CHUK, yes another one

[Jo]

I like both of those ideas,  thanks 

You may have noticed on some set ups I leave a long piece of rod in the tail stock poking through any holes as a safety device. One of the gentlemen  I used to work for told me tales of his chuck unwinding from the nose on his Myford, bouncing backward through his closed window, which was on the second floor and finally embedding itself in the ground  Luckily no one was standing below.

Jo

[Alyn Foundry]

Personal safety is paramount Jo. 

My late father lost his first love to an industrial accident during the last war. Whilst he was in Europe his girlfriend was working in an engineering factory, taken out by a lathe chuck key that had been left in the chuck.

You can NEVER be too careful in this hobby, in my humble opinion.

Cheers Graham.

[Noitoen]

Personal safety is paramount Jo. 

My late father lost his first love to an industrial accident during the last war. Whilst he was in Europe his girlfriend was working in an engineering factory, taken out by a lathe chuck key that had been left in the chuck.

You can NEVER be too careful in this hobby, in my humble opinion.

Cheers Graham.

Looks like in this case that the accident was a good thing 

[Alyn Foundry]

That's certainly a different way of looking at it!

Cheers Graham.

[Twizseven]

Jo,
Have you now got all three versions of CHUK.
Colin

[Jo]

No, not yet Colin 

Jo

[Alyn Foundry]

No, not yet Colin 

Jo

Hi Jo.

CHUK 3 is not for the feint of heart, one of most pernickety engines I've ever produced.... Hmmm. Hornsby Akroyd springs to mind.

A couple of videos taken at different times at the Anson Engine museum. This was a " GOOD " day!

<a href="https://www.youtube.com/watch?v=VvpzbZh-0OY" target="_blank">http://www.youtube.com/watch?v=VvpzbZh-0OY</a>

<a href="https://www.youtube.com/watch?v=QHO5y9bMegw" target="_blank">http://www.youtube.com/watch?v=QHO5y9bMegw</a>

Cheers Graham.

[Jo]

Good try Graham, I'm still trying to make sure Surus does not know he is missing one of the set   


The Cylinder had one last run through at the last setting to help smooth the bore before mounting it up on a mandrel to turn the outside of the fins round. With that done the cylinder was held in a three jaw with end support to have the end spigot added and I chose to also add a register for the cylinder head, which was not shown on the drawing  .

The cylinder was then remounted on the mandrel to have the gaps between the fins machined to make the fins look like they are all the same width and spacing. Finishing of the gaps was done with a hand file.

I also started converting a bit of scrap-bin-ium that had the desirable special coating into the cylinder head. That will have to be completed tomorrow. 

Jo

[steamer]

Nice set up!
 

[ChuckKey]

On the subject of chucking practice, I have had third thoughts and, because you show a picture of it (the first set-up in this thread) and others might follow, I am going to mention it after all. It is not considered best practice for the preservation of one's expensive and accurate 3-jaw chuck to stuff rough castings in it. (Especially not if winding it up with a pipe over the chuck key for a safe grip.) Castings, and cob-ends of rusty archaeological finds, go in the 4-jaw.

[Alyn Foundry]

On the subject of chucking practice, I have had third thoughts and, because you show a picture of it (the first set-up in this thread) and others might follow, I am going to mention it after all. It is not considered best practice for the preservation of one's expensive and accurate 3-jaw chuck to stuff rough castings in it. (Especially not if winding it up with a pipe over the chuck key for a safe grip.) Castings, and cob-ends of rusty archaeological finds, go in the 4-jaw.

Go back to your reference, you should notice that Jo has used a fairly " battered "  3 Jaw chuck for that particular operation.

To quote your word, I have been " stuffing " round castings into my 8" monoblock 3  jaw chuck for well over 30 years with virtually no detriment to its accuracy using no more than " White knuckle " force upon the key. I select a different chuck for any precision work, a case of " horses for courses "

Cheers Graham.

[Jo]

I use my collet chuck if I want accuracy, having said that the only battering on my three jaw is because it is 50 years old not and it suffered with coolant water damage over 30 years ago before I owned it not because it cannot hold true Something does not need to be perfectly circular to hold it in a three jaw, if the edges are uneven then that is overcome by using aluminium off cuts between the jaws and the casting it won't damage a decent quality chuck.


The Cylinder head is a simple turning operation.

The A frame takes a bit of thinking about: The feet and the top where the cylinder is going to mount have a lot of draft angle on them but it is the sides of the frame that need to be square so that is our surface we use to clamp the frame while milling the bottom of the feet and then turning it over to surface the top. Having taken the casting to height it is then possible to measure what is left and decide where the centre of the cylinder needs to go, this also provides a good indication of what is needed to complete the bottom of the cylinder.

So back on the Colchester to machine the 50.8mm diameter which is going to fit into the A frame and to add that sneaky extra fin that Graham adds to his engines to see if we notice it 

Jo

[Alyn Foundry]

Nicely done Jo....

Using the " Box " to support that awkward shaped casting is a great idea. I'm loving the extra fin BTW !

The late, Mike the Bike bored his cylinder mounting hole by first facing off the feet then securing the " A " frame to his already prepared base. He then mounted the whole assembly into the four jaw chuck and bored it out with a boring bar. We both used a hole saw for removing the majority of waste metal prior to the finishing work.

His other trick was to secure the " A " frame from underneath using two heavy studs and nuts, this gave the  " impression " of the base and frame being as one, so to speak.

Cheers Graham.

[Jo]

Thanks Graham  I think I prefer my holding method rather than Mike the Bikes one, it would hang out a rather long way 


I have bored the top the same diameter as the cylinder before the end of play today. In the morning I plan to do the counterbore to let the cylinder slide in and will have to think about how the two are going to be secured together 


In the meantime I see there is a set of castings awaiting me for a fondle, it must be Thursday 

Jo

[Jo]

The top of the A frame was counterbored so that the cylinder was a sliding fit in. To secure it I decided to use 6 out of a ring of 8 3mm holes on a PCD of 45mm so while it was still clamped in place I drilled the holes for the screws.


The base was slightly chilled on one side so I had to mill the bottom flat rather than hand file it to avoid damaging my files  this could then be turned over to have the top pads milled flat. Decision time do I want to use 4 studs and their nuts to secure the A frame to the base or try sneaking a bolt up into the A frame from below and have nothing showing 


While I think about that I had a visit from my parents so just before we sat down, socially distanced of course  , in the garden I put the pieces of the engine together so I could see how big it is 

Jo