Cylinder mounting.

[Garry ColesParticipant @garrycoles69390]

Hi, I'm currently building the D & NY in 2in scale. My question is to do with the mounting of the cylinder casting to the boiler. The boiler has the extra copper plate silver soldered to the outside where the cylinder is mounted. But do the cylinder mounting bolts/studs go into blind holes, or is it ok to drill right through and then use studs. It just seems that there is not enough thickness of the plate to use blind holes. Can someone please advise me.

Thanks

Garry

[Garry ColesParticipant @garrycoles69390]

[MichaelRParticipant @michaelr]

When building my D&NY I drilled and tapped right through the plates and used studs never had a problem with this method over the years I ran the engine.

Mike.

[Garry ColesParticipant @garrycoles69390]

Thanks Mike. That's what I would like to do my self but wasn't sure if doing it that way would tell the pressure in the boiler to tear along the dotted lines. ( Stud holes) !!

[JasonBModerator @jasonb]

Both my engines have the holes drilled right through

[Garry ColesParticipant @garrycoles69390]

Thanks Jason, that makes it a lot easier to do than a load of blind holes with not much depth.

[Anonymous]

Many full size engines have the cylinder fixing holes drilled right through the boiler shell. The only difference being the holes are not tapped; carrot bolts are used instead of studs.

Andrew

[SillyOldDufferModerator @sillyoldduffer]

Posted by Andrew Johnston on 12/05/2019 14:40:51:

… the holes are not tapped; carrot bolts are used instead of studs.

…

Are those 'carrot bolts' like the famous 'jive-ass' fixings used by Australian rock-climbers, ie a machine bolt shaved down to a point and then nailed into the hole. They claim carrot bolts were invented in 1962; be fun if they are actually a 19th century British boiler fitting!

 

Edited By SillyOldDuffer on 12/05/2019 15:21:47

[DMBParticipant @dmb]

Andrew,

It seems like I'm not the only one not understanding "Carrot bolts". Come on, spill the beans!

John

[JasonBModerator @jasonb]

Think of a "stud" shaped like a 5C collet where the end of the plain end of the stud tapers outwards. A lad would have been sent in via the manhole to poke the bolts through from the inside where they would be pulled up tight into the hole as the nuts were tightened preventing them turning and more importantly sealing the holes.

Edited By JasonB on 12/05/2019 16:17:37

[Anonymous]

Posted by DMB on 12/05/2019 15:24:51:

It seems like I'm not the only one not understanding "Carrot bolts". Come on, spill the beans!

Wot Jason said.

If there's trouble with vegetables I'd better not mention traction engine spuds!

Andrew

[not done it yetParticipant @notdoneityet]

Posted by Andrew Johnston on 12/05/2019 19:15:57:

If there's trouble with vegetables I'd better not mention traction engine spuds!

Andrew

Same as on agri tractors – at least the old ones?

[Anonymous]

Posted by not done it yet on 12/05/2019 22:07:06:

Same as on agri tractors – at least the old ones?

Errr, I think so? Burrell called them anchors, which is something of a misnomer as they're designed to get you out of a sticky situation rather than keep you in it.

Andrew

[SillyOldDufferModerator @sillyoldduffer]

Posted by Andrew Johnston on 12/05/2019 23:07:17:

Posted by not done it yet on 12/05/2019 22:07:06:

Same as on agri tractors – at least the old ones?

Errr, I think so? Burrell called them anchors, which is something of a misnomer as they're designed to get you out of a sticky situation rather than keep you in it.

Andrew

Had to look 'spud' up. Amused to find the traction engine meaning (which not many know) is proper English, whereas spud as in potato is slang.

Heard on Radio 4Extra this morning. 'American Spelling' = 'Mistake'

Dave

[Paul HorthParticipant @paulhorth66944]

Hello Garry,

I have come to this thread a little late. Regarding the cylinder mounting studs, I have done this job twice now. I have a 2 inch Durham engine, now nine years into its second boiler (don't ask). The studs are fitted into through holes and sealed with Red Hermetite, and there has been no problem with leaks on either of the boilers. So this procedure will work OK.

I'd like to say a few words about fitting these studs. They are made of bronze and I found them tricky to produce and fit. You need to take care about the exact length, they need to show one nut thickness plus one thread or so, with the cylinder and its sealing gasket in place, when tightly screwed in. The cylinder flange thickness may vary, depending on how the saddle was machined, mine did. There is not much length to grip the studs with, so you need to make a good stud driver to screw them tightly home against the end of the inner thread.I reduced this problem by fitting nuts with silver solder to all the studs except one row, thus making them into bolts. One row of studs can be put in before the cylinder is placed, this should be done with the stud driver, the cylinder is then located and the other stud holes can be carefully spotted through taking care about the angle. I had to drill the holes with a hand drill, aiming by eye, because I couldn't get the whole boiler, hornplates, cylinder etc under my machine drill. So I ended up not getting the angle accurate and having to draw over some of the holes in the flange to get the studs through.

And before doing any of this, the cylinder needs to be accurately located square to the crankshaft at the exactly correct distance and in good contact with the saddle pad.. I made a fixture which connected the cylinder squarely to a dummy shaft which could sit in the crankshaft bearings. So the hornplates and bearings have to be already in place.

Good luck!

Paul

Edited By Paul Horth on 28/05/2019 11:14:59

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