Project Halo

[John-Som]

Good on ya Bogs

John S

[bogstandard]

I was having a look thru my old posts, and when I came across this one, I realised I hadn't finished this bit off, so time to put it right.


As the finning was done, say in batches of half a dozen, I took a break to clean them up and get the threading done.
The first job was to get the rings of brass off that were displaced when the fins were cut. It was just a matter of cutting thru them with a small pair of nippers and pulling them off.
Next the holes to be tapped were given a nice angled lead in with a small countersink bit held in a pin chuck. This stops the threads throwing up a land around the hole and so causing seating problems for the cylinder head.
The 2-56 threads were cut using my tapping stand, and there were no problems. But I did break a tap after I cut the first hole. Not cutting a thread, but I had my tapping stand set incorrectly, and when I let go of the handle the spindle dropped, hitting the tap onto the base, and so snapping it clean in half. The other 80+ holes were all cut with the replacement tap with no further problems.
I bought the taps off Lance at Liney, and they really are very good quality and reasonably priced.




I can't remember whether it was Ralph or Stew who commented that they didn't realise how small the cylinders were when they called around.
So I have taken a piccy to show you some sort of scale, you will have to make the decision as to whether they are small or not.

They are less than 1" long.




So here are the finished cylinders. All 21 of them.
I started out with 23 blanks and two were lost along the journey, but the wayward ones were still put to good use setting up the lathe cutting, to save having to put the good ones in jeopardy.
Well over 200 fins were cut, and the original grooving tool that I used is still ready to do more if it was required. The rest of the tooling I ground up will be put into stock, because I am sure I will have fins like this to cut in the future, or some very thin parting off to do.



Now that things have stabilised a little on the home front, I hope to get back to making a bit more in the very near future.
There is no rush on the build now, as I have had to cancel my display for this year due to personal circumstances.


Bogs

[Darren]

Don't let my lack of comments fool you .......


I'm keeping an eye on you.....

[chuck foster]

bogs you make it look so easy 

one thing i would like to know is, are the drawings simple and easy to understand??

chuck 

[bogstandard]

Chuck,

In all honesty, with the experience of a few small engines under your belt, and with a little perseverance, almost anyone could make one of these if they have the equipment to do it with, and yes, the plans are very easy to understand.

With me looking ahead at what is to come, IMHO these cylinders, technically, are the hardest bits to make. The rest of the parts are just straight, but very accurate, machining jobs.


Bogs

[Stilldrillin]

Don't let my lack of comments fool you .......


I'm keeping an eye on you.....

Me too an all...... 

David D

[kvom]

It's funny how perceptions of difficulty vary.   Except for the fins, the cylinders didn't look particularly challenging to me.  OTOH, the heads look like more work.

[bogstandard]

Kirk,

Actually, my problems began when I opted for a round stock base to begin with, but it did make the boring and finning much easier. Starting with square, as long as it is spot on size, then getting the holes at 45degs to each other would be easier. I think it is just swings and roundabouts.

The heads pose no problems at all. It looks very complicated and difficult, but when broken down into each stage, it is just set up and drilling. The backstop and fixed vice jaw will take care of that very easily.
But again, if the square stock size isn't spot on, it would be very easy to get things a few thou out. That shouldn't bother me as I am making my own square bar.

Over the last year or so, I have made this engine dozens of times, in my head. Up to now, doing it physically has come out exactly to my expectations.

Bogs

[kvom]

My current thought is to use round stock as well, but to mill the square flange before drilling the 8 holes.