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Author Topic: Jerry C starts building a Stuart Twin Launch Engine from castings.  (Read 12183 times)

Jerry C

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #200 on: September 13, 2021, 12:16:34 pm »

Iíve absolutely now idea what all the additional gobbledygook is in the text. Can anyone fix it?
 Jerry C.

Jerry C

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #201 on: September 13, 2021, 12:40:36 pm »

Thereís got to be an easier way!


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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #202 on: September 19, 2021, 08:57:54 am »

The last two days Iíve been working on the crankshaft. Itís  a rough casting with a squareish lug on each end. The two faces adjacent to the shaft are at right angles to each other and itís relatively easy to mark the shaft centre axis on each lug. From this mark I drew two lines at right angles corresponding to the two journals and scribed a radius equal to the throw of the cranks with a pair of marking dividers, then, centre popped all six centres.  I mounted the piece in my mill vice vertically and drilled all three centres on each end with my largest centre drill.  Making substantial tapered holes. The holes corresponding with the crank / journals blew through the lugs and I tapped these holes on one end M6 and screwed an M6 capscrew in one to act as a lathe dog. I put the centre drill in the lathe chuck and used the centre drill as a dead centre ( it rotates with the piece) and a live centre on the tails stock.


 






I didnít Machine the shafts and centre journal in order to maintain rigidity while machining the crank webs themselves as [size=78%]much as possible in this arrangement but leaving the centre bearing surface and shafts until later. [/size]


[size=78%]I rearranged the piece and put one journalís centres on the lathe and finished one crank. Then rearranged again and machined the remaining crank before finally machining the shaft and centre bearing journal. [/size]






That was the lathe work done with so I put the piece on the mill vice and machined the crank webs to size.


[size=78%][/size]


Iíve left the lugs on until I can  check everything ok when mounted on the bed plate in case more turning required
[size=78%]Iíve been running in the cranks with the conrods loosely attached tightening up as I go. Oil and Brasso as running in medium. Another hour running in tomorrow then Iíll mount it in the bedplate and run in the three bearings. [/size]


Jerry C.

Jerry C

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #203 on: September 20, 2021, 06:15:40 am »

Thatís the bottom end completed. This morning I ran in the crankshaft to the bearings. All three sip oil and equally. Oil cups tomorrow then I start Stephensonís linkage.








Jerry C.

derekwarner

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #204 on: September 20, 2021, 08:26:29 am »

Fair flying Jerry  O0


I have gone back to your August 20th images & the 6 x bottom ends bearing holes appear as tapped holes for studs
You tapped 11 x tapping's, so implies this  :embarrassed:


So you must have a close shell tube spanner, small body open-ender?, or are they bolts & tighten the bottom end - otherside?


Derek


PS....how do you find the new Taig Mill?
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Jerry C

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #205 on: September 20, 2021, 09:41:11 am »

Hi Derek, I have a set of cheap lazer cut combination spannerís in BA sizes I get from Blackgates Engineering in Yorkshire. $12 a set. I grind the ring part to reduce their diameter and theyíre perfect for the job. Iíve got two new sets lost in the post atm, plus a load of various 1 size under BA nuts and bolts. Their website is tedious but theyíve got loads of stuff. They specialise in narrow gauge locomotives and anything steam. So far Iím 45 days ahead of the last build which I put down to my new milling machine and loads of decent tools and fixings. I was schooner rugged for the first Stuart. I wonít build another Stuart, overpriced and poor quality control. Next one will be P M Research excellent quality, better drawings and a tenth of the price!
Thanks for watching.


Jerry C



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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #206 on: September 21, 2021, 11:44:43 am »

Sorry Derek, I missed one of your questions. 5BA studs in the Soleplate and nuts for the caps. I donít have a Taig Mill, itís a Sieg SX2P with a large table. Itís brilliant. I got it from Ausee Tools in Melbourne. Theyíve got everything at a little over Chinese prices.





This morning I knocked up three oil cups for the main bearings.





Then I started on Stephensons gear beginning with a pair of connecting rods. Using a piece of 3/8Ēx 5/16Ē mild steel I mounted it in the mill vice, using DRO drilled the holes for the 3/16Ē reversing shaft and the 7BA clearance holes. Then milled one side to remove the bulk of the unwanted metal. Tomorrow Iíll flip them an do the other side. I dug out the mandrel I made for the Twin Launch only this time Iíve got a rotary table. I leave the R/T mounted to the left end of my mill table and my precision vice on the other end which saves time swapping over.





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Jerry C

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #207 on: September 22, 2021, 01:31:52 pm »

The previous photo showed two mandrels on the top of the vice. I forgot to take a photo of them in use but basically I bolt one in a hole and mount it in the rotary table chuck and put a broken drill through another hole to be driven by the table while I mill the bosses.





Using different sized broken drills to set the angles to get the tapered cut on the sides.
I use broken things like drills and endmills in place of gauge pins. Anything to get the job under control.


Jerry C.



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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #208 on: September 22, 2021, 07:00:12 pm »

   
        :-))
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Jerry C

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #209 on: September 26, 2021, 11:21:25 am »


I manage one pair of drag links made out of the square but of a door lock that the knobs are fixed to. It was rock hard and was hard work. I canít go out to get more because it means crossing the boarder back into ACT. Itís not with exposing myself to Covid and thereís plenty I can be getting on with until lockdown ends.


So, next, the Crosshead Guide plates. I was given a large sheet of 1/16Ē thick stainless steel plate but canít find it. It must have got lost in the house move. What to do?  I found an old toolbox under the house and the padlock latch looked about right, measured it and it was just a fraction over 1/16Ē thick but galvanised and I could get the 2 pieces out of it. I  drilled out the rivets, ground off one end of the hinge pin and salvaged the flap. Used a hacksaw to cut the unwanted bits off and got the ends square on the belt sander. I removed the galvanising on a sheet of wet & dry paper. I gripped the stock in the mill vice on parallels. Using DRO I drilled the four 7BA clearance holes in the ends then chain drilled the slot undersized then ran a 2.5mm end mill through the holes followed by a 5mm end mill. (When I machined the crossheads with this in mind as it saved buying a 3/16Ē end mill). I didnít square off the ends of the slot because the crosshead bit that slides in the slot is round. I think it looks neater. 
I repeated the process on the other side of the plate then sawed the pieces apart then, back in the vice together and milled the final edges to size.





The observant amongst you will see I got 4  countersinks on one side, just like I did on the Launch Engine. I knew before not to but things were going so well and the material was lovely to work that I forgot. Itís not a problem though because when to do them on the right side the plates are located by the c/s and not the clearance hole.


[size=78%][/size]


Everything lines up with the reversing bracket and the bottom cylinder covers so a result.





Next job, piston and valve rods.


Jerry C.



Jerry C

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #210 on: September 28, 2021, 09:03:06 am »

Yaaaay!! My parcel arrived from Blackgates!!!!  Ordered 30th July, sent 17th August arrived today 28th September.






Anyone not familiar with Blackgates catalog these are the Laser cut, stainless steel BA spanners. Cheap as chips and they work fine.


I boxed off the valves today. I havenít followed the plans on these. They donít allow the valves to float and get pressed onto the port faces by the steam.





Also I havenít got a 1/8Ē end mill so Iíve gone metric.





Jerry C.

derekwarner

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #211 on: September 28, 2021, 01:10:26 pm »

Evening Jerry...........certainly not familiar with the Blackgates offerings, but obviously laser-cut from a common thickness plate  %) , so are the smaller sized too thick?...or the larger sizes too thin?


As we know, the Knupfer laser-cut metric sized O/E spanners are certainly not Cheap as Chips >>:-(



In OZ, we were taught the lower set of images as 'Crows Foot' spanners [but always thought the jaws were set @ 15 degrees offset, or 75 degrees off to the spanner shank axis?]  :o


Is that a universal name?


Derek
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Jerry C

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #212 on: September 28, 2021, 01:29:50 pm »

Common thickness yes but all get the job done and you can bend the grip to whatever suits. Letís face it, not much torque needed for BA.
As for crows foot spannerís, Iím familiar with the name but associate with these?

Jerry C

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #213 on: October 01, 2021, 10:44:25 am »

I knocked off a pair of valve rods and adjuster thingamagigs, made four gaskets and boxed off the valve chests. We start 14 days quarantine today due to both daughter and son in law being exposed to active covid cases. Makes no difference to me as I seem to live in the shed anyway. Iíve got music, a couple of chaired on wheels and a toilet. I just need a hammock.





Last job today, before dinner, was to mark out the expansion links, well one anyway. Iíll superglue two pieces of steel plate together and make two at once. My new spectacles  should be ready in Specsavers tomorrow. I could have done with them today as I had difficulty setting my dividers to 64thsĒ. Achieved it more by feel than eyes!


Jerry C.

Jerry C

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #214 on: October 02, 2021, 09:58:48 am »

I superglued two pieces together and mounted them on a mandrel in the centre hole of my rotary table and bolted a strap across them to hold The securely. I centred the table under the chuck and moved the X axis of the table using DRO and drilled three holes then chain drilled the slot. Then ran a 4mm slot drill to clean out the slot. Then milled all the extremities before freeing the pieces and putting them back on a mandrel through each hole in turn and milling around them.
 Today was a good day, everything went as planned and I made no mistakes. My best piece of work so far. I shall refer to it as my quarantine period.


The first pic shows the setup.








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Jerry C

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #215 on: October 03, 2021, 09:18:44 am »

I made a string of expansion dies when I built the twin engine. On this build I left the ends of the die slot half round rather than square as in the drawings. I filed the ends round to match. I think itís an improvement.





I started on the steam pipe flanges. Thereís not enough meat on the Pb blanks supplied to make the LP exhaust flange out of so I used some 7/8 bras round stock to make it out of. It looks as though there my be some conflict between the flange set screw on final assembly but Iíll manage somehow.





Jerry C.

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Re: Jerry C starts building a Stuart Twin Launch Engine from castings.
« Reply #216 on: October 03, 2021, 06:05:32 pm »

Hi Jerry,
When you come to fitting the lagging shields fit the exhaust side over the exhaust hole and bore it out and then the bottom screw can be slotted on the head which allows a much better fit than profiling around the exhaust flange.
If there is any leakage you can put a gasket underneath the shield and on the underside of the exhaust flange.
What happened to the mid post thats a bit out of line ?


Nice job so far keep it up.


George.



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