Author Topic: Hemmingway kits Fieldhouse winding engine machining question  (Read 874 times)

Offline sierrasmith71

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Hemmingway kits Fieldhouse winding engine machining question
« on: October 31, 2020, 08:37:20 PM »
Hi,

I recently purchase the Hemingway Fieldhouse Engine kit. I have had the drawings for three years now and finally got around to ordering the kit. So I have been studying the drawings while I wait for the kit to arrive.

Lots of tiny parts and some large ones, should be interesting to machine. I wanted to build an engine that would be a challenge, and i think this is it!

There are, at least, two parts (a pair of connecting rods) that  I don't have a clue about how to proceed in their machining from what  I guess will be a mild steel bar stock. Parts of  these will be straight forward flat  milling but the threaded end connectors stump me. Each have a threaded stud and a round 1/4" boss connected to an otherwise flat arm that connects to the engine's crosshead.

I have attached a drawing  for you delight!

One thought I had was to make the threaded ends separately and silver solder them on to the flat  rods.

Any thoughts???

Best regards and stay safe

David Garrison
Gaithersburg, Maryland USA

Offline Jasonb

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Re: Hemmingway kits Fieldhouse winding engine machining question
« Reply #1 on: October 31, 2020, 08:46:38 PM »
I'd machine the end spigots and thread them quite early on by holding the rectangular bar in a 4 jaw, add a small ctr drilled hole for for later tailstock support though you will probably need that on the cranked one from the start as it may not fit inside your spindle bore.

Offline AVTUR

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Re: Hemmingway kits Fieldhouse winding engine machining question
« Reply #2 on: November 01, 2020, 01:02:30 PM »
David

I am making a Hick over crank engine from castings supplied by Hemingway. This is also a Geoffery King design and has many small fiddly parts. Your two connecting rods are quite typical. On my engine such items are smaller. I decided to make them from bar and machining the end first as Jasonb suggests. I then clamped them to simple prepared fixtures made from good quality 2" x 1/2" aluminium strip and milled away the surplus material. They took quite a bit of time to finish but I was happy with the results. Given that your rods are larger a silver soldered assembly may be a sensible option. If it does not work, it is not a disaster, just lost time and materials.

I have been posting a blog on my progress with the engine which mainly catalogues my disasters and difficulties. At present it is running about two months behind the actual work. Once the cold has forced me out of the workshop it will soon be up to date.

I attach a couple of photographs of one such item, finished and work in progress (the turned handle is held in a split clamp).

AVTUR

I wish you every success with the model and keep well.
There is no such thing as a stupid question.

Offline sierrasmith71

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Re: Hemmingway kits Fieldhouse winding engine machining question
« Reply #3 on: November 01, 2020, 05:34:12 PM »
Jasonb

Thanks for ideas on how to proceed with this part. Turns out that my lathe's spindle bore is 1.5" (38mm) and will just manage to accommodate the cranked connecting rod, as it is 0.75" at it widest from the centerline! I will give it a shot. 



BTW, still waiting for the kit. Hemmingway was one casting short and had to have one made. I ordered the full kit with all the bits required (but  no fixings) so I didn't have to hunt down small pieces of stock to machine) 

Thanks again

David

Offline sierrasmith71

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Re: Hemmingway kits Fieldhouse winding engine machining question
« Reply #4 on: November 01, 2020, 05:41:38 PM »
AVTUR

Looking good!

I have the same problem with my workshop. Mine is in my garage and it is not heated.  I will have a long winter waiting for spring, not a total loss as I will have all that time to workout how to make this model.  I have as much fun and pleasure building things in my mind as I do with the hands on part.

I still marvel at how much greater the setup and fixture making  time is than actually making the part!

Stay safe


David

Offline Lodalodge12

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Re: Hemmingway kits Fieldhouse winding engine machining question
« Reply #5 on: November 02, 2020, 12:24:05 AM »
David, When I built the winding engine I made those rods by carefully marking out and drilled and  tapped the end of the flatbar for 8BA thread. Then I made up the studs, threaded them into the 8BA. For the round parts I drilled 1/4" diameter steel rod, cut off the pieces to length, put them on the stud pushed up to the end of the flatbar and then just a drop of silver solder from behind and it worked perfect.  If you would like a photo or any more info please contact me off site.

Carson (British Columbia, Canada)

Offline Lodalodge12

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Re: Hemmingway kits Fieldhouse winding engine machining question
« Reply #6 on: November 02, 2020, 12:28:29 AM »
BA size mistake...Sorry David, I meant to say drilled and tapped for 10BA,

Carson