How can I make this tiny trim washer?

[WobblyHand]

I'm looking to make a small brass trim washer about 0.048" thick with an ID of 0.395" and an OD of 0.435". I have a piece of 360 brass in 5/8' I could use. I'd need a small boring bar and start out with a 5/16 hole and bore out to 0.395" I'm not sure the order of operations or strategy?

1. Bore out the stock to 0.395
2. Reduce diameter to 0.435
3. Part off the tiny washer?

Is this ok? Is there a better way to do this? By better I mean, more likely to have success?

 

[rjs44032]

That's exactly how I'd do it. You want your part off tool tip geometry to lead toward the part being cut off. So it doesn't leave much of a bur. Hope this helps.

Edit: I was thinking in terms of one off strategy. If you have lots to do then perhaps punch press is a better option. Or you could buy brass washers close to the right ID and thickness. Then turn the OD. I'v done similar jobs between nuts by turning down the end of one nut and clamping with the other. Let me know if you need further info.


Best Regards,
Bob

 

[francist]

Sounds good to me. One minor step I try to remember is lightly chamfer the two edges before completely parting it off. Saves time afterwards. I give myself about a 50-50 success rate in actually remembering to do this before it's too late!

-frank

 

[mikey]

How precise do you need to be? Could you just use a X-drill to end up near 0.397"?

 

[pontiac428]

If you are having trouble getting a flat washer at the end, you can always part it off thick and crazy glue it to the end of a round or whatever else fits in your lathe chuck and turn it to thickness. Then just heat to release the glue and remove your part.

 

[WobblyHand]

Edit: I was thinking in terms of one off strategy. If you have lots to do then perhaps punch press is a better option. Or you could buy brass washers close to the right ID and thickness. Then turn the OD. I'v done similar jobs between nuts by turning down the end of one nut and clamping with the other. Let me know if you need further info.

Definitely a one off. Next time I'll machine to the correct dimension. Oops.

 

[WobblyHand]

How precise do you need to be? Could you just use a X-drill to end up near 0.397"?

Probably would be ok, if it went straight. The OD of the barrel at that point is 0.392". Isn't an X drill 0.397". Don't drills usually make a larger hole?

I think I have some tailstock alignment issues. That's why I was thinking about boring rather than drilling in this thread. My drilling/alignment issue is in a different thread.

 

[WobblyHand]

If you are having trouble getting a flat washer at the end, you can always part it off thick and crazy glue it to the end of a round or whatever else fits in your lathe chuck and turn it to thickness. Then just heat to release the glue and remove your part.

That's a really cool idea.

 

[pontiac428]

That's a really cool idea.

Learned it right here from @RJSakowski. It really works!

 

[WobblyHand]

I made it! Turns out it needed to be thinner than expected, when I test fitted it. I had parted it off at 0.050" thickness. I then hand ground the thickness down to 0.028" on a diamond stone with my fingertip. First photo with an M4 screw for reference. The brass is only a trim piece and quite flimsy. Thanks for the help.