Author Topic: Clarkson Twin Horizontal Steam Engine  (Read 2166 times)

Offline Mike Bondarczuk

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #45 on: November 28, 2018, 04:08:29 PM »
Jason et al,

The attached pictures are all based on the trunk guides received and they are indeed very rough and have a few hard spots, though my problem is where do I start to obtain a datum point.

Initially I have placed one guide into the four jaw chuck and tried to centre it on the base, which assumes that that trunk is central to the base, and this is not 100% certain, or should I try to centralise the guide somehow and then turn the base on that datum.

The issue if how I clean up the trunk and still maintain the oval ridge which is the boundary for the guide relief opening and then bore the length of the guide to 5/8" whilst trying to hold an uneven surface.

Any suggestions are most welcome and if I was making this part from stock then it would not be a problem, well a slightly lesser problem.

Mike

"Everything I can't find is in a totally secure place"

Offline Jo

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #46 on: November 28, 2018, 04:43:38 PM »
E'ning Mike,

How much spare diameter is there on the part that goes against the cylinder? It might be worth a quick skim on that face but only the face not the outside so it can go flat against the chuck face in a second.

The hardest part to get true is the end of the guide and that is where any miss alignment will look worse so I would centre up on that for turning then mount it on an arbour to do the cylinder end   :)

Jo
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Offline Jasonb

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #47 on: November 28, 2018, 06:30:36 PM »
I'll come back to you a bit later, got something to do first.

J

Offline Jasonb

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #48 on: November 28, 2018, 08:01:05 PM »
I think I would hold it much as you have it but with a little more sticking out and some packers on the two sides so that the jaws are not inclinded to find the low spot in the opening.

It is unlikely that the outside of the trunk is round so when setting up in the 4 jaw get it central on the two sides and then central on the top/bottom. The face of the jaws will line it up along the lathes axis.

You can now face and bore all at the same setting which will ensure the bore is at right angles to the bolting face. If there is enough metal while still held like this you can tidy up the outside of the flange. There is also the option to skim the outer face of the flange so your nuts have a flat surface to seat on, alternatively the holes could be spot faced which would be my personal choice.

If the end of the bore does look a bit off when you take it out of the chuck that can just be fettled down until it is pleasing to the eye.


Good progress with the rest of the bits, you should have it running by Christmas at this rate.

Offline Mike Bondarczuk

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #49 on: November 29, 2018, 09:34:17 AM »
Hi Jo,

On the diameter at the foot end I have 163 thou to play with and on the thickness I have 140 thou spare. In your measuring system that would be 4.2mm on the diameter and 3.6mm on the thickness.

Mike
"Everything I can't find is in a totally secure place"

Offline Mike Bondarczuk

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #50 on: November 29, 2018, 09:37:25 AM »
Hi Jason,

I had overlooked the use of packing pieces to exclude the ribs one the shaft and will try that approach first off and then see how it goes.

I believe that I shall have enough material to be able to have sufficient sticking out so that I can tidy up the inside of the foot and will sort out the flatness for the nuts when drilled.

Mike
"Everything I can't find is in a totally secure place"

Offline Jasonb

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #51 on: November 29, 2018, 10:25:04 AM »
With that amount of metal you should be able to clean up the nut face completely and leave that unpainted if you want, just leave the cast in internal fillet where it joints the trunk.


Offline Mike Bondarczuk

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #52 on: December 01, 2018, 11:13:09 AM »
Hi all,

The Clarkson build continues and with Jason's guidance and help I have now cleaned up and bored the trunk guides to size and the 5/8" bore provides a very good concentric key for locating the rear covers when I go to drill for the mounting holes.

My smallest boring bar, with sufficient length to bore the full depth meant that I had to drill out to 13mm before I could start boring, so various sized drills were used with a focus on maintaining a true horizontal axis through the guide.

The remaining work on the trunk guides is to align them vertically relative to the ribs and bore out the 5/16" slots on both sides and also to drill and tap for an oil cup on each guide.

Mike

"Everything I can't find is in a totally secure place"

Offline Mike Bondarczuk

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #53 on: December 01, 2018, 11:16:21 AM »
Hi all,

The last two pictures show both guides finished apart from the horizontal slots and 8BA mounting holes and these operations will be completed in the next couple of days.

Hopefully the next steps will be the eccentric and eccentric straps and con-rod, though in this case the castings are quite generous in oversize and of apparently good quality in gunmetal and cast iron.

Mike
"Everything I can't find is in a totally secure place"

Offline Jasonb

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #54 on: December 01, 2018, 01:12:57 PM »
The have come out well and looking at the last photo the hole seems to be fairly concentric to the outside.

I see you have gone for hex glands, just think about how you will turn these through the slot in the guide when they need tightening on the assembled engine.

Offline Mike Bondarczuk

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #55 on: December 01, 2018, 04:09:46 PM »
Hi Jason,

Did not think that far ahead and was thinking that I could tighten the gland whilst the guide was disconnected and then couple the crank rod to the crosshead via the slot, as the access via the slots is very limited whatever type of end gland fitting I construct.

Mike
"Everything I can't find is in a totally secure place"