Model Engine Maker

Engines => From Kits/Castings => Topic started by: Jo on April 11, 2019, 05:35:47 PM

Title: Twin Oscillators
Post by: Jo on April 11, 2019, 05:35:47 PM
In the UK there are a number of suppliers of casting sets for Twin Oscillators. In Surus' collection he had acquired a Stuart Twin Oscillator at vast expense :ShakeHead: on my part for him at the midlands Show:

(http://listerengine.com/coppermine/albums/userpics/10007/IMG_1619~0.JPG)

To enable me to have an engine to make this week I managed to purchase a set of Blackgate Castings for their Twin Oscillator:

(http://listerengine.com/coppermine/albums/userpics/10007/IMG_1620~0.JPG)

If you buy these new the Stuart's set works out at 115 and the Blackgate one 62.50, the Blackgate engine is actually bigger than the Stuart one  :)

As expected both sets of castings came with legacy imperialistic drawings  :disappointed: so first they need to be converted into metric. While the drawing that came from Stuarts is very nice and clear the copying of the Blackgates drawing has degraded through poor photocopying (sample of drawing attached) :ShakeHead:

As with all legacy drawings my first job is to part them out into individual part jpegs, clean up the drawing of each part and lay them out on A4 sheets. They can then be printed out and ISO Metric measurements added - I normally do these in red pen. The drawings are then rescanned and individual pages can be printed off to take out into the workshop as required  :wine1:

Jo


Title: Re: Twin Oscillators
Post by: Jasonb on April 11, 2019, 06:30:59 PM
Jo is the Barstock included in the Blackgates price or have you added that to the photo? Also what material is the flywheel as it does not look like iron or steel?

It's about time you got the little fellow to make some of his own rather than just hoarding them away :)
Title: Re: Twin Oscillators
Post by: crueby on April 11, 2019, 06:32:07 PM
Yeah,. get him a Sherline, he can reach the cranks on those...
Title: Re: Twin Oscillators
Post by: Jo on April 11, 2019, 06:36:18 PM
Both kits come with all of the required bar stock JB. The Blackgates flywheel is BMS, the Stuart's one looks to be disc of brass :thinking:

I think Surus is still a bit young to be let loose on a Lathe  :o

Jo

P.S. He has Little C (ME Cowells) in the same room as his casting collection but has not shown it any interest  ::)
Title: Re: Twin Oscillators
Post by: Jasonb on April 11, 2019, 06:40:22 PM
That's a good buy then compared with the Stuart.
Title: Re: Twin Oscillators
Post by: Jo on April 11, 2019, 08:05:40 PM
That's the theory but both seem to be having foundry problems at the mo   :(

Jo
Title: Re: Twin Oscillators
Post by: Jo on April 12, 2019, 08:04:32 AM
Having spent our Thursday evening fondling the two sets of Oscillator castings the main observations are that while the Blackgate's engine is bigger the Stuarts Engine is much neater as it has a built in passages leading to the reversing mechanism and lost wax castings rather than sand castings.


Importantly the Blackgate's drawing does not detail the connecting up of the steam/air pipes. When I visited the Alley Palley show earlier this year I photographed the original Blackgates engine that has all the plumbing and a steam valve but I am not sure if that valve is also a reverser. It must be possible to do something prettier with the plumbing :noidea:

Jo

Title: Re: Twin Oscillators
Post by: Ramon on April 12, 2019, 08:50:48 AM
It must be possible to do something prettier with the plumbing :noidea:
Jo


How's this Jo ?  :)


(https://lh3.googleusercontent.com/NbA6u2sGcj7TarBcw61BguvseMw94VMgCBaLQgNQYoFkmSODYA3EcdYfm-2m2h0sNWFOXjBROjPeKZDLLqQUCechxoGNmHlHqo144wj3W750GIEIU7RGqTiOLVqEU7P_6MvDL5PHbmJA8_ETWxb211AjDpxmxSjg-QTu35OTFbUuJPC9cD2DHE5mDoe8rGIfCLF-JoH5S7cdkXGJXuNkJVVr_c3d52s4dcd3X6oKOWXAiBBv-cYrnk0MnKoxfGEI1UzfYhBE13u1X3om2lzuqCx16Ln-P9w1VlnqDFB4bPlEfLxdwpSZ_CvV6W5vRCvfoxrDHOH1vzmFWw9UVOlbw4IJ3fOMI4YIvplKIKSLKe7emMLggFozLBnHsuIaOfaOMhcUk3YPK_Y6iP9G6-EvWpqaLBNnp0oQK-PKks_TCYVwYSFQ27MLX35APtI4k5nS2c2FyN1Q8sTk_BEicTYBf9ErFIa7yfVRMZjdX9U9uT2HMAUGhAJJjo9uYVnfQBajuWd8rlU3O1IjDpJv68lye76xWkCi6Fxd2CF1R0NDf9GaKnL-0N1oUN5YCRZEpAX3mU4inxu_I6mMljRGaU-HPNCiQMB2Wbrx1LvU6knS69G-uX5egdQlaCeYf3243jXd3K4Fmx6QHU4RfoYMsBKcM9BDS_fZ0pg=w1218-h913-no)
Title: Re: Twin Oscillators
Post by: Jo on April 12, 2019, 09:17:01 AM
That's a big improvement Tug  :)

It would be much easier than trying to plug the lines in what I have been playing with.

Jo
Title: Re: Twin Oscillators
Post by: Jo on April 16, 2019, 05:05:50 PM
A few features of making the Blackgates engine:

Crankshaft - Having chucked the piece of bent bar stock provided for the crankshaft in a suitable storage container it was replaced with a nice piece of straight ground stuff. The balance weight has to be fitted on the end of the shaft then milled to allow the pin to be fitted.

Covers: nice and easy to make and lots of spare metal provided  :)

Cylinders: These castings have suffered with the two haves of the pattern being somewhat out of line and who ever hacksawed them apart doesn't know how to cut square :ShakeHead: Following a bit of filing to get the two haves level the cylinder could be held in a three jaw chuck for boring.

While there is still lots more to do on the cylinders - a pic of the bits of the engine so far.

Jo
Title: Re: Twin Oscillators
Post by: Roger B on April 16, 2019, 07:37:21 PM
Good progress  :ThumbsUp:  :ThumbsUp:  :wine1: I hope Surus is happy with it  :)
Title: Re: Twin Oscillators
Post by: Jo on April 16, 2019, 08:39:39 PM
Thanks Roger,

I haven't brought them back in yet as I am planning to get the cylinders completed before he gets his feet on them. In the mean time he is still fondling/guarding the Stuart Casting set, it looks like the stand is getting very shiney ::)

Jo
Title: Re: Twin Oscillators
Post by: K.B.C on April 16, 2019, 11:34:19 PM
JO,
You could also make a reversing block like this  which is much neater than Blackgates who have never attempted to make something neater than what they do.

Another thing that I do is to fabricate the cylinders and scrap the ones supplied, I think that they have been copied from existing casting,
You then need only buy the standard.
George.
Title: Re: Twin Oscillators
Post by: Jasonb on April 17, 2019, 07:15:25 AM
That's a neatly plumbed setup George and I'm sure the shorter pipe runs help with reducing condensate.

However do you really thing that the big eared one will ever let Jo scrap castings :LittleDevil:
Title: Re: Twin Oscillators
Post by: Jo on April 17, 2019, 07:45:20 AM
That is a very neat reversing block George  :)

Why did you scrap the cylinders? Were yours also suffering from out of line pattern parts  :facepalm2:

Jo
Title: Re: Twin Oscillators
Post by: K.B.C on April 17, 2019, 08:00:07 AM
Hi JO,
Yes the cylinder castings were so out of line and under size.
I have made several of these engines and after my first set of casting being so bad I now only buy the standard and make the cylinders from stock material.
The engine at 9/16" bore x 5/8 Stroke are so powerful that on 30 p.s.i. you can't stall the engine by grabbing the main shaft, all that you do is friction burn your fingers.

Jason,

like all oscillators they run a bit wet and I can't say that I have noticed less condensate but I like the modified pipe runs.

George.
Title: Re: Twin Oscillators
Post by: Jo on April 17, 2019, 03:51:57 PM
The cylinders were mounted on a mandrel for the remaining operations:

First was to turn the ends and the outside. You can see the nature of the gunmetal the cylinders are made of by the burr still hanging on on the end hoping to cut someone's fingers   :paranoia: Yes the casting was undersized so the ends have been turned 23mm rather than the 23.8mm of the covers - that was clearly intentional to leave space for a cylinder jacket   :-X

There wasn't much spare on the sides of the cylinder pivoting surface but there was plenty on the depth - which was needed as it had been cut off at a jaunty angle. Drilling the port holes had to be done carefully to avoid going into the bore of the cylinder - Thankfully the mandrel supports the inside and reduces the risk of the gunmetal being pushed down.

The cylinder could then have the steam port drilled down to meet the other hole, the cover holes drilled and a 1.2mm deep pocket so the steam can get into the end of the cylinder.

Two Cylinders  :)

Jo
Title: Re: Twin Oscillators
Post by: Johnmcc69 on April 17, 2019, 06:16:18 PM
Those are some nice plumbing/valving ideas.

 Nice work on those cylinders Jo!

 John
Title: Re: Twin Oscillators
Post by: Dave Otto on April 18, 2019, 01:11:58 AM
Nice work Jo!

Dave
Title: Re: Twin Oscillators
Post by: Jo on April 18, 2019, 11:39:18 AM
Thanks Guys  :)

I was a little worried about how to hold the stand but like the cylinders, after a quick fettle, it is designed to be initially held in the three jaw chuck  :ThumbsUp:

Having faced the centre and centre drilled it was possible to safely face the port faces and then drill/ream for the crank.  Turning round and mounting on an arbor the other end by the crankshaft could also be faced.

Now I just need to work out how to hold it to do the next bit  :noidea:

Jo
Title: Re: Twin Oscillators
Post by: Ramon on April 18, 2019, 01:10:40 PM
Now I just need to work out how to hold it to do the next bit  :noidea:

This any help Jo ?

(https://lh3.googleusercontent.com/JQ6Zyk0N07Zc4FZKk1vXYl7ctquC7rOXxFRGoAZkR55U9EUsM4wsKIF3HKEjRtFMQzgtOL0ozda3zgE18wf60ZCpwkYKrKI5QjrFxPPWbLkxVheAJPt8FVorPAowwDQ50HlRUSp2VXcsHZDojYvCwXp4E3Y48EjLR9nPtNDG6zW8FE_SwBI7VwQTMSvzXhI9V8W3LufpAa9Rx5L0YDiDfRto-iuS4wDiJqoOA8OUq6f09sFawZ2so65CoKonznH3Sh4KWNI7EV--o0HQ_Ss98e7lpn_W7NUOzpFJRx3KBcEiQkew0FzgHHXGzxnggY5LEfmv999XlW-DphCN1-ycFdl8VzfxLH6vw2DfboMAil_Z8sKzm9Mzf1YknrgcnNtQ-3-m-C7EJdMjS7ibJ8jBdlwj_M6O-LsQw7C-aabi_pCyq0U9dXpahO7SthU0JQFbtTBLZiicbwJfAryONw_F18SAJXw4BSo754FaPVrLTw2RoLTyX84mD25UTtesHL1L-6inJZXtdtCQXAqwyezahtvg7kjqcBbFrCv7vQAspx6-eVAo5_7m1EDiT4iklazrdepy4bxBfLNK_sDAvJ8SbyZuAuLKOg2W_G4hDGdkUNE8pCKi6_27_091jwSdUMs9bX1hOi9N_HZhdMXZOkwDNQpQ8dmMijg=w1218-h913-no)

Regards - Tug
Title: Re: Twin Oscillators
Post by: Jo on April 18, 2019, 04:02:58 PM
Thanks Tug  :ThumbsUp:

Like you I realised I had to start by squaring up the base of the casting to give me a reference. To be able to hold the top of the casting in a vice  :-X I clamped the casting face first onto the BCA bed and milled the back of the pivot blocks so that they were parallel to the front. Having clamped it in the vice The base was flycut and the last three sides squared up.

The next trick was to look to get the centre of the crank in the centre of the BCA table  :thinking: I chose to do this by finding a really long Allen screw (which I found was 1/4 UNF  :facepalm: ) and making a long nut that went into an existing BCA table collet.

A few hours later (the sun is also out which means the garden is very nice to spend time in  ::) ) and the Engine Standard is mounted in the centre of the BCA table, square with the angle measurements on the rotating table, ready for milling in the morning. In the meantime I am hoping Surus considers that this is sufficient progress for today to allow us to participate in a little casting fondling this evening :wine1:

Jo
Title: Re: Twin Oscillators
Post by: Jo on April 19, 2019, 03:58:58 PM
With a little jiggling around I managed to get the casting such that there was almost nothing to come off on the two insides of the bearings face and almost an equal extra on the two outsides, which was then milled off. The flat was milled across the centre of the face and then the holes drilled 6.5mm deep.

That was the easy bit: Having marked off the holes that needed to be drilled for the internal porting it was time to realise that the hole from the top is more than just a long hole, it is a very long hole relative to the drill diameter  :paranoia: To play safe I chose to start with a shorter very sharp PCB drill and finish off with a brand new dormer drill. The vice is there to make sure everything is truly square before starting to drill. The ones on the side were much less stressful to drill. A poke with a drill down each hole proved that they all join up where they should  :)

Finally time to check it the bits go together  :wine1:

Jo

Title: Re: Twin Oscillators
Post by: Bluechip on April 19, 2019, 05:39:24 PM
Hi Jo

Looks like it's gone together OK ...  :ThumbsUp:

So what's the finish? Crack a bit of filler in the holes and a slosh of paint ?

Thought you'd have been out in the garden culturing your horties today.

My toms are in their final pots and seem to be thriving.  ;D
Fence panel and other stuff came this AM .. Was going to rip down the crap and convert into firewood for you .. except I was expecting a delivery from CPC and hung about doing nowt so UPS would not have to go searching for me. Thought they were getting a bit late then I saw the tracking ...... Delivery by end of day ..TUESDAY 23rd  ... bugger .....  :headscratch: :old:  Another day I won't get back.  :paranoia:

Dave
 
Title: Re: Twin Oscillators
Post by: Jo on April 19, 2019, 06:00:16 PM
Thanks Dave  :)

I haven't decided on the finish: I normally avoid polished brass engines but paint  :toilet_claw:


The garden has been good today. My Toms are behind yours  :-\ I have two Cues in their final pots but am running out of space in the Conservatory as the triffids Courgettes are attempting world take over  :facepalm: Any amount of firewood is always welcome  :cheers:

I am still trying to work out where all the extra spare time went now that I am retired  :noidea:

Jo
Title: Re: Twin Oscillators
Post by: Jasonb on April 24, 2019, 08:05:52 PM
Any more progress on this one Jo or are you still to busy polishing off all those chocolate eggs?
Title: Re: Twin Oscillators
Post by: Jo on April 24, 2019, 08:28:43 PM
Yes thank you  ;D

There were no eggs round here  :disappointed:

Jo
Title: Re: Twin Oscillators
Post by: b.lindsey on April 24, 2019, 10:51:46 PM
Had totally missed this one Jo, and now it's almost finished. Looks great though, Surus' should be pleased.

Bill
Title: Re: Twin Oscillators
Post by: Jo on April 25, 2019, 07:09:53 AM
It is nearly finished Bill a little more fitting and a bit of plagiarism  ::) and I should be in a position to show some more photos.

Hopefully that will be today... if I have time  :embarassed:

Jo
Title: Re: Twin Oscillators
Post by: Jo on April 28, 2019, 03:10:10 PM
The two piston rods have big ends that have to be fitted together so I started by making up the two big ends and checking the fit. The rods and pistons are simple turnings. It gets tricky when the big ends have to be fitted to the piston rods and any amount of silver solder left on the rod is took much as when the crank goes round the big end gets very close to the gland, it took a bit of fitting to get them to miss.

Having decided to commit blatant plagiarism (thank you George  ;) ) it was time to knock up the reversing block. This was made in two halves of brass from the scrap bin.

The last task on the stand was to block up the unnecessary holes that were used to drill the ports, clearly a task for that nasty all thread studding stuff that some people think is suitable for engine studs  :hellno:

The steam lines were made from some 1/8" O/D copper tube that it was only after I had finished bending them did I find out that some of the tube was blocked and had to be poked clear  :facepalm:

Finally all fluxed up ready to be soft soldered together  :)

Jo
Title: Re: Twin Oscillators
Post by: K.B.C on April 28, 2019, 06:00:41 PM
"PLAGIARISM  indeed cries the offended, my lawyers will be after you in the morning."

Just glad that my idea was worth copying, I must confess that there has been many ideas on this forum that I have found to be of great help and that members freely give there ideas and methods of machining to this old self taught machinist who struggles on many occasions so thanks to all ( too many to mention )

I should have suggested to you that you drilled the base fixing holes before brazing up the steam pipes as it's a bit difficult to grip the casting once tubed up.

George.
Title: Re: Twin Oscillators
Post by: Admiral_dk on April 28, 2019, 09:12:06 PM
Nice work Jo and the"plagiarism" (inspired by George) looks fantastic  :cheers:
Title: Re: Twin Oscillators
Post by: Jo on May 02, 2019, 10:51:18 AM
Thanks Guys,

Having passed the Blackgates engine over for inspection to Surus he has let me remove the anti fondling wrapper from the Stuart's twin Oscillator. I was intrigued by the two large pieces of bronze until I realised that they are for the cylinder covers and it needs to be bronze as this engine does not have packing glands.

The installation of the anti fondling wrapper had melted the plastic bag with the fixings  :facepalm: Having decanted the items out into a small plastic box I was pleased to see they have provided real studs  8)

Time to finish off the Blackgates engine  :paranoia:

Jo
Title: Re: Twin Oscillators
Post by: b.lindsey on May 02, 2019, 02:54:53 PM
Looks like a nice set of fixings Jo. You will miss making the studs though  ;)

Bill
Title: Re: Twin Oscillators
Post by: Roger B on May 07, 2019, 08:10:05 PM
That looks to be a nicely put together kit  :ThumbsUp:  :ThumbsUp:  :wine1:
Title: Re: Twin Oscillators
Post by: Jo on May 12, 2019, 05:10:44 PM
Its still a bit tight as it won't always automatically reverse : 

ziwzJ5xzAio
but I think it might be acceptable as an exchange for the Stuart Oscillator castings   :wine1:

Jo
Title: Re: Twin Oscillators
Post by: Admiral_dk on May 12, 2019, 09:04:17 PM
I think that you got a great result as long as you do not put it into a RC boat  ;)
Title: Re: Twin Oscillators
Post by: Jo on May 12, 2019, 09:47:55 PM
Thanks Per  :) She was happily reversing without needing any encouragement every time I didn't have the camera in my hands  :headscratch:

I plan to take her back to my supplier on Wednesday to show him what he could have made  ::)

Jo
Title: Re: Twin Oscillators
Post by: K.B.C on May 13, 2019, 12:23:57 PM
Thanks Per  :) She was happily reversing without needing any encouragement every time I didn't have the camera in my hands  :headscratch:

I plan to take her back to my supplier on Wednesday to show him what he could have made  ::)

Jo

Jo.
If you look at your No 29 post you have drilled and tapped thro' the steam and exhaust ports  and the top and bottom holes are so much smaller , could your problem be that the kidney type rotary valve is connecting with the bigger hole and the smaller hole when it should not.

Look at your drawing of the Stuart Oscillator and you will see that the 4- holes should be 5/64" dia., this may be your problem.

Sketch from my note book.



George
Title: Re: Twin Oscillators
Post by: Jo on May 13, 2019, 01:06:51 PM
Thanks George,

I don't see it as a problem it just needs running in  ;)

Jo
Title: Re: Twin Oscillators
Post by: b.lindsey on May 13, 2019, 02:48:44 PM
Quite a nice result Jo. I hope Surus is pleased enough to let you move on to some of his other castings :)

Bill
Title: Re: Twin Oscillators
Post by: Jo on May 13, 2019, 03:37:28 PM
Thanks Bill  :)

I have been allowed the Stuart castings in exchange but it is gardening time of the year and I am currently planting laying just over 250 concrete blocks  :facepalm: In a day or two I hope to get the courgettes out of the greenhouse before they totally take over.  So please don't hold your breath waiting for me to start it.

Who was it who told me I would have plenty of time once I was retired  :noidea:

Jo
Title: Re: Twin Oscillators
Post by: crueby on May 13, 2019, 04:06:20 PM
The usual comment is that you are so busy after you retired that you wonder how you ever had time to go to w*rk!

Great job on this engine, looking forward to the next!
Title: Re: Twin Oscillators
Post by: Jo on May 14, 2019, 04:13:55 PM
Thanks Chris  :)

Having looked at the length of the cylinder casting  extrusion and compared it with the drawing I was concerned that something was wrong  :thinking: But having checked the throw of the crankshaft the 19mm length is correct.

The Stuart cylinders can be held in a three jaw just like the Blackgates one can  :ThumbsUp: This makes it easy to hold for both facing the end and boring. Don't expect it to run 100% true if you turn it over end for end and face the other end. As the cylinder is bronze the boring operation leaves a nasty sharp edge on the far end which can quickly be removed by a gentle rub on some fine emery paper.

The cylinder covers have to come out of two equally long pieces of bronze but I notice that the top cover drawing is trying to confuse as the side view shows a 0.8mm step on both sides but the face on view omits this.

Jo
Title: Re: Twin Oscillators
Post by: Jasonb on May 14, 2019, 04:24:17 PM
Coming along well Jo, When you go to show it off to your supplier could you enquire how his No1 is going or not?
J

PS your 12.7mm dimension is suspect ;)
Title: Re: Twin Oscillators
Post by: Jo on May 14, 2019, 04:56:23 PM
Coming along well Jo, When you go to show it off to your supplier could you enquire how his No1 is going or not?

I was planning on doing that tomorrow when I visit him  ;) He had been using the excuse that for months he had been waiting for a replacement Eccentric strap casting to turn up.. When I mentioned he could give them a  :stickpoke: at the Harrowgate show it had suddenly turned up the day before  :noidea:

Jo
Title: Re: Twin Oscillators
Post by: Jo on May 15, 2019, 06:21:53 PM
The latest on Eric's Stuart No 1 was: " I'll be getting back on those shortly".   I don't think any parts had moved since last time I visited  :disappointed:


He is now regretting letting me have the Blackgates castings, he is almost as difficult as Surus to recover your engine from when you take one round to show it to him  :ShakeHead:

Jo
Title: Re: Twin Oscillators
Post by: Jo on May 17, 2019, 02:57:37 PM
The cylinder ends come out of a nasty bit of bronze. Each piece was nearly enough to make a spare cover if needed. As is traditional I like to use as little material as possible so I chose to make the lower covers back to back and then part them off. Did I mention nasty bronze  :facepalm: it was none too happy at being parted off with a cheap as chips Chinese parting off carbide tip.

The other covers were turned to fit into the cylinders from the provided bronze  then parted off at 4mm total thickness and held on the 0.8mm long flange to machine the top of the covers. The three holes were put into the covers using my dividing head at the correct distance only to find that the slots in the cylinder are not supplied deep enough  >:( so they had to be hand filed out.

One cylinder done the second one to go. The spare piece of bronze has been added to the come-in-handy drawer  :)

Jo
Title: Re: Twin Oscillators
Post by: b.lindsey on May 17, 2019, 03:02:07 PM
Those still came out nice Jo! One can never have too much bronze in the come in handy bin...nasty or otherwisei  ;)

Bill
Title: Re: Twin Oscillators
Post by: AOG on May 17, 2019, 03:15:21 PM
I feel your pain Jo. I had to do the same thing on mine.

Tony
Title: Re: Twin Oscillators
Post by: Jasonb on May 17, 2019, 03:40:29 PM
Is it the photo or is your insert not parallel to the holder, looks to be pointing to the right. Parting a large dia while holding by a small spigot will always be "interesting"

Also a MGGN will be better than a MGMN on non ferrous
Title: Re: Twin Oscillators
Post by: Jo on May 23, 2019, 04:57:38 PM
The material provided for the crankshaft was tough as old boots  :ShakeHead: I don't know why people seem to think you need some sort of exotic hard bit of steel for a crankshaft when on our little aero engines (that run much faster and do potentially much more work) it is normal to use standard EN1A up until crankshafts of about 6mm diameter. I tried using it  :facepalm2: it was horrible :Doh: especially as the crank was only 4mm diameter so it would not fit in my crankshaft turning jig so I attempted to use a collet chuck in the jig and was still not happy turning the pin :disappointed:

In the end I threw that attempt away and make the crankshaft up out of some bits of silver steel and loctited it together.

On the other end of the crankshaft goes the flywheel it is supposed to be brass one the drawings but I didn't like the look of that so it has been replaced with a Cast Iron one which has the advantage that the grub screw is the same colour as the crank  :)

Edit: Just re-read the parts list  :facepalm: It shows that the crank pin is supposed to be a separate item. I should have realised as the drawing shows two part numbers for the crank  :Doh:


Its Thursday so it should be casting fondling evening, I wonder which set I will be allowed    :wine1:

Jo
Title: Re: Twin Oscillators
Post by: b.lindsey on May 24, 2019, 01:00:26 AM
Looks good Jo. Hope Surus will give you free run of the casting collection.

Bill
Title: Re: Twin Oscillators
Post by: Jasonb on May 24, 2019, 07:15:30 AM
it was horrible :Doh: especially as the crank was only 4mm diameter so it would not fit in my crankshaft turning jig so I attempted to use a collet chuck in the jig and was still not happy turning the pin :disappointed:

This looks to be a very similar problem to the earlier cylinder covers where a relatively large diameter is being machined while held by a small one. In this case a small BS-0 ctr drill in the end of the crankpin would have added additional support. In these situations a lot of fine cuts and patients with a sharp tool either **GT or HSS will be better than deeper cuts with a **MT insert, other alternatives are to mill away most of the material around the pin first.

The setup with jig and the length of the collet holder does not help with the increase in overhang, maybe an ER block in the 4-jaw would have been shorter and more rigid. Better still a block with a 4mm hole in it held in the 4 jaw.
Title: Re: Twin Oscillators
Post by: Jo on May 24, 2019, 09:44:26 AM
Thank you Jason it was the turning off of the centre support that I was concerned with - It would have needed a travelling steady.

I don't have any ER blocks. If I did then mounting it in a four jaw would still have had the same overhang and would have needed a travelling steady to remove the centre mark.


I am happy with how the crankshaft turned out and am now looking at how to drill the base, assuming that playing in the garden is not too tempting this morning :embarassed: and of course there are my village commitments  :facepalm: this afternoon. I am sure I had more time when I went to work  :noidea:

Jo
Title: Re: Twin Oscillators
Post by: Jo on May 24, 2019, 11:54:54 AM
I have started on the base: First up was to find a happy medium position for the three holes - I have a pointed tool I use to do this (it is also strong enough to be dropped down and used as a scribe if required  ;) ). I chose to reduce the distance out to the two cylinder pivots by 0.3mm to make the cylinders sit in the middle of the port faces.

First drilling the centre of the crank with a nice sharp PCB drill then a slow brass drill bit before reaming the required 4mm. The two cylinder pivot holes are drilled the same but I played it safe and used the machinist's level to keep checking the casting had not moved. All holes were de-burred before going further.

Turning it over the location of the holes looks good  :)

Jo
Title: Re: Twin Oscillators
Post by: Admiral_dk on May 24, 2019, 08:19:21 PM
They came through perfectly in place Jo  :praise2: - mission accomplished  :cheers: .... ups I forgot that you prefer  :wine1:
Title: Re: Twin Oscillators
Post by: Jo on May 25, 2019, 04:34:21 PM
Thanks Per  :cheers:

The stand was turned over and using a piece of 4mm in the collet vice to hold the stand in line it was clamped in the machine vice. Having first faced the ports it was then a case of offsetting to each cylinder pivot and co-ordinate drilling the four port holes.

Then the steam passages could be drilled, thankfully I had a long reach 2mm drill for the difficult hole. All the holes were checked they went through using a torch  ;)

The stand just needs the threads tapped and the plug fitted so time to celebrate  :wine1: 

Jo

P.S. I do like some beers as well as wine but preferably not on the same evening  :hellno:
Title: Re: Twin Oscillators
Post by: Admiral_dk on May 25, 2019, 08:27:14 PM
Looks like it's almost ready to have the "loose bits" applied to this center part  :ThumbsUp:

Quote
P.S. I do like some beers as well as wine but preferably not on the same evening  :hellno:

Agreed - very bad idea. I do actually hardly drink any beer anymore .... I usually tell people that I consumed far more alcohol as strong beer and hard liquor in my youth than most people consume in a lifetime (very true) => I do NOT drink alcohol any more ...!.... but I do enjoy some from time to time - preferably as a good Scotch (or Irish) whiskey, cognac, rum or white wine (Red is NOT an option - allergic), in the right company  :cheers:
Title: Re: Twin Oscillators
Post by: Jo on May 26, 2019, 12:40:57 PM
The two sets of four plugs are shown parallel but I chose to turn to 4mm long and leave the top rough cut so that there was something to get hold of if needed. I also countersunk the tops of the holes on the stand to give the solder a little more to grip on.

Each plug was then coated with flux and poked in their holes - one fell out while I was soldering the other side  :facepalm: luckily the workshop Gnome has not been seen since Surus arrived so it was easily found and refluxed before soldering into its hole. Once cool each of the plugs were filed flush.

Finally the threads were cut into the stand and I knocked out the two steam/exhaust adapters while I thought about them. Time to decide on the next bit  :thinking:

Jo
Title: Re: Twin Oscillators
Post by: b.lindsey on May 26, 2019, 03:09:30 PM
Coming along well Jo. That is quite an interesting casting too.

Bill
Title: Re: Twin Oscillators
Post by: Jo on May 26, 2019, 03:32:44 PM
Thanks Bill,

Yes Stuarts thought that base casting out very well to get all the steam pipes hidden away  :)


Before I headed in I decided I really should finish off the cylinders: On the flat face we need two holes drilled at an angle and the central pivot drilled and tapped 5BA. The face was rubbed on a piece of carbide paper over the surface plate to get it smooth, then the three hole centres marked out and centre popped. The pivot hole was easy to drill and tap but I was a bit concerned that the pressure of the drill may deform the bore so was careful not to go too far in.

The two port holes were drilled using the vice in a vice trick. But as it needed to be drilled at an angle and it is only drilled with a  rather flexible 1.6mm drill it was necessary to use a centre drill to start the drill hole before drilling through.

At this point I decided to check the bore with a piece of the appropriate sized silver steel to find that yes drilling the pivot hole had indeed caused a high point on the bore   :facepalm2: This was removed through honing.

I was a little worried when I saw the bit of Stainless supplied for the piston rod would be hard as nails as it had been cut off using an angle grinder  :paranoia: But when I tried turning it found it was just Stuarts using the standard Foundry parting off tool rather than a saw.

I would have liked to finish piston rod assemblies today but time is getting on and I am feeling tired so it is time to close up the workshop and go and think about dinner before its race time  :whoohoo:  :wine1:  :wine1:  :-X

Jo
Title: Re: Twin Oscillators
Post by: Jasonb on May 26, 2019, 04:38:55 PM
............... before its race time  :whoohoo:  :wine1:  :wine1:  :-X

Jo

Did not think you were a fan of Indy racing :LittleDevil:

The other race has finished and was won by  :-X :-X :-X :-X :-X :-X
Title: Re: Twin Oscillators
Post by: Jo on May 26, 2019, 05:16:11 PM

The other race has finished and was won by  :-X :-X :-X :-X :-X :-X


This is what comes if you have no self control   :disappointed:. You have to pay an arm and three legs to Sky every month to be able to watch the race live. Where as others of us wait a few hours (hoping that no one tells them the result before they can watch it   :stickpoke: ) have invested their money on early retirement   ::)

Jo
Title: Re: Twin Oscillators
Post by: Jo on May 28, 2019, 04:44:31 PM
The pistons were roughed out on the 12.7mm bar before drilling and tapping and turning to fit the bore of the cylinder.

The other ends of the rods has some odd looking big ends. these are taken out of two pieces of square bronze of 6.2mm sq  :headscratch: Having faced these and marked the centre of the rods there were set up in the four jaw chuck to have the end turned and drilled/tapped for the rod. It was necessary to drill to 4.5mm depth (which was near the running surface  :o ) to be able to get my plug tap to cut sufficient tread for the rod to fit tight. [Sorry forgot to take a pic  :Doh:)

Then the pieces of bronze were taken over and mounted in a machine vice to have the bearing surface drilled and to have the 2.1mm taken off the side next to the rod thread. The end could then be turned off and cleaned up with a needle file.

There are not many bits to go, I might have to start negotiating the next castings set, maybe it is time to deploy the Snickers Ice cream to see what casting sets might be forthcoming :thinking:

Jo
Title: Re: Twin Oscillators
Post by: b.lindsey on May 28, 2019, 06:07:50 PM
Those turned out well Jo. Hmmmmm...Snickers ice cream...that should do the trick and loosen Surus' grip some  :D

Bill
Title: Re: Twin Oscillators
Post by: crueby on May 28, 2019, 06:20:33 PM
Those turned out well Jo. Hmmmmm...Snickers ice cream...that should do the trick and loosen Surus' grip some  :D

Bill
Trail of chocolate covered peanuts into the other room as a distraction?
Title: Re: Twin Oscillators
Post by: Jo on May 28, 2019, 07:50:00 PM
I have his attention  :mischief:

Jo
Title: Re: Twin Oscillators
Post by: Jo on May 29, 2019, 05:07:46 PM
Initial assembly of the engine showed that the big ends on the piston rod need to be modified to enable the two rods to move next to each other.

As they were taken off I realised that I had not yet fitted the blued steel... or rather blued Aluminium  :headscratch: At least being Ali means it should be easier to bend. I checked the length of the ali and found it has sufficient length to go round the cylinders (the length on the drawings is rather tight)

It was a short day in the workshop today as the nice man from Waitrose was bringing us another 2 boxes of Snickers Choc Ices and if I hoped to see then I had to be in the house when they arrived  ::) All I can say is a new set of castings is looking likely, the question is how many of the new ice creams it will take to acquire them.

Hopefully this engine waill be finished tomorrow  :)

Jo
Title: Re: Twin Oscillators
Post by: Jasonb on May 29, 2019, 05:22:16 PM
Almost there.

Looking back at the drawing I wonder if the 9/32" dimension should have been from the rod end of the big end as that would have given the bit of clearance needed?

J

PS I'll stick to magnums :LickLips:
Title: Re: Twin Oscillators
Post by: Ye-Ole Steam Dude on May 29, 2019, 07:41:17 PM
Hello Jo,

You might have already stated and I am sorry if I missed it, but what is the angle between the two cylinders. Looks to be greater than 90 degrees.

Have a great day,
Thomas
Title: Re: Twin Oscillators
Post by: Jo on May 29, 2019, 08:16:20 PM
Hi Thomas,

Both engines have 90 degrees between the cylinders.

PS I'll stick to magnums :LickLips:

There are none of those left  :disappointed:

Jo
Title: Re: Twin Oscillators
Post by: Ye-Ole Steam Dude on May 29, 2019, 08:30:36 PM
Hi Thomas,

Both engines have 90 degrees between the cylinders.

PS I'll stick to magnums :LickLips:

There are none of those left  :disappointed:

Hello Jo,

I guess it is the angle of the photo, thanks for the info.

Have a great day,
Thomas

Jo
Title: Re: Twin Oscillators
Post by: Old Bill on May 29, 2019, 09:35:37 PM
Coming on nicely, Jo. You have just reminded me that I made one whilst I was at school and this is it! It could do with a good clean though, rather than the cursory dusting it has just had. This was my solution to the plumbing challenge. Many ways of skinning a cat!

(https://i.postimg.cc/fWmR4Q7Y/DSCN8330.jpg) (https://postimages.org/)

(https://i.postimg.cc/vTrY5580/DSCN8331.jpg) (https://postimages.org/)

What's next?

Steve   :)
Title: Re: Twin Oscillators
Post by: b.lindsey on May 29, 2019, 10:44:27 PM
Great news Jo. So what has Surus' been letting you look at or fondle for a next project??

Bill
Title: Re: Twin Oscillators
Post by: Jo on May 30, 2019, 07:12:57 AM
Nice engine Steve  :) I wonder when the Blackgates model first came on the market, it must have been years ago if you did it when you were at school  :mischief:


As for the next model there are many possibilities: The two orphaned Seals look interesting, as does the Halls Rotary and the Double Diagonal but it could all change between now and the end of the last box of Snicker's  ::)

Jo

P.S. I seem to recall booking the Wizard into display at the Guildford show   :thinking:
Title: Re: Twin Oscillators
Post by: Jo on May 30, 2019, 11:08:28 AM
The two cylinders still need to have their cladding added. I didn't like the spacing of 1.6mm from the edge of the Ali as I feared it would break through so moved mine to 2mm from the port edge. The piece of post-it used to measure the length of the cladding were stuck on one side and some magic tape on the other to protect the face of the Ali, before using the jaws of the vice to support the Ali while it was first sawn then filed to length. While still flat the holes were drilled 2.1mm for the 7BA tapping size.

The Ali was easily bent round a piece of 18mm steel to form the curve, then the two ends bent back by hand using a pair of parallel pliers. This cladding was then used as the drilling jig to mark then drill the cylinders for the cladding. The cylinders were tapped 7BA and the holes in the cladding opened up to 2.5mm (7BA clearance) using a Watchmaker's broach.

With the cladding in place it was then necessary to give the two cylinder ends a rub on some emery paper to make sure the cladding did not prevent the cylinder covers from sitting flat.

It is time for final assembly and we can see if it runs  :)

Jo

P.S. I have already spotted two bits still to do  ::)
Title: Re: Twin Oscillators
Post by: Jo on May 30, 2019, 01:53:52 PM
The two bits turned in to three bits  :ShakeHead:

First the spindle for the reverser had to have its length reduced by 7mm so that it stuck out the same distance as the two studs that mount the cylinders.

Then there was the 4mm diameter pin that goes beneath the reverser that stops it moving too far.

While I was at it I faced the reverser.

The final bit of fettling was the piston rod big ends  so that they do not jam.


The engine is together so all it needs is some air  :pinkelephant: And then maybe some paint  :noidea:

Jo
Title: Re: Twin Oscillators
Post by: Bluechip on May 30, 2019, 02:06:26 PM


The engine is together so all it needs is some air  :pinkelephant: And then maybe some paint  :noidea:

Jo

Nah. Bead blasting then some Rustin's Brass lacquer.  :D

Looks very nice though  :praise2:

Dave
Title: Re: Twin Oscillators
Post by: K.B.C on May 30, 2019, 09:24:05 PM
Hi Jo,
It's much easier to paint the engine as you would have to dismantle and mask off the port faces, I use Humbrol  dark green rather than the Stuart green which needs several undercoats and top coats, never seen a full size steam engine in a brass finish.
I suppose it's all matter of taste.

George.
Title: Re: Twin Oscillators
Post by: Admiral_dk on May 30, 2019, 10:32:35 PM
It looks nice as is  :ThumbsUp: and it will look more like a full size if painted .... there are a few that springs to mind : Green (as more or less suggested), black (maybe a bit boring), red, blue, brown and grey - if we are talking classic old style.
Title: Re: Twin Oscillators
Post by: Roger B on May 31, 2019, 07:35:11 AM
Almost there  :)  :)  :wine1: That's a fine collection of castings that Sursus is minding for you  :ThumbsUp:  :ThumbsUp:
Title: Re: Twin Oscillators
Post by: Jo on May 31, 2019, 08:15:33 AM
Thanks Guys, looks like Green is the colour  ;)

That's a fine collection of castings that Surus is minding for you  :ThumbsUp:  :ThumbsUp:

That's part of the small Aero engine department, some of those boxes have over half a dozen crankcase castings in them :mischief:

While Surus is sleeping off his Snickers  :paranoia: a quick pic of the extent of the small Aero engine department and the remnants of last night's engine fondling  ::)

Jo
Title: Re: Twin Oscillators
Post by: Jo on May 31, 2019, 01:16:45 PM
We have gone go faster green  :)

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So which of the two kits is better  :thinking: The Stuart is an easy build but the Blackgates one is half the price and bigger  :noidea:

Jo
Title: Re: Twin Oscillators
Post by: Ramon on May 31, 2019, 01:28:16 PM
That's a nice result Jo - on both of them and nice runners too  :ThumbsUp: :ThumbsUp:

Regards - Tug
Title: Re: Twin Oscillators
Post by: Roger B on May 31, 2019, 03:05:17 PM
Good runners  :praise2:  :praise2:  :wine1:  Were you blowing down the tube  :stir:
Title: Re: Twin Oscillators
Post by: b.lindsey on May 31, 2019, 03:41:39 PM
Well done on both counts Jo. Very nice looking twins...you should be very pleased with both!!

Bill
Title: Re: Twin Oscillators
Post by: Jo on May 31, 2019, 06:50:33 PM
Thanks Guys  :)

We are pleased with both of them. I can recommend them as nice beginners engines.

It looks like I will be allowed the casting sets that are currently sitting on the Dining room table in exchange for these two  :embarassed:

Jo


Title: Re: Twin Oscillators
Post by: Jasonb on May 31, 2019, 07:34:23 PM
Turned out nicely Jo. Just take it easy for the rest of the day - painting and running an engine all in one day may be overdoing things ;)
Title: Re: Twin Oscillators
Post by: K.B.C on May 31, 2019, 09:25:35 PM
Thanks Guys  :)

We are pleased with both of them. I can recommend them as nice beginners engines.

It looks like I will be allowed the casting sets that are currently sitting on the Dining room table in exchange for these two  :embarassed:

Jo

Jo

Do you ever run your engines on Steam ?

George.
Title: Re: Twin Oscillators
Post by: b.lindsey on May 31, 2019, 11:24:43 PM
Wow!!! That snickers ice cream must be good stuff if you have been allowed  multiple sets of castings.  :o

Bill
Title: Re: Twin Oscillators
Post by: Jo on June 01, 2019, 07:17:55 AM
Do you ever run your engines on Steam ?

I don't currently have a working test boiler to run them George. I do seem to recall a Orphaned Stuart 501 somewhere  :noidea:

Jo
Title: Re: Twin Oscillators
Post by: gary.a.ayres on June 07, 2019, 09:04:32 AM

As with all legacy drawings my first job is to part them out into individual part jpegs, clean up the drawing of each part and lay them out on A4 sheets. They can then be printed out and ISO Metric measurements added - I normally do these in red pen. The drawings are then rescanned and individual pages can be printed off to take out into the workshop as required  :wine1:

Jo

This is a good tip Jo. Simple but sound. I have a set of castings in imperial (still on my shelf, still scared to touch them) but my shop is geared up for metric and I have been a bit worried about the hassle of converting the units as I work. It makes a lot of sense to convert all the dimensions  and mark them in red on the drawings before starting the build as you suggest.

gary

 :ThumbsUp: