Topic: MACHINING & BUILDING a STUART D10 (Read 60060 times)

ooyah/2 · « **Reply #75 on:** February 03, 2015, 10:22:04 am »

xrad & Mark T.
Thanks for your suggestions which seams to have been lost after the shut down, they are the same thoughts that I had, however another suggestion was to make the covers
4- bolt fixing.
As I had a piece of Mehanite grade cast bar I parted off 2- discs and made new covers, reduced the P.C.D. to 1.062" and drilled the holes on the rotary table.
Plugged the holes with in the cylinders with 7 b.a. steel screws and a spot of Loctite 603 and flushed them of, this gave me fresh metal to bore and tap so I am now quite happy with the result.
George.

derekwarner · « **Reply #76 on:** February 03, 2015, 11:02:01 am »

George....

I had similar thoughts of plugging the tapping's by gas puddling brazing, however was concerned with heat distortion

However your fix of reverting to the alternate four bolt pattern on the reduced PCD is an excellent solution to the casting size glitch.

This rectification work is also serves as an example to [us/we] younger players of what can be achieved with a few more years of knowledge & experience under the belt

Derek

frazer heslop · « **Reply #77 on:** February 03, 2015, 11:11:30 am »

Hi George.
Nice save. If it was my engine it would have been hoyed and you tell me this steamy thingy ma bobs easier than the white mans magic.
It will never catch on you know
best wishes
frazer

AlexC · « **Reply #78 on:** February 03, 2015, 12:17:35 pm »

Hi Guy's.

Nice save there George, but it should not have happened in the first place.

Not your fault George, but rather one of legacy.

Stuarts have been through several take-overs in the past years and during the first of these a lot of the original patterns were either lost or destroyed.
The purchasing new owner chose not make new patterns, claiming High cost as a valid reason, but rather chose to use an existing casting (obtained in the take-over) as the replacement pattern.

This was a flawed decision, since the casting did not have sufficient allowance for shrinkage (it already having shrunk)... the net result being a casing with marginal remaining machining allowance.

This has occurred on more than one take-over and the latest castings are now lacking in any allowance at all... in some cases, such as your cylinders, the latest castings are too small in some areas to comply with the drawings.
What is really required is that the latest owners make NEW patterns, with proper shrinkage and machining allowances included... but I doubt that they will.

Sadly, this is a problem with many of the Stuart engines, not just the D10.

I would recommend that anyone building a new Stuart engine, from newish castings, to carefully check all dimensions before cutting metal.
The drawings have never been altered to match the new castings.

So... beware and double check.

It is a real shame that such well designed, and very well respected, engines are now being produced using inferior methods... it does the Stuart Name no service and, given the current prices, is not really acceptable.

Keep happy.

Best regards.

Sandy.

ooyah/2 · « **Reply #79 on:** February 04, 2015, 12:14:06 pm »

Sandy,
You are spot on with the castings so it's a must to plan forward rather than making from the drawings assuming that everything will fit in the end.
Although I must say that some weeks ago I ordered 2- off Gun metal castings for the top valve on the Stuart steam driven boiler feed pump and they were absolutely superbe,
but the stampings for the con rods on this engine were very poor and so much metal had to be taken off to get them correct.
I don't know how old these castings are as they were purchased on e-bay, so age is unknown.

Perhaps the new Gun metal castings are better than the Cast iron ones but it's a bad show if the Cast iron ones are getting smaller.

MACHINING PISTONS.

The piston rods are a simple turning job with each end threaded 7 b.a, I leave the piston end longer than the brass blanks suplplied for the piston which allows the piston blank to be fully screwed on to the rod to allow the blank to be machined on the 5/32" dia rod , all on the one setting.

The piston blank can be screwed onto the rod I with a spot of 603 on the thread, machine to length ( 1/4" ) and then turn down to size of .75" checking as you get near to the bore size, the groove for the "O" ring can now be done using my back post parting tool, before taking out of the chuck take the sharp edges of the groove with a fine file
as these sharpe edges can cut the rings when putting them on.

I allways when making pistons drill 2- holes in the piston crown to take a tool that I made to screw the piston rod down into the cross head, this saves so much time having to take the cylinder off of the standard if a small amount is needed to come off the piston crown or bottom.

To my great releif when the piston rods were screwed into the cross head the whole assembly turns over very smoothly with no tight spots.

Next is the valves and the steam chest covers.

George.

P.S.
Frazer the engines that you build are very Masonic ( it's a secret how they work. )

frazer heslop · « **Reply #80 on:** February 04, 2015, 01:43:09 pm »

Hi George, nice to see some progress. The D10 is a nice engine just a pity you've had to rework due to a casting fault.
At least she is moving forward.
My engines are a complete mystery to me as well . Although Iv gone over to the dark side on my new build (steam)
Cheers
frazer

Mark T · « **Reply #81 on:** February 04, 2015, 03:39:18 pm »

What a great solution to the casting issue - lovely job

ooyah/2 · « **Reply #82 on:** February 04, 2015, 04:03:14 pm »

Quote from: Mark T on February 04, 2015, 03:39:18 pm

What a great solution to the casting issue - lovely job

HI Mark,
Yes I am sure that it was the best solution, if I had brazed in studs and flushed off I would still have had to alter the p.c.d. as altering the 1.125" p.c.d. to 1.063" p.c.d. the holes would just break into the old ones and when tapping 7 b.a. the tap could snag on the steel and break.
As I had plenty of cast Iron on the bar it was easier to make new top caps and space the holes at 1.063" p.c.d. for 4- bolt fixing.

Thanks for your comments, all suggestions are appretiated.
George.

Ramon · « **Reply #83 on:** February 04, 2015, 10:46:20 pm »

Hi George - still following along, that's coming along well and at a good rate of knots too. Nice save on those faulty heads

.

I'm looking forwards to you doing the reversing gear (I assume you are going to fit one?) as have decided not to try the Lang gear after your comment and keep to the Stuart layout. The boat is coming together now so it won't be that long before I strip my D10 and rebuild it.

Keep up the good work - Ramon

rhavrane · « **Reply #84 on:** February 04, 2015, 10:47:22 pm »

Bonjour,

The piston rings of Jan D10 have been manufactured with Teflon for sealing and it works perfectly :

Besides this, we have added little screws with o'ring Viton joints on the heads of the cylinders to be able to add oil in after the navigations in order to prevent them from rust, see HERE.

DELAUNAY · « **Reply #85 on:** February 05, 2015, 10:29:44 am »

Hello

Raphaël , tes photos ne s'ouvrent pas

derekwarner · « **Reply #86 on:** February 05, 2015, 11:22:21 am »

Goodness........DELHUNTY........just go back to the posting from rhavane and click on the word HERE .... Derek

ooyah/2 · « **Reply #87 on:** February 05, 2015, 11:41:55 am »

Quote from: Ramon on February 04, 2015, 10:46:20 pm

Hi George - still following along, that's coming along well and at a good rate of knots too. Nice save on those faulty heads .

I'm looking forwards to you doing the reversing gear (I assume you are going to fit one?) as have decided not to try the Lang gear after your comment and keep to the Stuart layout. The boat is coming together now so it won't be that long before I strip my D10 and rebuild it.

Keep up the good work - Ramon

Hi Ramon,
I will be starting on the Stevenson link reverse gear very shortly, I have been very fortunate in that the castings purchased on e-bay came with a set of Stuart machined eccentrics and sheeves, all the bits and pieces required to make the reverse gear.
What I will be changing is the linkage, I don't like the small rods that have to be glued into place so I will be making the links from flat brass.
I know that on full size engines the links are steel but on a model that can sometimes be laid up they are inclined to rust hence brass.

When the linkage is done and the engine running I will start making the engine driven boiler feed pump, these parts will be made fron stock material as I don't like Stuarts pump casting.

Thanks for looking in.

George.

ooyah/2 · « **Reply #88 on:** February 05, 2015, 11:50:08 am »

Quote from: rhavrane on February 04, 2015, 10:47:22 pm

Bonjour,

The piston rings of Jan D10 have been manufactured with Teflon for sealing and it works perfectly :

Besides this, we have added little screws with o'ring Viton joints on the heads of the cylinders to be able to add oil in after the navigations in order to prevent them from rust, see HERE.

Raphael,
I have known that Teflon can be made into piston rings, I have never tried it as I prefer Silicone "O" rings.

As to the oil ponts on the cylinder head I don't think that they are neccessary, I have a D10 in a S.T. CERVIA at 43" long, the engine is 2 years old and has had a lay up over the winter of 5 months and there is no rust what so ever in the cylinders.
If you use a good quality steam oil the oil builds up in the "O" ring groove and stays there when cool which prevents rusting, I do however every now and then turn the prop over by hand which keeps the cylinders oiled, I don't know what happens with your Teflon rings but it's all a matter of choice.

George.

rhavrane · « **Reply #89 on:** February 05, 2015, 08:19:04 pm »

Bonjour George,

We choose the Teflon option because we rebuilt the D10 to 20,6 mm bore and we had no O ring wide enough to do the job.

About rust, it did not appear at the cylinder/piston level but at the cylinder/side valve level and the rust made little holes which destroyed its efficiency With my solution, I can gorge the cylinders and all the valves with oil as I do not navigate often with my heavy babies.

An this is also why I like my Reeves Warrior MK3 , kind of twin of the D10, which can not rust because made of bronze.

ooyah/2 · « **Reply #90 on:** February 08, 2015, 09:26:13 pm »

MAKING THE VALVE GEAR

I always start with the valves as they have to be some of the best and aqurate components in the Stuart range of parts.
It only needs cleaning up with files ensuring that the vertical and horizontal guides are set at 1/8" wide to take the valve buckle and the 1/8" dia rod.

The rod needs to be threaded 5B.A.at one end for the fork end and 5B.A. to take the buckle and reduced to 3/32" dia at the top to go into the steam chest.

This is where I deviate from the drawing, make the buckle from a piece of 1/8" thk brass drill it 1/8" dia and drill the top for a 2m x 2mm long grub screw, by doing this it means that the valve rod can be made plain withought the 5B.A. threading to take the buckle.
It's so much easier when timing the engine just to loosen the grub screw and adjust the valve up or down as required, also deviating from the drawing the steam chest is bored 1/8" dia for the rod and straight up into the top of the chest to allow the rod to go up into it and be supported .

Gland nuts are made from 5/16 A.F. Hex brass , threaded 1/4 x 32 t.p.i. and drilled and reamed 1/8" dia.

The fork ends are a simple turning job in the 4- jaw, 6- are required, 2- with the ends tapped 5B.A. for the valve rods and 4- with the ends tapped 7B.A. for the eccentric rods, slots can be drilled and filed or milled out to 1/8" wide.

The quadrants are a filing job as they are stampings and of good quality, with needle files the quadrant slots are filed out to 5/32" wide to take a small roller 5/32" dia x 1/8" long with a reamed hole ( 3/32" ) to take a 7 B.A. plain bolt, 2-off required.
Finally clamped together and drilled to take the fork ends of the eccentric rods.

Next is the eccentrics and the link bars which I hope to complete in the next few days.

George.

flashtwo · « **Reply #91 on:** February 09, 2015, 10:05:26 am »

Hi George,

I like the idea of the grub screw on the buckle, as you say it would make the timing adjustment so much easier.

Is this the first time that you've tried it, or have you used it on your previous engines and do they maintain their settings after the engine has been running for some period?

For what it worth, I've attached photos, that you've seen before, of my quadrant milling jig using a 4mm end mill, since my filing was not consistent enough to give a smooth travel.

all the best

Ian

ooyah/2 · « **Reply #92 on:** February 09, 2015, 08:10:55 pm »

Ian,
All of the Stuart Vertical slide valve engines that I have built I have used the grub screw fixing, never had any problem with them and they have never lost their settings.
This isn't a new idea as I picked this tip up from a Loco builder friend and this is common practice with a Loco valve gear..

The quadrants are so easy to file into shape and although I have a mill I thought that I would describe the filing method for those who may wish to have a go at building a D10 without milling facilities.
These engines can be made without a mill with careful filing but a lathe is required.

Last year I built a Stuart Launch engine and had to make the quadrants from 1/4" thk bright bar, so a jig like yours had to be made, mine is adjustable to suit varius radus.
The casting and fittings for the Launch engine are very sparse and many parts have to be made from stock bar.

Here is a pic of the jig and the Launch engine.

George.

southsteyne2 · « **Reply #93 on:** February 10, 2015, 12:34:52 am »

I too have used the grub screw method on both my slide valve engines with nearly six years running and no problems also nice work George, do you have plans to put the engine to use?
Cheers
John

flashtwo · « **Reply #94 on:** February 10, 2015, 12:10:37 pm »

Thanks George,

I like your adjustable quadrant milling jig.

I wish I'd known about the "grub screw" mod when I was building my D10, apart from the ease of adjustment, it makes the valve construction that little bit easier.

Ian.

ooyah/2 · « **Reply #95 on:** February 10, 2015, 08:26:26 pm »

Quote from: southsteyne2 on February 10, 2015, 12:34:52 am

I too have used the grub screw method on both my slide valve engines with nearly six years running and no problems also nice work George, do you have plans to put the engine to use?
Cheers
John

John ,
At present I have no plans to put the engine in a boat.
I have a 3/8" - 1ft model of Cervia which has a D10 in it which I made about 2- years ago, my problem is that I don't have enough space, my workshop is 9ft x 9ft and is not ideal for boat building that's why I stick to butchering metal and I don't like wood shavings and dust in the W/Shop.

The launch engine is in a box on the shelf until I decide what to do with it, probably sell it, it needs a big boiler , the engine at 1" bore x 7/8' stroke and each piston with 2- cast iron rings needs more steam than my test boiler can produce, so my delema will be compounded when I finish the D10, what to do with them !!!

George.

ooyah/2 · « **Reply #96 on:** February 10, 2015, 08:56:42 pm »

MAKING THE ECCENTRICS

These are made from a piece of 5/8" dia free cutting steel, ENIA I think, as I only had a small piece of bar I had to be caerefull holding it to get 2- eccentrics from it.
TYhe eccentrics are 3/32" of set and to get this I use a piece of 3/32" strip under one jaw of the 3- jaw chuck.
Drill and ream a hole 9/32" dia and then machine the boss on the outside, I used a parting tool to cut down nearly to the 9/32" bore but didn't part it of.
Using the parting tool I machined another eccentric with the bar in the same position and parted off as before but not going fully thro'.

The 3/32" strip was taken out of the chuck and then the grooves can be cut with a thinner parting tool that I have on the same post, this groove ids for a small stud that goes into the bottom of the eccentric sheeve to prevent it floating side ways.
The eccentrics can now be separated with a hack saw and the faced off.

When you buy a set of reverse gear you get an eccentric that doesn't have the boss on it and it has a 1/16" hole in to match a hole in the one with the boss thro' which a 1/6" dia pin is glued in place in the eccentric with the boss.

I mounted the eccentric with the boss first on a 9/32" piece of shaft material, then I put the one without the boss on top and clamped it with a parallel clamp, with the 2- pieces mounted like this ensures that when the 1/16" dia hole is drilled thro' every thing works out true and leaves the eccentrics when finally mounte at 120 deg to one and other.

Allt he little rods were then put in place and to my relief every thing lined up.

Next job is the drag links, the weigh shaft and brackets, I hope that you can follow my blethers.

George.

George.

malcolmbeak · « **Reply #97 on:** February 11, 2015, 06:16:25 pm »

George

I love following your progress building the D10, but I am rather surprised at how you get the 3/32 throw on the eccentrics. If you have a copy of Tubal Cain's "Model Engineers Manual" and you turn to section 13, you will find a paragraph "Eccentric turning in a 3 jaw chuck". You will see that the packing needed is much more than 3/32", actually .134". with 3/32 packing you will only get about 1/16" eccentricity.
I've attached the relevant portion. Note that D in the formula is the diameter gripped in the chuck jaws, not necessarily the sieve diameter as he says.

Malcolm

ooyah/2 · « **Reply #98 on:** February 11, 2015, 09:19:43 pm »

Hi Malcolm,

I have never been aware of this formula and of all the Stuart vertical engines that I have built I have used the method that I have described with no adverse problems.

I have just come from the workshop and after measuring the cam travel it is .164 giving a .082" lift which is only .010" short of the design figure of .093" and bearing in mind that this is a model engine and the castings are quite poor it has never effected the engine performances that I have noticed and I have no cause to doubt Tubal Cain's statement

If I may ask are the calcs for full size practice or does it apply to models as well ?

Getting back to Stuarts drawing of how to measure for the 1/16" drive pin to link the 2- sheaves there is a mistake in the drawing.
It shows the pin hole at 60 deg and at 1/4" rad from the center of the .625" dia sheave.
If it has to be drilled at this dimension if you subtract 1/4" from 5/16" rad of the sheave it only leaves 1/16" and then the rad of the pin at 1/32" leaves 1/32" to the outside edge of the 5/8" dia sheave and the drill breaks into the groove for the guide pin.

I would think that the rad would need to be max 7/32" which wouldn't matter as long as the angle was 60 deg.

Here is a copy of the drawing , what do you think, or have I got it wrong ?

Thanks for your comments.
George.

ooyah/2 · « **Reply #99 on:** February 11, 2015, 09:53:55 pm »

MAKING THE REVERSE GEAR BRACKETS.

Today I made and fitted the steam chest covers which have to be done in order to fit the reverse bracketry.

There are 2- brackets to hold the weigh shaft and they have to be of opposite hands, they were set up and squared inthe lathe and then with a newly sharpened and honed tool a very light cut was taken off of the face of the brackets, just enough to clean the faces up.
On this lathe setting the 3/16" dia holes were drilled and reamed.
The same process with the 2- brackets that connect to the quadrants and the operating lever was done as well.

When it was all set up instu the 3/16" dia weigh shaft turned quite freely so the next step is to link every thing up and see if all is well.

Must say that Malcolm gave me a jolt with his post but then I thought , this is how I have always made the eccentrics and the engines have worked, I may as a test piece make the eccentrics using a pice of .138" thk packer that I have found described in Andrew Smiths book ( BUILDING A VERTICAL SSTEAM ENGINE )

George.

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Author Topic: MACHINING & BUILDING a STUART D10 (Read 60060 times)