# Digital Angle Gauge Vs Space Blocks



## Joe Pitz (Jul 7, 2015)

Hello all

Question on milling angles, I have never used space blocks before.

Most digital angle gauges are accurate to .100 of a degree, that would translate to .0017"

The smallest division change on the space blocks is .001.

So it looks like with the space blocks or the digital angle gauge I could easily maintain accuracy of 1/10 of a degree.

Wanted to get some feedback from the more experienced machinists what their feeling is on using one or the other?

Thanks

Joe


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## T Bredehoft (Jul 7, 2015)

I needed an angle of .7º (point seven degrees) for a project.  I figured the width of my vise, (3.8") the sine of .7º (.012217) times 3.8 = .04642, placed two .020 shims and a .006 shim under the very end of a parallel and placed my work on top of the parallel.  Easy Peasy as they say somewhere else in the universe. (not where I live).


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## Joe Pitz (Jul 7, 2015)

Thanks Tom,  I figured it would be that easy, I can use my el cheapo Texas Instruments calculator to figure everything out.  I do not have space blocks or a digital angle gauge yet. So before I go off and buy either, I wanted to get a consensus.

Joe


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## T Bredehoft (Jul 7, 2015)

Are 'space blocks' the same as Jo Blocks?   I have a set, use them with larger angles with my sine bar.  I'd trust them, not a 'patented' gizmo.


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## Joe Pitz (Jul 7, 2015)

Tom,  Here is what Little Machine Shop lists them as:
http://littlemachineshop.com/products/product_view.php?ProductID=1757&category=

Thanks

Joe


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## Joe Pitz (Jul 7, 2015)

Ah come on Tom,  I have been working on high tech gizmo's for 30 years 

Joe


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## Tony Wells (Jul 7, 2015)

As a very broad generalization, space blocks aren't typically as accurate as "Jo" blocks. Still plenty accurate for 99.99% of home shop work, and available if chased, to a higher accuracy.


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## T Bredehoft (Jul 7, 2015)

Now I know what "Space Blocks" are. Hooda thunk.  

With the  Digital Angle Gauge all you can do is measure the result of a set up, isn't it?  Can use use that to set a fixture?  What I'd imagine is that you put the 'gizmo' on a block, put it in a vise and when the angle reads right you clamp the vise. Then mount your work on the block with a clamp of some sort. Or, conversely, use the gizmo to set each piece. If you only need to set one, sure, that would work.


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## Joe Pitz (Jul 7, 2015)

Good point Tom,  If you use a long parallel or sine block I guess you could lightly clamp either in the vice and then tap or pull either end
to get the correct angle, but it might be easier to set the sine block or parallel on the space blocks in the vice  in the first place.

Thanks

Joe


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## T Bredehoft (Jul 7, 2015)

My sine bar is 6" long, my vise is 3.8" wide.  They won't work together. Do what ever works for you, that's why its a hobby.


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## John Hasler (Jul 7, 2015)

Joe Pitz said:


> Hello all
> 
> Question on milling angles, I have never used space blocks before.
> 
> ...


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## jpfabricator (Jul 7, 2015)

T Bredehoft said:


> My sine bar is 6" long, my vise is 3.8" wide.  They won't work together. Do what ever works for you, that's why its a hobby.



Looks like its time for a bigger vise! 

Sent from somewhere in East Texas Jake Parker


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## Joe Pitz (Jul 7, 2015)

Or a smaller sine block

http://littlemachineshop.com/products/product_view.php?ProductID=3535&category=

This is the one I have my eye on.

Joe


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## T Bredehoft (Jul 7, 2015)

Or a smaller Sine Bar.

I've got one 3/8 in wide now, it works, I just have to make my own "space blocks"


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## RJSakowski (Jul 7, 2015)

Joe Pitz said:


> Or a smaller sine block
> 
> http://littlemachineshop.com/products/product_view.php?ProductID=3535&category=
> 
> ...


Wholesale Tool has a 3" sine bar for $14.95
http://www.wttool.com/index/page/pr.../WT+3"+Sine+Bar&update_continue_shopping=true


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## chips&more (Jul 7, 2015)

Space blocks are typically used for set-up, as stops and the like in shop environments.  Where as gage blocks should not be used for stops or misused in a shop environment. Also, gage blocks have a better accuracy statement…Dave


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## brav65 (Jul 7, 2015)

I have a 4" vise and needed a small sign bar.  I got and SPI on eBay for $24.00.  It goes for $200 retail, so it was a good deal.  Here it is:

http://www.penntoolco.com/91-279-0/...ju039pwF-nNqRNeXE9h8myiFIoJXyB-xMqRoC-J3w_wcB


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## Tony Wells (Jul 7, 2015)

You can use adjustable parallels instead of gage or space blocks.


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## RJSakowski (Jul 7, 2015)

Joe Pitz said:


> Hello all
> 
> Question on milling angles, I have never used space blocks before.
> 
> ...



You don't need a space block set to set an angle.  Turn a piece of scrap to the desired diameter and verify with your mike.  Part the piece to an appropriate length and place at one end of the vise with the end of the spacer touching the vise jaw and the cylindrical surface flush with the end of the vise jaw.  A magnet helps to hold it in place.  Lay your parallel with one end on the vise floor and the other on the cylinder.  (If your vise jaw overhangs the floor of the vise, you will have to correct for that overhang.)  
The relationship between the diameter of the gage pin, the width of the vise and the angle is: (D/2)/(W-D/2) = tan(a/2).  If you let A = tan(a/2), then D/2 = A/(1+A) * W.
The drawing shows the geometry of the setup.  With suitable care, very accurate angles can be set up.


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## Joe Pitz (Jul 7, 2015)

RJSakowski said:


> Wholesale Tool has a 3" sine bar for $14.95
> http://www.wttool.com/index/page/product/product_id/17572/product_name/WT+3"+Sine+Bar&update_continue_shopping=true



Sweet. much cheaper than LMS, got to go shopping

Joe


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## Joe Pitz (Jul 7, 2015)

RJSakowski said:


> You don't need a space block set to set an angle.  Turn a piece of scrap to the desired diameter and verify with your mike.  Part the piece to an appropriate length and place at one end of the vise with the end of the spacer touching the vise jaw and the cylindrical surface flush with the end of the vise jaw.  A magnet helps to hold it in place.  Lay your parallel with one end on the vise floor and the other on the cylinder.  (If your vise jaw overhangs the floor of the vise, you will have to correct for that overhang.)
> The relationship between the diameter of the gage pin, the width of the vise and the angle is: (D/2)/(W-D/2) = tan(a/2).  If you let A = tan(a/2), then D/2 = A/(1+A) * W.
> The drawing shows the geometry of the setup.  With suitable care, very accurate angles can be set up.
> View attachment 106968



Thanks RJSakowski, sounds like a lot cheaper method than purchasing as set of space blocks.

Joe


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## Zoltan (Jul 8, 2015)

Although I appear to be in the minority, my digital angle gauge has worked great for me. I zero it on bed or the vise (depending on how I'm holding the work) and then adjust the work to the angle needed. Super easy.


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## Joe Pitz (Jul 8, 2015)

Thanks Zoltan for the feedback.  

Joe


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## RJSakowski (Jul 8, 2015)

I have a digital angle cube too and use it for setup of non-critical angles.  Although the stated accuracy is +/- .1 deg., I have found it to be less than that at times.  It is based on a pendulum and friction is involved in settling the pendulum to a true vertical position.  Sometimes, there can be a difference of a couple of tenths of a degree.  The base of the cube is just over 2" so any variations in the surface become important. I usually make multiple measurements to verify the setting. 

The digital angle cube is a handy tool. You just have to appreciate its limitations.


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## Joe Pitz (Jul 8, 2015)

Thanks RJ,  It is good to know that even if the stated accuracy is .1 degrees, it actually is not.
I was wondering if these digital angle gauges were actually  accurate to the specs.

Thanks

Joe


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## Bill C. (Jul 8, 2015)

T Bredehoft said:


> My sine bar is 6" long, my vise is 3.8" wide.  They won't work together. Do what ever works for you, that's why its a hobby.



You need a 6" or longer parallel bar turned on it's side to sit on the bottom of your vice.  My shop had a couple of heavy bars so I would use one.


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## barrydc1 (Jul 8, 2015)

I also frequently use a Digital cube (Fowler brand).  It works extremely well when you don't need really critical angles.  I trust it to .5 degrees.  If you want accurate angles then guage blocks and sine bar are the most accurate. If I understand things correctly.  I don't know what a "Jo" block is.  The accuracy of gauge block is certified depending on the type.  A set is very expensive, but vital for complete accuracy.  I like the idea posted of using a turned rod with a mic'-ed diameter, though it seems hard to measure the distance of the one leg (can't remember which letter was used for the variable) from the point of contact with the mill or vice surface to the arc point of the rod's circle.  Anyway, I have both the gauge blocks and an electronic protractor http://www.use-enco.com/CGI/INPDFF?PMPAGE=396&PARTPG=INLMK3&PMITEM=317-0585 like this one.


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## Bill C. (Jul 8, 2015)

What I used to do was to do the trig to find the height I needed to set the angle. I would borrowed a few gage blocks from the shop and set the sine bar. It was my experience the bar was wider than the part so I would use a sacrificial spacer to hold the part tightly against the solid jaw of the vise then I would remove the sine bar.  No sense trying to catch all the gage blocks due to vibration from machining.


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## stevemetsch (Jul 8, 2015)

Joe Pitz said:


> Sweet. much cheaper than LMS, got to go shopping
> 
> Joe


My experience with an angle cube is that they are not really repeatable within a half degree. OK for wood work or "eyeball" work. Maybe OK for one off part. Similar to 3 jaw or 4 jaw chuck variations.
SteveMetsch in Santa Barbara


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## T Bredehoft (Jul 8, 2015)

Jo, or Johansen blocks were chosen by Henry Ford when he wanted a standard to use in his factory. Gauge blocks have become called Jo blocks, just through use, not that all are Jo Blocks the are nominally (chuckle) 5/16 by 1" by whatever, .100, etc., and finished to a degree that they will wring together, stick to each other. Mine are Brown and Sharp, .900 square and whatever thickness, with a hole in the middle so they can be held by screws and nuts. (I don't use them that way.)

_Edit_, correct typo.


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