Dake engine suggestion

This topic has 9 replies, 5 voices, and was last updated 4 March 2013 at 19:05 by Stewart Hart.

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2 March 2013 at 11:52 #113477
Eric Cox
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@ericcox50497
When machining the horizontal side rails to length, instead of mounting the rail vertical in the machine vice as shown in ME 4451, mount the rail horizontally in the vice and machine the rail with the side of the end mill. That way you won't have to "sneak up on them with light cuts" and you can measure the overall length without removing from the vice.
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2 March 2013 at 11:52 #22496
Eric Cox
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@ericcox50497
2 March 2013 at 12:57 #113479
roy entwistle
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@royentwistle24699
If I can add my own tuppence worth. Would it not be helpfull if we got a materials list at the start of the article then we could order in bulk Thanks

Roy
3 March 2013 at 10:37 #113576
roy entwistle
Participant
@royentwistle24699
I have just been looking at the drawings and I find that on page 352 part 5 the height is given as 81

howevr on page 353 part 7 the height of the same component is 83 Which is correct ?

Roy

also as an aside, the text states that the rails are made from 1 x 5/16 inch bar so why is an Americam machine being made in metric ?
3 March 2013 at 10:51 #113577
JasonB
Moderator
@jasonb
Stew's engines are not to any exact scale, more a general representation of the style, as he tends to work in metric thats why its being drawn mostly in metric. If you happen to know the exact dimensions of the original I'm sure we would all like you to share these but as it is Stew and the rest of us who like to model engines from scratch usually just have a few etchings or old photos to work from.

The use of commonly available imperial aluminium section makes it easier for builders to get hold of materials and allows for a light clean up skim to be taken.

J
3 March 2013 at 11:53 #113582
Sub Mandrel
Participant
@submandrel
I was musing yesterday that a 1/2 or even 1/3 size version of Stew's model would be a good challenge. It could be simplified as you might as well make some of the parts from solid brass.

Neil
3 March 2013 at 18:51 #113629
Stewart Hart
Participant
@stewarthart90345
Posted by roy entwistle on 03/03/2013 10:37:12:

I have just been looking at the drawings and I find that on page 352 part 5 the height is given as 81

howevr on page 353 part 7 the height of the same component is 83 Which is correct ?

Roy

also as an aside, the text states that the rails are made from 1 x 5/16 inch bar so why is an Americam machine being made in metric ?

Whoops sorry Chaps just checked it out and the correct size is 81

As for metric imperial switch I just use what ever stock size of material metric or imperial I can lay my hands on that will do the job, when I first started work we were on the imperial system then we changed to metric so I'm ambidextrous and can swap from one to the other with no problem.

I like to use metric sizes just to keep the cost down being the industry standard nuts bolts taps dies etc are a lot cheaper that going for BA etc OK you may not be able to scale things as well in metric but it's something I don't worry too much about, I don't want build to competition standard, that is just my way of working.

I've not worked to any particular scale in fact I've not tried to model any particular engine, I was just focusing on just getting a running engine that was an approximation of a real jobby. As Jason said working from etches etc is not easy particularly when you have no reference point to work from, and the Dake was particularly difficult as you couldn't see the innards of the engine,

Neil's point about size is a good one, the engine turned out to be a bit of a big bruiser, if any of you who've seen the engine at Manchester over the week end may have noticed, it such an odd ball I was very unsure on what size would work, and I think I over did it a bit, if i was to start again, I think it would make it 3/4 or even 1/2 the size that I did.

Thanks for you're interst

Stew
3 March 2013 at 20:08 #113644
Stewart Hart
Participant
@stewarthart90345
Posted by Eric Cox on 02/03/2013 11:52:21:

When machining the horizontal side rails to length, instead of mounting the rail vertical in the machine vice as shown in ME 4451, mount the rail horizontally in the vice and machine the rail with the side of the end mill. That way you won't have to "sneak up on them with light cuts" and you can measure the overall length without removing from the vice.

I missed this bit :- Eric you're correct that would be a better way, sometimes you can't see the wood for the trees ;o)

Stew
4 March 2013 at 15:53 #113691
JasonB
Moderator
@jasonb
Stew, if part No 7 is made to 81mm it won't leave you any material to mill the assembly square as shown in photo No 14.

Would it not be better to make it 83mm and then machine the assembly down to 81mmfinished size?

J
4 March 2013 at 19:05 #113711
Stewart Hart
Participant
@stewarthart90345
Thats a good point Jason.

When I made mine the part was very close to square so I only had to take a very light skim off each side to get it square:- no more than 0.2mm a side, so to be on the safe side making it 83mm would not be a bad idea.

The only thing you would have to be carfull of was keeping the centre of the square (Outer Piston) on the centre line of the crank shaft, otherwise there would be a danger of the inner piston fouling at top or bottom of its stroke, I have drawn it up so there is 2 or 3 mm clearance at the tops of its stroke to help avoid this, but if things did get to far off line, this would be a danger.

Its one of those engines where it helps to start getting parts arround you so you can visualise whats happening, when I made it I had to keep going back to the drawing board to tweek things.

Thanks again for your interest

Stew
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