Enlarging Bores in Thick Hardened Washers
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    Default Enlarging Bores in Thick Hardened Washers

    I want to upgrade my heavy equipment bolting methodology by incorporating ‘Extra Thick’ Through Hardened washers.

    I will predominately use these washers in bore sizes from 5/16” to 1-1/2” (8mm to 38mm).

    These washers are from .125” to .250” (3mm to 6mm) thick.

    As manufactured, these washers provide bolt clearances of 1/32” to 1/8”.

    However, I prefer all critical washers to have no more than 1/64” bolt clearance.

    So, I would need to enlarge the existing bores to provide tighter bolt clearances (i.e. a 1” washer with a standard 1-1/16” bore would be enlarged to a 1-9/64” bore to provide a 1/64” bolt clearance with a 1-1/8” bolt).

    What methods/machines/tooling would other forum members employ if faced with the same modification requirement?

    Would it be possible to ‘stack’ say 5 or 10 of these washers so multiple bores could be enlarged at the same time?

    Presumed appropriate machinery at my disposal currently includes a drill press, mill, radial arm drill, and a lathe.

    P.S. No washer supplier that I have contacted will provide non-standard bores unless I order at least 10,000 washers per size.

    Regards,

    SAE

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    Quote Originally Posted by sae8425 View Post
    I want to upgrade my heavy equipment bolting methodology by incorporating ‘Extra Thick’ Through Hardened washers.

    I will predominately use these washers in bore sizes from 5/16” to 1-1/2” (8mm to 38mm).

    These washers are from .125” to .250” (3mm to 6mm) thick.

    As manufactured, these washers provide bolt clearances of 1/32” to 1/8”.

    However, I prefer all critical washers to have no more than 1/64” bolt clearance.

    So, I would need to enlarge the existing bores to provide tighter bolt clearances (i.e. a 1” washer with a standard 1-1/16” bore would be enlarged to a 1-9/64” bore to provide a 1/64” bolt clearance with a 1-1/8” bolt).

    What methods/machines/tooling would other forum members employ if faced with the same modification requirement?

    Would it be possible to ‘stack’ say 5 or 10 of these washers so multiple bores could be enlarged at the same time?

    Presumed appropriate machinery at my disposal currently includes a drill press, mill, radial arm drill, and a lathe.

    P.S. No washer supplier that I have contacted will provide non-standard bores unless I order at least 10,000 washers per size.

    Regards,

    SAE
    If you're a real SAE-type, you'd know that any decent bolt has a root radius under the head, and trying to use a hardened washer with only a 1/64" clearance means that the sharp edge of the hard washer will "eat into" this radius, significantly reducing its fatigue life.

    It's OK to have a close clearance, but you MUST add a chamfer of sufficient size to clear the radius on the side of the washer against the head. Failure to do this will leave you in a much worse situation than using the correct washer that was made for the job (oversize hole to clear the radius).

    The Bolt-Meister has spoken. Heed the words of the Bolt-Meister!
    [Anyone abbreviating "Bolt-Meister" to "BM" will be severely punished!]

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    First off, will you be re-machining already hardened washers, or machining from new hardened bar? …………...and if so - how hard is what you call hard?

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    soft jaws in the lathe
    do enuff and you will get quick
    do multiples soft jaws in vice in mill

    how many you talking ?

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    I am not sure what thick means in washer speak. 325 (thicker than g5-g8) washers have what you might consider sloppy hole sizes- they are designed tested and engineered for full bolt load so not sure what a tighter hole will achieve.

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    Quote Originally Posted by memphisjed View Post
    I am not sure what thick means in washer speak. 325 (thicker than g5-g8) washers have what you might consider sloppy hole sizes- they are designed tested and engineered for full bolt load so not sure what a tighter hole will achieve.
    What it will achieve is reducing the area under compression, as the Op is using the next size down.

    Thereby destroying all bolt stretch calculations.

    Op is listed occupation as "educator" let's hope this endeavor is not being taught.

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    having unnecessarily tight tolerances is common with new engineers who are not responsible for a budget
    .
    many a boss will say
    .
    1) where is your data or proof that the tighter tolerances will have any sort of cost benefit. opinions mean nothing. usually got to prove stuff from data from history going back years to decades
    .
    2) i have worked with engineers who wanted everything within .001" when often parts that were 10x over tolerance didnt cause any problems. for example if engineer wants machine alignment of 100 parts within .001" i often measured .001 to .100 errors of the hundred parts first and asked "are you having actual problems" and "if we do not have enough time and money do you want to correct the worst ones first ?" or just start at one end of the machine and slowly work to other end and if run out of time stop in the middle of the machine, with possible parts way out of tolerance not corrected yet ?
    .
    i have often seen unnecessary waste on unnecessary features better spent on other things. old saying "dont fix it if it aint broke", basically if you run out of money you will not be able to get things done that actually might help based on history rather than from opinions.

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    Quote Originally Posted by digger doug View Post
    What it will achieve is reducing the area under compression, as the Op is using the next size down.

    Thereby destroying all bolt stretch calculations.

    Op is listed occupation as "educator" let's hope this endeavor is not being taught.
    One of the most important things to teach is what not to do.

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    Yes,Yes,Dont be deterred by the naysayers.I also have this fetish. Every time I repair machinery,it seems that half of the juncky washers are split, bent or extruded into a casting,often cracking the casting.What is so horrible,is the fact that a GOOD THICK WASHER should be the easiest and cheapest piece of hardware that can be made.And then YOU HAVE THE FOOLS that think that if you stack a bunch of thin washers,it is just as good as a thick washers.YES,HEED MR. BOLTMEISTER,You should chamfer your close fitting inside diameter,preferably on both sides,just for common decency when the next guy takes it apart and might not notice.Good luck Edwin Dirnbeck

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    Quote Originally Posted by digger doug View Post
    What it will achieve is reducing the area under compression, as the Op is using the next size down.
    Thereby destroying all bolt stretch calculations. . .
    Why would that have anything to do with bolt stretch, as long as the washer still covers the full area under the head of the bolt?

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    Quote Originally Posted by digger doug View Post
    What it will achieve is reducing the area under compression, as the Op is using the next size down.

    Thereby destroying all bolt stretch calculations.

    Op is listed occupation as "educator" let's hope this endeavor is not being taught.
    Unlless,you are talking about aircraft or engine connecting rods or highly engineered equipment,nobody even heard of bolt stretch.Edwin Dirnbeck

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    Quote Originally Posted by Gordon Heaton View Post
    Why would that have anything to do with bolt stretch, as long as the washer still covers the full area under the head of the bolt?
    The dynamics of bolted joints are a lot more complicated than most people think, but fortunately common (good) practice lets you get away with a lot. Given that folks like Alex Slocum (I've worked a bit with him, and did some instructing/advising to his kids) describe the clamping of a bolt head as a cone of compression around the head contact area, changes in washer height will affect the bolt stretch calculations a little, but just a tiny amount as long as the washer isn't crazy-thick.

    And since the washer will deflect (assuming not made of diamond) under load radiating from the underside of the bolt head out through the diameter, "diffusing" as distance from head increases, a thicker washer will (in general) increase the clamping cone diameter, even if of smaller OD that an existing (say, SAE design) washer.

    As long as you don't go nuts with OD reduction, and the bolted materials aren't too soft or uneven at the contact zone, a thicker, smaller OD washer is superior in clamping dynamics than a larger, thinner washer. Again, if you're clamping a piece of leather to a plate, you want a large OD, but a cast iron cylinder head to CI block - use a thick washer, perhaps 50% larger than the nominal OD of the bolt head washer surface (that circular relieved diameter under the bolt head).

    [Not really a Bolt-Meister, but please humor me]

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    Yes here is my assortment of sick washers that I often alter two other sizes I never throw away anything that looks like a thick washer or could be used as a thick washer


    Sent from my iPhone using Tapatalk

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    Quote Originally Posted by edwin dirnbeck View Post
    I never throw away anything that looks like a thick washer or could be used as a thick washer

    Sent from my iPhone using Tapatalk
    Hey, if you're using Al for some of the washers, you better go thick or go home. Or as the kids say now, thicc.

    [Is it any wonder I want to trebuchet some of the tykes?]

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    Quote Originally Posted by edwin dirnbeck View Post
    Yes here is my assortment of sick washers that I often alter two other sizes I never throw away anything that looks like a thick washer or could be used as a thick washer


    Sent from my iPhone using Tapatalk
    Seeing how the bins are labeled "SS Washers" I'm going out on a limb here, and
    figure you don't understand the OP.

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    Quote Originally Posted by Milland View Post
    The dynamics of bolted joints are a lot more complicated than most people think. . .
    Thanks. In my practical experience I've never needed to know that much! I do hold an aircraft powerplant certificate (which I don't use) and in training and testing we used bolt-stretch measurement on many parts. I've also done automotive con rods with the same requirement. These all specify use of a washer, but nothing so detailed as you mention. Also, the stretch spec is typically broad enough that I'd never be able to see that 'cone of compression' make a difference.

    The formal training I've had in that respect was mid 1970's and may well be out of date. I'll just leave that super-critical stuff up to those who enjoy it.

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    Quote Originally Posted by digger doug View Post
    Seeing how the bins are labeled "SS Washers" I'm going out on a limb here, and
    figure you don't understand the OP.
    Yes I did get carried away. It seem like most of the comments were about whether or not he should be doing this. I was just trying to encourage him to follow his own ideas. I will try to show him how I would enlarge The holes


    Sent from my iPhone using Tapatalk

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    Quote Originally Posted by sae8425 View Post
    I want to upgrade my heavy equipment bolting methodology by incorporating ‘Extra Thick’ Through Hardened washers.
    Quote Originally Posted by edwin dirnbeck View Post
    Yes I did get carried away. It seem like most of the comments were about whether or not he should be doing this. I was just trying to encourage him to follow his own ideas. I will try to show him how I would enlarge The holes
    ASTM F436 - Portland Bolt

    IIRC some others are made of thru hardened 1095.

    So before this goes much further, the OP needs to clarify some points.

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    Quote Originally Posted by sae8425 View Post
    I want to upgrade my heavy equipment bolting methodology by incorporating ‘Extra Thick’ Through Hardened washers.

    I will predominately use these washers in bore sizes from 5/16” to 1-1/2” (8mm to 38mm).

    These washers are from .125” to .250” (3mm to 6mm) thick.

    As manufactured, these washers provide bolt clearances of 1/32” to 1/8”.

    However, I prefer all critical washers to have no more than 1/64” bolt clearance.

    So, I would need to enlarge the existing bores to provide tighter bolt clearances (i.e. a 1” washer with a standard 1-1/16” bore would be enlarged to a 1-9/64” bore to provide a 1/64” bolt clearance with a 1-1/8” bolt).

    What methods/machines/tooling would other forum members employ if faced with the same modification requirement?

    Would it be possible to ‘stack’ say 5 or 10 of these washers so multiple bores could be enlarged at the same time?

    Presumed appropriate machinery at my disposal currently includes a drill press, mill, radial arm drill, and a lathe.

    P.S. No washer supplier that I have contacted will provide non-standard bores unless I order at least 10,000 washers per size.

    Regards,

    SAE

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    To answer the original question . Here is how I have been boring washers for years


    Sent from my iPhone using Tapatalk

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