I was picking up some washers for a shaper I'm making and went to the local hardware store for them. Every washer in the place was oversized. And not just a little but enough so a 1/4 washer would fit a 5/16 bolt. It wasn't just a mistake either I checked lots of different sizes and everything would fit the next size bolt. I even went as far as to open up a sealed box and they were wrong too. ( don't worry I bought the box) has anyone else noticed this ? I guess it could possibly be a mistake at the factory but for every size to be mislabeled seems excessive. I just bought the size down from what I needed to get the right fit but it just seems odd.
-
Welcome back Guest! Did you know you can mentor other members here at H-M? If not, please check out our Relaunch of Hobby Machinist Mentoring Program!
Hardware store washers
- Thread starter Ebel440
- Start date
- Joined
- Jan 22, 2011
- Messages
- 8,031
Flat washers are made to fit pretty loosely on bolts and screws. There is normally a radius under the head of the bolt. If you slip down a size, yes, most standard flat washers (USS) will fit over the body, but will not properly clear that radius. There are two basic styles of flat washers available here, USS and SAE patterns. The USS is typically what hardware stores will stock. If you need or want a smaller OD, find some SAE flat washers. I generally have seen them fit a little closer, but not enough to interfere with the radius. They are intended more for use under the nut, which of course, cannot have any such radius. As you go along checking the fit, as you did on some that fit the next smaller nominal size, you will find some that will not fit. There is enough overlap in the sizes to allow clearance enough to fit down one size but not all.
- Joined
- Feb 8, 2014
- Messages
- 11,151
USS washers are oversize, and I have noticed that the 1/4 inch USS have almost the same dimensions as a 5/16 SAE washer. SAE washers have a pretty tight fit on the bolt. As Tony says, the SAE washers are really designed to fit under the nut rather than the bolt head. A good hardware store will normally carry both. The big box stores are not a good place to buy good fitting washers, my local Ace Hardware has a good stock of both and also grade 8 SAE washers which have a much better fit and finish that the grade 2 washers. Normally the grade 8 washers will have a chamfer in the hole to clear the radius on the bolt.
- Joined
- Jan 22, 2014
- Messages
- 578
Yes, I hate that too. I do what you did and buy a size down. If I want real washers that are sized correctly or of a specific thickness or material, I order them from McMaster Carr.
- Joined
- Mar 1, 2012
- Messages
- 1,140
Here are the standards with tolerances. Do they fall within the tolerances.
- Joined
- Dec 2, 2012
- Messages
- 70
yes that is right on
- Joined
- Nov 27, 2012
- Messages
- 7,872
Yup I notice this too at the big box hardware stores, it didn't used to be like that. And it's not a matter of oversized for tolerances. I used to think that some worker dust dumped the wrong washer in the bins but nope. Sometimes they don't even have the proper sized washers for certain bolts, either too small or way to big like for the next fastener size up. But I really only see this for standard hardware & not metric.
I stand corrected At .322 Inner and .740 outer diameter for a 1/4 washer it does fit into the tolerance for a uss washer. I'm still not happy about it though. This wasn't at a big box store either but an ace hardware I went there because I used to be able to get better stuff there.