Hoglet (first IC engine)

[Jasonb]

Nick rather than reply in two places I will keep my comments to ME as you are/were further ahead on that forum.

J

[vcutajar]

Looking at the drawing, personally, I would leave the fins for last.

Vince

[Jo]

Yes the standard practise is to do all the drilling and the fins afterwards.

You could make a nasty mess and bend the fin is you try to bore that plug hole after cutting the fin  .

Jo

[Jasonb]

Bendy CI thats a new one on me

[Jo]

Clearly another one who breaks his piston rings rather than gently bending them before setting them using heat treatment 

Jo

[Jasonb]

That's springy not bendy and luckily for Nick the Hog uses Vitron rings

[Nick_G]

That's springy not bendy and luckily for Nick the Hog uses Vitron rings

.
Funny you should mention this Jason. I was 'considering' cutting 2 grooves in each piston and making cast iron rings over the single viton one shown on the drawing. - Opinions please. ?

Anyway. ........... We press on.  I am on a mission to finish mine before that Jason bloke completes his. 

.

After making the jig I have made a start upon the cylinder heads.

The 2 blanks were faced off to the required length in the lathe then over to the mill where I used an edge finder to get the best centre of the cast iron stock. The DRO was then used with a spotting drill for marking out the holes.



These holes will be the ref point for fitting to the jig for all the other machining stages to the heads.



The jig was then fitted into a 4 jaw and dialed in true. The head blank was then fitted to the jig for machining the sides to a 2 1/2 in dia.





Then to check they fitted.!







The jig and the blanks will be made friendly again upon the mill for the several hole drilling sessions of the inlet / exhaust and spark plug threaded hole. All hopefully at the correct angles. 

I must also remember to make one head a left sided one and the other a right as they are not interchangeable. This being due to the inlet and exhaust port holes being of different sizes.

Nick

[Brian Rupnow]

Nick--You are doing lovely work. I will follow along.---Brian

[Jo]

Anyway. ........... We press on.  I am on a mission to finish mine before that Jason bloke completes his. 

You should be ok for at least another 5 years 

I normally use a marker on parts to remind me where parts are handed and where I should or should not be cutting 

Jo

[Jasonb]

I have left mine unfinished to give Jo a chance to catch up and get a few of hers finished and running

Let me think what we have not seen completed and running

Cross compound
S&P
Double Tangye
Bolton & Watt
R&B
Centaur
Kitti
Kiwi
Another Aero engine
And also looks like the tripples have been abandoned for a simple No 9

Whats that they say about stones and glass houses

[Jo]

Six locomotives, one steam lorry, one ploughing engine and 65 sets of model engine castings

Maybe I am still short of machine tools 

Jo

[Nick_G]

.

On with drilling and milling the heads. Used the jig once again for the angles required.

Milled a recess for the spotting dill.



Then drilled out with a 9 mm drill as the spark plug thread is 10x1 mm



Then milled down to accept the spark plug body and giving enough room to also accept the spark plug spanner.








Question.?

The bottom of the electrode. (the 'earthy' one) is about 140 thou shy of the face of the cylinder head. This seems as if its sitting a bit high to me.! Should I make it lower by increasing the depth of the pocket above so that it's about flush with the cylinder head face.?

Easy to do now as the jig is still set up at the correct angle and centered in the mill. But not so easy if I have to go back and do it later.



Nick

[Admiral_dk]

Hi Nick

I can't remember how the top of the piston is shaped on the Hoglet or the distance between the piston crown and the combustion chamber at TDC, but I would make the pocket deeper as my first thought - unless that will create a problem.
Normally the sparkplug has it's "sides" flush with the combustion chamber and the electrodes are "inside" the chamber - not in a "pocket".

Best wishes

Per

[zeeprogrammer]

The finishes and workmanship is excellent. 

And I found something I have in common with Jo and Jason. Great starter, lousy finisher. 

[Jasonb]

Don't know about that Zee as I have 14 other engines completed, painted and running since I was working on the Hoglet.

Just looks like you and Jo are the Perfect match as I can only think of 2 engines from her