A precision tool from junk

[bogstandard]

Grab youself a bit of old steel tube.




Mount it up in the lathe and clean up the outside for whatever length you want, I made mine about 3" long.




Very gently, lock up your saddle, and carefully face the end.




Deburr the inside and very gently remove the outer sharp edge with a bit of emery cloth or W&D.




Part off the bit.




Turn the new part around and lightly grip it in your chuck, gently face the end and give it a good clean up. I put a large outside chamfer on it, to save this end being confused with the other, which is the working end.




You have just made yourself a perfect tube square that can be used almost anywhere a normal cheapo Chinese square can be used. They are very good for setting things upright in your vice jaws because they can be wider than a normal engineers square, and don't want to fall down into the gap.



Make up various lengths and diameters, you will find a use for them all, eventually.


Bogs

[Gerhard Olivier]

Made one of these - used 25mm solid bar and drilled a hole through. very handy on the mill. 

Gerhard

[Bernd]

Bog's

Very good bit of info for the newbie. IF he/she reads the thread.

One point though I'd like to pass along. Make sure your lathe is cutting straight and not a taper of a few thousands. So check both ends of your square to make sure it is the exact same diameter or it will not be square.

Bernd

[tinkerer]

  I think I have learned something from you fellas everyday since joining. I appreciate all of the information.

[one_rod]

At the place where I did my apprentice training we had some rather battered versions of these in the works stores, made from cast iron.
They were known a Circular Squares.

The instructor tried to send one of the lads on the course to the stores to fetch one, but he refused to go, thinking that "circular square" was another wind-up like "left-handed screwdriver" or a "long stand".

The instructor had to fetch it himself, just to prove it existed.

Happy days...




one_rod.

[crabsign69]

I think I have learned something from you fellas everyday since joining. I appreciate all of the information.

i too agree with this very good indeed quick set up     thanks   

[bogstandard]

I never said they were a new idea, or one of my own.

But it does go to prove with a little bit of ingenuity, good, and useable tooling can be made in a very short time, out of the most mundane bits.

These two only took about 15 minutes.

I just thought I would show how to do it, as I had a bit of time to waste at the end of the day.


Bogs

[GrahamC]

Excellent idea, I never thought of making one from a piece of pipe.

Mine was made from a scrap piece of leaded steel about three inches long and one and half inches in diameter with a bit of recess in the center on each end so it sits flat.

I will have to keep an eye open for a piece of scrap pipe and make another - very handy.

cheers, Graham in Ottawa Canada

[tinkerer]

I just thought I would show how to do it, as I had a bit of time to waste at the end of the day.


Bogs

I assure you, it was not a waste of time.

[NickG]

Good idea, could have done with this the other day.

[jim]

an excellent idea, i'll be making one of them next visit to the workshop.

just the job for the old column off a pillar drill 

best bit is, it'll be perfectly square!

best ideas are the simple ones, thank you

[GrahamC]

I made the one I have after reading a column written by Frank MacLean in one of the Village Press magazines, might have been called Projects in Metal at the time but now called Machinists Workshop or Practical Machinist. Frank's was larger than the one I made.

I couldn't remember what he called it so I looked it up this morning - he called it a Master or Cylindrical Square.

Very handy. My small one has served me well and I sometimes wish for a larger one - just need to get round to it.

cheers, Graham in Ottawa Canada

[psp]

Note to motorcyclists:  Bent front fork stanchions are available vey cheaply! The bottom end (from inside the fork leg) won't be bent.  Easy source of precision ground tube.

[NickG]

The thing is, for this it doesn't matter whether it's precision ground or not because you take a longitudinal and transverse cut at the same setting when you put it in the chuck to make it square! That's why bogs put a chamfer on the other end as that is not the working end.

Nick

[psp]

NickG
As Bernd said in his post; "One point though I'd like to pass along. Make sure your lathe is cutting straight and not a taper of a few thousands. So check both ends of your square to make sure it is the exact same diameter or it will not be square."

[bogstandard]

If you want to split hairs, if your lathe turns tapered to any noticeable degree, you shouldn't be using it to turn metal anyway.

If it is that far out, you should only be using it to cut brown stuff.


Bogs

[Davo J]

John,I would have to agree with Bernd and psp about taper.
Remember the wider audience that are watching this may have little or no experience, and may think their lathe is cutting strait right out of the box.
 It would only take a minute to measure each end, to check and be sure. That way they can rely on it to be square.
Dave
PS
I think you do a good job of posting these type of threads for the newer people starting out.
I have been trying to take pictures of my mill clean/fixup and other things, and find the camera to be a forgoten about untill I am finished a part and then I think I should have taken a picture of that on the way through. I find it does take alot of extra time to do but at least you can show and help others with your ideas.

[John Hill]

You could do a (crude?) check for taper by making two of these cylindrical squares and placing them side by side and touching on a machined surface (top of your cross slide maybe?) with a light behind. If your lathe is cutting a taper you will see light between the 'squares'.  The amount of gap between the squares will be twice the taper.

This test will show that the spindle is parallel with the ways.

[NickG]

I agree with John, You've got bigger problems to worry about if your lathe isn't cutting straight!

I'd like to think if you're making something intended to be square, it goes without saying that you are going to do some sort of check on it. A set square would be the obvious way to me.

[John Hill]

A set square would be the obvious way to me.

Yes if you can have confidence in the set square,  if you cut turn two cylindrical squares the error in one will add to the error in the other and be twice as easy to see.  If there is no error you can be sure they are at 90 degrees, however if the set square test shows no error that just means the cyclindrical square is the same angle as the set square so they might, conceivabley, have the same error.  Or you might find an error indicated by the set square then how do you know which is faulty?

[Bernd]

It be would just like getting a flat surface. It would take 3 surface plates to get one perfectly flat surface. The plates are worked against each other. The same can be applied to finding the perfect square.

Or it would be handy to know somebody that has an optical square.

Bernd

[ozzie46]

Or it would be handy to know somebody that has an optical square.

Bernd

   Uuuhhh Optical Square?? Please enlighten me.

  Ron

[Bernd]

I'm going to need to do a bit of research on this and see if I can find pictures. Much easier to explain.

I'll be back on the forum later with some answers I hope. Need to do some honey do stuff first.

Bernd

[Bernd]

Ozzie46,

Back about 25 years ago when I worked for a leading gear machine manufactureer I learned first hand about the optical flat. The company not only made gear cutting machines but also produced their own cutters. Without going into a lot of detail I'll give you a quick short version. The cutters needed to be held to diameters of 50 millionths. The tool room, were my dad worked, made gages for checking the cutters. Well in order to set up the gages you needed a fixture so you could set up the gage accuratley. The fixtures needed some of the parts to be as flat as possible after lapping. The only way to check that is to use an optical flat.

Now this is the best I could find on the net for a discription of what I remember as an optical flat. Optical Flat Here is a google link to a few more pics that may be of interest on optical flats and will help you understand how they are used. Google Pics

Now for the optical square. I have a picture of something that an optical square was used on. I'll post that at the end.

Now for the  optical square. This is the best I could find on short notice. Optical Square. If I remember right this is close as it going to get. It's the 5th picture to the right at the very top. Click on it and it'll give you a discription.

Now here's what I have from that tool room. The guys that worked nights made these as a project for themseleves plus a few extra. It's lapped "almost" perfectly square. It's the middle square with the rounded out inside corner.



I hope I've not made it to difficult to understand. I've played with optics before and it's a whole nother hobby that you can get into.

If you have any questions, ask, I'll see if I can answer them or find an answer.

Regards,
Bernd

[ozzie46]

  Thanks Bernard, Very interesting. If I ever start building Starships I may need to know how to use one. 

    Ron