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Quality of Engineer's squares

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John McNamara07/01/2012 13:34:34
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1341 forum posts
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Hi all
 
Cylindrical squares have many practical uses.
 
In the setup below I needed to bore two holes at 90 deg to the two slide rods
Two cylindrical squares were first bolted to the table then the work clamped to them
some packing under the work to make it parallel to the table and the setup was done.
(I drilled then bored)
 
The second square is at the back and a little hard to see.
 
Cheers
John
 

Terryd07/01/2012 14:41:08
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1936 forum posts
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Posted by MICHAEL WILLIAMS on 07/01/2012 10:33:34:
(1) Squares with settable blades are quite common in inspection departments . The normal method of making the hinge is to use a fitted dowel pin as the pivot and a ring of usually three holes around with small locking screws . The stocks of these squares are often more chunky than than on workshop squares so that they can sit solid on a surface plate . The blade never works in a slot but seats against a half cutaway in the stock thus giving a solid against solid lock down .
 

MW

Hi Michael,
 
That parallels almost exactly my experience in inspection during my apprenticeship.
 
One question regarding the use of cylindrical squares. How would one check the internal angle of the square? Is it sufficient to correct the external angle and then check the parallelism of the stock and blade? Or is there another method I'm missing here?
 
It is the internal angles which are most useful for marking out in benchwork (both inner and outer side of blade) and these are what the flip over against a straight edge tests.
best regards
 
Terry

Edited By Terryd on 07/01/2012 14:52:00

Terryd07/01/2012 14:51:01
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1936 forum posts
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Posted by Nicholas Farr on 07/01/2012 12:05:48:
Hi, I also agree that the turn around test is the best method for general use. There are a couple of things to consider though, firstly using this method you are only checking the inside edge of the stock to the outside and/or inside edge of the blade, therefore you will have to either accurately measure parallelism of the inside to outside edges of the stock, or have a reference for the outside of the stock to rest onto which has a rebate wide enough for the stock to lay into, to at least the depth of the stock to blade sides. Also the reference edge must be reasonably flat and straight and square to top of the side you will scribe your test line onto.....................
 
Regards Nick.
Hi Nick,
 
in the 'flip over' test there are three to be carried out. First outer angle against outer angle which proves the angle correct at 90 . Then inner angle against inner which if satisfactory proves the parallelism and as a final check, inner against outer. Surely that automatically checks and confirms (or otherwise) parallelism of the blade. A long , shallow upright can then be clamped to your test edge and the outer part of the stock can be compared to the previous tests, or then use the cylindrical square to test the outer angle of stock/blade.
 
Best regards
 
Terry

Edited By Terryd on 07/01/2012 14:51:35

Douglas Johnston07/01/2012 16:01:55
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773 forum posts
34 photos
One thing I would like to see is the use of stainless steel for squares and other similar measuring equipment. I bought a stainless square a couple of years ago which looks like the Warco one mentioned earlier and it is a joy to use since it is very well made and does not need to be oiled to prevent rust.
The problem is the range of stainless items is very limited. The largest square I can find is only 100mm and I would like a larger one. If we can get dirt cheap hardened stainless steel calipers, why can't we get other measuring stuff in this material?
 
Doug.
Russell Eberhardt04/02/2012 10:48:53
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2751 forum posts
86 photos
A cheap source of cylindrical squares is old gudgeon pins from a car scrapyard. I have a pair of Rover 2000 ones that I have used for years. They are precision ground to a couple of tenths under 1" dia. and just under 3" long. I'm sure something bigger could be found from a truck.
 
Russell.
Mike Poole02/03/2019 21:55:16
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Moderator
3373 forum posts
76 photos

I spotted on eBay hard chromed piston rod for hydraulic cylinders up to 70mm diameter, not exactly cheap but a short length could make a couple of squares just for the trouble of facing the ends square. I would hope they are parallel and round to better than I could make. If you make two then they can check each other.

Mike

David George 103/03/2019 09:17:45
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1869 forum posts
505 photos

I have three cylindrical squares made when I was an apprentice. I wouldn't be without them but I have two Moor and Wright blade squares of similar age which get used very frequently. I also have a Starrett square set of centre finder and protractor.

20190303_074114.jpg

David

Hopper03/03/2019 12:43:36
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6603 forum posts
345 photos
Posted by David George 1 on 03/03/2019 09:17:45:

... I have two Moor and Wright blade squares of similar age which get used very frequently. ...

David

This seems to be the way to go very frequently. If you can find older tools and equipment still in good condition, as much of it is, even after 50 years or so. I've bought garage-sale M&W squares for $2 a pop that are still as good as new in use. Others that you see have obviously been knocked around, used do drive in nails etc (I kid you not!) and are best left alone.

Nicholas Farr03/03/2019 13:32:37
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3413 forum posts
1586 photos
Posted by Hopper on 03/03/2019 12:43:36:
Posted by David George 1 on 03/03/2019 09:17:45:

... I have two Moor and Wright blade squares of similar age which get used very frequently. ...

David

This seems to be the way to go very frequently. If you can find older tools and equipment still in good condition, as much of it is, even after 50 years or so. I've bought garage-sale M&W squares for $2 a pop that are still as good as new in use. Others that you see have obviously been knocked around, used do drive in nails etc (I kid you not!) and are best left alone.

Hi, unless you feel you need a good solid hammer to knock the nails in square! smile

As Russell suggests, I have had for a long time now, a few gudgeon pins from a lorry engine or two, that are in good nick

Regards Nick.

KWIL03/03/2019 14:37:05
3562 forum posts
70 photos

Cutwel sell hardened stainless steel squares up to 300mm x 200mm (usual disclaimer)

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