Need Help Blueprinting A Part

Izzy

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Hey guys, I have a few parts from a car project I'm working on and I'd like to recreate old cast iron parts from aluminum to reduce weight, one of the most difficult parts (or atleast most difficult in my eyes) is the steering knuckle and I'm having trouble figuring out how I shoukd go abouts measuring and blueprinting it? Only thing I can think of or see to use as a nice flat refference surface is the front face of the bearing bore.
Any ideas on how I can accurately measure all the different angles, hole placement, and tapper is another thing I'm having troubles measuring any adivce is appreciated! There's a couple pics of the part, I can get more if need be.IMG_20161028_144853.jpg IMG_20161028_144904.jpg
 
That will take one large block of aluminum to make. I'm thinking everything should be measured to the bore of the bearing. That might require an insert to put in place of the bearing. Could be built with a shaft attached to it to measure from or have a hole like the bearing and then build a close fitting dummy shaft to insert to measure from.
A lot of the Gm's have aluminum knuckles. Have to wonder if one of those could be fitted.
 
@rgray this is for an older heavily modified Japanese car there are no American cars that will have anything that works for this without me extensively changing the rest of my pre-existing set-up. I didn't even consider how difficult it would be to track down a 1foot cube of aluminum I think I may have to cast my own cube unless someone knows where to get something that size?
I never considered Using the bearing bore to measure from but this deffinetly might solve my problems I'll have to explore this option a little deeper!
 
As far as reference surfaces and blueprinting goes, would it be in my best interest to have a reference surfaces for each axis? Sorry for the noobie question but I'm not overly experienced in this sort of thing
 
You need a minimum of a surface plate, height gage, a precision protractor like a Starrett 356, and maybe a machinist square. In your first picture posted, use the back side as your datum for plane "A". This surface would be against the surface plate. Now the rest of it would be by taking precised measurements, every thing referenced from the surface plate. May require making locating pins to put in the different holes as shown. This is not an easy task to perform for someone that doesn't have good equipment to work with. Ideal would be to find some one with a CMM that could record coordinates for all of the points/planes on the part. There are companies out there that do this kind of stuff every day, even for automotive parts. Ken
 
@rgray I didn't even consider how difficult it would be to track down a 1foot cube of aluminum I think I may have to cast my own cube unless someone knows where to get something that size?

I wouldn't try to cast my own block of aluminum for a part that's critical to personal safety. A home foundry does not lend itself to proper control of all the parameters required for good metallurgy. You're looking at casting a 170 lb. block in a single continuous pour.
 
With what RJ said, I strongly do not believe that is a cast iron part. More than likely, it is cast steel and is heat treated to a degree of hardness. I don't believe 7075 would give you the strength needed for that part, even if it was forged to that shape. There's a reason it's made from steel.
 
How about a functionally equivalent weldment? Also, you might want to make your replacement much beefier anywhere that there's room for more material: it doesn't have to look exactly like the part it's replacing.
 
@4gsr ive got those tools I've just never done anything this complex I've done alot more blueprint reading than I have making my own but I'd much rather do it myself and learn something in the process and maybe even expand my tooling that part itself is cast iron same stuff they would use for the block. What it's made out of doesn't really matter tho I would just like to remake it in aluminum there are aluminum automotive knuckles so I know it can be done I was planning on having a steel sleeve splined and pressed into the aluminum knuckle for the bearing.
I deffinetly plan on making it beefier but still have to keep the holes in the same place and on the same angle
I wouldn't have thought 12" cube of aluminum would be that heavy! What are my opyions with that if any?
 
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