|
|
Post by Deleted on Sept 15, 2014 17:51:43 GMT
|
|
jma1009
Elder Statesman
Posts: 5,900
|
Post by jma1009 on Sept 15, 2014 18:14:32 GMT
interesting!
i didnt think that a lap joint was allowed on a boiler barrel seam?
cheers,
julian
|
|
|
|
Post by houstonceng on Sept 15, 2014 18:22:17 GMT
If it was in the original published design or in an equally validated design calculation and is properly executed, a lap joint is OK.
Let us face it. A but strapped joint is OK, so why not a lap ?
|
|
|
|
Post by fostergp6nhp on Sept 16, 2014 6:38:12 GMT
Full size lap joints in barrels went out of favour because of the pressure flexing the plates against the joint edge as the barrel tried to become truly circular from its non pressurised slightly out of circular form. So the slight flexing used to cause grooving at the joints and if undetected the barrel then bursts in use.
|
|
Geoff
Hi-poster
Posts: 169 
|
Post by Geoff on Sept 17, 2014 2:01:15 GMT
How many have burst?
|
|
steam4ian
Elder Statesman
One good turn deserves another
Posts: 2,069
|
Post by steam4ian on Sept 17, 2014 6:32:22 GMT
In models,good question.
|
|
|
|
Post by ettingtonliam on Sept 17, 2014 9:07:43 GMT
Its a long time since I built a Juliet boiler (a long time since I built any boiler in fact) but I have a vague recollection of joggling one side of the barrel joint, so that although it was a lap joint, the finished product was truly cylindrical on the inside. Presumably this would overcome the flexing issue? Anyway, I think I worked strictly to LBSCs design, didn't know enough to criticise the work of the master, and I've never heard of Juliet boilers failing in the barrel joint.
Richard
|
|
|
|
Post by ejparrott on Sept 17, 2014 11:28:27 GMT
I think Phil's point is that full size boilers fail, not miniature, they also have corrosion to deal with. You get some interesting 'grooves' down the sides of lap joints sometimes
|
|
|
|
Post by Deleted on Sept 17, 2014 12:38:24 GMT
I can't see a silver soldered lap joint on a copper boiler being a problem, apart from you get a gap at the joint that needs filling at the tubeplate. The 2½" gauge King has a lap joint and that's a commercial boiler. I used a 'joggle' joint on the combustion chamber joint on my A1 boiler to avoid a joint strip. I can appreciate that a rivetted lap joint on a steel boiler could be a bit iffy.
John
|
|
|
|
Post by GWR 101 on Sept 17, 2014 18:17:22 GMT
Hi, I am building Juliet but have absolutely no boiler making experience, my boiler is currently being built by person who has lots of experience and has been recommended to me by several others including my club boiler inspector. I have just examined the drawings and the firebox wrapper is shown and noted with a 1/4" overlap. Hope this helps, regards Paul
|
|
