I got the stainless SHCS's and washers on Friday, so today I worked on taking the washers down to fit the recess they'll have to fit into. And just for documentation purposes I'll describe that process.

The washers measure .270" ID and .498" OD, but need to be turned down to .432" to fit in the .438" recesses. However, with the ID being larger than 1/4" they won't center on a 1/4" shaft. So I needed a mandrel that is about .267" OD onto which to mount the washers. And, since I want to turn 24 washers down to ensure I have enough I'll need 1.25" of length (24 x .052" = 1.250"). And, it would need a 1/4-20 threaded portion on the end for a nut. A bit of scrounging found a nice rod .310" in diameter - perfect.

So, as I was about to start I realized that the teens from church were to come over tonight, and this would make a nice project for them. But, for them to understand what we are going to do I'll need a drawing. Ergo:




As it turned out, the teens didn't come over as several of them had homework (their parents said) and others came down with the bug that's going 'round. So, I made the mandrel. Then I mounted 24 stainless washers, one plain washer, and a nut on it and mounted it in the lathe:




And then turned them down to .432". (The nut didn't seem to fit the wrench any more) :




And here's how it fits in the counterbore in the test piece:




Next up, some valve covers with a counterbore or four.

 

Got the counterboring done on the valve covers. They are .200" deep, which still has the heads of the cap screws sticking out about .1". Here are a few pics, but I have a question: Should I bevel the edges of the counterbores slightly? (The little bit of a lip will go away when I sand the top to get the brushed-aluminum look back.)

 

I would just use a deburring tool.
But then, I don't know how much sanding you are going to do, and with what grit.

A belt sander would be nice.
You wouldn't have all those little random swirls.

 

Yes, I think the belt sander is the way to go. Good idea.

For the edges, I was thinking about just rounding the edge a bit.

 

I think they need to be beveled some. Something about it just doesnt look right as they are. Maybe that will improve the looks.

 

They look odd above the surface when everything else is slightly below the surface. I think you should sink the head a little below to match the design.

 

Let me do two things tomorrow before counter boring further. Let me clean up the edges of the holes and mount the covers on the engine. Then I'll take more pics for your viewing pleasure.

 

Chamfer around the holes is going to end up showing the colored powdercoat, no?
In that case I think the chamfer should be deeper so the bullseye can compete with the other border on the valve cover.

If that is the case, maybe the head -should- be flush.
It will show about the same amount anyhow.

Try it on that scrap aluminum first Gary.
I'd like to see what it looks like with paint in the recess.

 

Jim - Thanks!!! That's something I'd not thought about. The walls of the counterbore will, indeed, have whatever color (OFB or black) the covers get. And chamfering the holes will enlarge the circle of color as well as allow you to see the wall's color better. I hadn't thought about that.

Ok, I'll play around with the piece of scrap. The edges of the covers are rounded, so I'm thinking a rounded entry to the hole would be appropriate to match. Not sure what I have that will do that, but I'll see.

 

The border "line" is a flute, not a "round over".
I think even a straight 45 would be fine.
But it looks like you will be getting into the side by the time you make that recess anyhow.
You will want to radius and soften that tangent before you do the PC.

I think MOST people will notice the color, not the shape so much.

 

Time for an update. And, so's the questions aren't buried in all of the pic's, it boils down to two:

1. Do I chamfer? As you'll see, any chamfer gets close to doing away with the aluminum at one hole on each cover.
2. Do I drop the counterbore so the heads are flush with the top?

Now for the details. Jim is right about "getting into the side" as the right hole on each cover is very close to the edge. Here's a pic of the close one on the left and the wide one on the right. As you can see it won't take much chamfer to do away with the line, although the more sanding I do the more line there will be. Also note that the hole on the left has no chamfer and the one on the right has a very light 45 degree one put on gently by hand.




I left the black cover w/o chamfer, sprayed the top and holes black, and then sanded back to aluminum - with the palm sander as I don't have a fine grit belt for the belt sander. And then I cleaned all of the sanding gunk out and the paint on one hole came out. Can you tell which? I can't - and it is even hard when the screw is pulled and I put a light on it. (It is the one on the right.)




Well, here's a closeup of the rear hole, which is the one w/o paint in the hole. Can you tell?




Ok, now to the blue cover. This one I chamfered lightly with a 45 degree countersink - by hand, which explains why one isn't even. Then painted it, sanded, and cleaned it. And on this one the paint stuck in the holes.




Here's a closeup of the one that's close to the edge and you can see that there's a ring of blue. So, a bit more chamfer, done on the mill so it'll be even, would give a little bit of color showing around the head.

 

And, just to confuse, here's another look. Nothing changed except the perspective. Here you can see the the top screws poking out about 1/8" as well as the other screws sitting on top of the cover's flange. I kinda like it, but what do y'all think?

 

I think it's silly.
Widen it up to approximate the line -border- and blend it into the side, so the color continues around and sets off the bolt head.

You might try just painting it in with a brush or q-tip to get a feel for what it *could* look like.

 

Jim - Please help me understand what is silly. The detail? The question about depth of the head? The chamfer? I'm just trying to understand.

And, just so we are on the same page, my last post was trying to say that I'm happy with the depth of the head as is and a light 45 chamfer to leave no sharp edge. I'm ready to move on but was trying to please everyone. Or most, anyway.

 

The most important thing is to please yourself. It's your project. Do what makes YOU happy. Nice work btw. I love the old Motorsport logos.