Kiwi Conrod

[vcutajar]

Hi gents

I am working on my Kiwi conrod. Today I drilled and tapped the big end where the bolts will hold the big end cap. The next step should be to saw the big end but I am having a little difficulty how I should do it.

I was thinking of marking a line through the centreline of the big end and saw 2mm away from this line and then mill both halfs of the big end. As I have never done this before I can't imagine how the holes for the bolts will remain aligned. I do not know if this description makes any sense to you.

Is there a particular way I should do this?

Vince

 

[arnoldb]

Hi Vince

I'm not quite getting your problem ??? - so my advice might be wrong.

If it's the big end in the last photo on your build thread, what I'd do is saw through like you describe, and clean up the faces. If you have a slitting saw and can set things up rigidly, you won't even have to clean up the faces; a good slitting saw makes a very tidy kerf, in which case you must slit leaving the end of the con rod side exactly to length on the center line (offset the saw to the cap end of the line so that it will remove material from the cap side and leave the rod to length).

Then drill out the threaded holes for the necessary bolt clearance in the cap side (I'm assuming the bolts will go in from the cap side), and bolt the lot together like it would be installed on the engine.

Then pick up the center line; your crank hole must go exactly on the split between the con rod and cap, and carefully drill out and bore/ream for the crank hole. You'll have to figure out a way once again to hold the rod securely for the process. Don't be greedy about opening out the hole, as the bolts' clamping force is not that great.

Hope this lot made sense...

Kind regards, Arnold

 

[smfr]

You might want to read this thread to find out how not to do it

http://www.homemodelenginemachinist.com/index.php?topic=18463.0

 

[vcutajar]

Thanks Arnold and Simon

Arnold what you say makes a lot of sense. I guess what happened is that I saw Simon's mishap this morning and I panicked. I must be creating a storm in a teacup.

Simon I hope you can fix your conrod.

Vince