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Thread: Angle blocks - which style?

  1. #1
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    Default Angle blocks - which style?

    I'm looking to make some lathe tool holders as a forthcoming project. It's about the first thing I've needed reasonably accurate angles so I see it as an excuse to buy some angle blocks....that's how it works, right?!
    Anyway, there are two styles that I see available and I figured I'd, obviously, want the more expensive style which are essentially very thin, offset vee blocks (these) rather than the style that are more like triangles (these). Sorry, I'm sure there's a proper name for each of the two styles....but I'm clueless as to what it may be.
    Before I do the wrong thing for the wrong reasons, could someone enlighten me on the pros and cons of each please?
    Initial project would be a 100mm length of 10x10mm bar for a TCMT on each end (just for chamfering) but future use is important too.

    Many thanks,
    Gareth
    Last edited by Cenedd; 06-12-2018 at 02:30 PM.

  2. #2
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    I have a set like the second, simpler ones that you refer to. I also pondered over which type to purchase and I never came up with any definite answer. Both types are 1/4" thick and both types will stack both ways to add or subtract angular values. You can get all values from 1 to 90 degrees, by 1/4 degree increments with the first set and by one degree increments with the second one. That may be the biggest difference between them. I purchased an additional 1/2 degree block to go with my set so that partially overcame that difference. I had another trick for beyond that, see my note below. I suspect that the first type may occupy a bit more space when several are stacked but then the second type would need some kind of extra support if stacked vertically to get a high angle in the stack. So the first type may be advantageous there: I say may because I don't really know.

    I have used mine to set angles on the lathe and mill. I usually have them stacked horizontally so the simpler ones that I have work OK. I just need a flat surface to lay them on, like the mill table or a 1-2-3 block sitting on the cross slide or compound of the lathe. Perhaps someone with more experience can provide more advantages or disadvantages.

    Note: In the Jan-Feb 2009, Home Shop Machinist I had an article explaining how I use these angle blocks and some pins of known diameter (drill bits, etc.) to imitate the action of a sine bar. It is titled "Setting Up Accurate Angles - Inexpensively". This technique allows you to use two or more angle blocks to get any angle and not just the whole degree values that adding and subtracting the values of the blocks in the set provide. Not quite as accurate as a real sine bar, but better than a Vernier protractor and good enough for most purposes, including turning tapers. I talk about the relative accuracies in the article. Oh I also used a small piece of modeling clay in the set-up. I think I may make that article available shortly. I will post the information here if I succeed with that.
    Paul A.

    Make it fit.
    You can't win and there is a penalty for trying!

  3. #3
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    Thanks Paul. Already starting to look like, uncharacteristically, I wasn't cynical enough! This is going to be one of those things where the answer is that, to cover all situations, you need both, isn't it.
    Would still appreciate people's experiences though as it'd be good to understand the benefits/restrictions of each before I buy one.

  4. #4

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    A moldmaker I once worked with had shop made angle blocks, some with a toe or stop that let them stack easily and some without. He was nice enough to let others of us borrow them for occasional use. Actually, in one of those cringe-worthy incidents, another machinist had borrowed two to make up the angle he needed, had his part set in the vise and was tapping it down to seat it. I don't know what he used to "tap" but he broke the end off one of the blocks for the old toolmaker.

    But I digress. I started making up some of my own, a gradual process since this was a government job (sometimes called a Swiss Navy project) so there couldn't be too much time and material invested at once. My blocks have a #4 tapped hole where the toe would be so that they could be used with or without a stop. I don't know if the commercial sets are hardened or not, some V-blocks seem to arrive ground but soft. I'd actually prefer hardened sets to reduce wear and the possibility of dings, but if one knew the blocks could be drilled and tapped, you could buy one set and modify them to do the work of the other.
    .
    "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

  5. #5
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    Quote Originally Posted by Cenedd View Post
    I'm looking to make some lathe tool holders as a forthcoming project. It's about the first thing I've needed reasonably accurate angles so I see it as an excuse to buy some angle blocks....that's how it works, right?!
    Anyway, there are two styles that I see available and I figured I'd, obviously, want the more expensive style which are essentially very thin, offset vee blocks (these) rather than the style that are more like triangles (these). Sorry, I'm sure there's a proper name for each of the two styles....but I'm clueless as to what it may be.
    Before I do the wrong thing for the wrong reasons, could someone enlighten me on the pros and cons of each please?
    Initial project would be a 100mm length of 10x10mm bar for a TCMT on each end (just for chamfering) but future use is important too.

    Many thanks,
    Gareth

    Fixed it for ya. Forgot the square bracket.

  6. #6
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    Quote Originally Posted by General Zod View Post
    Fixed it for ya. Forgot the square bracket.
    Cheers, hadn't spotted that. I think I might have got auto-corrected - the joy of tapping it on a phone. At least it didn't turn it all into emoji's


    TGTool: That sounds like a great way of doing it. If I had a surface grinder and means of hardening them I'd have a go at that......but I'm sure as hell not doing that much hand-lapping!

  7. #7

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    Then there's handy little buggers. The one I made has a step ground in it to act as a stop.

    https://www.huronindustrial.com/3-sine-bar-5-32-thick

    I use mine for a variety of tasks, mostly putting something at an angle relative to the back rail on a surface grinder, but I have used it to set an angle on a lathe compound.

  8. #8
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    I did briefly think that a sine bar would be cheaper (of the quality I'm likely to be looking at, at least) and offer more angles.....but then I remembered I'd need a set of gauge blocks to make it work. Unless there's a good way of doing it without...?

  9. #9
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    Quote Originally Posted by Cenedd View Post
    I did briefly think that a sine bar would be cheaper (of the quality I'm likely to be looking at, at least) and offer more angles.....but then I remembered I'd need a set of gauge blocks to make it work. Unless there's a good way of doing it without...?
    The error equation for a sine bar looks like...

    dangle = dstack/(L*cos(angle))

    where:

    dangle = error in angle
    dstack = error in stack
    L = length of sine bar (measured btw centerlines of rollers)

    Taking a worst case angle of 45 deg (sine bars are seldom used for angles larger than this) and a typical length of 5":

    dangle = 0.283 * dstack

    so a stack error of 0.001" will produce an angular error of 2.828E-4 radians or 0.016 deg, about an arc minute.

    Unless you're building mission-critical optics, forget the gauge blocks and set an adjustable parallel with your micrometer.
    Regards, Marv

    Home Shop Freeware - Tools for People Who Build Things
    http://www.myvirtualnetwork.com/mklotz

  10. #10
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    the ones with the 90 degree seat, you described as offset V blocks are imo the most handy, at least I use them more often. Work is much less likely to move sitting in one in the vise or clamped to angle plate. Sine bars are imo an inspection tool or maybe for certain grinding setups, but less so milling.
    .

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