'WIDE A WAKE' a steam launch tale

[Jasonb]

Ramon, Andrew did some hobbing with a spiral flute tap recently

http://www.modelenginemaker.com/index.php/topic,5008.msg103352.html#msg103352

[steamer]

Another point in the  plus column for a worm driven pump is that it slows the pump down, with a fast pump speed you are more likely to "vapor lock" it and it won't pump anything...especially when hot...

For that reason, on my launch, I am removing the engine driven pumps from the cross head and driving them via timing belt and reduced speed.   ( 12" to the foot size......)   My engine runs at 600 rpm...so it's fast

These small model ones can run 2000 rpm at a drop of a hat, so I'm not that surprised it's gear driven.

Big launch and ship sizes though....eccentric driven pumps are awesome.

Just showing the lump I got the hard way.....

Dave

[Ramon Wilson]

Ok guys - back on the con rods 

As mentioned they machined up okay despite being a tad narrower than the bronze originals across the fork. As they've turned out they are lighter but probably much stronger than the originals. I realise now that what George thought was the webs the wrong way was just excess material for holding with and this was left on as long as possible. The crankpin holes were done first followed by the slot for the yoke. This followed by roughing the ends in the chuck then turning between centres to give an accurate spigot to hold in the collet. The tapers were then turned using the top slide


The holes were drilled and reamed in one web and the other tapped 5BA then the palm was reduced to width. A couple of filing buttons were turned from silver steel to fit either hole with an 8BA bolt  through and the end bosses filed to shape. This went much better than anticipated and it was at this stage that it looked obvious there was sufficient material width for the task in hand without the need to solder on pads.


With Sue on holiday this week and the weather fine for gardening, workshop time has been a bit limited but the rods are finished, the crossheads made from EN1a freecutting mild steel - a great combination with cast iron - and hardened and tempered pins (the thread portion is an insert of 5BA threaded rod - allows the pin to pull up tight with maximum thread engagement) the parts are now ready for assembly next session


Having looked at the colour off and on for a few days I finally came to the conclusion I didn't like it so re-masked and over sprayed all the parts with a lighter grey which seems far more agreeable to the eye - well my eye at least 


As you can see the gears arrived today - the single most expensive part on this project so far I think  .
Your link to Andrews post came about an hour too late to save the day Jason - by then the money was spent  Obviously there are 'for(s)' and against(s) in this area but I will stick to Georges recommendation now. I have counter-bored the end of the worm to sit on the reduced portion of the shaft and turned a small boss (6mm dia) for the other end in which the 4BA cap head locates
(the head of which was reduced to 4.5mm dia). Run out is negligible and it should sit in a bronze bearing nicely. Once the design is sorted out the worm will be reduced in bulk to look more in keeping.

Well that's it for another night - I must admit I'm tiring of this - when I look at all the photos in the album as they come up on Picasa it reminds me that it's been a long haul

Regards - Tug

[zeeprogrammer]

Still   

[crueby]

Love the look of those con rods, clever how you left the blocks on for support. Gotta remember that one!

[Ramon Wilson]

Zee - is that pop corn or a bag of peanuts 

Chris - leaving pieces on as long as possible for use as machining aids is a good method to adopt - it can make a big difference on work-holding particularly on awkward shaped parts.


Just a couple of pics tonight

First shows the lagging and method of attachment. The inserts were turned 2.5mm diameter, 5.8 long, drilled and tapped on the lathe - no danger of breaking the tap in the head itself plus not having to tap CI. I began with 14BA which were more scale like but after doing the first six decided against it on the basis that the threads are easily stripped. They were drilled out and the lot tapped 12BA.

The lagging is walnut strip super glued with 'Zap' CA to a 1/64 plywood panel. The bands were held in a fixture then milled down from 5mm X 0.3mm strip to 2.8mm wide and a drill jig made for drilling the holes. The inserts are Loctited in the holes, the central ones held in place with 'Hafix' CA before filleting with JB Weld.

There was a question elsewhere on here recently about JB Weld and I remarked on it's tendency to slump.  I commented that colloidal silica is used to thicken epoxy but wasn't sure if that would have an effect on the JB's properties. Well, time for a test piece

The JB was well homogenised before adding a small amount of the silica. It certainly thickened it up without affecting the ease of application. The pic above was taken about twenty minutes after applying - as you can see no hint of slump or glossing over. About an hour later it had begun to cure enough to allow smoothing and shaping with a moistened finger tip.

Once this has cured fully and been fettled I can get the head painted then at last begin to put it all together.

Hope the latter is of interest to potential users

Regards - Ramon

[crueby]

Neat use of the inserts to handle the lagging bolts. Engine is coming along terrific!

I have used the silica for thickening epoxy and polyester resins a lot for boat building, no reason it should not work on the JB Weld too, glad to see it does. Have to remember that.  If you use the silica, just be sure not to breath it in, it is a super fine powder that tends to float around as you measure it out and start to mix. Very handy stuff, it does not absorb the resin like a wood flour does so it does not impede absorbtion into other materials. Great for thickening up resin to make a filet in corners, is still sandable/fileable when hardened.

[K.B.C]

Ok guys - back on the con rods 

As mentioned they machined up okay despite being a tad narrower than the bronze originals across the fork. As they've turned out they are lighter but probably much stronger than the originals. I realise now that what George thought was the webs the wrong way was just excess material for holding with and this was left on as long as possible. The crankpin holes were done first followed by the slot for the yoke. This followed by roughing the ends in the chuck then turning between centres to give an accurate spigot to hold in the collet. The tapers were then turned using the top slide


The holes were drilled and reamed in one web and the other tapped 5BA then the palm was reduced to width. A couple of filing buttons were turned from silver steel to fit either hole with an 8BA bolt  through and the end bosses filed to shape. This went much better than anticipated and it was at this stage that it looked obvious there was sufficient material width for the task in hand without the need to solder on pads.


With Sue on holiday this week and the weather fine for gardening, workshop time has been a bit limited but the rods are finished, the crossheads made from EN1a freecutting mild steel - a great combination with cast iron - and hardened and tempered pins (the thread portion is an insert of 5BA threaded rod - allows the pin to pull up tight with maximum thread engagement) the parts are now ready for assembly next session


Having looked at the colour off and on for a few days I finally came to the conclusion I didn't like it so re-masked and over sprayed all the parts with a lighter grey which seems far more agreeable to the eye - well my eye at least 


As you can see the gears arrived today - the single most expensive part on this project so far I think  .
Your link to Andrews post came about an hour too late to save the day Jason - by then the money was spent  Obviously there are 'for(s)' and against(s) in this area but I will stick to Georges recommendation now. I have counter-bored the end of the worm to sit on the reduced portion of the shaft and turned a small boss (6mm dia) for the other end in which the 4BA cap head locates
(the head of which was reduced to 4.5mm dia). Run out is negligible and it should sit in a bronze bearing nicely. Once the design is sorted out the worm will be reduced in bulk to look more in keeping.

Well that's it for another night - I must admit I'm tiring of this - when I look at all the photos in the album as they come up on Picasa it reminds me that it's been a long haul

Regards - Tug





Hi Ramon,
I have just started to look back at things, I have been laid up with a very back attack of Sciatica on my left leg, the pain of which I would not wish upon my worst enemy, I now think that I will live.

I see that you had enough material on the Con rods to make the Eye at 90 deg to the main shaft, on your pic it looked as if there wasn't enough and you could have ended up like my first attempt.
I like the idea of making the cross head out of M/S, something that had never crossed my mind but I shall keep that in mind for the future.
Your machining is an inspiration and drives me to get better , thanks for your postings and pics.

George

[zeeprogrammer]

Did a little more than just  this morning. (And that's popcorn Ramon. I eat peanuts out of a can  )

When through the entire thread again. Geesh. Really can't say enough. Wonderful work. A great motivator too.
Really looking forward to the launch.

[Ramon Wilson]

Hi George - Just in from my plastic model night  and pleased to see your post but sorry to hear you've been in pain again - hope it's easing for you by the day.

I now have the engine erected and working on the valve gear. It turns over very smoothly and I'm well pleased with the alignment of the one piece head. I have made the expansion links from steel and have the eccentrics well under way. I'll try to post some pics tomorrow.

Zee - I admire your tenacity  - that's a long mornings worth of popcorn buddy  . Thanks for your kind comments too - much appreciated. If you, or anyone else, can find some motivation or inspiration from then it makes the time spent doing it all worthwhile. It does get a bit tiring I have to confess but the end is not that far off - I even have a new stripey blazer just for the launching 

Back tomorrow with some pics with luck,

Keep on improving George

Regards - Ramon

[Tennessee Whiskey]

Well I hope you've also chosen an appropriate bottle of bubbly to go along with the blazer  . Here's to blue skies,  calm winds,  and smooth water  .

Cletus

[Don1966]

Still following your resolve Ramon, alway great work.......


 
Don

[pgp001]

Ramon

Top Tip on the use of brass inserts for the 12BA lagging screws, I was dreading tapping those into Agnes's cylinders but now the job will be easy.

Thanks
Phil

[Ramon Wilson]

Hi Guys - nice to hear from you  - thanks for your continued support. Good to hear from you too Don  .

Yep Whiskey, I have the bubbly all ready even have some of those disposable 'champoo' flutes to hand it out in. Recipe downloaded for Cucumber sandwiches and we're all set to go - just need a bloody boat  (oh and a Boater)

Phil - glad that's of use. It's something I have thought about doing for some time but this is the first time I've tried it. I can recommend it - it's proved totally successful. Were I to do it again (and it's a big 'were' at this stage) I would back drill the inserts first to leave about 3 mm of material for tapping. Though a bit longer in preparation that would cut down on the need to tap so deep for clearance.

Following on from the post on using the silica to thicken the JB Weld this proved successful and did not appear to have any detrimental effect on the strength. It was fettled with the usual rotary burr in a power tool and finished up like this. Incidentally I noticed that I ended up with a more cast like surface by fettling through the previously primed surface. Perhaps something worth bearing in mind if a rough cast like effect is required


The expansion links mentioned last post were milled from the same material as the con-rods and were milled on a sacrificial ali bed plate on the R/T




Once fettled up they don't look too bad and should last a bit longer than the ST brass stampings. The die blocks were milled from a slab of Manganese Bronze on the same fixture to the given radius then milled to width before cutting off with a slitting saw.


The eccentric straps were machined from a bar of Manganese Bronze. The slabs were rough milled but had the lower portion milled to a set size (15mm). Once soft soldered together and the faces milled all over that join line is then at a known distance.


The outer profiles were milled and the bolt holes drilled and tapped so they could be reinforced with the bolts for the remaining machining ops


They were rough bored with a series of slot drills 6.5, 10, 12, 15,


Then finished bored in the mill to a plug gauge


A previously made expanding mandrel was recycled.....


...in order to face the width to size


And this is it for tonight - not too many parts left now


The pistons are fitted  - I decided in the end to use graphite packing - yes I know, I know but I'm a traditionalist you see  The engine turns over extremely smoothly with no tight or loose spots which I was pleased about given the use of new and old parts.



Well that's it for tonight - a couple of more days and I should be able to start to put it all together but tomorrow is a garden day.


I note the thread has passed the 50,000 mark  so thanks to all who look in on such a regular basis - I know this is only a Double Ten but bear with it - it'll be back in the boat afore too long.

regards - Ramon

[crueby]

Coming together wonderfully! That engine block is great!