Author Topic: 'WIDE A WAKE' a steam launch tale  (Read 233755 times)

Offline K.B.C

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #510 on: April 15, 2016, 09:29:30 AM »
Hi Ramon,

 Just had a thought this morning , are you going to drive the pump by worm and wheel , or are you goint drive the pump via an eccentric on the main shaft ?

George.
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Offline Ramon Wilson

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #511 on: April 15, 2016, 12:15:02 PM »
Hello Joe - thanks for your interest - it's always nice to hear that someone is following along. It will be a while before the launch but hopefully if things work out right it should be this summer.

George, my thanks as always for your continued interest. Re the con-rods when I read your post I wasn't sure what you were referring to at first. A quick look at the pic soon put my mind straight however  :( At first I hoped it might be an optical illusion but then a quick visit to the workshop put things in perspective  :-[  I realised then that when I selected the material I had the dimension of 8mm in my head - that of the diameter of the boss and not the width across  them  ::)   Agh! we've all been there 

I've taken a good look at it and think I will press on with what I have - the material is just over 10mm wide - as I think, if necessary, I should be able to solder some pads on the outside to increase the width. I could also decrease the width of the slot slightly as I can make new cross heads to fit. Call them the new slim line D10 rods  ;)

With regards to the pump drive my intention is to make a wheel and worm. I have never done it before but intend trying to make the wheel using a 3/8 whit tap as a hob - this will very much be a 'suck it and see op' first and if successful will make the worm to match - is the HPC worm single or multiple start? as I have been thinking that it may run too slow on a single start. The intention is for the worm to be held on the shaft with a 4 ba caphead bolt. If this doesn't work out as well as hoped I will re-machine the shaft to take an insert on which to mount an HPC worm as you have done. Just in case do you have the HPC part no's required?

I still have the pics of your pump set up so will copy them in the most part, if not all.

Thanks again - I don't know how much further I would have gone before the penny dropped but at least I'm setting off now with the mistake firmly in mind  ;)

Hope this finds you well and improving

Kind regards - Ramon



« Last Edit: April 26, 2016, 01:33:36 PM by Ramon »
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Offline Jasonb

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #512 on: April 15, 2016, 12:24:37 PM »
George, regarding etch primer for ease of use I use ACID-8 made by U-Pol which comes in a spray can. Available from Halfords or the Net. If I'm airbrushing then I will tend to use the one from Precision Paints.

Ramon, you could try a bit of heating and twisting to get those conrod blanks back into a usable shape.

Could the eccentric and worm be made as one or the worm soldered onto teh eccentric to keep the length down and they could share the same grub screw so only one boss needed
« Last Edit: April 15, 2016, 12:27:50 PM by Jasonb »

Offline Ramon Wilson

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #513 on: April 15, 2016, 01:06:28 PM »
Hi again - George I overlooked your question  ::).

This is what I have used on the water tanks in the wide a wake and for the engine parts. I got it from my local car accessory shop. Jason's suggestion will be much the same I guess.


I can't say anything about it other than it went on well and evenly. How durable it is and how well it etches to brass remains to be seen.

Jason there will be two eccentrics each end. Stuarts show them as separate with a 1/16 hole drilled in each I guess to take a pin such to put them 120 degrees to each other. Only one has a boss with the grub screw in. I'm thinking at the moment to make each separate without a boss and have a hole in the straps to access the socket grub screws to allow a degree of independence however your thought that the worm and one could be soldered together is worth investigating further - nice one  ;)

I'm not quite sure quite what you are meaning about heating and twisting ? Soldering two thin pads toward the end of machining seems a much less stressful approach unless I'm missing something  :-\

Regards - Ramon

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Offline Jasonb

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #514 on: April 15, 2016, 01:27:09 PM »
I was thinking of holding it vertically in a vice, heating the main shaft to red heat and then giving the top a quater turn which looks like it should then give you the right width metal at 90deg to the bearing end. Bit like a blacksmith puts a twist in a poker handle. I seem to recall seing it done for two throw crankshafts cut from flat plate and then twisted to set the throws at 90deg.

Another soldering option would be to cut a semicircle out of the end and then solder in a wider round bar, this could then be drilled/reamed and the ends machined back to the required width. Something along these lines.







J
« Last Edit: April 15, 2016, 01:31:34 PM by Jasonb »

Offline Ramon Wilson

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #515 on: April 15, 2016, 08:34:42 PM »
Thanks Jason - but I think that sounds a bit too 'hot to handle'  ;)

I like the idea you show with the soldered on bosses though - however I have just milled the slot out to 6mm and am thinking that the 'missing' volume can be taken up with either pads soldered on the outer faces as first thought or possibly exchanging the cross head pin from the original to one with a head and a nut that will act as pseudo ( :o) bosses.

Very little else done today I'm afraid. I realised earlier that I've had the misfortune to lose my access to my AutoCAD files resulting in a bloody big gulp indeed  :( - whatever, after some delving I have down loaded Draft Sight and it appears I can access them through that - Phew.

Thanks for the input - always welcome  :)

Regards - Ramon
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Offline K.B.C

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #516 on: April 16, 2016, 12:50:13 PM »
Hello Joe - thanks for your interest - it's always nice to hear that someone is following along. It will be a while before the launch but hopefully if things work out right it should be this summer.

George, my thanks as always for your continued interest. Re the con-rods when I read your post I wasn't sure what you were referring to at first. A quick look at the pic soon put my mind straight however  :( At first I hoped it might be an optical illusion but then a quick visit to the workshop put things in perspective  :-[  I realised then that when I selected the material I had the dimension of 8mm in my head - that of the diameter of the boss and not the width across the them  ::)   Agh! we've all been there 

I've taken a good look at it and think I will press on with what I have - the material is just over 10mm wide - as I think, if necessary, I should be able to solder some pads on the outside to increase the width. I could also decrease the width of the slot slightly as I can make new cross heads to fit. Call them the new slim line D10 rods  ;)

With regards to the pump drive my intention is to make a wheel and worm. I have never done it before but intend trying to make the wheel using a 3/8 whit tap as a hob - this will very much be a 'suck it and see op' first and if successful will make the worm to match - is the HPC worm single or multiple start? as I have been thinking that it may run too slow on a single start. The intention is for the worm to be held on the shaft with a 4 ba caphead bolt. If this doesn't work out as well as hoped I will re-machine the shaft to take an insert on which to mount an HPC worm as you have done. Just in case do you have the HPC part no's required?

I still have the pics of your pump set up so will copy them in the most part, if not all.

Thanks again - I don't know how much further I would have gone before the penny dropped but at least I'm setting off now with the mistake firmly in mind  ;)

Hope this finds you well and improving

Kind regards - Ramon

Ramon,
 The only reason that I questioned your conrod blanks was that I made the same mistake when doing the mconrods on a Launch engine, see pic showing cross head eye 90deg out, fortunately I discovered this before I had both made.

I can't agree with your suggestion on making the worm and wheel drive.

As using a Whit bolt it's only a single start and when your engine is reving it willpump too much water into your boiler.
Stuarts worm and wheel ar Helical and the small wheel is a 10 start and the big wheel is 50 t to give 5:1 ratio.

I have included a pic of the Stuart gear set up. and a pic of the H.P.C. gear set up

I always try for a ratio of 4: 1 or 6:1  and I buy my worm and wheel from H.P.C. gears . ( www.hpcgears.com ) they have a free catalouge which is well worth having.

The worm is a  48 D.P.  4 start No W48-4 and the wheel is No  M48-20 giving me 5: 1 ratio, both items have 3/16" bore, this is just right for my D10 in a tug with a 4.75" dia x 5" between end plates Scotch Marine boiler.

If you do as suggesteted by bolting the worm to the main shaft you will have no outer bearing support on the 3/16" dia worm shaft and I think that it woild not run true enough to drive the wheel with the load on the pump, I could be way out but to me it's not good practice.

First pic is the Duff Conrod.
Second pic is the Stuart gears
Third pic is the H.P.C. gears which I think is much neater, and the disc on the end of the cross shaft is the drive for the pump, I like to make it large enough to have various pitched holes to be able to adjust the pump stroke.

You will need to make bearing blocks and bearins to support the cross shaft and the outer end of the worm shaft.
Hope this helps.
 George.

Jason, thanks for the info on the Etch primer.
« Last Edit: April 16, 2016, 01:05:59 PM by K.B.C »
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Offline steamer

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #517 on: April 16, 2016, 01:20:29 PM »
Hmmm....I think if it's a multi start worm, the lead is greater than a single start worm.....so a double start with twice the lead would be half the ratio.....

What am I missing here?

Dave
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Offline K.B.C

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #518 on: April 16, 2016, 02:03:45 PM »
Hmmm....I think if it's a multi start worm, the lead is greater than a single start worm.....so a double start with twice the lead would be half the ratio.....

What am I missing here?

Dave

Dave ,
According to H.P.C. gear manufacturer  and I quote, (  The ratio is No of teeth on the wheel divided by the No of teeth on the worm )

Think of a 10 tooth spur wheel and a 20 tooth wheel.  2:1 ratio

George.
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Offline Ramon Wilson

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #519 on: April 16, 2016, 02:41:34 PM »
Hi George, Thanks again  for keeping an eye on things and posting those pics. ThumbsUp:

I have now realised that though I feel I could make a successful wheel with a tap as a hob I had overlooked the fact that though the pitch will be the same it will not have the same helix angle (lead) as the two or four start worm that I intended to match it with  ::)

I shall have a go at making a four start worm then and a hob to suit and try that to begin with. This will be a first for me so it will provide some added interest  ;)

With regard to the shaft bearing, my intention was to recess the head of the caphead screw into a counter bore on the end of the 'worm' and have the outer diameter (which will be slightly smaller in diameter than the root depth) as the bearing surface.

That said if this does not work out then I shall go the HPC route and try to extend the shaft.

We've had another wet and extremely cold abortive day sailing - didn't even put the bouys out this week :(

I'm now off to make a start on those blanks then  :).

My thanks again,

Regards - Ramon
« Last Edit: April 16, 2016, 02:47:21 PM by Ramon »
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Offline Ramon Wilson

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #520 on: April 18, 2016, 10:18:32 PM »
Hi George - the con rods have turned out okay - I will not need to solder pads on  :) I should get them completely finished tomorrow so a couple of pics then.

I had long thought that it was possible to make a worm wheel using a tap as a hob. Couldn't remember where I had seen that but having spent some time reading through what I have on cutting gears it certainly isn't in there  ::)  Eventually though it surfaced through the fading grey matter - it was Lou Blackmore describing his Bentley BR2 - he used the technique to get the worm and wheel for the oil pump.

Having read what is required in order to produce such parts suitable for the D10 I have taken your advice and ordered a set of gears from HPC today. Not cheap but the cost is well offset by not having to devote the time required to produce two parts and not least that having done so they might not be successful at that. With the engine at the angle it is I shall have to introduce a plinth of some kind to mount the bearings on but that shouldn't prove too problematical.

Thanks again for your help George - much appreciated.

Back soon with a further update guys

Regards - Ramon




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Offline Maryak

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #521 on: April 19, 2016, 02:41:17 AM »
Hmmm....I think if it's a multi start worm, the lead is greater than a single start worm.....so a double start with twice the lead would be half the ratio.....

What am I missing here?

Dave

Dave ,
According to H.P.C. gear manufacturer  and I quote, (  The ratio is No of teeth on the wheel divided by the No of teeth on the worm )

Think of a 10 tooth spur wheel and a 20 tooth wheel.  2:1 ratio

George.

Yes, a single start worm has 1 tooth, a 2 start worm has 2 teeth..........................and on

So lets take a worm and a worm wheel of 60 teeth

1 start ratio = 60:1
2 start ratio =30:1
3 start ratio = 20:1
4 start ratio = 15:1

IMHO, both George and Dave's statements are correct as written above.

All that to one side, why not an additional eccentric on the crank to power the pump? Seems simpler to me but perhaps moves too far from replication.

Regards
Bob
« Last Edit: April 19, 2016, 03:03:31 AM by Maryak »
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Offline K.B.C

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #522 on: April 19, 2016, 11:39:21 AM »
Bob,

Yes you could drive the pump from a main shaft eccentric but it would pump too much water into the boiler.

I can only say that by experience with D10"s and Scotch marine type boilers, my current boiler is 4.75" dia x 5" between end plates, a 1/4" dia pump x max 3/4 " stroke  running at 120 strokes /min is enough to keep my boilers up all day as long as I have enough gas and water, I use pond water and that is why I have found that a reduction of between 4/1 and 6/1 is about right.
I also make a disc on the cross shaft that has various pitched holes that allows you to increase or reduce the stroke as required.

If you came direct from the main shaft which depending on boat size  and prop the main shaft on the D10 will turn  between 500- 700 r.p.m. so that would produce too much water for the boiler so then you have to start thinking about boiler level control and feed water bypass valves either manual or electronic.

I should have read Daves post closer as his quote  (  so a double start with twice the lead would be half the ratio  ) which is correct, it was the  ( What am I missing here ? ) quote that Foxed me.

At College 60 years ago as a first year student it was drummed into us that  " The number of teeth on  the follower divided by the number of teeth on the driver " gave you ratio  it's the same with worm gears.

Thanks for your input

George.
« Last Edit: April 19, 2016, 02:28:20 PM by K.B.C »
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Offline Maryak

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #523 on: April 20, 2016, 01:30:27 AM »
Bob,

Yes you could drive the pump from a main shaft eccentric but it would pump too much water into the boiler.

I can only say that by experience with D10"s and Scotch marine type boilers, my current boiler is 4.75" dia x 5" between end plates, a 1/4" dia pump x max 3/4 " stroke  running at 120 strokes /min is enough to keep my boilers up all day as long as I have enough gas and water, I use pond water and that is why I have found that a reduction of between 4/1 and 6/1 is about right.
I also make a disc on the cross shaft that has various pitched holes that allows you to increase or reduce the stroke as required.

If you came direct from the main shaft which depending on boat size  and prop the main shaft on the D10 will turn  between 500- 700 r.p.m. so that would produce too much water for the boiler so then you have to start thinking about boiler level control and feed water bypass valves either manual or electronic.

I should have read Daves post closer as his quote  (  so a double start with twice the lead would be half the ratio  ) which is correct, it was the  ( What am I missing here ? ) quote that Foxed me.

At College 60 years ago as a first year student it was drummed into us that  " The number of teeth on  the follower divided by the number of teeth on the driver " gave you ratio  it's the same with worm gears.

Thanks for your input

George.

Hi George,

What made me ask about the eccentric was your comment on drilling various holes in the disk to arrive at a satisfactory flow rate for the boiler.

If your direct drive eccentric coupled to the pump shaft via a yoke ala the engine eccentric reversing system you should end up with a variable pump stroke from zero to full stroke and thus good control over water flow into the boiler.

Just a thought and in no way intended as a criticism.

Best Regards
Bob
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Offline K.B.C

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Re: 'WIDE A WAKE' a steam launch tale
« Reply #524 on: April 20, 2016, 11:04:01 AM »
Bob,
I am always open to new ideas and had no thoughts that your post was a critisism.
I do like the idea of using a quadrant as the reverse gear but I don't think it would be a good idea on a D10 as the linkage would need to be made and the assembly would stick out from the centre line and could foul the inside of the hull.

Also all that it would do is alter the stroke from Zero to full stroke as there is very little movement on the quadrant 
If the engine was running at 600 r.p.m. at say mid  stroke the pump would be stroking at 600 strokes /min and it will be too much water going into the boiler, I think that it would be quite difficult to get to Zero stroke you would need a very large quadrant, I think that the idea of the eccentric and the quadrant would take you into electronic boiler control with extra servos to operate the quadrant from Zero to Full.

With the worm and wheel the cross shaft having a disc on the end with a few tapped holes to allow adjustment of the stroke allows the pump to be mounted on the side of the base plate which takes up less space and with the 4- start worm and a 20 T wheel gives 5/1 reduction and at 600 r.p.m. gets the pump down to 140 stroke/ min. and this way gets rid of the clutter of rods and levers. All that is required with this set up is a water bypass valve to divert the water back into a tank if the pump is pushing too much water.
By experience you soon get to know your boilers needs, I am not ashamed to say that I am very anti electronic controls where boilers are concerned, I like to know what is happening rather than electronics doing it for me.

Maybe some day I will give your idea some fuller thought but at present it's much simpler to go for the worm and wheel.

George.
« Last Edit: April 20, 2016, 11:18:41 AM by K.B.C »
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