Washer bore sizes

DAT510 said:
I actually believe the larger clearance you are referring to, may be for the Bolt head to Washer interface vs Nut to Washer interface. Proper bolts are radiused at the head to shaft junction. Those radius are called out by standards. Since it's not a 90 degree corner, clearance will be needed allow the bolt head to properly seat flat against the washer vs hanging up on the radius.

Given it would double the sizes, if there were washers for the bolt head and different washers for the nut end, my guess is they went with the "larger" size for both.
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Good point. The radius under the head of the bolt should help centralize the washer although I feel there could be less clearance as the washers can still be assembled visually off centre.
 
I suspect that washers are made that way because that's the way they were always made. Originally, they were made by a blacksmith pinching the hole over a bolster. He probably gave the punch an extra blow to make sure that it the fit the bolt. Since he didn't like having to check and repunch, he probably gave punch an extra hard final blow. By the time the process became industrialized, a standard was set and that's what we have today.

If there are any questions, ask me about the roast.
 
SAE washers have less bolt to washer clearance...all though they also have a smaller OD
 
Without looking up standards or other "official" documentation, I have always considered the "hole" part of a washer to be a matter of the punch press that makes them. The punch and die have a reasonable life span, being closer to nominal size when new and the size increasing by some small amount as it wears. For my personal fasteners, I stock both 1/4" and 6mm washers. The 6mm washers fit most 1/4" bolts, but very tightly. I use them when I need (for my purposes) a snug fit. The "inside" of a fastener has a small but pronounced radius. There must be a small amout of allowance, meaning the washer must be a fuzz oversized. It's that fuzz that is allowed for in the punch press. There are other allowances that are made, generally the cheap hardware store washers tend to be a little oversized to allow for "iffy" sizing on the fastener itself. I have worked with (in the mills) washers that were of a more optimum bore. But they had sharper edges for a more optimal fit. With all that babbling about washers, it comes down to having cheap, loose fitting versus snug tight fitting for when I need something snug. I acquired a couple of hundred 6mm washers in a horse trade. I didn't go looking for them but they do fit when I need them. Handy. . .

.
 
Sloppy fitting washers drive me crazy too. Another thing that gets my goat is US electrical fittings and conduit hardware. Everything is so loose it
seems like you are in a funhouse or some kind of military mind control experiment. Argggg. Drives me nuts. I could never be an electrician.
-M
 
Looking on line, I see that there are two standards for inch flat washers, USS and SAE. USS are typically 1/16" larger than nominal bolt size while SAE are 1/32" larger. Unfortunately, the hardware/diy store variety are the former. No information on metric standard sizes though.
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RJSakowski said:
I suspect that washers are made that way because that's the way they were always made. Originally, they were made by a blacksmith pinching the hole over a bolster. He probably gave the punch an extra blow to make sure that it the fit the bolt. Since he didn't like having to check and repunch, he probably gave punch an extra hard final blow. By the time the process became industrialized, a standard was set and that's what we have today.

If there are any questions, ask me about the roast.
Click to expand...
I'm a new member, what does the roast mean?
 
I've always considered this a feature, instead of a bug. I guess it's all about where your standing. Lol
I like Bills explanation. That sounds reasonable to me. Although from what I know, the punch diameter never changes. Just the length of the punch. I still like his notion.
 
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