Want to buy a really accurate square

[Ped]

I didn't mention the laser level but you can buy one for a lot less than than £300.

So you're going to buy one fireball square and attempt to copy it? That no less work than making one from scratch.

You could be overthinking this. Use fishing line to get it square and long site levels to get it flat, throw in a bit of patience too of course. You'll get it as flat as it needs to be.

 

[eLuSiVeMiTe]

Laser levels arent particularly accurate and thats wihout taking into account laser line thickness.
Accurate enough for a chippie or builder though.

 

[Ped]

Yeah, they claim 0.3mm over a metre. But I'm guessing this thing is going to made from welded square tube and that isn't going to be that flat either.

 

[ned]

Cheers Ped, you have a point, I may well be overthinking it. However I do think I'll use them again.

I can use I-beam or channel also, I've run through all of them as possibilities. I went and looked at different sizes and the one that looked right was 160x80x6mm.

 

[daedalusminos]

I'll go ahead and call me stupid, but I don't understand what you did there, sorry. the device attached to the tube looks manufactured, do you have a link to it?

Sorry I should have explained....

Principal
The surface of a continuous body of water will (approximate) to a planar surface. Ok it's actually a spherical due to the curve of the surface of the earth, but at the scale we're talking near enouth to a flat plane.

Now if you take a piece of ''u" shaped tubing filled with a liquid, the liquid will settle and the surface of the liquid in each "arm" of the "U" will settle to the same level.
Now take 2 "U" pieces of tubing and join them at the lowest point, the liquid in each of the 4 "arms" now settled to the same level and dictates a planar surface. If you attach these pieces of tubing to the corners of your frame you can level the corners to eliminate twist. The benefit of this method over something like a laser level is that accuracy is not degraded over distance.

My jig was 2.7m long and I was easily able to maintain 0.5mm of level over that distance. The white device you see was simply a clip I 3D printed to attach the tube to the corners of my frame - I added a scale so that I didn't need to keep adjusting the volume of liquid in the tube. The choice of liquid is important...in this PVC tubing water was no good as it formed bubbles, I used concentrated screen wash but red wine should work well!

 

[Windy Miller]

Sorry I should have explained....

Principal
The surface of a continuous body of water will (approximate) to a planar surface. Ok it's actually a spherical due to the curve of the surface of the earth, but at the scale we're talking near enouth to a flat plane.

Now if you take a piece of ''u" shaped tubing filled with a liquid, the liquid will settle and the surface of the liquid in each "arm" of the "U" will settle to the same level.
Now take 2 "U" pieces of tubing and join them at the lowest point, the liquid in each of the 4 "arms" now settled to the same level and dictates a planar surface. If you attach these pieces of tubing to the corners of your frame you can level the corners to eliminate twist. The benefit of this method over something like a laser level is that accuracy is not degraded over distance.

My jig was 2.7m long and I was easily able to maintain 0.5mm of level over that distance. The white device you see was simply a clip I 3D printed to attach the tube to the corners of my frame - I added a scale so that I didn't need to keep adjusting the volume of liquid in the tube. The choice of liquid is important...in this PVC tubing water was no good as it formed bubbles, I used concentrated screen wash but red wine should work well!View attachment 144542

Very nice gadget and a very concise explanation. Your 3D printed brackets are brilliant!
Red wine does indeed work very well, it just makes the level smell weird.

 

[JonE]

I really like the fireball design I emailed him a while back asking about UK distribution nothing on the cards and shipping is costly from over there. I did find a UK company making something similar in design but smaller than what your after:

http://www.mig-welding.co.uk/forum/threads/fireball-tools-square-any-uk-equivalent.76388/page-2

have also thought about knocking up a larger design and having it laser cut myself.

I see that the same seller also has a 12" square now, I think that's new..

https://www.ebay.co.uk/itm/113055755436

Cheers, Jon.

 

[postie jon]

I recently made a jig to rebuild a GT6 body shell on. Obviously I wanted it as square and true as possible. I used liquid in a tube and let gravity do the rest....pics below should explain. I verified squareness by measuring diagonalsView attachment 144485 View attachment 144486

when we were repairing cars on the jig, the manufacturers recomendations were 3mm either side of a datum point.

 

[R-D-R]

I see that the same seller also has a 12" square now, I think that's new..

https://www.ebay.co.uk/itm/113055755436

Cheers, Jon.

So they do!

I'lll get one, ill be passing by their workshop Monday, cheaper and less hassle than me having one cut and the accuracy on the small one is bob on with my speed square which is enough for my fabrication skills

 

[normspanners]

I got an accurate square angle it was quite cheap-------- I cant remember now if it was 3-4-5 -------pounds feet or millimeters but it doesnt matter... really.

 

[ned]

daedalusminos hey, thanks for the explanation, i spent the last 15 mins reading it, the waterlevel bit was a revelation, a eureka moment, then i decended into confusion lol. I think I see what you are doing though, the tube in your pic, stretches from one side of your beam, to the other, and gravity dictates that the liquid will be level on either end, which you then use to say, okay, this beam is truly leve in space.

I dont get how it eliminates twist, though i do see that your device is really cleverly constructed.

I'm not that bright! It sometimes takes me a long time to learn things.

Here is my aborted 8x4 CNC table

I added a 10x5 sheet of 6mm plate and am going to use it as a level surface to build things on. Below we can see the square chew through the paint. I've never had a welding table before. I had to paint it cos its going to live outside.

I got the square today. I asked them to mark it as a gift, and in total I paid something like 269 euros. It's chunky enough that at least I feel like I got some scale for my money.

My plan is to build 4 corner squares, more accurate than the one in the background below, but similar in construction. I will then weld those into the corners of the newer, bigger table I'm building.

The steel resting on the square is 50mmx12mm bar, I need to go buy some. I'm not going nuts on these, I want them to work, not be pretty.

I spent all my wages on steel plate and the square. I am now totally broke.

 

[slim_boy_fat]

I spent all my wages on steel plate and the square. I am now totally broke.

But, you could have spent it on [many] worse things.

 

[ned]

yes yes, thats true. I spend 460 euros on steel plate, and I'm going to spend the same if not more on box section and I-beam in the month ahead. An expensive hobby for sure but its great to be outdoors building stuff again, weathers been glorious.

 

[daedalusminos]

I had a liquid filled tube at each corner, all 4 pieces joined together (you can see this in the firstfphoto of my first post). The surface of the liquid in each tube defines a plane - that's a twist free surface. Now adjust each corner of your frame to that same plane and it will be twist free.

 

[slim_boy_fat]

I had a liquid filled tube at each corner, all 4 pieces joined together (you can see this in the firstfphoto of my first post). The surface of the liquid in each tube defines a plane - that's a twist free surface. Now adjust each corner of your frame to that same plane and it will be twist free.

Yes, but one beam had a very slight 'corkscrew' twist along it's length, the corner-to-corner method wouldn't allow/compensate for that, would it?
Anything resting on the one beam might be sufficiently 'off' to affect the OP's needs for accuracy across the entire machine bed?

 

[DAPPH]

Sorry I should have explained....

Principal
The surface of a continuous body of water will (approximate) to a planar surface. Ok it's actually a spherical due to the curve of the surface of the earth, but at the scale we're talking near enouth to a flat plane.

Now if you take a piece of ''u" shaped tubing filled with a liquid, the liquid will settle and the surface of the liquid in each "arm" of the "U" will settle to the same level.
Now take 2 "U" pieces of tubing and join them at the lowest point, the liquid in each of the 4 "arms" now settled to the same level and dictates a planar surface. If you attach these pieces of tubing to the corners of your frame you can level the corners to eliminate twist. The benefit of this method over something like a laser level is that accuracy is not degraded over distance.

My jig was 2.7m long and I was easily able to maintain 0.5mm of level over that distance. The white device you see was simply a clip I 3D printed to attach the tube to the corners of my frame - I added a scale so that I didn't need to keep adjusting the volume of liquid in the tube. The choice of liquid is important...in this PVC tubing water was no good as it formed bubbles, I used concentrated screen wash but red wine should work well!View attachment 144542

Good choice in the screen wash the soap in it breaks the skin of the water ( meniscus SP? ) by making it wetter/ more penetrating , it will allow the water to climb up the wall of the tube so be very careful to consistently look at /take the reading through the same angle consistently .

I think Blue dyed methylated spirits is going to be even better as the meniscus should be even less for it is a spirit ( check before buying ) .. buy a half gallon bottle for a tenner at a horse equipment suppliers along ith a tiny funnel , they use it for cleaning & polishing show horses hooves apparently .

 

[jordan1]

Have you tried Chronos Engineering Supplies, I have used them before. I see they have these various sizes:-
https://www.ebay.co.uk/itm/Dasqua-9...693116?hash=item4d3b703cbc:g:ozwAAOSw7ApZ1R~y

They also have others.

 

[ned]

Aw man they look really nice, really really nice.
Pity I didn't see them, though the shape of the fireball square is a better fit for what I want to do.
More stuff to drool at though )

 

[Arclikeharrypotter]

The fireball square is designed to be clamped to where as that isn't.

 

[ned]

Looking again at those Chronos squares... there are models with flat sides and other models with bevelled edges.
Why would a square have bevelled edges please, and whats the purpose of the recess in the inside corner?