Mk1* steering parts

[meduffer]

A quick machining question for the seasoned professionals. I'm working my way through the steering on our Mk1* and I've run into a snag. I just returned from a machine shop and my guy suggested thermal spray welding (which he does not do) on these parts to build them up without distortion and then machine them down. I suppose my question is, how much pitting is too much pitting? I don't think I should be messing too much with the geometry of CTL 36.
Thanks,
Mike Snetsinger
Whitby, Ont.

[Lynn Eades]

If it is bad, use it to profile a new one from something like bizaloy 80 (I'm no metalurgist) Something that work hardens. I had some done from something "300" I can't remember what it was. So far , unproven.

[charlie fitton]

If there was a constant edge of metal all the way around the cam...ie no pitting that has eaten all the way through (top to bottom) on the edge, I'd use it as is.

There would be little trouble to replace it later.

Funny - I was thinking about this this morning....anyone remember the MIMIC tracer? would a tracing device be capable of making a new steering cam?

[meduffer]

Bisalloy 80. Just looked it up. Sounds like really tough steel...
Use it as a pattern and make a nice new one - got it.
Thanks Lynn
There's ~ 2" of heavy pitting on one side which might be an issue. The rest looks passable. I think it might be felt when steering.
Thanks Charlie

Mike

[Lynn Eades]

Mike , we have a metalurgist on this site, just can't remember who it is. Some of the other guys might suggest a more suitable steel. The biz 80 work hardens (which is why I liked it)
The symmetry of the profile is important. The rollers should have a .001" clearance.
I think the clearance gives an indication of how accurate they were supposed to be.

I did have a few laser cut from the 250 or 300 or what ever it was, but I can't remember exactly what I used

[charlie fitton]

build up the missing section with braze, and file (patiently) the correct contour into the rebuilt sections.

use a template taken from the undamaged part of the cam, you should be able to get well within workable tolerances..

again - nothing that couldn't be re-done later

[rob love]

I worked on the steering of one of the museum's carriers a number of years ago. The cam had been overbuilt up with weld. I replaced the cam with one that had been buried for the last 40 years, and despite the bit of pitting, it worked out beautifully.

There is geometry to those plates that should not be taken lightly, a Lynn has pointed out. You could try and build up the effected areas, but don't over-do it. Or try it just as it is....I think you would be surprised at how well it works.

[meduffer]

Thank you for all the advice gentleman. I'm heading out this morning to look at a heavy belt / disk sander that needs to be rebuilt (inexpensive and can grind at 90 deg.). As suggested, I'll just take my time, building with weld, grind, etc. If need be, I'll use the contour from the other side and make a pattern. I'll post a picture of the finished product it's sorted out..

[charlie fitton]

Keep in mind that it's not a space shuttle, or a heart / lung machine. You are not going into Formula 1 carrier racing, and the fate of the free world doesn't depend on it.

This can be done "good enough"

f

[Hans Mulder]

I may have one for sale if I can get it off...