Missing M3 x 12 Washers - U.S. equivalent?
So I just got my rapman in the mail this week and I get to building the X Motor Plate. I see that there is 1 M3 x 12 Washer required for this part. According to the parts list, it should be located in Bin 5. However, the bag in Bin 5 contains no washers at all (but does appear to contain all other parts that it should). I know that I have not dropped or lost any parts from that bag, and I've already checked to make sure that I didn't accidentally use the washers in any other parts that I have put together so far. Is there a U.S. equivalent size for this part that I could run out to the store and buy? The only hardware stores I have in my area are a Lowes, Home Depot, and Ace Hardware. I'm not 100% sure, but I don't think any of them carry metric parts.
The nearest you will probably get, is something like 1/2" OD, 1/8" bore. However, you may be able to find washers for #4-40UNC, 1/2" OD. If so, these will be a tiny fraction small in bore, but given the normal tolerances, should be great. The 'OD' of #4-40, is 2.845mm, and washers are normally 0.1mm larger, so would be 2.945mm. Given that M3, uis typically 2.93mm on the outside of the threads, this should be a really good fit!....
Other possibility, is to look for 6BA washers (as in the UK, some electrical stuff uses this, and again it should be a good fit), nominally just a fraction small.
Large diamter washers may be hard to find. If so, look at the section where 'pop' rivets are stocked/sold. 1/2" washers for the smallest size of these are common, and again a good substitute, and often sold in small quantities.
Best Wishes