bevel/vernier protractor use

[yadnom1973]

I need to pick up a bevel/vernier protractor of eBay but have not used one before. Watching some explanations on youtube it looks quite straight forward but one thing that has got me a little confused is if it can read angles below 90 degrees without the attachment.

Most of the used ones on eBay seem to be missing this part and it’ll cost me more money and or time to find one with it. Looking at the thing it looks like it would read an angle below 90 degrees just fine and if it couldn't you’d think they’d make more of a point of it as it’s hardly a minor drawback but in every introduction video or description I’ve read, they always seem to add the note that this part is for reading angles less than 90 degrees without clarifying whether it's needed or just assists in reading them.

Does anyone know how to use one and if this is true?

 

[yadnom1973]

To be clear they all seem to come with one adjustable straight edge that slides up and down if you loosen a nut and the angle is measured by holding this against one side and rotating the protractor’s fixed bar against the other. Here’s a picture still from a video of one measuring what I think is an angle below 90 degrees but he states as showing this that you need the attachment to do so?

The acute angle attachment I’m talking about is another part shown here:

 

[BaronJ]

I need to pick up a bevel/vernier protractor of eBay but have not used one before. Watching some explanations on youtube it looks quite straight forward but one thing that has got me a little confused is if it can read angles below 90 degrees without the attachment.

Most of the used ones on eBay seem to be missing this part and it’ll cost me more money and or time to find one with it. Looking at the thing it looks like it would read an angle below 90 degrees just fine and if it couldn't you’d think they’d make more of a point of it as it’s hardly a minor drawback but in every introduction video or description I’ve read, they always seem to add the note that this part is for reading angles less than 90 degrees without clarifying whether it's needed or just assists in reading them.

Does anyone know how to use one and if this is true?

To be honest, I've never found the need for anything more than a simple protractor ! As far as negative angles are concerned that's just a matter of turning the protractor around.

 

[yadnom1973]

Thanks for the reply.
Negative angles? By that do you mean under 90 degrees? And do you mean the protractor your using dose that or the bevel protractor I showed?

 

[clockworkcheval]

While you are at it you can also opt for a very precise sinus-protactor. It works with gauge blocks and their precision.

 

[Brian Hutchings]

Wow, that Sinus Protractor is great, never seen one before.
Brian

 

[clockworkcheval]

You can still find them in the wild in Germany - search for' Sinus-Winkelmesser'.

 

[grahamgollar]

Does the sinus protractor come complete with a nasal spray?!

 

[xpylonracer]

I use a Zeiss optical protractor, it has 6" and 12" rules and is shown here fitted into the base fitting and is adjusted to set the work in the vice to 30 degrees off vertical.

 

[HennieL]

To answer the original question...

I need to pick up a bevel/vernier protractor of eBay but have not used one before. Watching some explanations on youtube it looks quite straight forward but one thing that has got me a little confused is if it can read angles below 90 degrees without the attachment.

I have never seen a protractor that could not measure angles smaller than 90° - and all without an attachment. In your first photo, the angle measured is 30°.

Most of the used ones on eBay seem to be missing this part and it’ll cost me more money and or time to find one with it. Looking at the thing it looks like it would read an angle below 90 degrees just fine and if it couldn't you’d think they’d make more of a point of it as it’s hardly a minor drawback but in every introduction video or description I’ve read, they always seem to add the note that this part is for reading angles less than 90 degrees without clarifying whether it's needed or just assists in reading them.

Does anyone know how to use one and if this is true?

If the "missing part" you are referring to is the piece indicated with an arrow in your second photo - then no, you do not need that to measure angles smaller than 90°. I've had a protractor similar to the one in your photo for about 30 years, and have never needed to use that part when measuring any angle. It is used to offset an angle of 90° from whatever angle you are measuring, and I suspect the reason why so many of them are missing in the second-hand sets is that most people never use them, and when misplaced don't bother to search for them because they are not needed... Mine is still brand new after all this time...

 

[Richard Hed]

Thanks for the reply.
Negative angles? By that do you mean under 90 degrees? And do you mean the protractor your using dose that or the bevel protractor I showed?

I've got one, I hardly ever use it,but it comes in very handy when I needs it. Sorry you can't just turn it over, but generally, you can manipulate MOST all angles if you have some patience. the 90deg attachmenht helps make it easier. The one I have has 3 blades and the attachment. They are easy to use with angles 0 to 180 but it may not be straight forward as it sounds. I'd just get a complete one and go to it. It's not that hard and it's quite accurate.

 

[BaronJ]

Hi Guys,

This is what I use !

 

[goldstar31]

I agree with John Baron. I have a nice plastic one. I have a fancy one- somewhere. Once. found, it cn go to the Museum fo White Elephants.

I had a plastic one on a surface grinder to do lathe tools etc and for a party piece, I overhauled a worn out Myford lathe belonging to a friend.

I've got a 5" sine bar and a lot of Jo blocks which haven't seen the light of day- for years. I know how to use them- but find little use.

I moved into the 19th Century- or some like that and bought one and then two little magnetic thingies that do degrees. My Clarkson tool and cutter grinder has degrees but only a few on the tool tilt. You may drool but that is what factories had until one eventually found its way to my workshop.

I was reading the exploits of a guy who won awards aftr awards and he suggested that his angles were made out of ---------plywood.

I've got one of those nigh impossible to make Quorn tool and cutter grinders that if you do understand it, it will almost do everything except work out the tide tables in HongKong Harbor.

I've got 'little graduations' all over the workshop- Do I use them?

Nah!

My thoughts- hmmmm

Norman

 

[clockworkcheval]

Setting the 2 degree angle to make a Thornton type cycloidal wheelcutter. The sinus-protactor is set between a nice flat and square disc on the headstock and the toolpost. The lathe is a Schaublin 102 VM.

 

[Richard Hed]

Hi Guys,

This is what I use !
View attachment 117320

Naturally that can be used for 99% of all needs you have, -- but the 1 out of a hundred is where you need higher accuracy. there might be betterr ways than one of these precision protractors in some cases too.

 

[yadnom1973]

Thanks for all the replies, my answer is in there, nice but not vital I gather. Yes, the combination gauge block sinus ones look very nice but I don't have a full set of gauge blocks. Found one for £30 without and bought it. With the attachment, they have all been twice that at least. If I can't live without it I'll sell it and bite the bullet at a later date.

 

[tornitore45]

Being a compulsive tool hoarder I had to have one. Bought a Chinese made and is actually well made but in years of ownership I used it twice and it took 1/2 an hour to fiddle with the pieces to find the right configuration.

Measuring and angle is not as simple as it it sound. The part has physical constraints, the angle cam be inside, outside or buried in a place difficult to reach by the clumsy protractor.

 

[yadnom1973]

I did look at the Chinese ones but found I could pick up a second hand More and Wright for the same price and I'm a fan of buying good quality use tools as I can always pop them back on eBay and get my money back if it doesn't work out.
That's the idea anyhow, I seem to break a lot of them.