Author Topic: Hemingway 1/12 Ransomes and May horizontal engine  (Read 6977 times)

Offline samc88

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Re: Hemingway 1/12 Ransomes and May horizontal engine
« Reply #30 on: October 17, 2024, 10:28:21 PM »
Thanks Per!

I got the port face finished tonight, the slots were milled out first and then the 10BA clearance holes were drilled and 5 were countersunk for mounting the plate to the block. It does call for the lower ones to be countersunk but as you will be able to see these I will use studs and nuts rather than countersunk screws. To make the countersink I first tried using a centre drill but it didn't work very well due to it being a little too small so I used a drill and carefully pecked down until the screw head was just flush. The ports then had the corners filed square as per the drawing.I then lapped both faces with 600 grit wet and dry to take off the machining marks. The DRO is again proving to be an excellent investment, all the bolt holes lined up perfectly, quite pleased with how this has come out
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Offline samc88

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Re: Hemingway 1/12 Ransomes and May horizontal engine
« Reply #31 on: October 30, 2024, 11:01:02 PM »
Some progress has been made on the steam chest . Was first milled to dimension (the top surface I will do later as it has a circular boss in it, I will do that feature on the rotary table). The slot was then opened up and filed to final.size to be a good fit with the previous port face part. Once that was done I marked out the hole locations, will hopefully drill these tomorrow night 10Ba clearance
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Offline Michael S.

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Re: Hemingway 1/12 Ransomes and May horizontal engine
« Reply #32 on: October 31, 2024, 06:13:26 PM »
That was good work with the file. 👍

Michael

Offline samc88

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Re: Hemingway 1/12 Ransomes and May horizontal engine
« Reply #33 on: October 31, 2024, 10:00:56 PM »
Thanks Michael!

Bit more done tonight, drilled the mounting holes and then machined away the top surface leaving enough for the boss to be machined circular later. I did put a centre in there though after edge finding so I can use it to centre up on the rotary table. I then worked on the gland end, drilling 3/32 through the centre and following with a 1/4" end mill. The 2 mounting holes were then drilled and tapped 10BA. This was then flipped upside down and the 3/16" x 40 thread put in for the tail piece to support the valve rod.
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Offline modelsteam

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Re: Hemingway 1/12 Ransomes and May horizontal engine
« Reply #34 on: November 01, 2024, 08:36:39 AM »
Excellent progress, keep up the good work.
      Chris

Offline Charles Lamont

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Re: Hemingway 1/12 Ransomes and May horizontal engine
« Reply #35 on: November 02, 2024, 10:38:18 PM »
A little suggestion for a small detail. Portface wear is often uneven. As the valve only covers the ends of the travel momentarily it tends to wear the portface more in the middle and less at the ends, making a hollow depression in the portface. This tendency can be much reduced by relieving the portface at the ends of the valve stroke, so that the valve overlaps the edge by a small amount at each end. As you have a raised portface this would by quite easy to do. The red bits show where I mean.

« Last Edit: November 02, 2024, 10:42:04 PM by Charles Lamont »

 

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