I've read a lot of information about getting my flat tops milled for hi-steer arms, but I have found a lot of conflicting advice... my question is: What is the proper way to mill the knuckles?

I have read that it is proper to:
-Mill the top perpendicular to the spindle mounting surface
-Mill the top parallel to the ball joint holes
-Mill the top 80* off of the spindle surface
-Mill the top 10* off the ball joint holes

Also, when drilling and tapping the holes... I assume you just have to drill and tap perpendicular to the surface you have milled?

When people refer to the stock 10* OEM flat top (i.e. the driver's side that already has steering studs)... which direction does that angle point? Is the spindle side taller than the ball joint side? Or is it the other way around?

I can't find any really clear answers to these questions and I'd really like to know if any of y'all know!

 

Read this he does a good job explaining some things.

http://77cj.littlekeylime.com/flatop_knucles.html

Hope it helps and keep me updated on what you find out. I need to mill mine soon.

Looks like you are suppose to mill an angle away from the balljoint?

 

Zach, I just read that and didn't see anywhere that it mentioned the milling surface angle... Only that it said that if you mill it perpendicular to the spindle mounting surface, you can remove some of the material surrounding the ball joint and weaken the knuckle... where did you read about the steering arm surface?

 

Give a call to parts-mike.com, he did my milling on my knuckles, im sure he would be cool with talking to you about it, he was more then helpful to me. He also has killer prices on the machining too.

 

I got a reply from an email I sent John Nutter (recommended by that Mr. N that Zach's website belongs to) and this is what he told me:

Kyle,

10 degrees is correct. You can verify this very easily by putting a
carpenters square on a Chevy driver's side knuckle with the steering arm
removed. I only machine knuckles to GM (Chevy) specs. I machine
passenger side knuckles to be a mirror image of the driver's side. Most
arms work with this.

Are you sure the 10 degree corrected arms refer to the angle the knuckle
is milled at? I always thought that the arms were meant to mount on
correctly milled knuckles and the angle correction meant they tilted the
tie rod end of the arm 10 degrees to minimize angles on the tire rod
ends themselves. This would have to apply to both side equally to do any
good. I would suggest you check with your arm manufacturer to find out.
I would not buy any arms that were meant for anything but machining to
the correct GM specifications.

I hope this helps.

John Nutter

He charges $40 including return shipping, and his process is all CNC machined. I think I will probably be sending him my knuckle.

 

sounds good, i still dont really understand which way this degree is done? i guess i will jsut check my arms and make them like that.

my buddy is gonna mill them on his machine.

 

On my knuckles it looks like the edge of the top of the knuckle closest to the spindle surface is taller than the ball joint edge... so it slopes outside to inside.

 

by 10* ? interesting. I have never noticed before and i still dont understand the advantage to it.

I should be able to see with my arms I bought...

 

See I think the mill surface is supposed to be flat with my arms. Because they have 10* built into the arm for the TRE... or is that separate angle?

http://www.ballisticfabrication.com/...p_19-1248.html

 

The angle on the arms is supposed to put the tie-rod end at a better angle to itself under normal conditions I think. John said that the best way to mill the knuckles was with the 10* OEM slope. I can't say for sure why this is, but the powers that be at Chevy/GMC decided it was optimal.

 

lol ok Well I am just gonna do mine flat and hope for the best. unless the drivers side is something different. I have Ford F250 Flattops so who knows what Ford did then.

 

I used the service on e-bay to have two knuckles machined and have had very good success with them. They are about the same price as parts Mike and also utilize a CNC machine to do the mill work on it. So long as you use a reputable service you should be good.