Measuring and grinding a V block for a suburban master grind

I purchased a suburban master grind awhile back and unfortunately it didn't come with the v block assembly. I ended up purchasing the v block from suburban and it states when buying that finally fitment is necessary. Okay so I mounted a pin gauge in the V block and did some measuring. Of course every measurement I take has like .0002 variance. I am pretty new to this but from my understanding this thing needs to be perfectly centered within the master grind or whatever you grind will be off.
My questions are am I measuring this the correct way. The V block needs the sides ground only so that's it's centered in the groove of the face of the master grind. The height of block is adjusted by slots on block. Here's my setup for measuring. Tenths indicator pin lightly clamped in V and taking measurements from the sides.
image.jpegimage.jpegimage.jpeg
My problem is the first picture I have .0003 difference from left to right,how do I know if pin is placed correctly in V. I've read that the hold down is touchy when locking down a part ,can shift part.
Now if you take the 1st picture and flip it 180 and measure pin it is .0002 off from 1st measurement which tells me the pin or V in block is pretty dang close to center. I just need to take equal amounts off each side so it stays that way but get it down to near 0.
In the third picture I'm getting a .0002 difference left to right.
I've been able to research and find one person talking of this same task on another forum. A experience grinder was talking about grinding the V block to fit and was getting a .0001 difference when spinning the fixture. Unfortunately you really only get one chance at this. Can't take material from one side and put back on the other.
So what would be the steps a knowledgable person would do to complete this job. Let me hear it. Thanks and this is what it should look likeimage.png
 
I've done a lot of grinding in the past down to the millionths for dies and such . You first need an accurate pin . Reamer blank , deltronic , large gage pin etc . Clamp in your vee and locate off the pin on top of a ground angle plate . Get both sides the same . ( you say you're .0002 off side to side ) which ain't too shabby . Dust the .0002 off the high side and then measure the overall dimension . Split the difference for what your mounting plate needs . Then you're going to need that angle plate to grind it square .


I had to grind a titanium cube for NASA years ago . Space flight material so it had to be perfect . Overall tolerance was .0002 . Perpindicularity was .0002 . Parallelism was .0002 . Bores going thru the 6 sides true position was .0002 mmc .

The job drove me to drinkin ! It tested the inspectors as well as the cmm back then . We finally inspected the cube on one of our Deckel Jig Grinders .
 
Just read what Bob Korves wrote . He is definitely correct . Better have the ducks in a row cuz it's a 1 shot deal . I had my Sine-a-dex down to the millionths . I sold it some time back but I still have gobs of nice grinding accessories laying around . If you could use any of it , shoot me a pm .
 
I think part of my issue is the unknown precision of the tools and tooling I have. Ive bought 90% of my tooling from auctions and stuff. All in really good shape just let say used. I’m gonna need to inspect my toolage and get a little more confident of my measurements.
So what is being suggested is to fasten block to a angle plate than zero part and grind. I originally was gonna put block on mag chuck grind one side then flip. The V block had pretty good support but I was gonna back it with a block to prevent tipping. So that’s how you grind a perpendicular plane is with angle block not just placing on chuck? I’m new
 
You need to grind 1 side of the block parallel to the vee slot first , then grind the other side to match the first . Then you can split the difference for the slot size you need . ;) Correction ……………...parallel ! Fixed .
 
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You need to grind 1 side of the block parallel to the vee slot first , then grind the other side to match the first . Then you can split the difference for the slot size you need . ;) Correction ……………...parallel ! Fixed .

So if sides or one side is already parallel with V then just a matter of getting to final size.
If not parallel to V then I need to use angle plate align V block to zero make one side parallel and then bring to size.
 
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