Chips are a flyin'!

[Locobob]

Sounds like you are being way too aggressive with the cutting bits if you are punching through that fast. I like to switch back and forth between cutting bits and sanders throughout the process - helps with keeping the dimensions even and the work consistant. I'll work a runner with a bit for a minute or so then try to do the same thing to others. Then I use a sanding drum to smooth out the surface. After that I measure the worked areas with a telescoping gauge to see where I'm at. Rinse and repeat.
You should be concentrating on the short side radius of the curve - not the outside. You want to straighten out the curves as much as possible. It's also an easier fix if you go through on the underside as you don't have to clean up the welds perfectly.

[Paul Workman]

Originally Posted by Locobob

Sounds like you are being way too aggressive with the cutting bits if you are punching through that fast. I like to switch back and forth between cutting bits and sanders throughout the process - helps with keeping the dimensions even and the work consistant. I'll work a runner with a bit for a minute or so then try to do the same thing to others. Then I use a sanding drum to smooth out the surface. After that I measure the worked areas with a telescoping gauge to see where I'm at. Rinse and repeat.
You should be concentrating on the short side radius of the curve - not the outside. You want to straighten out the curves as much as possible. It's also an easier fix if you go through on the underside as you don't have to clean up the welds perfectly.

"Too agressive"... Yep! My first time porting with aluminum - always done it on cast iron before, so the first couple of holes brought on some "wholly chit!" moments. I think that is behind me now, but a less aggressive, 4" shanked bit would be to my liking, especially when I get to the IH & heads!

Thanks for the input! (And I do have some snap gauges that I'll put to use!)

P.

[Paul Workman]

Originally Posted by A26B

What method are you using to keep the port centerline & spacing to spec?

To maintain the initial centerline at the port opening, I scribed a circle using the 36mm gasket as a template. "Coloring inside the lines" has been a little challenging.

As far as maintaining the centerline throughout, with the exception of the first couple of runners, I'm actually attempting to straighten the line a bit - more to avoid getting too close to the outside radius, as much as anything.

I figure that (within reason) nothing on the plenum can't be filled and re-ground if necessary. So, except for a couple of initial "boo boos", it hasn't been bad at all (and getting better!).

First time for everything, and I have 16 "tries" to break out of rookie status before I move onto the IH. It's coming together now, and I don't feel the least bit intimidated...yet.

P.

[Pete]

Originally Posted by flyin ryan

similar to that but single cut, not double cut. will be an SE-6. i get mine from Quality Carbide Tool in Elk Grove, IL. tool # 170171.

Yeap,that's it with what flyin ryan said single cut.

Ryan thanks for info and part # need to get a new one.
Elk Grove is next town over from me.

Pete

[Paul Workman]

Originally Posted by Pete

Yeap,that's it with what flyin ryan said single cut.

Ryan thanks for info and part # need to get a new one.
Elk Grove is next town over from me.

Pete

Yeah, I wanna try it too. I'll grab one today, time permitting!

Much as I hate Chicago (or any big city, for that matter - congestion and traffic and crowds n all, and did I mention traffic?), the outlying areas in N. IL are a Mecca for ZR-1'ers. Buncha hard core Z drivers up there!

P.

[LGAFF]

I am using a gasket set to center as well, I know it may not be ideal, but when you measure the stock ports there is a wide variation to ports size, etc. I measured the primaries on the current set I am working on at the head surface and they varied from 31.25 to 32.7MM.

[A26B]

Gasket is good if it's OEM (or mine:wink) only saying that because those are the only ones I am certain that are made to spec. Others may be copied from gaskets.

In addition to port dia variance, there is core shift in the castings so ports often to not center in the gasket, as you have probably noticed.

It is a tedious job! My hat's off to you!

[Zr1 Destroyer]

You need a Bridgeport.....makes porting a snap!

[XfireZ51]

Be still my heart.

[Paul Workman]

Originally Posted by Jagdpanzer

Pete,
You mean like this type?


http://www.ruffstuff.com/pages/carbide.html#cut

Can you tell us what shaft length you find works best?

Starting on the yellow brick road with the link you gave, I ended up at Fleetwood Industrial Supply Corp in Addison, IL (800-321-5288)

(OSG) 906-6250, SE-6 5/8" dia. x 1" long, oval, fine (single) cut flute, standard 2" shank @ $19.68 ea.

SE5L6 = 1/2" dia x 7/8" long, oval, fine (single) cut flute, 6" shank, @$24.90 ea.

These appear to be very nice, well made tools! (I'll put them to the test today.)

With that I got both the OSG and Fleetwood catalogs - great reading.

FYI,

P.