Screwfix Angle Divisor, how do you work out external angles?

[kilo_4que]

Hi guys, I bought this today
http://www.screwfix.com/prods/66588/Hand-Tools/Measuring/Carpenters-Measuring/Angle-Divisor

Thought its pretty good for internal corners, very easy to use but i dont understand how you actually work out external angles using this. Anyone pls help

 

[Symptoms]

kilo - I don't have one of these jobbies but would imagine if you loosen the sliding clamp, re-configure the tool so it looks like a letter Y, then use the open Y top to copy the angle. Read the measured °s from the scale.

 

[kilo_4que]

Aah I was wondering whether i would do this as the tightening screw actually comes off but the issue is, the angle slider would no longer be active as the parts that make it slide have been detached.

 

[gregers]

is there any instructions included????
or are you doing the normal 'bloke thing' and not bothering with them?.

 

[Symptoms]

kilo - I can just make-out that there are 2 sets of marking along the 'tail' of the tool, maybe one set is to be used for reading the internal angle , other for the external.

Now, if my earlier suggestion won't work hows-about copying the external angle using the abc in the diagram below (or abe)? Presumably you're using cde to copy internal angles. It's all about the geometry of the parallelogram bcde & it's (not the wall's) internal & external angles.

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• Symptoms
• 17 Nov 2008
• 1

 

[kilo_4que]

Lol gregers, no im one of thosethat likes to be safe than sorry. Problem is it come in a little see through packet with no instructions what so ever.

Symptoms, thank you for the reply matey. There are two sets of marking however they are not what you think. Basically the markins are parallel to one another and all they show is the actual angle and the angle halved. So if you work out 90 degrees on a wall, the 90 degress marking will have another marking next to it with 45 degrees maybe to make it easier when mitring or something. Still cant work out even from the diagram you have provided how to find the external

 

[morrik27]

Does it work if you flip the tool round, then slide it so it forms a 'T' shape:

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• morrik27
• 18 Nov 2008
• 1

just tried to put it into a picture, but not that good with paint (as you can see!

 

[kilo_4que]

Morrik you can just about make it into a T but you have to add a little force to do so in that as soon as it becomes an acute arrow like shape there becomes friction between the pieces.

 

[Symptoms]

kilo - it is possible to measure an external corner with your tackle, but you'll need to apply a little mental arithmetic. The reason is because your indicator is 'missing' a basic part, more about that later. How to use you tool:

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• Symptoms
• 19 Nov 2008
• 1

internal wall angle as per top right of my diagram then read the scale for angle and the bisecting angle (½ size - the one you set the mitre saw to)

external wall angle as per bottom left of my diagram then read the ½ scale only. You then subtract this number from 180 to get the wall angle; clearly, if you then want a mitresaw setting you have to ½ again.

Why all this aggravation with subtraction? Well, the Screwfix tool is a cheap copy (£5) of the proper jobby (£45 from Trend - see below) which has an additional element, see the diagram below:

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• Symptoms
• 19 Nov 2008
• 1

With this tool you'll notice that eb is extended to f (it's a longer arm) and it's this bit you copy the wall with and just read off the scale, same as an internal.

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• Symptoms
• 19 Nov 2008
• 1

A pal of mine has one of these and I check it today.

 

[kilo_4que]

Symptoms you great man, thanks for the equation lol

I must admit the screwfix one does seem cheap but it does the job for internal very very easy and for 5 squids its good value but a bummer for externals however you have sorted that out for me

Really appreciate your help.

I just dont understand why the screwfix one didnt have the extra bit and add another pound to the tool lol

weirdos