT
I've always assumed that the thickness is the same as our SWG for wire. This seems to tie in with the metric equivalent that suppliers quote.
Don't be too OTT with your tube thicknesses. 20swg for the fire tubes and 18swg for the superheater flues should be plenty adequate if you want to go thicker than the originals.
John
|
|
redmog
Part of the e-furniture
Not Morgan weather
Posts: 461
|
Post by redmog on Nov 15, 2009 17:20:25 GMT
Wooden Tubeplate. To try and work things out in my own mind - I've been on the milling machine with a block of MDF. If I ditch the combustion chamber and go for slightly larger tubes, they need repositioning, so I made a wooden model to see how I could fit in 7/16" tubes instead of 3/8". I can still get the same amount of tubes in even with a 3mm spacing between them. Chris
|
|
redmog
Part of the e-furniture
Not Morgan weather
Posts: 461
|
Post by redmog on Nov 15, 2009 19:09:04 GMT
Backhead. JB. LBSC doesn't give dimensions on my Bantam Cock backhead either. It is worth doing a bit of research on backheads before drilling for bushes. The layout of a backhead can make things easy or hard when you come to fire the thing. Firehole door needs to swing wide open for easy firing and the like. I put 4 boiler feed bushes on mine for 2 injectors and a hand pump, and axle pump if required. Not that I'm an axle pump fan. Size of threads needs some thought. It's all looking good JB. It could be the 'Big Hydraulic' next month! Chris.
|
|
redmog
Part of the e-furniture
Not Morgan weather
Posts: 461
|
Post by redmog on Nov 20, 2009 18:21:42 GMT
Back on Track. Ok. so I've decided to ditch the combustion chamber and use larger diameter flue tubes. 18 feet of 7/16" x 20g arrived yesterday, along with 3 feet of 3/4" x 18g for the superheater tubes. So, I've been able to drill the firebox tubeplate to take these tubes. I'm ready for assembly so that I can silver solder next week. Shall I leave the firehole plate IN or OUT? The previous 3 boilers I made I put the stays in after the backhead and foundation ring. Is the advantage of leaving the backhead off just for access and inspection? Chris.
|
|
redmog
Part of the e-furniture
Not Morgan weather
Posts: 461
|
Post by redmog on Dec 1, 2009 21:17:28 GMT
Firebox Update. Things are quiet on the making seen of the forum at the moment. JB's taking time out from the Brit, so I thought it time to update interested parties on the V4 boiler. After receiving a delivery of the flue tubes last week I was able to drill the firebox tube plate to size in order to take them. So then soldered the firebox tubeplate to the wrapper. All went well with a nice fillet and good penetration through to the inside. Yesterday I soldered in the firehole to the backplate. Again good penetration producing a nice fillet on the inside as well as outside. Tomorrows task - to solder in the firebox backplate and hope that I keep up this successful streak. Chris. Firehole in place. Penetration to produce an inner fillet.
|
|
|
Post by 2tenths on Dec 1, 2009 21:40:03 GMT
redmog
THAT'S what I call a fine bit of soldering.
Tony
|
|
|
Post by Deleted on Dec 1, 2009 21:40:31 GMT
That's a remarkably neat fillet Chris, any chance you can beam it up to my Brit boiler joint? JB
|
|
ace
Statesman
Posts: 528
|
Post by ace on Dec 1, 2009 21:44:15 GMT
Thats nice work there Chris, like the soldered joints neat and tidy. Enjoying this thread on your V4 only wish mine was moving on but I have been busy over the last few months on other projects and work is now getting busy with the bad weather, went to Cumbria last week to assist with the emergency work so I don't have much spare time left at present. I am building a Flame Gulper for a friend who is retiring soon so that will keep me going for now.
Steve
|
|
redmog
Part of the e-furniture
Not Morgan weather
Posts: 461
|
Post by redmog on Dec 1, 2009 21:53:46 GMT
If Only. That's a remarkably neat fillet Chris, any chance you can beam it up to my Brit boiler joint? JB I wish I could JB.
|
|
redmog
Part of the e-furniture
Not Morgan weather
Posts: 461
|
Post by redmog on Dec 1, 2009 22:04:15 GMT
Nice Comments. Thats nice work there Chris, like the soldered joints neat and tidy. Enjoying this thread on your V4 only wish mine was moving on but I have been busy over the last few months on other projects Steve I've been following and admiring your progress also. This is what it's all about. Not only enjoying my own sense of achievement but also other. Thanks Tony - probably more luck than judgment, but there are a few 'tricks'
|
|