|
|
Post by runner42 on Jun 10, 2022 7:43:29 GMT
In your boiler CAD above, why do you have the steam dome protruding so far into the boiler? It will suck water up like a tornado... Yes I agree extending the steam dome flange so it contacts the normal water level is unneccessary and could suck up water. The only mitigating issue is that the large clearance hole through which the transfer tube from the regulator to the wet header passes will tend to provide a bleed to reduce this effect. I assume that your boiler design will comply with the AMBSC Code part 1, if so your stay diameter (not indicated) and stay spacing tends to suggest that either the minimum stay diameter is below that specified by the code (3 mm) or that the stay spacing is closer than specified. My Black 5 boiler which is comparable to your boiler design when using a 3mm stay diameter requires only 5 rows of stays to stay the whole of the vertical firebox side. Is the regulater actuating rod entering the side of the boiler prototypical so you are copying full size, if not then a backhead mounted actuating rod is feasible and IMHO more elegant. How is the regulator being held inside the steam bush? Brian |
|
44767
Statesman
Posts: 538
|
Post by 44767 on Jun 10, 2022 22:55:05 GMT
In your boiler CAD above, why do you have the steam dome protruding so far into the boiler? It will suck water up like a tornado... This CAD model is not finished for the boiler. The protrusion into the water space is so the mounting bosses to the regulator and operating rod can be combined with it and then the excess cut away. It will be cut back to just inside the boiler barrel. Hopefully, this shows the arrangement albeit still showing the protrusion.  Thanks for your comment! Mike |
|
44767
Statesman
Posts: 538
|
Post by 44767 on Jun 10, 2022 23:52:45 GMT
I assume that your boiler design will comply with the AMBSC Code part 1, if so your stay diameter (not indicated) and stay spacing tends to suggest that either the minimum stay diameter is below that specified by the code (3 mm) or that the stay spacing is closer than specified. My Black 5 boiler which is comparable to your boiler design when using a 3mm stay diameter requires only 5 rows of stays to stay the whole of the vertical firebox side. Is the regulater actuating rod entering the side of the boiler prototypical so you are copying full size, if not then a backhead mounted actuating rod is feasible and IMHO more elegant. How is the regulator being held inside the steam bush? Brian The boiler will comply with the current code when finalised. All I have done here with the stays is to use the same pitch of stays as on Don Young's Black 5 drawing (from which I have already built a boiler, to the code at the time) and used larger diameter stays at 6mm. Other than the extra cost, there's no problem with having more stays than the code shows as a minimum; if nothing more there is more capacity to transfer heat to the water from the fire through conduction. The regulator rod follows full size practice as this model is designed from the works drawings. The actual regulator has its origins from Don's drawings and has been made to fit the space available. Mike |
|
|
|
Post by runner42 on Jun 11, 2022 5:43:37 GMT
Apologises for second guessing your boiler design and getting it wrong. I used 1/4" rods as 6mm wasn't available, not 3mm. Yes using DY's stay spacing is going to add to the cost, 140 stays instead of 84 stays assuming the same footprint size as the Black 5 for the vertical sides of the firebox. DY didn't use 6mm stay diameter. Also complexity in construction, which you are not only imposing on yourself but others who will be using your design.
However, I am very impressed with your project and envious of your 3D CAD ability.
Brian
PS You only need 4 rows of stays in the top side of the firebox.
|
|
44767
Statesman
Posts: 538
|
Post by 44767 on Jun 11, 2022 10:14:16 GMT
However, I am very impressed with your project and envious of your 3D CAD ability. Brian PS You only need 4 rows of stays in the top side of the firebox. Well, there's an average of four rows of stays on the top of the fire box!  Cheers,Mike |
|
|
|
Post by suctionhose on Jun 13, 2022 23:47:47 GMT
Belpaires get very congested above the crown with crown stays, cross stays and longitudinal stays not to mention placing backhead bushes amongst them so the fittings layout looks right. Less stays in number is helpful as are doubling plates, palm stays, gussets and increasing knuckle radii to reduce the stayed area.
|
|
44767
Statesman
Posts: 538
|
Post by 44767 on Oct 28, 2023 11:19:42 GMT
Jumping ahead quite a few months from where I last posted, here is the latest assembly. This time I'm machining the whole cylinder and valve assembly to find any issues before I release the drawing to those already building a model. Once I've done this I will finish the detail drawings for all parts and supply castings knowing they are fit for purpose. Here we can see the valve crosshead and its guides and the cylinder rear cover. Apart from scale thread sizes, this is as close to scale as you can get. I will be making the pistons and rings next, then machining the features for attaching the cladding and for the drain cocks and steam chest drains.  |
|
johan
Seasoned Member
Posts: 118
|
Post by johan on May 24, 2024 20:34:31 GMT
WOW! Those cylinder and piston ends, are those 3D prints? Going on from the fine lines all in the horizontal direction.
|
|
44767
Statesman
Posts: 538
|
Post by 44767 on May 25, 2024 8:50:02 GMT
These were lost wax cast from 3D printed waxes. I use a true castable wax, not a resin.
|
|
