Thread: Metrology Tools

Now that I have a lovely granite plate in my shed (thanks Greg and John ) I need to buy or make some metrology tools. (I am new to machining so have limited stuff)

I think my plan is to use the mill, lathe and surface grinder to make some bits - squareness comparator, 123 blocks and possibly indicator holders. In order to make measurement tools it appears I need measurement tools (chicken and egg) to ensure accuracy.

How would you peeps suggest I proceed? Are there some basic measurement tools I need to buy such as indicator holders, angle plate, height gauge so that I can make other stuff? I have a few indicators although I cannot recall if they are tenths (or the real world equivalent - 0.001mm?). I cannot throw a huge amount of money at this hence the desire to make stuff (plus its fun and interesting).

Where would you suggest I source the bits you think I need? There are plenty of places selling the Chinese Vertex brand. I have nothing against Chinese as long as its accurate. Anybody got excess bits laying around that you want to sell?

Any thoughts appreciated as I am a little lost.............

A surface gauge, good test indicator and granite plate will allow you to measure for geometric accuracy. Add gauge blocks to that list for measuring dimensions, but for most projects you could just use micrometers. you can make a lot of things with a few simple tools once you have a flat plane to measure off. checkout Oxtools and stefan gotteswitter on youtube, i think one of them has a video that deals with this sort of measuring.

Some reading material
https://www.google.com/url?sa=t&rct=...Lidd3cuDoybG6P

Some good videos

https://www.youtube.com/watch?v=-lgMcDOkeg8
https://www.youtube.com/watch?v=4F-bUiyFmWc

Vertex make good stuff for the price, but I wouldn't go there for everything; indicator holders, angle plates and the like are fine, their dial indicators are definitely a step down from the Japanese and Swiss made stuff.

Also, ebay is your friend. I've built up a collection of really good quality stuff from there.

Thanks for the videos - I have pretty much worked thru Tom's archive. He has some great stuff.

Making a squareness comparator is possibly first on the list but it is useless without a standard to set it to. As I said above, I feel I need a standard that is accurate from which I can make other tools. It would seem that a cylinder square is what I need. Is there anywhere in Australia that sells decent cylinder squares or will I have to go overseas (at the current exchange rates ahhhhh)?

I have considered making a cylinder square from a 130mm round of 4130 that I have but at the end of the day I am not confident that it would be accurate enough to be my master - best to purchase that!

I found that the magazine Model Engineers Workshop is an excellent magazine for a hobby machinist. It has tools and other interesting articles to make, pretty sure that a recent article had an article on making a squareness comparator.
If you're ever up Murray Bridge way, I've a great stack of them, probably going back 7-8 years, that you can borrow.
As for a cylindrical square, I've been told a gudgeon pin from an engine is ideal. The Gudgeon pin is what holds the piston onto the conrod which goes onto the crankshaft. Finding one 130mm long might be a bit hard.
Kryn

Originally Posted by Mk1_Oz

Thanks for the videos - I have pretty much worked thru Tom's archive. He has some great stuff.

Making a squareness comparator is possibly first on the list but it is useless without a standard to set it to. As I said above, I feel I need a standard that is accurate from which I can make other tools. It would seem that a cylinder square is what I need. Is there anywhere in Australia that sells decent cylinder squares or will I have to go overseas (at the current exchange rates ahhhhh)?

I have considered making a cylinder square from a 130mm round of 4130 that I have but at the end of the day I am not confident that it would be accurate enough to be my master - best to purchase that!

Check out this video from Tom that shows how to use a squareness comparator to test for square without already having a standard.

https://www.youtube.com/watch?v=aFBZFComFQc

Steve

Thanks for the offer Kyrn.

Originally Posted by KBs PensNmore

I've been told a gudgeon pin from an engine is ideal.

I had thought about a piston pin from a large diesel but I would then be in a position of not knowing if it was ground exactly square or not until I make my squareness comparator. I'm sure CAT or other diesel specialists would have some. Some CAT engines have 170mm+ pistons so a 130mm pin should be easy to come by. I may ring CAT at Gepps Cross tomorrow.

The subject of using Gudgeon Pins as Cylindrical Squares was covered in this thread https://metalworkforums.com/f65/t204...ndrical-square

You should note that a used pin will not be round or parallel and the ends will definitely not be square to the o/d so unless you have access to a cylindrical grinder they are pretty useless.

As Oxxandbert says Check Tom Lipton's video. You dont need a standard just a block of steel with two parrallell surfaces.

You will also need a 36inch camelback....I am thinking about selling mine.