Thread: Small Fixture Blocks

Double Checking Square with DTI. this is the bad edge one reads 0.09 the other 0.13 so I will use 0.02mm shim under one edge and back on the grinder.
DSCN2574.jpg

Posting in real time. so if you spot a mistake pipe up..

-josh

Block A blued and shimmed and ready to

DSCN2576.jpg
Light Pass you can still just see the 9 under the blue
DSCN2577.jpg
Opposite side ground as well and them tested again
DSCN2579.jpg
This time it is ok. some faces better than 0.005mm others within 0.01mm, I'm fine with that. Time to do the next Block. Then dimension the three faces.

Hi Josh,
Looking good so far.
which holes will be threaded? Just the vertical ones in your drawing?

Stuart

p.s. you need a curved piece of steel like RC is using. (well so I'm told )

Originally Posted by Stustoys

Hi Josh,
Looking good so far.
which holes will be threaded? Just the vertical ones in your drawing?

Stuart

All holes will be threaded M6 apart from the counterbored ones. I'm toying with the idea of reaming them to 8mm to accept standard shouldered m6 capscrews.

I think I might have missed something.... What needs to be curved and why?? :S

I should also mention that these are part of an extended fixture setup. all based on a 12.5mm grid of alternating counter bored to M6 tapped holes.

If it works out ok I will make.

Setup Blocks
4x 300x50x50
4x 150x50x50
6x 100x50x50
8x 50x50x50

Setup Plates
1x300x300x25
2x300x150x25
2x300x100x25

4x 100x100x100 V blocks
8x cylindrical stops/stands

Plus others as I need them..


I have a drawing with them all on there. I'll see if I can dig it up..

-Josh

Dimensioning Three sides take a bit longer,
The blocks after squaring where at ~ 44.07x44.58x44.90mm

all side are now down to ~44.05 now just to take off the last 0.05mm and check..

I do the last 0.05mm by dressing the wheel getting close to the block with some blue on. just start to take of the blue but no metal and set the down feed for 0.05mm in 0.002mm steps. when the down feed stops, I demag deburr and rotate 90 degrees and leave the stop where it is, repeat once more and check.

I'm doing this atm will post pics with DTI

Originally Posted by Brobdingnagian

.... What needs to be curved and why?? :S

Thats sort of what I said.

RC's posts will reveal all.

https://www.woodworkforums.com/f65/yo...ml#post1607237

Stuart

Hi Josh, Stuart,

Stuart's already referred to this post, but I'll re-quote it in full...

Originally Posted by RC Block Measurements

Here you go Stuart, this is where I borrowed the idea from.

How To Check A Block For Squareness - YouTube

The 1,2,3 blocks I have are a bit small for this block, plus are an unknown quantity when it comes to squareness..

Also I was just wanting to see how good I could get it, the side with the two lapped feet is actually according to the indicator dead nuts on...

I think the curve is better for this sort of application as you are rolling the indicator onto the work.... With the ball method or two point method with a 1 micron indicator I found just hitting the work against the dial gauge with that bit too much force moved the indicator that smidgen amount and stuffed the readings up...

With this precision you need consistency, even down to where you hold the block for rolling, hold it too high and I was inadvertantly pushing the top in just that small amount according to the indicator...

I also checked with my tesatast 0.0001 test indicator and went very close to confirming what the dial indicator was telling me...

RC's said it perfectly... The care needed to get micron level consistency is daunting... When Joe was here last Saturday and we were mucking about with the HP Laser, just pushing on the plate was sufficient to flex it by a micron ( actually it measured the flex as 36 millionths, 0.91 micron)


Regards
Ray

Originally Posted by Brobdingnagian

I do the last 0.05mm by dressing the wheel getting close to the block with some blue on. just start to take of the blue but no metal and set the down feed for 0.05mm in 0.002mm steps. when the down feed stops,

25 passes to take off 0.05mm?(you dont have a 45mm wide wheel do you?)
You guys are going to need temp controled coolant soon!!

Stuart

p.s.

Originally Posted by RayG

0.91 micron

Hi Josh,
Like the idea. Are you planning on case hardening the "real" ones?
Just don't go out at lunchtime tomorrow and re-check in the heat of the day.....

It does not take too long. Just keeps the wheel wear a little more predictable when used with a fast cross feed (about 50% overlap).

Originally Posted by Brobdingnagian

(about 50% overlap).

Didnt even think about not being HSS, I just assumed my "default" crossfeed of about 0.5mm lol
50% overlap would speed things up nicely

Stuart

It's just low or medium carbon steel. I will need to case harden it after drilling then regrind. I just need a perfect cube to minimise error for drilling and since I have never made a cube before I thought it would be good practice.

Originally Posted by RayG

Hi Josh, Stuart,

Stuart's already referred to this post, but I'll re-quote it in full...

RC's said it perfectly... The care needed to get micron level consistency is daunting... When Joe was here last Saturday and we were mucking about with the HP Laser, just pushing on the plate was sufficient to flex it by a micron ( actually it measured the flex as 36 millionths, 0.91 micron)


Regards
Ray

Just a thought, but here is how I do it. I roll on to the indicator off the parallel that im using. I then also run the work piece along the parallel to see if I have any dust on the work piece or the parallel if I do I see that as an change in the reading, either that or my work piece has a twist or the parallel is not parallel, both of which wont help me find square.
-Josh

PS. I like the idea, and will have to give it a go.